United States v. Richard Junior Frazier

[PUBLISH]

IN THE UNITED STATES COURT OF APPEALS

FOR THE ELEVENTH CIRCUIT FILED
________________________
U.S. COURT OF APPEALS
ELEVENTH CIRCUIT
No. 01-14680 October 15, 2004
________________________ THOMAS K. KAHN
CLERK
D. C. Docket No. 00-00070-CR-WCO-2-1

UNITED STATES OF AMERICA,

Plaintiff-Appellee,

versus

RICHARD JUNIOR FRAZIER,

Defendant-Appellant.

________________________

Appeal from the United States District Court
for the Northern District of Georgia
_________________________

(October 15, 2004)

Before EDMONDSON, Chief Judge, and TJOFLAT, ANDERSON, BIRCH,
DUBINA, BLACK, CARNES, BARKETT, HULL, MARCUS and WILSON,
Circuit Judges.*

MARCUS, Circuit Judge:

*
Judge William H. Pryor Jr., became a member of the Court on February 20, 2004, which
was after this case was argued. He did not participate in the decision of this case.
 Richard Junior Frazier appeals his conviction for kidnapping. He claims

that the district court abused its discretion by excluding certain expert testimony of

a forensic investigator, while allowing the government to present expert evidence

on the same issue. After thorough review of the record, we conclude that the

district court’s evidentiary rulings were neither an abuse of discretion, nor

“manifestly erroneous.” Gen. Elec. Co. v. Joiner, 522 U.S. 136, 142, 118 S. Ct.

512, 517, 139 L. Ed. 2d 508 (1997) (citation omitted). More generally, we

reaffirm the basic principle that an appellate court must afford the district court’s

gatekeeping determinations “the deference that is the hallmark of abuse-of-

discretion review.” Id. at 143, 118 S. Ct. at 517. Accordingly, we affirm.

I.

A.

The defendant, Richard Junior Frazier, was charged on December 6, 2000,

by a grand jury sitting in the Northern District of Georgia in a one-count

indictment with kidnapping in violation of 18 U.S.C. § 1201(a)(1).2 The

2
The kidnapping statute, 18 U.S.C. § 1201, provides in pertinent part:

(a) Whoever unlawfully seizes, confines, inveigles, decoys,
kidnaps, abducts, or carries away and holds for ransom or reward
or otherwise any person, except in the case of a minor by the parent
thereof, when--

(1) the person is willfully transported in interstate or foreign

2
indictment also alleged that, pursuant to 18 U.S.C. § 3559(c), the “three-strikes”

statute, the defendant had multiple prior convictions for qualifying serious, violent

felonies to mandate a life sentence.3 He entered a plea of not guilty and vigorously

contested the charges at trial.

The relevant facts in this sad case are these. At some time after eight

o’clock on the evening of October 31, 2000, an eighteen-year-old student (“the

commerce, regardless of whether the person was alive when
transported across a State boundary if the person was alive when
the transportation began;

....

shall be punished by imprisonment for any term of years or for life
and, if the death of any person results, shall be punished by death
or life imprisonment.

18 U.S.C. § 1201(a).
3
The indictment alleged, specifically, that Frazier had been previously convicted of the
following serious violent felonies:

1974 - #9519 - Armed Robbery - Gwinnett County Superior Court, Lawrenceville,
Georgia;
1974 - #43674 - Robbery - Hall County Superior Court, Gainesville, Georgia;
1979 - #K-45837 and K-45838 - Robbery by Force - Hall County Superior Court,
Gainesville, Georgia;
1980 - #11684 - Armed Robbery - Houston County Superior Court, Perry,
Georgia;
1980 - #80R-23 - Aggravated Assault - Crisp County Superior Court, Cordele,
Georgia;
1993 - #93-CR-94-S - Aggravated Assault - Habersham County Superior Court,
Clarkesville, Georgia.

3
victim”) stopped at a Wal-Mart store in Cornelia, Georgia to check the prices of

Halloween candy. According to the victim’s account, she was abducted by the

defendant after leaving the Wal-Mart. She walked to her car and unlocked the

door, when she was confronted by the defendant, Frazier, who was carrying a

knife in his right hand pointed at her. He asked the victim: “Will you take me

where I want to go?” R7 at 149. Fearing for her life, the victim complied and at

Frazier’s demand sat in the driver’s seat. Frazier entered the back seat of the

vehicle, sat directly behind the victim, and directed her to drive out of the parking

lot.4

Frazier initially told the victim that he wanted to visit his son in White

County, Georgia, but eventually directed her off the paved road and onto a dirt

road leading to a secluded, wooded area. After they reached this deserted location,

Frazier instructed the victim to turn the engine off, moved into the front passenger

seat, positioned the knife in his right hand, and ordered the victim to remove her

pants and underpants. She disrobed. The defendant then removed his own

clothing and sexually assaulted her at knifepoint, raping her repeatedly and

4
A surveillance video camera trained on the Wal-Mart parking lot was played for the jury
at trial. The video tape showed the victim walking alone toward her vehicle and approaching the
driver’s side of the car. The tape also revealed Frazier’s approach, coming from behind the victim,
and showed Frazier and the victim standing on the driver’s side before entering the car. However,
the video tape view was partially obscured, Frazier’s hands were not visible, and the video did not
show the knife.

4
variously in a crime of unspeakable brutality, in the front of the vehicle and in the

back seat of her car. According to the victim, the defendant apologized for not

being able to ejaculate because he was drunk.

After the sexual assaults were completed, the defendant dressed, took

control of the car, and drove north on U.S. Highway 441 toward North Carolina.

Frazier stopped twice, first at a Citgo convenience store where he bought gasoline,

and then at a Circle-K store where he bought cigarettes. At both stops, Frazier

made the victim accompany him into the convenience stores, warning her not to do

anything “stupid.”5 R7 at 162, 163.

In the meantime, the victim’s fiancé and family members became alarmed

over her absence. Her fiancé, Anthony Defoor, expected to meet her after she

visited the Wal-Mart, and by eleven o’clock, had become very concerned. He

began searching for her and contacted her parents. The victim’s mother called 911

to report her missing, and her father, Larry Kimsey (“Kimsey”), drove off in

search of his daughter. Kimsey spotted his daughter’s vehicle, followed it for

several miles, and pulled up alongside it, noticing that his daughter was in the

5
An in-store video surveillance camera in the Circle-K captured Frazier and the victim in
that convenience store, and was played for the jury. The videotape showed the two entering the store
and purchasing cigarettes. On the videotape, the victim was not visibly restrained by Frazier, and
the store clerk testified that the victim did not seem noticeably upset or distressed, nor was it readily
apparent that she was being directed by Frazier.

5
front passenger seat and a stranger was driving the car. He attempted

unsuccessfully to flag down his daughter’s car by driving alongside the vehicle,

flashing his brake lights, and rolling down his windows and motioning with his

arm for the car to stop. Kimsey continued to chase the vehicle, mile after mile, at

speeds up to 80 miles per hour. Indeed, when Kimsey pulled alongside his

daughter’s car, the defendant swerved and cut him off. Eventually, although he

was unable to stop the car, Kimsey was able to attract the attention of a passing

deputy sheriff by repeatedly flashing his brake lights.

At this point, the officer driving a marked police car made a u-turn and

began chasing the two vehicles. The deputy activated his flashing blue lights in an

attempt to stop the victim’s car, but Frazier did not pull over. The deputy called

for back-up and additional officers joined the chase, pursuing the victim’s car with

their lights and sirens activated. Still, Frazier did not stop; instead he accelerated

the vehicle, leading the police on a chase at speeds of up to 100 miles per hour for

many miles, passing stop signs, repeatedly crossing the center line, and running

red lights without slowing or stopping.6 Twice, when law enforcement officers

6
At trial, consistent accounts of the defendant’s flight from police were given by the
victim, Kimsey, and three of the officers involved in the chase: Shawn Wilson, a deputy sheriff
with the Rabun County Sheriff’s Department, Sergeant Terry Smith of the Macon County
Sheriff’s Department, and Donald Willis, a deputy sheriff with the Macon County Sheriff’s
office. In addition, videotapes recorded by video equipment in the vehicles of Sergeant Smith
and Deputy Sheriff Willis were played at trial, and reinforced the officers’ accounts.

6
tried to cut him off, Frazier tried to hit their cars. Frazier continued his flight at

high speeds, crossing into North Carolina, and driving north on North Carolina

Route 28. Driving at high speed on this twisting, winding road, Frazier frequently

swerved out of the proper lane, until eventually he lost control of the vehicle and

crashed into a power pole alongside Route 28. The officers radioed for emergency

medical and fire authorities.

The police immediately removed both Frazier and the victim from the car.

After being asked why the vehicle was fleeing the police, the victim replied that

the defendant had kidnapped her from the Wal-Mart at knifepoint. When Frazier

was searched immediately following his arrest, the officers discovered two knives

on his person. One of the knives was found in his right hip pocket, locked in the

open position with a partially serrated blade.

The victim was transported to a local hospital where, because she claimed to

have been sexually assaulted, she was treated by a Sexual Assault Nurse

Examiner. The nurse examined the victim and prepared a rape kit by removing

loose hairs from the victim and from her clothing. She also swabbed for fluids.

The nurse-examiner later testified that the victim’s manner and demeanor were

consistent with what she described as a post-traumatic stress demeanor, and said

7
that the victim had suffered traumatic bruising to her cervix.7 Later testing of the

swab and hair evidence recovered from the examination failed to establish that any

hair or fluid recovered from the victim’s person or clothing matched Frazier’s.

Similarly, although various pieces of evidence, including seat upholstery, were

removed from the victim’s car, no hair or fluid evidence was recovered that

matched the defendant’s.

When the victim testified at trial, she gave a detailed account of these events

that was consistent with those recounted by her father, and by three of the police

involved in the pursuit of Frazier. On cross-examination, Frazier vigorously

challenged the victim’s account. Frazier elicited from the victim that at some

point after the night of her abduction, she retraced the route she and Frazier had

taken with law enforcement officers, and initially was unable to locate the dirt

road on which the sexual assaults had taken place. Frazier’s counsel questioned

the victim regarding the sexual assaults, asking her to recount, in detail, nearly a

dozen sexual acts that occurred in the front of the vehicle, as well as in the back

seat. Frazier elicited the fact that the victim had not mentioned that she had been

sexually assaulted to the first doctor, a male, who examined her at the hospital.

7
The nurse did not offer an opinion regarding the cause of this bruising to the cervix,
stating only that the injury was not caused by the automobile accident.

8
The victim also conceded that she had lit a cigarette for the defendant while they

were in the car together.

On the evening after his arrest Frazier was questioned, and, after receiving

Miranda8 warnings, he gave an account of the previous evening that differed

dramatically from the victim’s account. Frazier told an FBI agent interviewing

him that he had been drinking beer all day, and “had a good buzz on” after

consuming three twelve-packs. R7 at 211, 214. Frazier recounted that he was

sitting on a bench outside the Wal-Mart, wearing a baseball hat that read “Official

Booze Guzzling, Beer Chugging, Sud Sucking, Ass Kicking Party Cap,” id. at

218, when he was approached by the victim, a complete stranger, who initiated a

conversation with him and offered to give him a ride back to his residence.

After he accepted the offer, according to Frazier, they began to drive

around; when Frazier mentioned an ex-girlfriend in Silva, North Carolina, whom

he wanted to visit, the victim offered to drive him there and he accepted. The

defendant also told the FBI that the victim asked him to drive the car, even though

he had consumed a large amount of alcohol and had told her that he did not have a

valid driver’s license. Finally, Frazier said that he refused to pull over when

chased by the victim’s father and the police only because the victim told him not

8
See Miranda v. Arizona, 384 U.S. 436, 86 S. Ct. 1602, 16 L. Ed. 2d 694 (1966).

9
to stop. According to Frazier, the victim told him not to stop the car because if he

did, her father “would beat his ass.” Id. at 217. There is no evidence that Frazier

acknowledged to the FBI that he had swerved to hit or cut off either Kimsey or

any of the police officers chasing him. Frazier denied that any sexual contact had

occurred.

B.

Prior to trial, Frazier gave notice to the government that he intended to offer

the expert testimony of Robert Tressel, a forensic investigator and former police

officer. In essence, Tressel was prepared to testify that none of Frazier’s hairs or

bodily fluids were recovered from the victim, her clothes or her car; that “it would

be expected that some transfer of either hairs or seminal fluid would occur in this

case,” Def. Ex. 2; and that “there is no forensic evidence to substantiate the claim

of rape in this case.” Id. The object of this testimony and, indeed, the basic thrust

of Frazier’s defense, was that the victim fabricated her account of kidnapping and

rape in order to avoid being punished by her parents for violating her curfew. To

establish this defense, Frazier hoped to undermine the credibility of the victim’s

account of abduction and rape by, among other things, suggesting that she had lied

about the sexual assaults.

10
 The Government timely moved in limine to exclude Tressel’s testimony

under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S. Ct.

2786, 125 L. Ed. 2d 469 (1993), and the district court conducted a thorough

Daubert hearing before trial. At the hearing, Tressel testified that he had been a

police officer in Cobb County, Georgia, for more than a decade. For ten years,

Tressel worked as an investigator in Cobb County’s Crimes Against Persons Unit,

which investigated homicides, rapes, other sexual assaults, and armed robberies.

Tressel said that during his tenure in Cobb County he worked on thousands of

cases, including between 150 and 250 sexual assault cases. In addition, he worked

for thirteen years in the Cobb County Medical Examiner’s Office.

At the time he testified, Tressel was self-employed as a consultant in the

area of forensic investigations. Tressel recounted the forensic training he had

received, which included training in crime scene processing for his work with the

Cobb County Police Department; additional education at the University of Georgia

in crime scene analysis and processing; and “training at the University of Virginia

through Quantico, the FBI laboratory, on crime scene processing.” R5 at 12.

Tressel also stated that he had “been involved in criminalistic studies that were put

on by the FBI at various law enforcement academies” in the state of Georgia, id.,

and explained that “the chief of police magazine that has sections on it where you

11
can conduct kind of an at-home study program where you go through and you

have to answer certain questions and everything. I have been involved in that.”

Id. at 13. Tressel said that he had taught classes in crime scene investigation at the

North Central Law Enforcement Academy and at the Northwest Georgia Law

Enforcement Academy, and had qualified as an expert in various state and federal

courts.

After presenting his general qualifications, Tressel opined that, based on all

of the information which was available to him, it appeared that the forensic

investigation of the alleged sexual assault had been performed properly and

thoroughly. Tressel testified that he saw “no forensic evidence to substantiate the

claim of rape in this case.” R5 at 25. Tressel offered the view that, given the

allegations of sexual assault made by the victim, “[t]here should have been some

transfer of either hairs, fibers or fluids between the victims [sic] in this case.” Id. at

27. Or, as he put it in his expert report, “[w]ith the amount of sexual activity

described . . . it would be expected that some transfer of either hairs or seminal

fluid would occur.” Def. Ex. 2 at 2. Tressel also opined that, after reviewing the

report of the victim’s medical examination, he concluded that the reported

conditions were consistent with the victim’s account that she had had sexual

intercourse with her boyfriend on the day preceding the examination. Tressel

12
explained that the victim’s condition would be consistent with either a sexual

assault or the consensual sexual contact she described.

On cross-examination, the government sought to elicit from Tressel the

foundation for his opinions. Tressel acknowledged, first, that as for his medical

opinions, he had no training in performing medical examinations generally, or,

specifically, in performing pelvic examinations of female sexual assault victims.

Tressel conceded that he had no education, training or experience as a doctor, and

that he was not a physician.

The government also questioned Tressel at some length concerning the

bases for his opinions that hair was the most common form of forensic evidence

found in rape investigations, and that “it would be expected that some transfer of

either hairs or seminal fluid would occur.” Tressel said that he relied on his

experience and a text entitled Practical Aspects of Rape Investigation, by Robert

Hazelwood and Ann Burgess, for the opinion that the transfer of hair is the form of

forensic evidence most commonly found in rape investigations.9 When asked to

clarify what in his experience provided a more specific foundation for his general

9
Frazier did not proffer this or any other text into evidence to support Tressel’s opinions.
Tressel also said that he relied on another text, “Crime Scene Search and Physical Evidence
Handbook, by Carl Cunningham,” R5 at 37, which was not offered into evidence. See Richard
H. Fox & Carl L. Cunningham, Crime Scene Search and Physical Evidence Handbook (U.S.
Dept. of Justice 1973).

13
opinions, Tressel identified a single investigation he had worked on, in which hair

evidence was recovered during the investigation of a serial rapist. He cited to no

other case or investigation, and made no effort to quantify in any way the number

of cases he was personally involved in that showed a transfer of hair or seminal

fluid.

Tressel also observed that “I don’t think anybody has ever studied the rates

of transfer” of hair evidence, and clarified that he was not familiar with any

scientific literature on the rate of transfer of hair in sexual assault cases. R5 at 37.

Tressel again cited his experience (albeit only as a general matter) and the

Hazelwood and Burgess text as the foundation for his opinion that seminal fluid

was frequently found in sexual assault cases.

The government then explained the reasons underlying its motion to

exclude Tressel’s opinions in these terms:

If you look back at what the witness stated, he says the forensic
evidence most commonly found during the analysis of a rape
investigation is the transfer of hairs from the victim to the perpetrator
and from the perpetrator to the victim.

There is no evidence placed before this court at this hearing as
a basis for the admission of this evidence that a lack of hair evidence
found means necessarily that no sexual assault took place. There is no
evidence that’s been placed before you that leads you, your Honor, to
conclude that hair will be transferred in X percentage of cases . . . .

14
 All we have is there is no transfer here, and hair is the most
commonly found piece of evidence during a rape investigation. No
evidence that when he says it’s most commonly found, no evidence
that that means that it’s found in 90 percent of the cases, 70 percent of
the cases, 3 percent of the cases, and seminal fluid evidence is found
in only two percent of the cases. . . .

....

There is no evidence that routinely in a rape investigation you
will have hairs transferred or hairs found. None. Nothing before the
Court to that effect.

....

. . . Again, there is no evidence that a lack of seminal fluid present or
found means necessarily that no sexual assault or sexual contact took
place.

Id. at 44-46. The government argued that Tressel provided no foundation or

support, either from the relevant literature or from his own experience, for his

specific opinion that the recovery of hair or fluid evidence “would be expected” in

a case like this one. The government also objected to Tressel’s proffered medical

opinions based on the lack of any medical training and the fact that he had not

personally examined the victim.

The district court ruled that Tressel was qualified to testify and could

explain the standard procedures employed in investigating the crime scene of a

sexual assault, that Tressel could recount that no hair or fluid matching Frazier’s

15
was found on the scene, and that “the forensic evidence most commonly found

during the analysis of a rape investigation is the transfer of hairs.” Def. Ex. 2 at

2.10 Conversely, however, the district court ruled that Tressel would not be

10
Specifically, the district court ruled that Tressel could offer the following testimony
based on these paragraphs taken from his expert report:

[A] thorough examination of the motor vehicle was performed by
[the] Evidence Recovery Team.

. . . [T]he laboratory was unable to find any transfer of any head or
pubic hairs from the suspect, Richard Frazier, to the body of [the
victim], or to the interior of the vehicle.

....

. . . All [tests] were negative for seminal fluid [and for blood].

. . . During the course of a rape investigation, it is an investigator’s
responsibility to collect all pertinent evidence that can be of
assistance in determining whether or not an alleged sexual assault has
occurred. It is the duty of the investigator to substantiate the alleged
claim of sexual assault, whether it be rape or sodomy charges,
through the collection of forensic evidence.

The forensic evidence most commonly found during the
analysis of a rape investigation is the transfer of hairs from the victim
to the perpetrator and from the perpetrator to the victim. These hairs
are routinely pubic hairs that become transferred during sexual
intercourse. Head hairs can also be transferred during a sexual assault
and can be found in the clothing of both the victim and the
perpetrator.

Seminal fluids are frequently found in sexual assault cases,
especially when multiple episodes of sexual activity occur and no
condom is used by the perpetrator. These fluids can be found not
only in the orifices of the victim, but also on the clothing worn by
both the victim and the perpetrator.

In review of the documents that I have been provided on this

16
permitted to opine that, based on the sexual activities described by the victim, “it

would be expected that some transfer of either hairs or seminal fluid would occur.”

Id. (emphasis added). Similarly, Tressel was not permitted to opine that the

forensic evidence did not substantiate the rape claim, or that “there is no forensic

evidence to substantiate the claim of rape.” Id.11

case, it appears that a thorough forensic investigation and a thorough
rape examination of the victim in this case were performed.

Def. Ex. 2 at 2.
11
Specifically, the trial judge ruled that Tressel could not offer testimony based on the
following paragraphs of his expert report:

With the amount of sexual activity described in the search
warrant affidavit, it would be expected that some transfer of either
hairs or seminal fluid would occur in this case.

The resulting laboratory findings in this case, do not
substantiate the claim of rape through forensic evidence. All findings
of the samples that were taken, all of which are essentially routine
rape investigation procedures, were negative in finding a transfer of
seminal fluid or hair from the defendant in this case. The medical
examination of the victim only shows evidence of sexual activity on
the part of the victim at some time prior to the examination taking
place. The documented finding of bruising around the labia major
indicates that the bruising may be substantially older than only a few
hours.

Based on my review of the available documents, it is my
professional opinion that there is no forensic evidence to substantiate
the claim of rape in this case. The only indication that any type of
sexual activity occurred is the redness around the labia major and the
redness of the cervix. These two injuries, in and of themselves, can
occur during routine normal sexual activity. [The victim’s] medical
records indicate that she had sexual intercourse on 10/29/2000.

17
 The district court excluded Tressel’s proffered opinions about the absence

of hair and fluid evidence because it found the opinions to be unreliable. The trial

court said that while Tressel was generally qualified as an expert forensic

investigator,12 he had not provided any specific basis -- quantitative, empirical or

otherwise -- for his opinions. Precisely because Tressel could not specify in what

percentage of cases hair or fluid evidence might reasonably be expected to be

recovered, his opinion that the recovery of such evidence “would be expected”

would mislead the jury. Simply put, there was no basis for assessing the reliability

of Tressel’s opinion of what might reasonably be expected, or even its exact

meaning.

The district court explained its decision in these terms:

Def. Ex. 2 at 2-3.
12
The district court explained:

I think that he’s an expert in what you normally look for, and I don’t
have any difficulty with that. That’s where his area of expertise is.

....

I have no problems with his expertise as he is obviously a very
qualified criminal investigator, and as to investigative procedures, but
that’s not the -- if here we were dealing with procedures that were
used and whether they were adequate or inadequate, then I would
consider him a good expert to testify to those matters.

R5 at 51, 66.

18
[I]f there is any scientific evidence that shows that in 99
percent of the time you find pubic hair, I would have no
problem with that, but he has no study. He just says that
in a very nebulous statement that he used of -- it wasn’t
generally. It was commonly found.

Well, this may not be a commonly case. I have no
problem with him saying that’s what they’re looking for,
but I do have a problem with him saying that that’s
what’s found, and if it’s not there, I don’t believe there
was a rape, and I am not going to allow that. . . .

If you have any scientific evidence that would
indicate you should [find forensic evidence], I have no
problem, as I said, with his testifying that’s what they
look for, but when you start trying to prove that there is
no case because they didn’t find it, you have got to have
something more than just his opinion. You need
something showing some study.

I have no idea whether -- I don’t have enough to
tell me how often that is, and I have no basis of knowing,
and based upon what you’ve presented today, I would
not and will not allow it. I don’t think that helps the
jury. . . .

At most, it’s a method of going to the credibility,
and I hesitate to start trying to say that a witness is not
credible because I would have expected some pubic hair
to be found.

I don’t know what the percentage is. Are you
going to say then there is a 50 percent chance she’s not
credible, or there’s a 25 percent [chance] or there’s a 75
percent [chance] she’s not credible[?] I have difficulty
with that, and I just don’t think that under those
circumstances I would admit it.

19
R5 at 68-70.

The trial judge also excluded Tressel’s medical opinions because he was not

qualified as a medical expert by background, training or experience. The court

explained that it would allow a medical doctor to testify on the issue, but that

Tressel’s experience and background were simply inadequate.

At trial, Frazier chose not to call Tressel at all, but did clearly establish that

no seminal fluid or hair matching Frazier’s was recovered during the investigation

by calling two FBI laboratory technicians who had worked on the investigation.

The defense first called Karen Lanning, an FBI hair and fiber examiner, who

testified that she analyzed hair, clothing, and automobile upholstery collected

during the Frazier investigation, and that none of the hairs recovered matched

Frazier’s. On cross-examination, the government asked Lanning how often, in her

experience, she found a transfer of hairs. The defense objected, observing that

Lanning had been called only as a fact witness, and not as a general expert. The

trial judge overruled the objection, after which Lanning testified that she found

hair transfers in 10% of the cases she worked on, and found no hair 90% of the

time. When the government attempted to question Lanning further about the

significance of finding no hair in the case, the defense renewed its objection that

Lanning had not been called as an expert. The district court agreed that she had

20
been called as a fact witness and could not testify on cross-examination as to

studies done on hair transfers, sustaining the objection. The government observed

that it would call her on rebuttal.

The defense also called Anthony Onorato, a forensic DNA examiner in the

FBI’s laboratory. Onorato explained that he had received evidence recovered in

the Frazier investigation and tested it for the presence of bodily fluids, including

blood and seminal fluid. Onorato was unable to identify any semen, nor was he

able to identify any blood. On cross-examination, the government sought to

question Onorato as to the frequency of finding evidence of semen. Frazier again

objected, arguing that the government was seeking to use Onorato as an expert

witness. The trial judge stated, “well, that’s a factual determination, I will allow

that.” R9 at 359. Nevertheless, the government ceased this line of cross-

examination, observing that it would call Onorato on rebuttal “and do it all at

once.” Id.

After the defense rested, the government announced that it would call

Lanning and Onorato as rebuttal witnesses. Frazier objected, arguing only that the

government had failed to give notice of its intent to use Lanning or Onorato as

expert witnesses, in violation of Rule 16 of the Federal Rules of Criminal

Procedure. The defense suggested that, while the text of Rule 16 referred only to

21
disclosure requirements for the government’s case-in-chief, calling these expert

rebuttal witnesses without notice violated the spirit of the Rule. Frazier suggested,

further, that it would be unfair to allow the government to call these experts to

opine on the significance of the absence of hair or fluid evidence, since Frazier’s

expert -- Tressel -- had been precluded from opining on the same subject.13

Notably, the defense never objected to the government’s use of Lanning or

Onorato on the grounds that either of them was not qualified as an expert, or that

their opinions were based on methodologically unreliable or unsound foundations.

The district court overruled the objection, reasoning that Rule 16 only requires

notice when the government calls an expert during its case-in-chief, and here the

witnesses plainly were called on rebuttal.

On rebuttal, Lanning recited her experience and qualifications, stating that

she was a member of the Midwestern Association of Forensic Scientists and had

testified as an expert forensic scientist more than one hundred times in state and

13
Frazier objected in the following terms:

Your honor, I think that it’s just wholly unfair for the
government to attempt to use these witnesses that I’ve called as fact
witnesses who were under their control -- Now, the Rule does say in
their case in chief, but here I think that what the government is doing
is playing games to avoid [the rule] -- to sandbag the defendants. [sic]

R9 at 359-60.

22
federal courts across the country. Lanning had worked for six years in the Trace

Evidence Unit of the FBI laboratory in Washington, D.C., after previously

working for just under six years with the Kansas Bureau of Investigation. Lanning

stated that she had never been rejected as an expert by any court, and the

government proffered her as an “expert in the area of hair analysis” and forensic

investigation, R9 at 369, without objection.

Lanning said that she was familiar with various scientific studies of the rate

of hair transfer during sexual contact. She was familiar with a 1990 study by Mary

Jacque Mann entitled “Hair Transfers in Sexual Assault” from the Journal of

Forensic Sciences which found no pubic hair transfers to the victim’s underwear in

97% of the cases involved in the study; no pubic hair transfers in combings of the

victim’s pubic hair in 96% of the cases; no head hair transfers in the victim’s

underwear in 96% of the cases; no pubic hair transfers in the victim’s outer wear

in 98.5% of the cases; and no head hair transfers in the victim’s outer wear in 97%

of the cases. Lanning also said that she was familiar with a 1998 study in the same

journal, entitled “Frequency of Pubic Hair Transfer During Sexual Intercourse,”

which found no transfer of pubic hairs to the female partners in the study in 82.7%

of the cases, and concluded that a failure to transfer pubic hair did not indicate that

no intercourse had taken place. Consistent with the latter study, Lanning opined

23
that the failure to recover any of Frazier’s hair did not necessarily mean that no

sexual contact had taken place between Frazier and the victim.

On cross-examination, Lanning observed that if sexual contact occurred

within an enclosed area, as opposed to an open space, it would be more likely that

transferred hairs would remain in that area. She also said that the likelihood of a

hair transfer might increase as the duration of the sexual encounter and range of

activities increased. Lanning also clarified her earlier testimony that she found

hair transfers in 10% of the cases she worked on, specifying that hair was only

recovered in between 2% and 5% of the rape cases she worked on.

The government also called Onorato on rebuttal, and elicited that Onorato

was a member of the American Academy of Forensic Sciences, the Canadian

Society of Forensic Science, and the American Society of Clinical Pathologists.

Onorato stated that he had testified as an expert in forensic serological analysis in

approximately 15 courts, and was an expert in the search for the presence of semen

on evidence. Onorato testified that he had a bachelor’s degree in biology and

master’s degrees in clinical immunology and microbiology as well as in forensic

science. Onorato worked for two years in the crime lab of the Pennsylvania State

Police, and for approximately two years in the medical center of the University of

Alabama at Birmingham, before spending approximately five years in the DNA

24
Analysis Unit of the FBI. The government proffered Onorato as an expert “in the

search for the presence of semen on evidence” and forensic investigation, id. at

384, again without objection. Onorato testified that he found semen in materials

present in 75% to 80% of the sexual assault cases he worked on. Onorato

observed that in a sexual assault where the perpetrator did not ejaculate, the

likelihood of recovering semen would be reduced. He also opined that the absence

of a defendant’s sperm did not necessarily mean that no sexual contact took place.

On cross-examination, Onorato explained that in sexual assault cases where

there were multiple erections and penetration over a period of time, the chances of

recovering a chemical emitted by the prostate gland, P30, would be increased.

Onorato observed that the likelihood of finding bodily fluids in the evidence he

examined would increase with the number of sexual encounters.

Following Frazier’s trial, on June 20, 2001, the jury rejected his defense and

returned a verdict of guilty. Soon thereafter, Frazier was sentenced to a term of

life imprisonment without parole, pursuant to the federal “three-strikes” statute, 18

U.S.C. § 3559(c).14 Frazier timely appealed on August 15, 2001.

14
18 U.S.C. § 3559(c) provides:

(1) Mandatory life imprisonment.--Notwithstanding any other
provision of law, a person who is convicted in a court of the United
States of a serious violent felony shall be sentenced to life
imprisonment if--

25
 A divided panel of this Court reversed Frazier’s conviction, holding that the

district court abused its discretion in limiting the testimony of Robert Tressel. The

majority found that the district court erroneously required scientific evidence as a

prerequisite to expert status, and that by excluding portions of Tressel’s testimony

it violated the defendant’s substantial rights because the heart of the defense

turned on undermining the victim’s credibility. See United States v. Frazier, 322

F.3d 1262 (11th Cir. 2003). Following the issuance of the panel’s opinion, on

September 12, 2003, this Court entered an order vacating the panel opinion and

directing that the case be heard en banc. See United States v. Frazier, 344 F.3d

1293 (11th Cir. 2003) (en banc).

II.

(A) the person has been convicted (and those convictions have
become final) on separate prior occasions in a court of the United
States or of a State of--

(i) 2 or more serious violent felonies; or

(ii) one or more serious violent felonies and one or more serious drug
offenses; and

(B) each serious violent felony or serious drug offense used as a basis
for sentencing under this subsection, other than the first, was
committed after the defendant’s conviction of the preceding serious
violent felony or serious drug offense.

18 U.S.C. § 3559(c)(1).

26
 We review for abuse of discretion the district court’s decisions regarding the

admissibility of expert testimony and the reliability of an expert opinion. Joiner,

522 U.S. at 141-43, 118 S. Ct. at 517; see also Kumho Tire Co., Ltd. v.

Carmichael, 526 U.S. 137, 142, 119 S. Ct. 1167, 1171, 143 L. Ed. 2d 238 (1999)

(explaining that, under Joiner, “courts of appeals are to apply ‘abuse of discretion’

standard when reviewing district court’s reliability determination”). Indeed, the

“deference that is the hallmark of abuse-of-discretion review,” Joiner, 522 U.S. at

143, 118 S. Ct. at 517, requires that we not reverse an evidentiary decision of a

district court “‘unless the ruling is manifestly erroneous,’” id. at 142, 118 S. Ct. at

517 (quoting Spring Co. v. Edgar, 99 U.S. 645, 658, 25 L. Ed. 487 (1878)). Thus,

it is by now axiomatic that a district court enjoys “considerable leeway” in making

these determinations. Kumho Tire, 526 U.S. at 152, 119 S. Ct. at 1176.

This Court has uniformly applied the deferential abuse-of-discretion review

that Joiner mandates. See Quiet Tech. DC-8, Inc. v. Hurel-Dubois UK Ltd., 326

F.3d 1333, 1340 (11th Cir. 2003) (trial court’s exclusion of expert testimony

reviewed for abuse of discretion; “this standard of review requires that we defer to

the district court’s evidentiary ruling unless that ruling is manifestly erroneous”

(internal quotation marks and citations omitted)); McCorvey v. Baxter Healthcare

Corp., 298 F.3d 1253, 1257 (11th Cir. 2002) (“[O]ur review of evidentiary rulings

27
by trial courts on the admission of expert testimony is ‘very limited.’” (quoting

Maiz v. Virani, 253 F.3d 641, 662 (11th Cir. 2001))); Michigan Millers Mut. Ins.

Corp. v. Benfield, 140 F.3d 915, 921 (11th Cir. 1998) (“It is very much a matter of

discretion with the trial court whether to permit the introduction of [expert]

evidence, and we will not reverse the decision of the trial court regarding the

exclusion or admission of such evidence unless the trial court’s decision is

‘manifestly erroneous.’”); see also Toole v. Baxter Healthcare Corp., 235 F.3d

1307, 1312 (11th Cir. 2000) (“We review a trial court’s evidentiary rulings on the

admission of expert witness testimony for abuse of discretion.”); United States v.

Paul, 175 F.3d 906, 909 (11th Cir. 1999) (“This court reviews the district court’s

decision to exclude expert testimony under Federal Rule of Evidence 702 for

abuse of discretion.”); United States v. Gilliard, 133 F.3d 809, 812 (11th Cir.

1998) (“A district court’s decision to admit or exclude expert testimony under

Rule 702 is reviewed for abuse of discretion.”).

The application of an abuse-of-discretion review recognizes the range of

possible conclusions the trial judge may reach.

By definition . . . under the abuse of discretion standard of review
there will be occasions in which we affirm the district court even
though we would have gone the other way had it been our call. That
is how an abuse of discretion standard differs from a de novo
standard of review. As we have stated previously, the abuse of

28
 discretion standard allows “a range of choice for the district court, so
long as that choice does not constitute a clear error of judgment.”

Rasbury v. I.R.S. (In re Rasbury), 24 F.3d 159, 168 (11th Cir. 1994) (quoting

United States v. Kelly, 888 F.2d 732, 745 (11th Cir. 1989) (citing Kern v. TXO

Prod. Corp., 738 F.2d 968, 970 (8th Cir. 1984))); see also Kern, 738 F.2d at 971

(“The very concept of discretion presupposes a zone of choice within which the

trial courts may go either way.”). Thus, when employing an abuse-of-discretion

standard, we must affirm unless we find that the district court has made a clear

error of judgment, or has applied the wrong legal standard. Maiz, 253 F.3d at 662.

III.

A.

The starting point for our analysis is Rule 702 of the Federal Rules of

Evidence, which controls the admission of expert testimony. It provides:

If scientific, technical, or other specialized knowledge will assist the
trier of fact to understand the evidence or to determine a fact in issue,
a witness qualified as an expert by knowledge, skill, experience,
training, or education, may testify thereto in the form of an opinion or
otherwise, if (1) the testimony is based upon sufficient facts or data,
(2) the testimony is the product of reliable principles and methods,
and (3) the witness has applied the principles and methods reliably to
the facts of the case.

As the Supreme Court made abundantly clear in Daubert, Rule 702 compels the

district courts to perform the critical “gatekeeping” function concerning the

29
admissibility of expert scientific evidence. 509 U.S. at 589 n.7, 597, 113 S. Ct. at

2795 n.7, 2798. The trial courts are also required to play the same gatekeeping

function considering the admissibility of technical expert evidence. Kumho Tire,

526 U.S. at 147, 119 S. Ct. at 1174. This function “inherently require[s] the trial

court to conduct an exacting analysis” of the foundations of expert opinions to

ensure they meet the standards for admissibility under Rule 702. McCorvey, 298

F.3d at 1257.

The importance of Daubert’s gatekeeping requirement cannot be overstated.

As the Supreme Court framed it in Kumho Tire: “[t]he objective of that

requirement is to ensure the reliability and relevancy of expert testimony. It is to

make certain that an expert, whether basing testimony upon professional studies or

personal experience, employs in the courtroom the same level of intellectual rigor

that characterizes the practice of an expert in the relevant field.” 526 U.S. at 152,

119 S. Ct. at 1176. The district court’s role is especially significant since the

expert’s opinion “can be both powerful and quite misleading because of the

difficulty in evaluating it.” Daubert, 509 U.S. at 595, 113 S. Ct. at 2798 (quoting

Jack B. Weinstein, Rule 702 of the Federal Rules of Evidence is Sound; It Should

Not Be Amended, 138 F.R.D. 631, 632 (1991) (“Weinstein”)). Indeed, no other

kind of witness is free to opine about a complicated matter without any firsthand

30
knowledge of the facts in the case, and based upon otherwise inadmissible hearsay

if the facts or data are “of a type reasonably relied upon by experts in the particular

field in forming opinions or inferences upon the subject.” Fed. R. Evid. 703.

Thus, it comes as no surprise that in determining the admissibility of expert

testimony under Rule 702, we engage in a rigorous three-part inquiry. Trial courts

must consider whether:

(1) the expert is qualified to testify competently regarding the matters
he intends to address; (2) the methodology by which the expert
reaches his conclusions is sufficiently reliable as determined by the
sort of inquiry mandated in Daubert; and (3) the testimony assists the
trier of fact, through the application of scientific, technical, or
specialized expertise, to understand the evidence or to determine a
fact in issue.

City of Tuscaloosa v. Harcros Chems., Inc., 158 F.3d 548, 562 (11th Cir. 1998)

(citing Daubert, 509 U.S. at 589, 113 S. Ct. at 2794). While there is inevitably

some overlap among the basic requirements -- qualification, reliability, and

helpfulness -- they remain distinct concepts and the courts must take care not to

conflate them. Quiet Tech., 326 F.3d at 1341.

The proponent of expert testimony always bears “the burden to show that

his expert is ‘qualified to testify competently regarding the matters he intend[ed]

to address; [] the methodology by which the expert reach[ed] his conclusions is

sufficiently reliable; and [] the testimony assists the trier of fact.’” McCorvey, 298

31
F.3d 1253, 1257 (alterations in original) (quoting Maiz, 253 F.3d at 664). The

burden of establishing qualification, reliability, and helpfulness rests on the

proponent of the expert opinion, whether the proponent is the plaintiff or the

defendant in a civil suit, or the government or the accused in a criminal case.

Turning first to the qualification of the expert, we observe that experts may

be qualified in various ways. While scientific training or education may provide

possible means to qualify, experience in a field may offer another path to expert

status. In fact, the plain language of Rule 702 makes this clear: expert status may

be based on “knowledge, skill, experience, training, or education.” (emphasis

added). The Committee Note to the 2000 Amendments of Rule 702 also explains

that “[n]othing in this amendment is intended to suggest that experience alone . . .

may not provide a sufficient foundation for expert testimony.” Fed. R. Evid. 702

advisory committee’s note (2000 amends.).

Of course, the unremarkable observation that an expert may be qualified by

experience does not mean that experience, standing alone, is a sufficient

foundation rendering reliable any conceivable opinion the expert may express. As

we observed in Quiet Technology, “while an expert’s overwhelming qualifications

may bear on the reliability of his proffered testimony, they are by no means a

guarantor of reliability. . . . [O]ur caselaw plainly establishes that one may be

32
considered an expert but still offer unreliable testimony.” 326 F.3d at 1341-42.

Quite simply, under Rule 702, the reliability criterion remains a discrete,

independent, and important requirement for admissibility.

Indeed, the Committee Note to the 2000 Amendments of Rule 702 expressly

says that, “[i]f the witness is relying solely or primarily on experience, then the

witness must explain how that experience leads to the conclusion reached, why

that experience is a sufficient basis for the opinion, and how that experience is

reliably applied to the facts. The trial court’s gatekeeping function requires more

than simply ‘taking the expert’s word for it.’” Fed. R. Evid. 702 advisory

committee’s note (2000 amends.) (emphasis added); see also Daubert v. Merrell

Dow Pharmaceuticals, Inc. (on remand), 43 F.3d 1311, 1316 (9th Cir. 1995)

(observing that the gatekeeping role requires a district court to make a reliability

inquiry, and that “the expert’s bald assurance of validity is not enough”). If

admissibility could be established merely by the ipse dixit of an admittedly

qualified expert, the reliability prong would be, for all practical purposes,

subsumed by the qualification prong.

Thus, it remains a basic foundation for admissibility that “[p]roposed

[expert] testimony must be supported by appropriate validation -- i.e., ‘good

grounds,’ based on what is known.” Daubert, 509 U.S. at 590, 113 S. Ct. at 2795.

33
As the Supreme Court put it, “the Rules of Evidence -- especially Rule 702 -- . . .

assign to the trial judge the task of ensuring that an expert’s testimony . . . rests on

a reliable foundation.” Id. at 597, 113 S. Ct. at 2799.

When evaluating the reliability of scientific15 expert opinion, the trial judge

must assess “whether the reasoning or methodology underlying the testimony is

scientifically valid and . . . whether that reasoning or methodology properly can be

applied to the facts in issue.” Id. at 592-93, 113 S. Ct. at 2796. To evaluate the

reliability of scientific expert opinion, we consider, to the extent practicable:

(1) whether the expert’s theory can be and has been tested; (2)
whether the theory has been subjected to peer review and publication;
(3) the known or potential rate of error of the particular scientific
technique; and (4) whether the technique is generally accepted in the
scientific community.

15
In Daubert, the Court noted that “[s]cience is not an encyclopedic body of knowledge
about the universe. Instead, it represents a process for proposing and refining theoretical
explanations about the world that are subject to further testing and refinement. . . . [I]n order to
qualify as ‘scientific knowledge,’ an inference or assertion must be derived by the scientific method.”
509 U.S. at 590, 113 S. Ct. at 2795 (internal quotation marks and citation omitted). “[S]cience is
a process, a way of examining the natural world and discovering important truths about it. In short,
the essence of science is the scientific method.” David Goodstein, “How Science Works,” Reference
Manual on Scientific Evidence 69 (Federal Judicial Center, 2d ed. 2000).

Scientific evidence encompasses so-called hard sciences (such as physics, chemistry,
mathematics and biology) as well as soft sciences (such as economics, psychology,
and sociology), and it may be offered by persons with scientific, technical, or other
specialized knowledge whose skill, experience, training, or education may assist the
trier of fact in understanding the evidence or determining a fact in issue.

William W. Schwarzer & Joe S. Cecil, “Management of Expert Evidence,” Reference Manual on
Scientific Evidence 39 (Federal Judicial Center, 2d ed. 2000).

34
Quiet Tech., 326 F.3d at 1341 (citing McCorvey, 298 F.3d at 1256 (citing

Daubert, 509 U.S. at 593-94, 113 S. Ct. at 2796-97)). These factors are illustrative,

not exhaustive; not all of them will apply in every case, and in some cases other

factors will be equally important in evaluating the reliability of proffered expert

opinion. See Kumho Tire, 526 U.S. at 150-152, 119 S. Ct. at 1175-76; Fed. R.

Evid. 702 advisory committee’s note (2000 amends.); see also Heller v. Shaw

Indus., Inc., 167 F.3d 146, 155 (3d Cir. 1999) (“[N]ot only must each stage of the

expert’s testimony be reliable, but each stage must be evaluated practically and

flexibly without bright-line exclusionary (or inclusionary) rules.”).

The same criteria which are used to assess the reliability of a scientific

opinion may be used to evaluate the reliability of non-scientific, experience-based

testimony. Kumho Tire, 526 U.S. at 152, 119 S. Ct. at 1176; see also Clark v.

Takata Corp., 192 F.3d 750, 758 (7th Cir. 1999) (“In determining whether an

expert’s testimony is reliable, the Daubert factors are applicable in cases where an

expert eschews reliance on any rigorous methodology and instead purports to base

his opinion merely on ‘experience’ or ‘training.’”). As the Supreme Court

explained in Kumho Tire:

In certain cases, it will be appropriate for the trial judge to ask, for
example, how often an engineering expert’s experience-based
methodology has produced erroneous results, or whether such a

35
 method is generally accepted in the relevant engineering community.
Likewise, it will at times be useful to ask even of a witness whose
expertise is based purely on experience, say, a perfume tester able to
distinguish among 140 odors at a sniff, whether his preparation is of a
kind that others in the field would recognize as acceptable.

526 U.S. at 151, 119 S. Ct. at 1176. Sometimes the specific Daubert factors will

aid in determining reliability; sometimes other questions may be more useful. As

a result, “the trial judge must have considerable leeway in deciding in a particular

case how to go about determining whether particular expert testimony is reliable.”

Id. at 152, 119 S. Ct. 1176. Exactly how reliability is evaluated may vary from

case to case, but what remains constant is the requirement that the trial judge

evaluate the reliability of the testimony before allowing its admission at trial. See

Fed. R. Evid. 702 advisory committee’s note (2000 amends.) (“The trial judge in

all cases of proffered expert testimony must find that it is properly grounded, well-

reasoned, and not speculative before it can be admitted.” (emphasis added)).

The final requirement for admissibility of expert testimony under Rule 702

is that it assist the trier of fact. By this requirement, expert testimony is admissible

if it concerns matters that are beyond the understanding of the average lay person.

See United States v. Rouco, 765 F.2d 983, 995 (11th Cir. 1985) (expert testimony

admissible if it offers something “beyond the understanding and experience of the

average citizen”). Proffered expert testimony generally will not help the trier of

36
fact when it offers nothing more than what lawyers for the parties can argue in

closing arguments. See 4 Weinstein’s Federal Evidence § 702.03[2][a].

Because of the powerful and potentially misleading effect of expert

evidence, see Daubert, 509 U.S. at 595, 113 S. Ct. at 2798, sometimes expert

opinions that otherwise meet the admissibility requirements may still be excluded

by applying Rule 403.16 Exclusion under Rule 403 is appropriate if the probative

value of otherwise admissible evidence is substantially outweighed by its potential

to confuse or mislead the jury, see Rouco, 765 F.2d at 995, or if the expert

testimony is cumulative or needlessly time consuming. See, e.g., Hull v. Merck &

Co., Inc., 758 F.2d 1474, 1477 (11th Cir. 1985) (per curiam) (finding that

admission of speculative and “potentially confusing testimony is at odds with the

purposes of expert testimony as envisioned in Fed. R. Evid. 702”); see also United

States v. Stevens, 935 F.2d 1380, 1399 (3d Cir. 1991) (finding expert testimony

properly excluded because its probative value was outweighed by concerns of

“undue delay, waste of time, or needless presentation of cumulative evidence”).

16
Federal Rule of Evidence 403 provides:

Although relevant, evidence may be excluded if its probative value is
substantially outweighed by the danger of unfair prejudice, confusion
of the issues, or misleading the jury, or by considerations of undue
delay, waste of time, or needless presentation of cumulative evidence.

Fed. R. Evid. 403.

37
Indeed, “the judge in weighing possible prejudice against probative force under

Rule 403 . . . exercises more control over experts than over lay witnesses.”

Weinstein, 138 F.R.D. at 632; see also Salem v. U.S. Lines Co., 370 U.S. 31, 35,

82 S. Ct. 1119, 1122, 8 L. Ed. 2d 313 (1962). Simply put, expert testimony may

be assigned talismanic significance in the eyes of lay jurors, and, therefore, the

district courts must take care to weigh the value of such evidence against its

potential to mislead or confuse.

B.

The application of these basic principles yields the conclusion that the

district court did not abuse its discretion (that is, commit manifest error) in

excluding certain portions of Tressel’s proposed expert testimony.

We begin by observing that the first requirement, qualification, is satisfied

here. Based on his training and experience as a forensic investigator, Tressel was

qualified as an expert in forensic investigations. In fact, the trial judge

acknowledged as much during the Daubert hearing. The district court said: “I

think that he’s an expert in what you normally look for [in a rape investigation],

and I don’t have any difficulty with that. That’s where his area of expertise is.”

R5 at 51. Later, the trial judge reiterated this point, observing: “I have no

problems with his expertise as he is obviously a very qualified criminal

38
investigator . . . . [I]f here we were dealing with procedures that were used and

whether they were adequate or inadequate, then I would consider him a good

expert to testify to those matters.” Id. at 66. Tressel’s qualification as an expert

forensic investigator was based on his experience with the Police Department of

Cobb County, Georgia, and within the Cobb County Medical Examiner’s Office.

Were Tressel’s qualification as an expert the only prerequisite to the admissibility

of all his opinion testimony, we have little doubt that he would be competent to

testify generally as an expert forensic investigator.17

Frazier argues, however, that the district court erroneously treated scientific

background as a prerequisite to expert status, and we agree that, had the court

done so, it would have erred as a matter of law, because Rule 702 expressly

contemplates that experts may be qualified based on experience. However, our

review of the entire record suggests that the district court excluded Tressel’s

testimony not because he lacked a scientific background, but because he failed to

establish that his opinions were methodologically reliable or sound.

17
While the district court found Tressel qualified as an expert forensic investigator, it
reached the opposite conclusion concerning his qualification to offer medical opinions. The trial
judge said that “I am not going to allow him to testify about the bruising [to the victim’s genital
area]. I would [allow] a medical doctor but not a witness with these credentials.” R5 at 50-51.
Frazier does not appeal the district court’s ruling that Tressel was not qualified to offer expert
medical testimony. We add that evidence of bruising to genitalia, just like hair and bodily fluids,
may be forensic evidence of a sexual assault.

39
 Two factors support our conclusion that the district court did not exclude

Tressel’s testimony because he lacked scientific expertise or was otherwise

unqualified. First, as we have noted, the trial court explicitly said that Tressel was

qualified by experience as an expert forensic investigator. Second, the district

court allowed FBI investigators Lanning and Onorato to offer expert opinions

after they were qualified as experts based in substantial measure on their

experience.18 The record taken as a whole indicates that the district court properly

understood that experience can provide a basis for qualifying an expert. And we

discern no abuse of discretion in the district court’s conclusion that Tressel was a

qualified forensic investigator.

We turn then to the central issue on appeal: whether the district court abused

its discretion by excluding some of Tressel’s opinion testimony because he failed

to establish its reliability. We reiterate that the district court has the same broad

discretion in deciding how to assess the reliability of expert testimony that it has in

18
As detailed, supra, Lanning had worked for just under six years with the Kansas Bureau
of Investigation, and for six years in the Trace Evidence Unit of the FBI laboratory in Washington,
D.C.; she was a member of the Midwestern Association of Forensic Scientists and had testified as
an expert forensic scientist more than a hundred times. Onorato had worked in the University of
Alabama at Birmingham’s medical center for approximately two years, and in the crime lab of the
Pennsylvania State Police for two years, before joining the FBI, where he had worked for
approximately five years at the time of the trial. Onorato also had experience as a member of the
American Academy of Forensic Sciences, the Canadian Society of Forensic Science, and the
American Society of Clinical Pathologists, and qualified as a court expert in approximately 15 cases.

40
its ultimate reliability determination. In this case, after the government moved to

exclude Tressel’s testimony, the district court assessed the reliability of his

opinions by conducting a thorough Daubert hearing in which Tressel was asked,

repeatedly, what the bases for his opinions were. While some expert testimony

will be so clearly admissible that a district court need not conduct a Daubert

hearing in every case, see Kumho Tire, 526 U.S. at 150-52, 119 S. Ct at 1175-76,

in this case, the district court’s decision to evaluate the admissibility of Tressel’s

opinions in the context of a pre-trial hearing was a perfectly reasonable one.

Moreover, Frazier has not attacked the timing or conduct of the Daubert hearing.

And the record amply establishes that Frazier was afforded every opportunity at

the hearing to adduce the foundations of Tressel’s challenged opinions. The

district court did not abuse its discretion when it conducted a Daubert hearing.

The reliability of Tressel’s opinion that the recovery of inculpatory hair or

seminal fluid “would be expected” is undermined in two ways. First, the very

meaning of his basic opinion is uncertain. Whether Tressel opined that “expect,”

as he used the term, meant that it was more likely than not that trace evidence

would be found, or that it was substantially more likely than not that it would be

found if there was a sexual assault, or that discovery was a virtual certainty, is

altogether unclear from Tressel’s report or his testimony. The specific meaning of

41
the opinion is impossible to discern. As the government pointed out at oral

argument, even the dictionary definition of the term “expect” -- meaning to

consider something either likely or certain -- is itself ambiguous, and could imply

a likelihood anywhere between 50% and 100%. See Webster’s Third International

Dictionary 799 (1961) (defining “expect” as “to consider probable or certain”).

More fundamentally, even if we take Tressel’s opinion to mean simply that

it was more likely than not that hair or seminal fluid would be transferred, and

therefore recovered, Tressel offered precious little in the way of a reliable

foundation or basis for his opinion. After the government moved to exclude

Tressel’s expert testimony, the district court was obliged to exercise its

gatekeeping role by determining whether Tressel provided a reliable foundation

or basis for his opinion. When questioned specifically about the basis for his

opinion, Tressel said his opinion was based on his experience, and on various texts

in forensic investigation. However, even after repeated prompting, Tressel never

explained just how his own experience, or the texts he mentioned, supported his

“expectancy” opinion. Indeed, Tressel identified only a single investigation he

had worked on in which hair evidence was recovered during the investigation of a

serial rapist, and could suggest no study that had ever examined the rate of transfer

of hair in sexual assault cases.

42
 While the expert’s statement that the recovery of hair or seminal fluid

“would be expected” expresses an intrinsically probabilistic or quantitative idea,

the probability it expresses is unclear, imprecise and ill-defined. And the basis for

that probabilistic opinion is left unstated. Without knowing how frequently hair or

seminal fluid is transferred during sexual conduct in similar cases -- whether

derived from reliable studies or based on some quantification derived from his

own experience -- it would be very difficult indeed for the district court (or for that

matter the jury) to make even an informed assessment, let alone to verify that the

recovery of hair or fluid evidence in this case “would be expected.” Nor could the

district court tell from Tressel’s testimony whether his opinions had been

subjected to peer review or, even, the percentage of cases in which his opinion had

been erroneous. Simply put, Tressel did not offer any hard information

concerning the rates of transfer of hair or fluids during sexual conduct.

Since Tressel was relying solely or primarily on his experience, it remained

the burden of the proponent of this testimony to explain how that experience led to

the conclusion he reached, why that experience was a sufficient basis for the

opinion, and just how that experience was reliably applied to the facts of the case.

Again, “[t]he court’s gatekeeping function requires more than simply ‘taking the

43
expert’s word for it.’” Fed. R. Evid. 702 advisory committee’s note (2000

amends.).

Our review of this record leads us to the conclusion that the district court

did not abuse its discretion in finding the absence of a sufficiently verifiable,

quantitative basis for Tressel’s opinion.19 As we have noted, the application of an

abuse-of-discretion standard recognizes a range of possible conclusions that the

trial judge may reach. In this case, we are satisfied that the district judge acted

well within that range in finding an insufficient nexus between the experience

proffered by the expert and the essential opinion propounded.

Turning finally to the third requirement for admissibility of expert opinion

testimony -- whether it will assist the trier of fact in understanding the evidence --

the district court also concluded that Tressel’s opinion regarding “expectation”

would not aid the jury.20 Again, because Tressel’s opinion was imprecise and

19
Tressel’s other opinion -- that there was no forensic evidence to substantiate the rape --
plainly was premised on his basic opinion that “it would be expected that some transfer” of hair or
seminal fluid would occur in this case. Accordingly, if the district court did not abuse its discretion,
that is, commit manifest error, in excluding the opinion concerning “expectancy,” then it did not (nor
on this record could it) commit manifest error in excluding the derivative opinion either.
20
We read the record to suggest that the district court concluded Tressel’s ambiguous
“expectation” opinion would not aid the jury, although the court’s statements are, on this point,
not altogether clear. The court said:

I have no problem, as I said, with his testifying that’s what they look for, but when
you start trying to prove that there is no case because they didn’t find [trace
evidence], you have got to have something more than just his opinion. . . .

44
unspecific, the members of the jury could not readily determine whether the

“expectation” of finding hair or seminal fluid was a virtual certainty, a strong

probability, a possibility more likely than not, or perhaps even just a possibility.

As a result, Tressel’s imprecise opinion easily could serve to confuse the jury, and

might well have misled it. More importantly, as we have noted, the

methodological foundation or reliability of Tressel’s “expectancy” opinion was

sufficiently slender to allow the district court to conclude that the trier of fact

would not be assisted by the opinion. In short, we can discern no abuse of

discretion (let alone manifest error) in the trial court’s finding that the third prong

of Rule 702 had not been met either.21

I have no idea whether -- I don’t have enough to tell me how often that is, and
I have no basis of knowing, and based upon what you’ve presented today, I would not
and will not allow it. I don’t think that helps the jury.

R5 at 69 (emphasis added).
21
Moreover, even if the district court had abused its discretion in excluding portions of
Tressel’s opinion testimony -- and on this record we find no abuse of discretion -- any such error
would have been harmless.

Evidentiary decisions do not constitute reversible error “unless a substantial right of the party
is affected,” Fed. R. Evid. 103(a), and errors that do not “affect substantial rights must be
disregarded.” Fed. R. Crim. P. 52(a). In a case involving non-constitutional evidentiary errors, we
read these rules of evidence and criminal procedure along with the federal harmless-error statute, 28
U.S.C. § 2111, which requires that “the court shall give judgment after an examination of the record
without regard to errors or defects which do not affect the substantial rights of the parties.” See
United States v. Guzman, 167 F.3d 1350, 1353 (11th Cir. 1999); United States v. Hernandez, 160
F.3d 661, 670 (11th Cir. 1998); United States v. Lankford, 955 F.2d 1545, 1556 (11th Cir. 1992);
United States v. Sellers, 906 F.2d 597, 601 (11th Cir. 1990). Errors do affect a substantial right of
a party if they have a “substantial influence” on the outcome of a case or leave “grave doubt” as to

45
whether they affected the outcome of a case. Kotteakos v. United States, 328 U.S. 750, 764-65, 66
S. Ct. 1239, 1248, 90 L. Ed. 1557 (1946). The exclusion of a portion of Tressel’s opinion testimony,
even if erroneous, did not affect Frazier’s substantial rights.

As we’ve repeated, the substance of the excluded portions of Tressel’s testimony was
presented to the jury through the testimony of other witnesses. Frazier argued vigorously that the lack
of hair and fluid evidence meant that there had been no rape and therefore no abduction. We
reiterate that the district court did not exclude all of Tressel's testimony. Indeed, it allowed him to
testify that a thorough investigation was performed; that no inculpatory evidence was recovered; that
hair is the evidence “most commonly found” in rape investigations; and that seminal fluids are
“frequently found in sexual assault cases,” especially when (as in this case) there is a claim that
multiple episodes of sexual activity occurred and no condom was used. Whatever impact the failure
to present this evidence through Tressel had on the outcome of the trial, Frazier cannot now
complain that his rights were violated, since it was his decision, not a ruling by the trial judge, that
kept Tressel from testifying at all.

Moreover, the excluded portion of Tressel’s opinion testimony was offered as secondary
evidence targeted solely at impeaching the victim’s credibility on her claim of rape, rather than being
offered as substantive evidence relating to Frazier’s guilt or innocence on the kidnapping charge.
The excluded opinion testimony related to whether Frazier raped the victim, not whether he
kidnapped her. Cf. United States v. Burroughs, 830 F.2d 1574, 1578-80 (11th Cir.1987) (effect of
withholding impeachment evidence not sufficiently prejudicial to merit new trial where sufficient
evidence of substantive guilt was presented and government’s witness was impeached through other
means). Nor was Frazier prevented from impeaching the victim’s credibility through other means,
and indeed, he took ample advantage of other opportunities to do so. The defense sought to
undermine the credibility of the victim’s account of kidnapping and rape by, among other things,
presenting evidence that she did not appear to be upset or afraid when she accompanied the
defendant when he purchased gasoline and cigarettes, nor, notably, did she try to escape; that she lit
a cigarette for Frazier while in the car; and that she did not initially tell police she had been raped
immediately after being removed from her car. Evidence was also offered establishing that the
victim was calm and did not appear upset when she was taken to the hospital. This evidence, when
combined with the undisputed presentation of facts that neither the defendant’s hair nor semen were
found on the victim’s person or in her car, provided Frazier ample opportunity to present to the jury
his basic defense that the victim had manufactured the entire account of abduction and rape.

Finally, the exclusion of some of Tressel’s opinion testimony (even if error) was harmless
because the other evidence of Frazier’s guilt was so substantial. See United States v. Fortenberry,
971 F.2d 717, 722 (11th Cir. 1992). The defendant’s own account of the night in question was
patently incredible and unbelievable, and Frazier’s account itself constituted substantive evidence
of his guilt. See United States v. Bennett, 848 F.2d 1134, 1139 (11th Cir. 1988) (observing that “a
defendant’s implausible explanation may constitute positive evidence in support of a jury verdict,”
and that where the defendant’s story was “dubious, if not wholly incredible . . . [a] reasonable jury

46
might well disbelieve the explanation and conclude that the [defendant was] lying in an attempt to
cover up illegal activities”). After his arrest, Frazier told the FBI that, after drinking beer all day
(indeed, after finishing off three 12-packs of beer by 6:00 that evening), he was sitting on a bench
in a Wal-Mart parking lot, when he was approached by an 18-year-old woman who was a complete
stranger, and who initiated a conversation with him, offering to give him a ride home. Frazier
claimed that, after driving out of the parking lot, the victim asked him to drive for awhile, in spite
of the fact that he was intoxicated and had told her he had no valid driver’s license. The defendant
also claimed that he did not pull over when her father tried to flag him down, and when the police
joined the lengthy, high-speed chase, because the victim directed him to do so. Plainly, the jury
could find this account wholly implausible.

Even leaving aside Frazier’s own dubious explanation of the events that Halloween night,
there was other substantial evidence from which the jury inferred his guilt. Frazier entered the
vehicle at Wal-Mart on the driver’s side and sat in the rear seat directly behind the victim, an action
consistent with an abduction under the threat of violence. Indeed, if the victim had volunteered to
give Frazier a ride, he likely would have sat in the front passenger seat. In addition, Frazier was
arrested carrying a knife locked in the open position, a development wholly consistent with the
victim’s account. We add that, given his intoxicated state, the very fact that he was driving
suggested he took control of the car by force and against the victim’s will. Finally, and perhaps most
importantly, Frazier’s long and harrowing flight from the police -- at speeds up to 100 miles per hour
-- was strong evidence of consciousness of guilt, as this Court has repeatedly held. See, e.g., United
States v. Blakey, 960 F.2d 996, 1000 (11th Cir. 1992) (evidence of flight is admissible to
demonstrate consciousness of guilt and thereby guilt itself); United States v. Beard, 775 F.2d 1577,
1581 (11th Cir. 1985) (evidence of flight can raise inference of consciousness of guilt); Monnette
v. United States, 299 F.2d 847, 851 (5th Cir. 1962) (flight from law enforcement officers is evidence
of guilt).

Thus, given the substantial evidence presented at trial from which Frazier’s guilt could be
inferred, and the exculpatory hair and semen testimony actually presented, we find it exceedingly
remote that the jury’s verdict would have been different even if Tressel’s “expectancy” opinion had
been admitted. Its exclusion did not have a substantial impact on the outcome of the case, nor are
we left with grave doubt that the case’s outcome was affected. Any claimed error was harmless.
See, e.g., United States v. Darwin, 757 F.2d 1193, 1204 (11th Cir. 1985); United States v. Vesey,
338 F.3d 913, 918 (8th Cir. 2003); United States v. Smith, 736 F.2d 1103, 1108 (6th Cir. 1984).

47
 IV.

A.

Frazier also claims that the district court’s decision to permit the testimony

of FBI investigators Lanning and Onorato -- while at the same time excluding

some of Tressel’s opinion -- was a fatal error. We remain unpersuaded.

Frazier makes three broad arguments in support of this claim. First, he says

that the government’s failure to provide notice of its intent to call Lanning and

Onorato violated the spirit and purpose of Rule 16 of the Federal Rules of

Criminal Procedure. Next, Frazier suggests that it was improper for the district

court to allow the government to use Lanning and Onorato as rebuttal witnesses.

Having excluded Tressel’s testimony, Frazier argues, there was nothing for

Lanning and Onorato to rebut. Finally, Frazier maintains that it was simply unfair

to allow the government to present evidence -- through Lanning and Onorato -- on

the very issue he was unable to offer evidence from Tressel.22

22
On appeal, Frazier has raised a fourth claim. He says that the trial court made no pre-
trial determination that Lanning and Onorato were qualified as experts, or for that matter, that their
opinions were reliable. However, at trial Frazier never objected to the testimony of Lanning and
Onorato as being unreliable, and never challenged their expert qualifications. Absent some objection
from Frazier as to the qualifications of Lanning and Onorato, or concerning the reliability of their
opinions, we review only for plain error the district court’s implicit determination that they were
qualified and their opinions were reliable. See Christopher v. Cutter Labs., 53 F.3d 1184, 1192 (11th
Cir. 1995) (absent objection to expert’s testimony, court of appeals reviews challenged testimony
only for plain error); see also Macsenti v. Becker, 237 F.3d 1223, 1231-32 (10th Cir. 2001) (decision
to admit expert testimony reviewed only for plain error when timely objections under Daubert are

48
 At trial, Frazier’s primary objection was that, absent notice, allowing the

testimony of Lanning and Onorato violated Rule 16 of the Federal Rules of

Criminal Procedure. The pertinent portion of Rule 16 provides:

At the defendant’s request, the government must give to the
defendant a written summary of any testimony that the government
intends to use under Rules 702, 703, or 705 of the Federal Rules of
Evidence during its case-in-chief at trial.

Fed. R. Crim. P. 16(a)(1)(G) (emphasis added). Our case law establishes that,

consistent with the plain language of the Rule, the government’s presentation of

rebuttal testimony without prior notice does not violate Rule 16, since the Rule’s

not made); McKnight v. Johnson Controls, Inc., 36 F.3d 1396, 1406-07 (8th Cir. 1994); 4
Weinstein’s Federal Evidence § 702.02[6][a] (“In the absence of an objection, rulings admitting or
excluding expert testimony without a reliability determination are reviewable only for plain error.”).

It is true that the trial judge did not make an explicit determination on the record as to
Lanning’s and Onorato’s qualifications, or concerning the reliability of their opinions, and doing so
may have been the better course here. Nevertheless, we are not persuaded that the district court,
when faced with no objection, was obliged to formally memorialize its determinations regarding
qualifications and reliability on the record. See, e.g., United States v. Locascio, 6 F.3d 924, 938-39
(2d Cir. 1993). Here, then, we examine the district court’s implicit rulings that Lanning and Onorato
were qualified and their opinions were reliable for plain error. We find plain error only where (1)
there is an error; (2) the error is plain or obvious; (3) the error affects the defendant’s substantial
rights in that it was prejudicial and not harmless; and (4) the error seriously affects the fairness,
integrity, or public reputation of a judicial proceeding. See United States v. Chisholm, 73 F.3d 304,
307 (11th Cir. 1996).

After reviewing the testimony offered by experts Lanning and Onorato, we conclude that the
district court did not commit plain error in failing to exclude their testimony because they were
unqualified or because their opinions were unreliable. As discussed supra, both Lanning and Onorato
demonstrated expert qualifications before offering any opinions, and provided specific and detailed
quantitative bases for their opinions, in marked contrast to Tressel. There was no error, let alone one
that was plain or obvious. Moreover, we can discern nothing that calls into question the fairness,
integrity, or reputation of the judicial proceeding.

49
notice requirements apply only to the government’s case-in-chief. See United

States v. Windham, 489 F.2d 1389, 1392 (5th Cir. 1974) (“Rebuttal witnesses are

a recognized exception to all witness disclosure requirements.”);23 see also United

States v. DiCarlantonio, 870 F.2d 1058, 1063 (6th Cir. 1989) (Rule 16 does not

require disclosure of expert rebuttal testimony not offered during government’s

case-in-chief); United States v. Barrett, 766 F.2d 609, 617 (1st Cir. 1985) (same);

United States v. Angelini, 607 F.2d 1305, 1308-09 (9th Cir. 1979) (same). Thus,

so long as this testimony was properly characterized as rebuttal, Rule 16 did not

require the government to give notice or a summary of the testimony.

Frazier argues, nevertheless, that the testimony of Lanning or Onorato is not

rebuttal because Tressel’s testimony was excluded and, thus, there were no

opinions for them to contradict. We disagree. We have explained that “[t]he

purpose of rebuttal evidence is ‘to explain, repel, counteract, or disprove the

evidence of the adverse party,’ and the decision to permit rebuttal testimony is one

that resides in the sound discretion of the trial judge.” United States v. Gold, 743

F.2d 800, 818 (11th Cir. 1984) (quoting United States v. Delk, 586 F.2d 513, 516

(5th Cir. 1978)); see also Luttrell v. United States, 320 F.2d 462, 464 (5th Cir.

23
The Eleventh Circuit has adopted as binding precedent the decisions of the former Fifth
Circuit rendered prior to October 1, 1981. Bonner v. City of Prichard, 661 F.2d 1206, 1209 (11th
Cir. 1981) (en banc).

50
1963) (“‘It is within the distinct office of rebuttal to explain, repel, counteract, or

disprove the evidence of the adverse party.’” (quoting Shepard v. United States, 64

F.2d 641, 642 (10th Cir. 1933))).

During his case-in-chief, Frazier’s counsel called Lanning and Onorato

(instead of Tressel) in order to establish that no hair or fluids matching Frazier’s

were found at the scene of the crime, after suggesting in opening statement that the

absence of this evidence meant that no sexual assault had taken place, and

therefore that the victim’s accounts of abduction and assault were not credible.24

24
In her opening statement, Frazier’s counsel explained that the defense hinged on
attacking the credibility of the victim’s story by suggesting, among other things, that the failure to
recover hair or fluid evidence implied the victim was lying. She said:

[I]n the end what it comes down to is going -- it’s going to be -- your decision is
going to be based on whether or not you believe [the victim] or don’t believe [the
victim].

....

Now, as we all know from common sense the -- if there has been a sexual
encounter, the lengthier the encounter, the more contained the area, the more likely
there is going to be some transfer of hair, some transfer of body fluids, things that for
you as jurors are important because if they exist, if they can be corroborated, it
corroborates [the victim’s] version of what happened. . . .

And after the fact . . . nothing is recovered that corroborates [the victim’s]
description of what happened.

. . . I submit to you . . . that when you hear all of the evidence in this case . . . you will
have not just a reasonable doubt, you will have a substantial doubt about what [the
victim] has told you happened on Halloween night last year.

R7 at 79-81.

51
The government offered the rebuttal testimony of Lanning and Onorato to explain

and attempt to counteract the viewpoint that the absence of finding hair or seminal

fluid meant no sexual assault had occurred.

We add that by introducing the fact that the investigators had failed to

recover any inculpatory hairs or bodily fluids, and arguing the significance of that

failure, Frazier plainly opened the door for the government to offer reliable

evidence that could help explain the significance of that failure. He cannot now

complain that the government stepped through that door and rose to the challenge

he presented. See United States v. Hall, 653 F.2d 1002, 1006 (5th Cir. Unit A

Aug. 1981) (“The underlying rationale [of rebuttal evidence] is that when the

defendant has opened the door to a line of testimony by presenting evidence

thereon, he cannot object to the prosecution’s accepting the challenge and

attempting to rebut the proposition asserted.” (citing Delk, 586 F.2d at 516)).

This was the purpose animating the government’s use of Lanning’s and Onorato’s

testimony, and the district court did not abuse its discretion in allowing the

testimony of Lanning and Onorato on rebuttal. No violation of Rule 16 has been

established on this record.

Frazier also argues that, regardless of whether there was any violation of the

terms of Rule 16, it was unfair to allow Lanning and Onorato to testify because

52
Tressel was not permitted to testify on the same point. Frazier says that if the

government was allowed to present evidence on an issue, he too should have been

afforded the same opportunity to do so. Frazier relies on United States v. Gaskell,

985 F.2d 1056 (11th Cir. 1993) for the proposition that a district court may abuse

its discretion when it excludes one party’s testimony on a critical issue while

allowing the other party to present evidence on the same issue.

Gaskell is inapposite and Frazier’s reliance upon it is misplaced. In Gaskell,

a panel of this Court ruled that the district court erred by excluding the expert

testimony of one party while allowing the other party to present expert testimony

on the same issue. However, in Gaskell, the district court’s reason for excluding

the testimony was the lack of relevance. We held that if testimony for one party

was relevant, testimony for the other party on the same issue would be relevant

and, if otherwise admissible, should not be excluded. See Gaskell, 985 F.2d at

1063 (“Any doubt as to the relevance of this evidence should have been resolved

in favor of Gaskell in light of the fact that the government’s expert was allowed to

opine [on the same subject]. ‘It is an abuse of discretion to exclude the otherwise

admissible opinion of a party’s expert on a critical issue, while allowing the

opinion of his adversary’s expert on the same issue.’” (quoting United States v.

Lankford, 955 F.2d 1545, 1552 (11th Cir.1992) (emphasis added))).

53
 Here, however, the government has not disputed that Tressel’s testimony

was relevant; rather, it objected and the district court ruled that some of Tressel’s

opinion testimony was not reliable, and for that reason inadmissible. Because the

district court did not abuse its discretion in finding the opinion unreliable, Gaskell

does not illuminate this case.

B.

Nor are we persuaded by Frazier’s broader claim that the aggregate effect of

the district court’s evidentiary rulings was to deny him “a meaningful opportunity

to present a complete defense.” California v. Trombetta, 467 U.S. 479, 485, 104

S. Ct. 2528, 2532, 81 L. Ed. 2d 413 (1984).

It is surely true that a defendant must be afforded the opportunity to present

a defense. Indeed, the right of the accused to assert a complete defense is well

established, and has its roots in the Fifth, Sixth, and Fourteenth Amendments to

the Constitution. The Supreme Court has explained:

Whether rooted directly in the Due Process Clause of the Fourteenth
Amendment, or in the Compulsory Process or Confrontation clauses
of the Sixth Amendment, the Constitution guarantees criminal
defendants a meaningful opportunity to present a complete defense.
We break no new ground in observing that an essential component of
procedural fairness is an opportunity to be heard.

54
Crane v. Kentucky, 476 U.S. 683, 690, 106 S. Ct. 2142, 2146-47, 90 L. Ed. 2d 636

(1986) (internal quotation marks and citations omitted). As the Court observed in

Chambers v. Mississippi: “[f]ew rights are more fundamental than that of an

accused to present witnesses in his own defense.” 410 U.S. 284, 302, 93 S. Ct.

1038, 1049, 35 L. Ed. 2d 297 (1973).

While the Constitution unquestionably provides a defendant with the right

to be heard, this right is not unbounded. Thus, “[t]he accused does not have an

unfettered right to offer testimony that is incompetent, privileged, or otherwise

inadmissible under standard rules of evidence.” Taylor v. Illinois, 484 U.S. 400,

410, 108 S. Ct. 646, 653, 98 L. Ed. 2d 798 (1988). A trial would not be

considered unfair because the defendant was prevented from offering perjured

testimony. See Nix v. Whiteside, 475 U.S. 157, 173, 106 S. Ct. 988, 997, 89 L.

Ed. 2d 123 (1986) (“Whatever the scope of a constitutional right to testify, it is

elementary that such a right does not extend to testifying falsely.”); Harris v. New

York, 401 U.S. 222, 225, 91 S. Ct. 643, 645, 28 L. Ed. 2d 1 (1971). Nor are an

accused’s constitutional rights necessarily violated because he was prevented from

introducing hearsay, see United States v. Pena, 527 F.2d 1356, 1362 (5th Cir.

1976), or from presenting otherwise relevant evidence that is privileged, such as

communications between a doctor and patient, a lawyer and client, or between a

55
husband and wife, see United States v. Brown, 634 F.2d 819, 830 (5th Cir. 1981)

(“The district court did not violate either [the defendant’s] Sixth Amendment right

to confront the witnesses against him or his Fifth Amendment right to due process

of law when it upheld [the] claim of marital privilege as a bar to the . . .

testimony.”). And courts may constitutionally preclude defendants from offering

otherwise relevant evidence if they fail to comply with procedural rules that

require notice to be given. See Michigan v. Lucas, 500 U.S. 145, 152-53, 111 S.

Ct. 1743, 1748, 114 L. Ed. 2d 205 (1991); Taylor, 484 U.S. at 417, 108 S. Ct. at

657. Thus, for example, a district court may constitutionally preclude an accused

from calling an alibi witness if he has failed to disclose the witness, as required

under Rule 12.1 of the Federal Rules of Criminal Procedure. See, e.g., Williams v.

Florida, 399 U.S. 78, 81-82, 90 S.Ct. 1893, 1896, 26 L. Ed. 2d 446 (1970) (finding

analogous state notice-of-alibi rule constitutional).

As the Supreme Court observed in Chambers, the accused, just like the

state, “must comply with established rules of procedure and evidence designed to

assure both fairness and reliability in the ascertainment of guilt and innocence.”

410 U.S. at 302, 93 S. Ct. at 1049; see also Crane, 476 U.S. at 690, 106 S. Ct. at

2146; United States v. Scheffer, 523 U.S. 303, 308, 118 S. Ct. 1261, 1264, 140 L.

56
Ed. 2d 413 (1998); Rock v. Arkansas, 483 U.S. 44, 55-56, 107 S. Ct. 2704, 2711,

97 L. Ed. 2d 37 (1987).

A policy which aims at preventing the use of unreliable or misleading expert

evidence in criminal trials is far from arbitrary. Accordingly, a court may

constitutionally enforce evidentiary rules to limit the evidence an accused (or for

that matter any party) may present in order to ensure that only reliable opinion

evidence is admitted at trial. “The Sixth Amendment does not confer the right to

present testimony free from the legitimate demands of the adversarial system; one

cannot invoke the Sixth Amendment as a justification for presenting what might

have been a half-truth.” United States v. Nobles, 422 U.S. 225, 241, 95 S. Ct.

2160, 2171, 45 L. Ed. 2d 141 (1975); see also United States v. Nixon, 418 U.S.

683, 709, 94 S. Ct. 3090, 3108, 41 L. Ed. 2d 1039 (1974) (“The ends of criminal

justice would be defeated if judgments were to be founded on a partial or

speculative presentation of the facts. The very integrity of the judicial system and

public confidence in the system depend on full disclosure of all the facts, within

the framework of the rules of evidence.”).

While the Federal Rules of Evidence -- notably Rule 702 -- aim to ensure

that the fact-finder weighs only sound and reliable evidence, it is also worth

repeating that a district court’s exercise of its gatekeeping responsibilities must not

57
“supplant the adversary system or the role of the jury.” Allison v. McGhan Med.

Corp., 184 F.3d 1300, 1311 (11th Cir. 1999); see also United States v. 14.38 Acres

of Land, More or Less Situated in Leflore County, Miss., 80 F.3d 1074, 1078 (5th

Cir. 1996) (“[T]he trial court’s role as gatekeeper is not intended to serve as a

replacement for the adversary system . . . .”). As the ultimate fact-finder, it is the

jury that must determine, finally, where the truth in any case lies, and the district

judge as gatekeeper may not usurp this function. See Fed. R. Evid. 102 (“These

rules shall be construed . . . to the end that the truth may be ascertained and

proceedings justly determined.”); Nix, 475 U.S. at 171, 106 S. Ct. at 996

(explaining that “governance of trial conduct” should aim at “what we have long

called ‘a search for truth’”). However, the trial judge’s role as gatekeeper is

designed to ensure that the jury, in carrying out its prescribed role, bases its

determinations on relevant and reliable evidence, rather than on speculation or

otherwise unreliable conjecture. These bedrock principles establish that, while a

criminal defendant must be given every meaningful opportunity to present a

complete defense, in doing so he must comply with the procedural and evidentiary

rules designed to facilitate a search for the truth.

Turning to the case at hand, Frazier’s right to put on a meaningful defense

did not include the unfettered and unreviewable opportunity to present all expert

58
opinion, even if it did not meet the basic requirements for admissibility found in

Rule 702. See Taylor, 484 U.S. at 410-11, 108 S. Ct. at 653-54. And we have

found that the district court acted well within its discretion in excluding some of

Tressel’s opinions.

Moreover, Frazier’s view that the exclusion of Tressel’s testimony denied

him a fundamentally fair trial must also fail because, as we’ve noted, the essence

of Tressel’s proposed testimony was admitted at trial through alternative means.

The basis for Tressel’s expectancy opinion -- that no transferred hair or fluid

evidence inculpating Frazier in the sexual assault was recovered -- was actually

admitted at trial through the testimony of FBI examiners Lanning and Onorato.

Tressel’s opinion that the recovery of hair or semen would be expected was argued

vigorously to the jury by Frazier’s counsel, who contended that the lack of

evidence suggested the victim’s story of rape had been manufactured, and

maintained that if the victim’s account of the sexual assault could not be believed,

then the jury could not believe her statement that she was kidnapped as well.

In short, the district court’s exclusion of some portions of Tressel’s opinion

testimony did not prevent Frazier from introducing the key elements of his defense

and placing his story before the jury. See Sheffield, 992 F.2d at 1170.

59
 V.

After painstaking review of this record we are satisfied that the district court

did not abuse its discretion, that is commit manifest error, in excluding a portion

of Tressel’s opinion testimony while allowing the government’s rebuttal evidence

on the same issue. Nor, finally, was this defendant denied a fair trial. Accordingly,

we affirm.

AFFIRMED.

60
TJOFLAT, Circuit Judge, specially concurring:

The critical issues in this appeal concern evidentiary rulings. Frazier

contends that the district court abused its discretion when it barred his expert,

Robert Tressel, from expressing his opinions (1) that “there is no forensic

evidence to substantiate the claim of rape in this case,” and (2) that, if the victim’s

claim of rape were true, “it would be expected that some transfer of either hairs or

seminal fluid would [have] occur[red].” Frazier also challenges the court’s

decision to permit two FBI forensic investigators, Karen Lanning and Anthony

Onorato, to testify on rebuttal that the absence of hairs and seminal fluid does not

mean that no rape occurred. I concur in the court’s holding that the district court

did not abuse its discretion in overruling Frazier’s objection to Lanning’s and

Onorato’s testimony.1 I also concur in the court’s affirmance of the district court’s

rejection of Tressel’s opinions. The analytical model I use in reaching this result,

however, differs from the model the court uses. Because the difference is

significant, an explanation is in order.

1
I also agree with the court’s conclusion that Frazier failed to object at trial to Lanning
and Onorato’s opinions on the ground that they were unreliable and therefore inadmissible under
Federal Rule of Evidence 702. See ante at 53 n.21. Finally, I agree with the court that if
examined for plain error, the district court’s failure to determine sua sponte whether these
opinions are reliable does not satisfy the first element of plain error: that an error occurred. Id. I
cannot imagine a situation in which a court of appeals would hold that a district court has a duty
to intervene on its own initiative and convene a Daubert hearing for the purpose of ascertaining
whether an about-to-be-introduced expert opinion is reliable.

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 I.

A.

I begin by observing what happens after a party objects to the introduction

of an expert witness’s opinion on the ground that the opinion is unreliable.2

Assume that the party explains why the opinion is unreliable,3 that the explanation

may have merit, and that the court, recognizing this possibility, convenes a

Daubert hearing.4 Whether the proffered opinion is reliable is a question of fact.

2
In the following hypothetical scenario, I assume that the expert is “qualified” and that
the proffered opinion is relevant—that is, it “will assist the trier of fact to understand the
evidence or to determine a fact in issue.” Fed. R. Evid. 702. Thus, I focus solely on the issue of
reliability.
3
In a criminal case, if the defendant, invoking his right under Federal Rule of Criminal
Procedure 16(a)(1)(G), has obtained “a written summary of any testimony that the Government
intends to use under Rules 702, 703, or 705 of the Federal Rules of Evidence,” the defendant
should be in a position to support his objection to the opinion of a government expert with an
explanation of why he believes the opinion is unreliable. Under this scenario, the government
would be entitled to reciprocal discovery under Federal Rule of Criminal Procedure
16(b)(1)(C)(i) and thus should be able to explain why it objects to the reliability of a defense
expert’s opinion. When, however, the opinion of an expert witness is proffered in rebuttal, the
objecting party may not be able articulate specific reasons for believing the opinion to be
unreliable. In this case, for example, because the Government called Lanning and Onorato in
rebuttal, Frazier had not obtained summaries of their testimony or the bases for any opinions they
might express. Consequently, he could not have been expected to provide a specific ground for
objecting to their opinions. Nonetheless, as the court’s opinion points out, see ante at 53 n.21,
Frazier made no objection based on Rule 702; his sole objection to Lanning and Onorato’s
testimony was based on his misguided argument that Rule 16 required the Government to give
him prior notice of what their testimony would be. The court therefore had no obligation to hold
a Daubert hearing before the Government elicited the testimony at issue.
4
See Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S. Ct. 2786, 125 L. Ed.
2d 469 (1993); see also Kumho Tire Co. v. Carmichael, 526 U.S.137, 119 S. Ct. 1167, 1175, 143
L. Ed. 2d 238 (1999) (holding Rule 702 imposes an obligation upon federal trial courts to ensure

62
It is an ultimate fact not susceptible to direct proof, so it must be inferred from

certain circumstantial facts, which the Supreme Court has referred to as “factors.”5

The proponent of the opinion has the burden of establishing the ultimate fact of

reliability by a preponderance of the evidence.6 The proponent satisfies that

burden by establishing to the trial court’s satisfaction circumstantial facts

sufficient to yield the inference that the opinion is reliable.

If the proponent does this, and the court thereafter finds the opinion reliable,

the court must admit the opinion unless it concludes that, though relevant and

reliable, the opinion’s probative value is “substantially outweighed” by the

that every item of expert testimony has “a reliable basis in the knowledge and experience of the
relevant discipline.” (alterations and quotations omitted)).
Of course, the procedural handling of an objection to proposed expert testimony is a
matter committed to the trial court’s discretion, and a formal Daubert hearing will not in all cases
be necessary. In some cases, an evidentiary hearing is unnecessary because the parties’
reciprocal submissions are sufficient to enable the court to resolve the reliability issue without
taking live testimony. See Kumho Tire, 526 U.S. at 152, 119 S. Ct. at 1176 (stating that trial
courts must retain the discretionary authority “both to avoid unnecessary ‘reliability’ proceedings
. . . and to require appropriate proceedings in the less usual or more complex cases where cause
for questioning the expert’s reliability arises”).
5
See, e.g., Kumho Tire, 526 U.S. at 153; 119 S. Ct. at 1176 (referring to the indicia of
evidentiary reliability suggested in Daubert as “the specific factors identified in Daubert” and
“Daubert’s specific factors”).
6
See Daubert, 509 U.S. at 592-93 & n.10, 113 S. Ct. at 2796 & n.10 (stating that the
reliability issue is to be decided by the trial court under Rule 104(a), and that an opinion’s
reliability must be proven by a preponderance of the evidence).

63
considerations outlined in Federal Rule of Evidence 403.7 If the proponent fails to

establish circumstantial facts sufficient to yield the inference that the opinion is

reliable, or the court, after weighing the facts the proponent has established, finds

that the opinion is unreliable, the opinion is inadmissible as a matter of law.8 Just

as a coerced confession is inadmissible because it lacks probative value as to the

issue of whether the defendant committed the criminal act to which he has

“confessed,” an unreliable opinion is inadmissible because it lacks probative value

as to the factual issue it addresses.

B.

Identifying the circumstantial facts, or factors, that are to serve as the indicia

of reliability in a given case is a matter committed to the trial court’s sound

7
Rule 403 provides,
Although relevant, evidence may be excluded if its probative value is substantially
outweighed by the danger of unfair prejudice, confusion of the issues, or
misleading the jury, or by considerations of undue delay, waste of time, or
needless presentation of cumulative evidence.
Fed. R. Evid. 403. We review a trial court’s exclusion of a relevant and reliable opinion
pursuant to this rule under the abuse-of-discretion standard. See Old Chief v. United States, 519
U.S. 172, 174 n.1, 117 S. Ct. 644, 647 n.1, 136 L. Ed. 2d 574 (1997).
8
In determining whether a circumstantial fact, or factor, exists, the court conducts in a
very real sense a miniature bench trial. The only difference between this bench trial and a bench
trial held under the Federal Rules of Procedure is that the Federal Rules of Evidence generally do
not apply. See Fed. R. Evid. 104(a) (“Preliminary questions concerning . . . the admissibility of
evidence shall be determined by the court . . . . In making its determination it is not bound by the
rules of evidence except those with respect to privileges.”).

64
discretion.9 In Daubert, the Supreme Court suggested that a trial court assessing

the reliability of proposed scientific testimony might consider, among others, the

following factors: (1) whether the theory or technique underpinning the expert’s

opinion “can be (or has been) tested”; (2) whether the theory or technique “has

been subjected to peer review and publication”; (3) whether, with respect to

particular theory or technique, there is a high “known or potential rate of error,”

and whether there are “standards controlling the technique’s operation”; and (4)

whether the theory or technique enjoys “general acceptance” within the “relevant

scientific community.” Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S.

579, 593-95, 113 S. Ct. 2786, 2796-97, 125 L. Ed. 2d 469 (1993). Kumho Tire

Co. v. Carmichael, 526 U.S.137, 119 S. Ct. 1167, 143 L. Ed. 2d 238 (1999),

clarified that these factors may be considered in determining the reliability of

nonscientific expert opinion testimony as well. General Electric Company v.

Joiner, 522 U.S. 136, 118 S. Ct. 512, 139 L. Ed. 2d 508 (1997), offered an

additional indicium of reliability: the analytical distance between the particular

opinion offered and the data, principles, and methods from which it is purportedly

9
See Kuhmo Tire, 526 U.S. at 153, 119 S. Ct. at 1176 ([W]hether Daubert’s specific
factors are, or are not, reasonable measures of reliability in a particular case is a matter that the
law grants the trial court broad latitude to determine.”). Put another way, it is the trial court’s
task to decide which factors are relevant to the opinion’s reliability.

65
derived.10 The factors relied upon to test reliability, however, must be “tied to the

facts of the particular case,” Kumho Tire, 526 U.S. at 150, 119 S. Ct. at 1175

(quotations omitted), and the trial court has “broad latitude” to determine which

are appropriate indicia of reliability. Id. at 153, 119 S. Ct. at 1176.

C.

Understanding the model for determining the reliability of an expert’s

opinion sheds considerable light on the operation of the standard a court of appeals

employs in reviewing the trial court’s ruling on the opinion’s admissibility. We

review a trial court’s decision admitting or excluding evidence for “abuse of

discretion,” Old Chief v. United States, 519 U.S. 172, 174 n.1, 117 S. Ct. 644, 647

n.1, 136 L. Ed. 2d 574 (1997); United States v. Abel, 469 U.S. 45, 54-55, 105 S.

10
Joiner clarified that, though the focus of the reliability inquiry “must be solely on
principles and methodology, [and] not on the conclusions they generate,” Daubert, 509 U.S. at
595, 113 S. Ct. at 2797, “conclusions and methodology are not entirely distinct.” Joiner, 522
U.S. at 146, 118 S. Ct. at 519. Thus, even when an expert is using reliable principles and
methods, and is extrapolating from reliable existing data, “[a] court may conclude that there is
simply too great an analytical gap between the data and the opinion proffered.” Id. “[N]othing in
either Daubert or the Federal Rules of Evidence requires a district court to admit opinion
evidence that is connected to existing data only by the ipse dixit of the expert.” Id. This
consideration has been incorporated into the text of the amended Rule 702, which requires not
only that “the testimony [be] the product of reliable principles and methods”—the focus of the
specific considerations offered in Daubert—but also that “the testimony [be] based upon
sufficient facts or data,” and that the witness be shown to have “applied the [reliable] principles
and methods reliably to the facts of the case.” Fed. R. Evid. 702.

66
Ct. 465, 470-71, 83 L. Ed. 2d 450 (1984), and this is true when we review rulings

admitting or excluding the testimony of expert witnesses under Rule 702.11 See

Joiner, 522 U.S. at 146, 118 S. Ct. at 519; Kumho Tire, 526 U.S. at 152, 119 S. Ct.

at 1176. A trial court abuses its discretion in making an evidentiary ruling “if it

misapplies the law or makes findings of fact that are clearly erroneous.” E.g.,

Kelley v. Sec’y for the Dep’t of Corr., 377 F.3d 1317, 1333 (11th Cir. 2004).12

What would a reviewing court say if the trial court, in determining whether

an expert’s opinion was reliable, based its finding on irrelevant factors?13 The

11
Rule 702 provides,
If scientific, technical, or other specialized knowledge will assist the trier of fact
to understand the evidence or to determine a fact in issue, a witness qualified as an
expert by knowledge, skill, experience, training, or education, may testify thereto
in the form of an opinion or otherwise, if (1) the testimony is based upon
sufficient facts or data, (2) the testimony is the product of reliable principles and
methods, and (3) the witness has applied the principles and methods reliably to the
facts of the case.
Fed. R. Evid. 702.
12
We apply the same standard in reviewing the admission or exclusion of expert opinion
testimony. See, e.g., Oddi v. Ford Motor Co., 234 F.3d 136, 146 (3rd Cir. 2000) (“We afford a
district court's application and interpretation of Rule 702 plenary review, but we review the
court's decision to admit or reject testimony under an abuse of discretion standard. An abuse of
discretion arises when the district court's decision rests upon a clearly erroneous finding of fact,
an errant conclusion of law or an improper application of law to fact.” (quotations and citations
omitted)); Westberry v. Gislaved Gummi AB, 178 F.3d 257, 261 (4th Cir. 1999) (stating, in
reviewing a Daubert ruling, that “[a] district court abuses its discretion if its conclusion is guided
by erroneous legal principles, or rests upon a clearly erroneous factual finding” (citations
omitted)).
13
If, for example, a court were to exclude an expert’s opinion on the ground that the
expert has red hair, it would be a clear abuse of discretion. The reason, of course, is that the
expert’s hair color has no logical relevance to, and therefore lacks probative value on, the

67
answer is obvious. The reviewing court would say that the trial court misapplied

the law and therefore abused its discretion.14 What would the reviewing court say

if the trial court based its reliability finding on crucial circumstantial fact findings

that were clearly erroneous? Again, the answer is obvious. The reviewing court

would say that the trial court’s reliability finding amounted to an abuse of

discretion because it was based on clearly erroneous findings of crucial

circumstantial facts.15

II.

reliability of his opinion.
14
The same would be true if the district court ignored factors that were plainly crucial to
the reliability determination. I cannot imagine upholding a determination of the reliability of
expert scientific testimony when the trial court ignored every consideration specified by the
Supreme Court in Daubert. Indeed, in ruling on the admissibility of scientific testimony, the trial
court might abuse its discretion if it failed to consider any of the considerations outlined in
Daubert. See Kumho Tire, 526 U.S. at 152, 119 S. Ct. at 1176 (“[W]e conclude that the trial
judge must have considerable leeway in deciding in a particular case how to go about
determining whether particular expert testimony is reliable. That is to say, a trial court should
consider the specific factors outlined in Daubert where they are reasonable measures of the
reliability of expert testimony.”); id. at 159, 119 S. Ct. at 1179 (Scalia, J., dissenting) (“Though,
as the Court makes clear today, the Daubert factors are not holy writ, in a particular case the
failure to apply one or another of them may be unreasonable, and hence an abuse of discretion.”).
15
The foregoing responses to the question, “What would the reviewing court say?”
assume that the trial court’s decision to admit or to exclude the expert’s opinion could have
“affected” the complaining party’s “substantial rights” See Fed. R. Evid. 103(a). It goes without
saying that the potential for undue prejudice—that is, for the denial of a party’s substantial
rights—should inform the trial court’s decisions as to the timing and scope of the Daubert
hearing and the need for explicit findings of fact.

68
 With this model for determining the reliability of expert opinion testimony in

mind, I turn to the question of whether the district court abused its discretion in

barring Frazier’s expert, Robert Tressel, from testifying to the two opinions at issue

in this appeal.

Frazier sought to use Tressel, now a private forensic investigator, for the

purpose of challenging the veracity of the victim’s claim that Frazier forced her

into sexual intercourse and, thereby, her credibility as to whether she had been

kidnaped. Tressel proposed to summarize the findings of the FBI’s forensic

investigation of the car and the victims clothes, as well as the records of a medical

examination of the victim, and to offer three opinions: (1) that “a thorough forensic

investigation and a thorough rape examination of the victim . . . were performed”;

(2) that “there is no forensic evidence to substantiate the claim of rape in this case”;

and (3) that “it would be expected that some transfer of either hairs or seminal fluid

would [have] occur[red]” if the victim’s account were true.16 Thus, Tressel sought

to move analytically from the thoroughness of the investigation, the absence of

16
I quote from the report Tressel prepared for Frazier’s attorney (the “report” or the
“expert report”), Defendant’s Exibit 2, because it was on this report that the district court based
its rulings. In his report, Tressel also stated: “The resulting laboratory findings in this case[] do
not substantiate the claim of rape through forensic evidence.” At the Daubert hearing, Tressel
said: “I see no forensic evidence to substantiate the claim of rape in this case.” He also said:
“[T]here should have been some transfer of either hairs, fibers or fluids between the victims [sic]
in this case.”

69
forensic evidence, and his opinion that such evidence would be “expected” if the

victim’s claims were true, to the implication that some hair or seminal fluid should

have been, but was not, recovered, and that the rape therefore never occurred.17

This, in turn, was meant to impugn the credibility of the victim, whose testimony

provided the primary foundation for the kidnaping charge.

The district court allowed Tressel to offer all of his proposed testimony

except two of his ultimate opinions: that there was no forensic evidence to

substantiate the claim of rape, and that the transfer of some hairs or fluids would

have been “expected” if the victim’s claim were true. It is the exclusion of these

opinions that Frazier now questions.

The district court did not abuse its discretion in excluding these opinions.

The court correctly identified as crucial to the reliability of both opinions

circumstantial facts that Tressel either did not attempt or was not qualified to

establish, and Frazier offered no supplementary proof to establish these facts.

Thus, Frazier failed to prove by a preponderance of the evidence that these two

17
In fact, at the Daubert hearing, Tressel’s ultimate opinion was elicited with the
question, not whether the claim of rape was supported by forensic evidence, but whether, in
Tressel’s opinion, the rape occurred. Defense counsel asked, “[B]ased on the information I
provided to you, do you have an opinion about whether or nor a rape occurred in this case?”
Tressel responded, “I do. I see no forensic evidence to substantiate the claim of rape in this
case.”

70
opinions were reliable, and the court implicitly found them unreliable. Because the

court’s findings that Tressel’s opinions were unreliable were not clearly erroneous,

the exclusion of these opinions was not an abuse of discretion.

A.

I first address the district court’s ruling excluding Tessel’s opinion that he

saw “no forensic evidence to substantiate the claim of rape in this case.” The

obstacle Frazier had to overcome to establish the reliability of this opinion was

Tressel’s inability to negate the inculpatory power of one item of “forensic

evidence” that squarely corroborated the victim’s story: bruising to and

discoloration of the victim’s genital area discovered during a medical examination

conducted shortly after she and Frazier were pulled from her wrecked automobile.

To overcome this obstacle, Tressel attempted to provide an explanation for this

bruising and discoloration that would not inculpate Frazier.

Tressel stated in his expert report, and proposed to testify at Frazier’s trial,

that “[t]he documented finding of bruising around the labia major indicates that the

bruising may be substantially older than only a few hours,” and that “[t]he only

indication that any type of sexual activity occurred, . . . the redness around the labia

71
major and the redness of the cervix . . . . can occur during routine normal sexual

activity.” Tressel implied that the bruising and discoloration was caused by sexual

intercourse between the victim and her boyfriend, which, according to the victim’s

medical records, had occurred two days before the alleged kidnaping.18

On cross-examination, however, Tressel acknowledged that he was not a

physician and had no experience in the medical field. He had no training in pelvic

examinations of sexual assault victims, nor had he examined the victim in this case.

The district court reasonably (indeed, necessarily) recognized that the reliability of

Tressel’s “no forensic evidence” opinion was, as Tressel had presented it in his

report, dependent on the establishment of the fact that someone other than Frazier

18
For his opinion that there was that there was no forensic evidence to substantiate the
claim of rape, Tressel relied upon the following circumstantial facts:

All findings of the samples that were taken, all of which are essentially routine
rape investigation procedures, were negative in finding a transfer of seminal fluid
or hair from the defendant in this case. The medical examination of the victim
only shows evidence of sexual activity on the part of the victim at some time prior
to the examination taking place. The documented finding of bruising around the
labia major indicates that the bruising may be substantially older than only a few
hours.

Based on my review of the available documents, it is my professional opinion that
there is no forensic evidence to substantiate the claim of rape in this case. The
only indication that any type of sexual activity occurred is the redness around the
labia major and the redness of the cervix. These two injuries, in and of
themselves, can occur during routine normal sexual activity. [The alleged
victim’s] medical records indicate that she had sexual intercourse on 10/29/00.

Def. Ex. 2, at 2-3.

72
caused the genital bruising and discoloration. The court ruled that Tressel could

not testify as to the cause of the bruising and discoloration because he was not

qualified to do so; a physician would have to provide that testimony.19 Frazier

proffered no such testimony.20 Because Frazier failed to present competent

evidence of a circumstantial fact the court deemed essential to the admissibility of

Tressel’s opinion, the court excluded the opinion. Although the court did not make

an explicit finding that Tressel’s opinion was unreliable, it made an implicit finding

to that effect. Because that implicit finding is not clearly erroneous, it cannot be

said that excluding the opinion constituted an abuse of discretion.21

19
The court said, “I am not going to allow him to testify about the bruising. I would a
medical doctor but not a witness with these credentials, and particularly one who did not conduct
the examination.” This ruling was later reiterated:

[T]he primary evidence is going to produce negative reports in every area but one,
and that’s the question of the bruising. . . .
I am not going to allow him to testify in his opinion those bruises were old
or something. I just think that is not a field of his expertise. You have to have a
medical opinion given on that . . . .

20
If Frazier had proffered a physician’s (or other qualified expert’s) opinion that the
victim’s sexual intercourse two days earlier probably caused the bruising and discoloration,
defense counsel could have asked Tressel to assume the validity of the opinion and then asked
him whether, in light of that opinion and his experience as a forensic investigator, he had an
opinion regarding the presence or absence of forensic evidence of rape. Had this taken place, I
suggest that the court would have permitted Tressel to give the opinion at issue.
21
The court treats Tressel’s opinion that there was “no forensic evidence to substantiate
the claim of rape” as Tressel’s ultimate opinion—that is, as one built on his other opinions,
including that hair or fluid transfers “would be expected” if the victim’s claims were true. See
ante at 48 n.18. The court concludes that the district court properly excluded Tressel’s “no

73
 B.

Frazier also challenges the district court’s exclusion of Tressel’s opinion

that, given the circumstances of the alleged rape, some transfer of hairs or seminal

fluid between Frazier and the victim would have been expected.22

To support his opinion, Tressel purportedly relied on his extensive

experience in forensic investigations, including investigations of sexual assaults,

and several abstract factual propositions about the types of evidence found in

sexual assault investigations and the factors affecting the likelihood of transfer and

recovery. These abstract factual propositions are actually inferences that Tressel

drew from a combination of (vaguely identified) law enforcement texts and his

professional experience and training.23 I number them for convenience:

forensic evidence” opinion because it relied upon Tressel’s “expectancy” opinion, which the
district court properly excluded as unreliable. But Tressel’s statement that there was “no forensic
evidence to substantiate the claim of rape” is not, on its own terms, dependent on any
foundational opinions about what forensic evidence one would have expected to find at the crime
scene. Tressel did not offer the opinion that the victim had lied, that no rape had occurred, or
even that the lack of forensic evidence contradicted the victim’s story. He testified only that
there was no forensic evidence to substantiate the victim’s claim, and this statement was
dependent only on his finding that no fibers, hairs, or seminal fluids were recovered and his
ability to explain away the victim’s bruising.
22
The record is silent as to whether any hairs or seminal fluid was found on Frazier’s
clothing or body following his arrest. Apparently, only the victim, her clothing, and her car were
examined for such evidence.
23
The law enforcement texts and the information Tressel gleaned from investigating
sexual assaults provided him with the circumstantial evidence from which he inferred the
abstract factual propositions. These propositions, in turn, served as the circumstantial facts for

74
 (1) “The forensic evidence most commonly found during the analysis of a
rape investigation is the transfer of hairs from the victim to the perpetrator
and from the perpetrator to the victim.”
(2) “These hairs are routinely pubic hairs that become transferred [sic]
during sexual intercourse.”
(3) “Head hairs can also be transferred during sexual assault and can be
found in the clothing of the victim and the perpetrator.”
(4) “Seminal fluids are frequently found in sexual assault cases, especially
when multiple episodes of sexual activity occur and no condom is used by
the perpetrator. These fluids can be found not only in the orifices of the
victim, but also on the clothing worn by both the victim and the perpetrator.”
(5) “The smaller crime scene, the more likelihood [sic] that you are going to
find evidence to support a claim.”
(6) “The number of sexual encounters that occur between a suspect and
victim raises the likelihood of some transfer of forensic evidence.”

Tressel apparently combined these circumstantial facts with the “very confined

area” in which the rape allegedly occurred, the quantity and duration of the sexual

acts it involved, and the lack of any mention of a condom being used to conclude

that hair or seminal fluid transfers “would be expected” or “should” have occurred.

What troubled the court about Tressel’s “expectancy” opinion was that

Tressel was unable to indicate the frequency with which hairs and seminal fluid

transfers occur in sexual assault cases and, in particular, cases like the one at hand.

Tressel could not testify to such frequency from his own experience, and he was

the ultimate inference Tressel drew—that is, that one would have “expected” that hair or seminal
fluid transfers would have been recovered during the investigation of the rape that allegedly
occurred in this case.

75
unable to cite any published findings on the subject. Without some indication of

the frequency with which hairs and seminal fluid are transferred during sexual

assaults, the court concluded, it could not find reliable Tressel’s opinion that hair or

seminal fluid transfers “would be expected” or “should” have occurred in this case.

In my view, the court acted well within its discretion in placing great weight on this

frequency factor. Thus, when Frazier failed to provide that missing link, the court

was fully justified in striking Tressel’s opinion as unreliable.

The court’s focus on the transfer rates for hair and seminal fluid was entirely

reasonable because Tressel’s “expectancy” opinion was not permissibly inferable

from the circumstantial facts upon which he purportedly based it, and the most

obvious gap in Tressel’s reasoning was his inability or unwillingness to say how

often hairs and seminal fluid are transferred between victim and perpetrator during

sexual assaults. Tressel’s “expectancy” opinion expresses an estimate of absolute

probability. At minimum, it implies that, given the events alleged by the victim, it

is more likely than not—that is, there is more than a fifty-percent chance—that a

transfer would have occurred.24 Most of the propositions upon which Tressel

24
I do not agree with the court that the ambiguity of the phrase “would be expected” in
any way affects the reliability of Tressel’s opinion. Lack of precision in expert testimony might
properly form the basis for its exclusion, but such a ruling would be made under Rule 403, not
under the reliability requirement of Rule 702. There is no requirement that experts use precise,
as opposed to general, statements of probability. Indeed, Tressel would have only guaranteed the

76
relied, however, are statements of relative probability—that is, that a substance is

more or less likely to be found under particular circumstances than others, or that

one substance is more or less likely to be found than another. Without knowing the

baseline at which we start—the average rates of transfer for hair and seminal fluids,

generally or under particular circumstances—these propositions cannot support a

statement of absolute probability like the one Tressel made. It helps none, for

example, to know that the forensic evidence “most commonly” found is the transfer

of hairs, or that hairs and seminal fluid are “more likely” to be found if the crime

scene is small or if multiple incidences of sexual contact occur; since we do not

know the baseline probabilities, we cannot say whether “most commonly” or “more

exclusion of his testimony on reliability grounds had he opined that there was a specific
percentage chance that hairs or seminal fluid would have been transferred in this case, since it is
patently impossible to state such an estimate with any confidence. That Tressel phrased his
probability estimate in general terms made it much more likely that the estimate could have a
basis in his experience as a forensic investigator.
Similarly, I do not agree that Tressel’s opinion could have properly been excluded under
Rule 702 on the ground that it does not “assist the trier of fact to understand the evidence or to
determine a fact in issue” because “Tressel’s imprecise opinion easily could serve to confuse the
jury, and might well have misled it.” Ante at 49. As the Supreme Court made clear in Daubert,
the requirement that expert testimony “assist the trier of fact” “goes primarily to relevance,” 509
U.S. at 591, 113 S. Ct. at 2795; it is not a requirement that expert testimony be given in specific
and certain terms. Again, if the ambiguity of expert testimony, and its concomitant potential to
confuse the jury, is to form the basis for its exclusion, this ruling would properly be made under
Rule 403, not Rule 702.
On the other hand, neither do I agree with Judge Birch’s characterization of Tressel’s
opinion as “qualitative.” In expressing his opinion that hairs or seminal fluid “should have been”
transferred or that some transfer “would be expected,” Tressel was making an inherently
probabilistic statement. At minimum, it suggested that it was “more likely than not” (i.e.,
something more than a fifty percent chance) that such transfers would have taken place. Such a
statement is general, and non-numerical, but it is certainly not “qualitative.”

77
likely” could be enough to move the probability of finding hairs or seminal fluids

in a particular case over the fifty-percent boundary. In other words, without some

indication of transfer rates, the court was unable to gauge whether it is possible for

Tressel or any other expert to conclude that under a particular set of specific

circumstances, one would “expect” to find hair or seminal fluid transfers.

Some of the factual propositions upon which Tressel relied—for example,

that seminal fluid is “frequently” found, or that head hairs “can” be found on the

perpetrator’s clothing—are statements of absolute probability, but they do not

logically get us near the fifty percent mark. “Can” necessarily connotes only a bare

possibility (something over one percent), and though “frequently” suggests

something more, it does not connote “usually” or “most of the time” or in any way

suggest that something happens “more often than not.”

Logically, then, the factual propositions Tressel relied upon, even if

inferrable,25 could not support his statement that hair or seminal fluid transfers

25
See supra note 23. I emphasize “if.” I have grave doubts about whether Tressel
established the reliability of even the circumstantial facts upon which his opinion was
purportedly based. On cross-examination, Tressel vaguely identified three texts, none of which
were produced for the court: “Practical Aspects of Rape Investigation by Robert Hazelwood,” “a
forensic science handbook by Dr. Saperstein,” and “Crime Scene Search and Physical Evidence
Handbook by Carl Cunningham, United States Government Printing Office, 1973.” Contrary to
Judge Birch’s suggestion, however, see post at 5 n.3, Tressel did not “rely upon” these texts: he
neither quoted from nor cited specific portions of them, nor did he provide excerpts for the
district court to examine. The court consequently had no basis on which to conclude that they
supported his testimony. Nor do these sources, to the extent they are identifiable, support

78
should have occurred, much less the implication the jury was to draw from this

evidence, that hairs or seminal fluid should have been recovered.26 Instead, the

circumstantial fact upon which the reliability of Tressel’s opinion turns is the rate

at which hairs or seminal fluid are transferred from the perpetrator and the victim.

Without some evidence in this regard—whether from scientific studies or from

Tressel’s testimony. The one text he clearly identified, Practical Aspects of Rape Investigation,
does say that “hairs, fibers, blood, semen, and saliva appear with frequency in sexual assault
cases,” and that “[t]he type of evidence most frequently associated with sexual assault
investigations is semen.” See Practical Aspects of Rape Investigation 111 (Robert R. Hazelwood
& Ann Wolbert Burgess ed., 1987) (emphasis added). But Tressel said neither of these things.
Instead, he said that hairs transferred between victim and perpetrator are the forensic evidence
“most commonly found,” that such hairs are “routinely” public hairs, and that seminal fluids are
“frequently found” (emphasis added). Even assuming that “found with frequency” is
synonymous with “frequently found,” the quoted portions of text do not support the notion that
the evidence “most commonly found” is hairs transferred between victim and perpetrator.
In any event, the court did not preclude Tressel from making these foundational
statements, but instead precluded him from testifying that either hairs or seminal fluid “would be
expected” in this particular case, an opinion that is an analytical chasm away from hairs and
seminal fluid being “frequently found” in sexual assault cases generally. Among other patent
logical gaps, Tressel never explained how his ultimate opinion was affected by the victim’s claim
that Frazier never ejaculated, nor did he account for the fact that the search for forensic evidence
included the victim, her clothing, and the car, but not, apparently, Frazier or his clothing. Even if
the circumstantial facts upon which Tressel relied are entirely true, and Tressel had shown them
to be so, they would not establish the reliability of his opinion that some hairs or seminal fluid
“would be expected” in this case.
26
Though Frazier did not object to the reliability of the testimony offered by the
Government’s experts, Karen Lanning and Anthony Onorato, it bears noting the substantial gap
between their testimony and Tressel’s proffered opinion. Lanning and Onorato offered (1)
estimates of how often, in their experience, hair or seminal fluid evidence is recovered in sexual
assault investigations, and (2) their opinion that the absence of such evidence does not
necessarily mean that no assault occurred. Neither purported to say that, given these preliminary
propositions and the facts of this particular case, one would not have “expected” to find hair or
seminal fluid.

79
Tressel’s personal experience, whether in the form of specific figures or general

probabilities, and whether in sexual assault cases generally or in cases similar to

this one—the court had no basis on which to find that Tressel’s opinion was

reliable.

Yet Frazier produced no evidence on this point. On cross-examination at the

Daubert hearing, the Government repeatedly invited Tressel to explain how his

experience informed his “expectancy” opinion. Tressel pointed only to one case he

had investigated in which the head hair and pubic hair of a serial rapist was found

on four of the rapist’s victims, drawing no comparison between the facts of that

case and those of this one. He offered no general observations about the frequency

with which, in his experience, either hair or seminal fluid is transferred or

recovered, much less the frequency of transfers in cases involving multiple

episodes of unprotected sexual contact, and he stated that he was unaware of any

studies that could provide this information. Because Frazier failed to produce any

evidence on the circumstantial fact the court reasonably found crucial to the

reliability of Tressel’s “expectancy” opinion, the court correctly excluded the

opinion.27

27
It is true that the Government did not ask Tressel if he could state the frequency with
which, in his own experience, seminal fluid or hair is found, and that the Government focused
primarily on whether there was any “scientific literature” to support Tressel’s probability

80
 Frazier argues that the district court required that the opinion be based on

published, scientific studies or scientific expertise that Tressel did not possess, and

he sees this as evidence of a mistake of law—that is, that the court incorrectly

assumed that Rule 702 requires that an opinion like Tressel’s have scientific

foundations. The district court did not, however, find Tressel’s opinion unreliable

because it had no grounding in scientific studies; it found the opinion unreliable

because Frazier, who had the burden of proof, offered no evidence—experience-

based or otherwise—on the factual issue the court correctly identified as central to

the reliability of the opinion. To ask whether there are studies validating part of the

testimony of a skill- or experience-based expert is not improperly to require that the

testimony rest on scientific foundations or that the expert have scientific expertise.

See Kumho Tire, 526 U.S. at 157, 119 S. Ct. at 1178 (“Nor, despite the prevalence

of tire testing, does anyone refer to any articles or papers that validate Carlson’s

approach.”). When the expert’s experiences have not alone been shown to be

capable of providing a sufficient foundation for a particular opinion, corroboration

from somewhere—whether in the opinions of other experience-based witnesses or

statement. But the Government did not have the burden of proving that Tressel’s opinion was
not grounded in his experience. Rather, Frazier, as the proponent of the opinion, bore the burden
of establishing that the opinion was reliable. If Tressel was prepared to offer a probability
statement from his own experience, whether specific (e.g., that he finds hairs in 75% or even
51% of his investigations) or general (e.g., that hairs are “usually” found), it was Frazier’s
obligation to put that forward.

81
in published, scientific studies—is necessary to establish the opinion’s reliability.

The district court made an implicit finding that Tressel had not sufficiently

established how his experience led him to the opinion he offered. It then went on

to require that, in the absence of such evidence, Frazier show that the opinion had

some support in scientific literature. Requiring that the proponent of an expert

opinion provide some basis for a determination that the opinion is reliable is never

an abuse of discretion.

III.

In summary, the model for reviewing a trial court’s finding as to the

reliability of an expert opinion requires that we uphold the finding unless the court

abused its discretion in reaching it—that is, unless the court misapplied the law or

based its finding on a clearly erroneous finding as to one or more circumstantial

facts crucial to a finding of reliability. Keeping these points in mind, I think it

clear that the district court did not abuse its discretion in arriving at its findings that

Tressel’s opinions—that “there is no forensic evidence to substantiate the claim of

rape in this case” and that if the victim’s claim of rape were true, “it would be

expected that some transfer of either hairs or seminal fluid would [have]

82
occur[red]”—were unreliable. Frazier simply failed to establish by a

preponderance of the evidence the circumstantial facts that the court, in the

exercise of its discretion, identified as crucial and highly relevant indicia of

reliability. Because the district court did not abuse its discretion in the manner in

which it resolved the reliability issues, and because the court’s findings as to the

opinions’ reliability were not clearly erroneous, the court was bound to exclude

them. Indeed, the court would have abused its discretion had it permitted the jury

to hear them.

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BARKETT, Circuit Judge, concurring:

I concur in the majority opinion and find exceedingly useful its parsing of

the methodology for admitting expert testimony that is based on experience. As the

dissent accurately notes, the requirements of qualification and reliability are “often

blurred in the case of experience-based expert testimony.” Birch Dissent at *111.

That is precisely what the majority now clarifies and will not permit. The

reliability prong is not to be “subsumed” by the qualification prong – “the

reliability criterion remains a discrete, independent, and important requirement for

admissibility.” Majority Op. at *33.

While experience may be sufficient to qualify a person as an expert, the ipse

dixit of an expert in a given field is simply not enough to establish the reliability of

a particular opinion. Id. The majority makes clear that where a witness relies

solely or primarily on experience, then the witness must explain how
that experience leads to the conclusion reached, why that experience is
a sufficient basis for the opinion, and how that experience is reliably
applied to the facts. The trial court’s gatekeeping function requires
more than simply ‘taking the expert’s word for it.’

Id. (quoting Fed. R. Evid. 702 advisory committee’s note (2000 amends.)).1

1
As the dissent notes, past cases have not always explicitly required more than mere
experience in order to establish the reliability of a specific opinion in cases involving physicians,
valuation experts, handwriting analysts, police officers, and so forth. Yet, as the majority makes
clear, courts must always take care to establish (1) how the expert’s specific experience leads to

84
 I agree that the district court properly excluded Tressel’s testimony because

he failed to establish how his experience led to the specific conclusion that “it

would be expected that some transfer of either hairs or seminal fluid would occur.”

R5 at 24, Ex. 2 at 2. Indeed, the only support Tressel offered to validate his claim

was that in one rape case he worked on he “identified head hair and pubic hair” of a

serial rapist on four victims. R5 at 37-38.2 Had the government’s expert witnesses

similarly failed to establish how their experience led to their conclusions, the court

would have been compelled to exclude their testimony as well.3 However, as the

majority points out, the government witnesses provided specific and detailed

quantitative bases for their opinions. Thus, the district court acted within its

discretion.

the conclusion reached; (2) why the expert’s experience is a sufficient basis for the opinion; and
(3) how the expert’s experience is reliably applied to the facts. Majority Op. at *33.
2
Tressel also asserted that this conclusion was derived from his knowledge of scientific
literature but admitted that he “doesn’t think anybody has ever studied the rates of transfer.” R5
at 37.
3
Obviously, a trial court would abuse its discretion in admitting the testimony of only one
side’s expert, where the experts on both sides proffer testimony that is equally reliable. United
States v. Gaskell, 985 F.2d 1056, 1063 (11th Cir. 1993) (per curiam) (“It is an abuse of discretion
to exclude the otherwise admissible opinion of a party’s expert on a critical issue, while allowing
the opinion of his adversary’s expert on the same issue.”) (internal punctuation omitted).

85
BIRCH, Circuit Judge, dissenting:

For the reasons that follow, I respectfully dissent. This is the classic case

that law students study to understand the adage “hard facts make bad law.” Those

hard facts (the majority calls it a “sad case” and a “crime of unspeakable brutality”)

have caused the trial court and a majority of this court to elevate an evidentiary

rule, improperly administered, over a criminal defendant's basic right to “present

his own witnesses to establish a defense. This right is a fundamental element of

due process of law.” Washington v. Texas, 388 U.S. 14, 19, 87 S. Ct. 1920, 1923

(1967); Chambers v. Mississippi, 410 U.S. 284, 302, 93 S. Ct. 1038, 1049 (1973)

(“Few rights are more fundamental than that of an accused to present witnesses in

his own defense.”). As demonstrated below, the exclusion of the defense's expert

“gutted” its only viable defense. See, infra, notes 6 & 10. And, while the trial

court is indeed vested with broad discretion in ruling upon the relevancy and

admissibility of evidence, we have appropriately, until this case, held that “[s]uch

discretion does not, however, extend to the exclusion of crucial relevant evidence

necessary to establish a valid defense.” United States v. Kelly, 888 F.2d 732, 743

(11th Cir. 1989).

What is particularly disturbing is that the trial court allowed the government,

over objection, to use two FBI laboratory technicians who were called as fact

86
witnesses in the government's case-in-chief, on rebuttal to testify as to the import of

a lack of forensic evidence found at the crime scene without requiring any support

for their testimony of a statistical or scientific nature. The presence of lack of such

forensic evidence and its import was precisely the testimony the defense expert

witness was prohibited from providing. See, infra, notes 7 & 22. What was good

for the government gander essentially cooked the defense's goose in this case.

I. BACKGROUND

The trial court's ruling in this case was an abuse of discretion for two

principal reasons: (a) the district court committed a Daubert1 error, which involved

two parts: (1) requiring scientific evidence for the defense's experience-based

expert to be reliable while (2) not similarly requiring the Government's experience-

based experts to have a scientific basis for their testimony; and (b) the district

court's Daubert error essentially deprived Frazier of the opportunity to present a

meaningful defense. I address each error in turn.

A. Erroneous Daubert Rulings

Before trial, Frazier gave notice to the Government that he intended to offer

the testimony of Robert Tressel, a forensic investigator and former police officer,

1
Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993).

87
as an expert under Federal Rule of Evidence 702. Rule 702 “assign[s] to the trial

judge the task of ensuring that an expert's testimony both rests on a reliable

foundation and is relevant to the task at hand.” Daubert v. Merrell Dow Pharms.,

Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993). Accordingly, the Government made a

motion in limine to exclude Tressel's testimony under Daubert, and the district

court accordingly held a hearing on the motion. During the Daubert hearing, it

became clear that Tressel's expertise was based on his experience,2 which also was

2
Defense counsel explained that “we are not offering Mr. Tressel for his scientific
expertise. Rather, we believe that he's qualified . . . based on his experience . . . in crime scene
investigations.” R5 at 42. Defense counsel stressed that “someone like Mr. Tressel” was
necessary “to tie all this evidence together” for the jury. Id. Defense counsel reiterated Tressel's
qualifications: “Again, we are not offering him as a scientific expert but strictly based upon his
experience.” Id. at 43 (emphasis mine).

During the Daubert hearing, Tressel expressed his opinion that the investigation of the
crime scene was “thorough” and that proper “protocol for [a] rape examination was followed.”
Id. at 22 (“the proffer”). Defense counsel then asked Tressel whether, based on all the
information he reviewed about the crime, he had an “opinion as to whether or not the description
of the sexual assault provided by [the victim] . . . [was] accurate?” Id. at 23-24. Tressel
responded that, “based on my review of the available documents, it is my professional opinion
that there is no forensic evidence to substantiate the claim of rape in this case.” Id. at 24. Asked
if he had “an opinion about whether or not a rape occurred,” id. at 25, Tressel responded that he
“s[aw] no forensic evidence to substantiate the claim of rape in this case,” id. Based on where
the sexual assault allegedly occurred [the passenger compartment of a small car], the amount of
sexual contact involved, and the evidence examined by Tressel, he stated that he formed his
conclusion because “[t]here should have been some transfer of either hairs, fibers or fluids
between the victims in this case.” Id. at 27 (emphasis mine).

Recall that the FBI laboratory found absolutely no transfer of hair (pubic, body, or head)
or fluid, despite a closed and confined collection site and meticulous collection protocol. See R9
at 343-44, 352, 356-58.

88
informed by scientific studies3: for ten years,

3
When asked by the Government during the Daubert hearing whether his experience was
informed by any academic literature, Tressel responded in the affirmative:
Government: What did you rely on, sir?
Tressel: Practical Aspects of Rape Investigation, a Multi-Disciplinary
Approach.
Q: And that's by whom?
A: Robert Hazelwood and Ann Burgess.
Q: And generally what does the book say about this particular opinion you
have here?
A: That the most common thing that you find is transfer of hair and fiber
evidence from victim to victim – victim to perpetrator, perpetrator to victim.
Q: The most common thing you find?
A: In a rape case. . . .
Q: What scientific literature are you familiar with concerning the transfer
of hair during a sexual assault?
A: I just told you Practical Aspects of Rape Investigation. There's also a
Forensic Science Handbook by Dr. Saperstein.
Q: And what does it say?
A: It just deals with hair transfer. They don't discuss pubic, head, body,
limb hair. They just talk about hair transfers.
Q: Any other scientific literature that you are familiar with or you're
relying on?
A: No, sir. There is an – one of the first things I ever received as a law
enforcement officer, and I'd have to really look this up because I can't remember it
exactly.
It's a crime scene search and physical evidence handbook by Carl
Cunningham, United States Government Printing Office, 1973.
Q: What does it say in regard to this area?
A: Essentially the same thing. . . .
Q: I want to ask you specifically what does it say about the rates of transfer
of hairs?
A: I don't think anybody has ever studied the rates of transfer that I can say.
They all indicate that transfer of hair is the most common trace evidence that can
be found in a sexual assault case.
Q: So when you issued your opinion, you weren't familiar with any
scientific literature in regard to the rate of transfer of hairs in sexual assault cases;
isn't that correct?
A: I am not, no, sir. . . .
Q: Now in regard to your opinion that you placed in your report that
seminal fluids are frequently found in sexual assault cases . . . what particular
scientific literature did you base that on?

89
Tressel worked as an investigator in Cobb County's unit on Crimes Against

Persons, a unit which investigates homicides, rapes, other sexual assaults, and

armed robberies. R5 at 5-6. Tressel estimated that he worked on as many as 250

sexual assault cases during his tenure. Id. at 9. In addition, Tressel spent thirteen

years as chief investigator in the Cobb County Medical Examiner's Office, id. at 10,

and currently owns and operates a private forensic investigation office. Def. Ex. 1.

Based on Tressel's background, the district court deemed him “a very qualified

criminal investigator.” R5 at 66.

1. Requiring Scientific Evidence

Despite Tressel's qualifications as an expert, the district court decided to

tightly circumscribe the limits of Tressel's proposed testimony on the ground that

Tressel, as an experience-based expert, needed some scientific data or study on

A: Again, it was the Practical Aspects of Rape Investigation and from my
experience in investigating rape cases.
R5 at 35-38.

The academic literature relied upon by Tressel support his contention that the following
types of evidence “appear with frequency in sexual assault cases”: “hairs, fibers, blood, semen,
and saliva.” ROBERT R. HAZELWOOD & ANN WOLBERT BURGESS, PRACTICAL ASPECTS OF RAPE
INVESTIGATION : A MULTIDISCIPLINARY APPROACH 97 (1987). In fact, “[t]he type of physical
evidence probably most frequently associated with sexual assault investigations is semen.” Id. at
111. Moreover, “especially if there was physical force, hair is frequently found as evidence.”
JAMES E. DOYLE, WISCONSIN DEP'T OF JUSTICE , PHYSICAL EVIDENCE HANDBOOK 138 (5th ed.
1993).

90
which to base his conclusions in order for them to be reliable4––even though the

4
The majority concedes:
Frazier argues, however, that the district court erroneously treated scientific
background as a prerequisite to expert status, and we agree that, had the court done
so, it would have erred as a matter of law, because Rule 702 expressly
contemplates that experts may be qualified based on experience. However, our
review of the entire record suggests that the district court excluded Tressel’s
testimony not because he lacked a scientific background, but because he failed to
establish that his opinions were methodologically reliable or sound.
Maj. Op. at * 40 (emphasis mine).

A review of the following quoted portions of the Daubert hearing, however, clearly
demonstrates that the trial court did in fact require a scientific basis for Tressel's testimony.
Perhaps the majority can point and quote directly from the record for the reader, as opposed to
the “our-review-of-the-entire-record-suggests” approach to justify its unjustifiable conclusion
that the trial court required scientific evidence—even in the face of its own concession.
Court: Taking Defendant's Exhibit Number 2 [Tressel's Report of
Findings], and using that as the basis for my rulings, . . . I have no problems with
his expertise as he is obviously a very qualified criminal investigator. . . .
But when it comes to the conclusions that you propose to offer him for, I
believe that's exactly what the line of cases beginning with Daubert are aimed at,
and I guess as the gatekeeper, I won't open it for those paragraphs [the last two
full paragraphs on page 2 and the first two paragraphs on page 3 of Tressel's
report, R5 at 24, Ex. 2] that I am talking about. . . .
Defense Counsel: Your honor, I see it as the converse to the FBI
Agent or the DEA Agent, for instance, in a drug case that says typically based on
my experience in a drug case, we expect to see pagers, we expect to see baggies,
we expect to see code in their talk on the telephone, we expect them to see
rendezvous at the fast food restaurants. All the stuff that we typically see that is
based on their experience. . . .
Court: Now, I do have a problem and particularly if there is any
scientific evidence that shows that in 99 percent of the time you find pubic hair, I
would have no problem with that, but he has no study. . . .
I have no problem with him saying that's what they're looking for, but I do
have a problem with him saying that that's what's found, and if it's not there, I
don't believe there was a rape, and I'm not going to allow that.
Defense: But he's only saying it doesn't corroborate her claim of
rape, and it seems to me that those concerns that he didn't do a scientific study are
issues for cross-examination.
And the government is distressed or objecting because he is too specific
rather than talking in broad terms. Where I would have thought that the reason
that he is narrowing it to his opinion to that the physical evidence does not

91
Government admitted during the Daubert hearing that such scientific evidence

existed.5 The district court ruled that Tressel would be allowed to testify regarding

corroborate her story is a very specific statement without him drawing the
conclusion that she wasn't raped, but he's saying that it doesn't support her story,
doesn't substantiate her story.
Court: Well, what you're trying to do is get a witness to testify to
what you should be arguing. . . .
Defense: But how is a lay jury going to know whether or not
you should be finding this stuff, some trace evidence, some fluid evidence.
Court: If you have any scientific evidence that would indicate you
should, I have no problem, as I said, with his testifying that's what they look for,
but when you start trying to prove that there is no case because they didn't find it,
you have got to have something more than just his opinion. You need something
showing some study.
I have no idea whether - - I don't have enough to tell me how often that is,
and I have no basis of knowing, and based upon what you've presented today, I
would not and will not allow it. I don't think that helps the jury.
R5 at 64, 66-69 (emphasis mine).
5
The following illustrative exchange took place during the Daubert hearing:
Government: If you look at what the witness stated, he says the
forensic evidence most commonly found during the analysis of a rape
investigation is the transfer of hairs from the victim to the perpetrator and from
the perpetrator to the victim. . . .
There is no evidence that's been placed before you that leads you, Your
Honor, to conclude that hair will be transferred in X percentage of cases, under X
circumstances or even what the variables might be that control whether hair is
transferred.
All we have is there is no transfer here, and hair is the most commonly
found piece of evidence during a rape investigation. No evidence that when he
says it's most commonly found, no evidence that that means that it's found in 90
percent of the cases, 70 percent of the cases, 3 percent of the cases, and seminal
fluid evidence is found in only two percent of the cases. You don't have any basis
based on the foundation placed before you in this record to conclude that this
assists the jury in any way. . . .
There is no evidence that routinely in a rape investigation you will have
hairs transferred or hairs found. None. Nothing before this court to that
effect. . . .
No scientific evidence has been placed before you to show you at what
rate you can expect to see a transfer of seminal fluid after sexual contact or after

92
 specific types of sexual activity. . . . He is not even familiar with any scientific
literature to that effect. . . .
Court: Is there any scientific literature available?
Government: It is not my duty to present it. I am not moving this,
Your Honor.
Court: I realize that, but is there any available that you are aware
of?
Government: Yes, there is, Your Honor.
Id. at 44-46 (emphasis mine). At this juncture, as an officer of the court, the prosecutor,
who was well aware of the scientific literature and its inconclusive nature, as discussed
below, should have advised the court of same so that the court could have made a fully
informed judgment as a gatekeeper. I find the prosecutor's failure to be forthcoming a
serious ethical lapse. See note 11, infra.

While limited in scope, application, and probativeness, examples of the scientific
literature available (other than the two sources relied upon by Tressel) are principally two
academic articles. One article studied the rate of pubic hair transfers “following one
episode of sexual intercourse by each of 15 volunteer test couples”––a small sample size
in a controlled environment. Mary-Jacque Mann, Hair Transfers in Sexual Assault: a
Six-Year Case Study, 35 J. FORENSIC SCI. 951, 953 (1990). This study admitted that
“[p]ublished controlled hair transfer studies are a valuable source of clarifying
information, but . . . such studies are disappointingly few in number.” Id. at 951. This
article also conceded that “controlled transfer studies and the results of casework
examinations should not be given equal weight.” Id. at 955 (emphasis mine).
A second, more recent article measured “the frequency of pubic hair transfer
between a limited number of consenting heterosexual partners”––another admittedly
“limited study.” David L. Exline, M.S.F.S., et al., Frequency of Pubic Hair Transfer
During Sexual Intercourse, 43 J. FORENSIC SCI. 505, 507 (1998). The article made two
conclusions: “[f]irst, pubic hair transfer does occur during sexual intercourse, and is
significant forensic evidence when found. Second, further studies in the area of hair
transfer frequencies are needed to better evaluate hair transfer evidence.” Id. at 507.
While this study explained that “[i]t is well known that pubic hairs may be transferred
during certain sexual offenses,” it also admitted that “[f]ew controlled studies have
been reported which could allow predictions of how frequently examiners might
expect to observe such transfers.” Id. It also conceded that “[w]ithout additional
studies, it is not clear that our results with a limited number of people would be
found if larger numbers of individuals were examined, even under the controlled
conditions described.” Id. (emphasis mine). Importantly, the article did note that
“[p]rior to this study [i.e., before 1998], research concerning the transfer frequency of
pubic hair was based on either forensic casework or limited human subject data” and
“[u]ntil now, when asked in court about the frequency of pubic hair transference, experts
could rely only on experience because of the lack of scientific literature.” Id.

93
the standard procedures in investigating the site of an alleged sexual assault and to

testify that no hair or fluid matching Frazier was found. Tressel could testify, for

example, that “[t]he forensic evidence most commonly found during the analysis of

rape investigation is the transfer of hairs.” R5 at 24, Ex. 2 at 2. Tressel was

forbidden, however, from testifying to two key propositions: (1) “Based on my

review of the available documents, it is my professional opinion that there is no

forensic evidence to substantiate the claim of rape in this case,” and (2) “With the

amount of sexual activity described in the search warrant affidavit, it would be

expected that some transfer of either hairs or seminal fluid would occur in this

case.” R5 at 24, Ex. 2 at 2, 3. Both the defense and the trial judge recognized that

excluding this key testimony left no further use for Tressel as a witness.6 R5 at 65-

(emphasis mine). But this study was also of little probative value in that it examined the
rate of hair transfer of “six Caucasian couples who collected their pubic hair combings
immediately following intercourse.” Id. at 505.
The relevant academic literature cited by these studies also reveals significant
inconsistencies in reported transfer rates between these and the few other studies that
have been performed. Indeed, the rates ranged from zero to forty-five percent. See id. at
506; Mann, supra, at 953. If applied rigidly to specific cases of alleged rape, each with
their dissimilar circumstances and variables, these studies may be a significant source of
potential error. Overall, the paucity of, inconsistency between, and lack of appropriate
controls and common situational variables in these studies demonstrate that the body of
knowledge in this area is still in its infancy. By comparison, the qualitative testimony
offered by Tressel would have been relatively inoffensive, unobjectionable, and hardly
polemical, as evidenced by its wholesale endorsement by one of the field’s leading
textbooks.
6
Defense counsel advised the court that whether a sexual assault occurred is “absolutely
critical to . . . impeaching [the victim's] credibility on the kidnapping itself,” R5 at 54, and that, if

94
66. As a result, the defense was left to elicit the lack of forensic evidence matching

Frazier from two FBI laboratory technicians––Agent Karen Lanning and Agent

Anthony Onorato––who examined the evidence discovered at the crime scene after

a meticulously careful collection process that no one disputed. See, e.g., R5 at 24,

Ex. 2 at 2; id. at 67.

2. The Error Compounded

On rebuttal, however, the district court's initial Daubert error was

compounded when the Government was allowed to use these same FBI laboratory

technicians––used by the government as fact witnesses––to testify as experts. The

Government offered the FBI agents as experience-based experts who would be

asked to testify to the import of the lack of forensic evidence––the same “leap” that

Tressel was not allowed to make. The defense objected, arguing that the

prosecution had failed to communicate its intention to call expert witnesses,

violating the notice provisions of Federal Rule of Evidence 16.7 The district court,

the jury did not believe the victim, the defense would have “a very strong argument . . . that all of
[the victim's] testimony including the kidnapping portion of her testimony should be
disregarded,” id. at 56. The court acknowledged that expert testimony would be relevant to the
sexual assault issue, see id. at 56-67, and, after eviscerating Tressel's proposed testimony,
acknowledged that the Defense had no further use for Tressel, id. at 65-66.
7
After the Government called Agent Lanning to present rebuttal evidence, the defense
objected and the following exchange took place:
Defense: Your honor, I think that it's just wholly unfair for the
government to attempt to use these witnesses that I've called as fact witnesses who

95
were under their control - - now, the rule does say in their case in chief, but here I
think that what the government is doing is playing games to avoid - - to sandbag
the defendants. They - - I repeatedly asked [the Government] both in writing and
with my initial discovery motion, but also subsequently, if he intended on calling
any expert witnesses. And his routine response was, I know, I know my
obligations under Rule 16, and I don't have access to these witnesses. They are - -
you know, I can subpoena them, but, you know, for instance, I can't get their
curriculum vitae, can only subpoena them as witnesses, as fact witnesses. . . .
Court: Well, now, let me ask you a couple of questions. They
didn't give you copies of these reports?
Defense: All I got was the - - these - - I - - this is what I got, your
Honor.
Court: The scientific reports.
Defense: The scientific report that lists - - that is very - - it states
what exhibits they received, what their - - what their analysis showed as to item to
item, and what their conclusion was. Nothing about their underlying, you know,
like what their opinion was as to the likelihood that this should or shouldn't be
present, the sorts of things you would use an expert to testify to. And other than
what they've elicited on the stand as to their qualifications, I don't know what, you
know, what basis they have for making these opinions. I don't know how many
rape offenses they have been involved in, I just don't have any way to challenge
them. And I didn't have any information to anticipate what they would say to use
with another expert that I could call because the Government has avoided Rule 16
by calling them in rebuttal. . . .
[I]f I knew what their - - what they were going to testify to regarding their
experience in other rape examinations, like how frequently body fluids are
exchanged or whatever, then I could have called perhaps somebody from the GBI
lab or from some other lab who is similarly situated to refute that information. . . .
Government: Your Honor, as we said at the beginning, Rule 16
requires us to give expert notice on experts we're going to call in our case in chief.
We made a decision not to call experts in our case in chief. We didn't - - we
provided the laboratory reports to them, we didn't provide summaries of what they
might testify to on other things because we weren't calling them as witnesses.
These people have been called by the defense. The rule does not require us to
provide a summary of their testimony or anything else if they are going to be in
the defense case or in our rebuttal case. . . .
Government: We proffer that we're going to be asking them about
their experience and qualifications in these matters, and asking them what the
import of this testimony they gave in this case was. To wit, what is the import of
the fact that there was nothing found? Specifically, does the fact that there is no
hair transfer found necessarily mean that there is no sexual contact? Does the fact
that there was no seminal fluid found necessarily mean that there was no sexual

96
though agreeing with the defense that the Government should have been more

forthcoming with its witnesses, ultimately overruled the defense's objection,

reasoning that Rule 16 only requires notice when the prosecution calls an expert

during its case in chief.8 Unlike Tressel, the court permitted the technicians to

testify as experts regarding “the import of the fact that there was nothing found.”

R9-363. Not surprisingly, both agents testified that the lack of forensic evidence

contact? And we'll talk about the variables that go into whether there is a transfer
of seminal fluids. And we'll ask them questions about scientific journal articles
that have been written about transfer of hairs. [Other than alluding to the two
articles in a very tangential way, the articles were never introduced or entered into
evidence. See R9 at 370-71.]
I mean, this, this is to rebut the testimony that the defense has put in. They
are telling the jury that this means something, and I've got a right to shine the light
on it in rebuttal. That's all.
Defense: How am I without any prior notice supposed to cross-
examine a witness on this? And I think in all honesty, Your Honor, what the rule
contemplates is that if I call an expert that I have given notice under Rule 16, then
the Government can refute that expert in their - - in their rebuttal. But it does not
contemplate that out of the blue they are going - - they are going to call an expert
witness who they have control over, who they have access to in advance of this
trial, and I did not convert this fact witness that they created into an expert witness.
R9 at 359-64 (emphasis mine).

8

Court: It's not contrary to the rules because it's not your case in chief. I
want to be clear, though, that there is not an inconsistency in my rulings. I said
that you could not use Mr. Tressell [sic] as an expert, and I had concerns there
about his qualifications in scientific areas. I think - - and I don't want to think - -
I'm convinced that I did say at the time you could use him for a factual witness
and how often this was - - the same as I allowed here, how often this occurs or
how often he saw it, but that I would not allow him to express opinions that I
thought were beyond his field of expertise.
Id. at 364-65 (emphasis mine).

97
matching Frazier did not necessarily lead to the conclusion that no sexual contact

had occurred. R9-371, 387.

B. Frazier's only Viable Defense was Eviscerated

Allowing the FBI agents to testify as to the import of finding no forensic

evidence, while not allowing Tressel to do the same, essentially eviscerated

Frazier's principal and only practical defense––questioning the credibility of the

victim to show that if the rape did not occur, neither did the kidnapping.9 The

9
These inconsistent rulings were perhaps exacerbated by the trial judge's confusion
regarding the issue on which he was being asked to rule––namely, whether it was an issue
regarding rape or kidnapping. The following comments illustrate the trial judge's confusion:
Court: They are endeavoring to prove her raped, as I understand it
here . . .
Government: Excuse me, Your Honor, I hesitate to interrupt, but
we're trying to prove a kidnapping.
Court: I know you're trying to prove a kidnapping, but the issue of
the rape is part of it, is it not? . . .
Am I not correct that you're endeavoring to prove a rape which changes the
nature of the sentence?
Government: Not necessarily. To the extent . . . that we're going
to put up a complaining witness who says during my kidnapping I was sexually
assaulted, yes . . .
Court: I may have the wrong impression about this case. . . .
I in my mind have been trying to evaluate this to the proof of the crime of
rape incidental to the kidnapping, . . .
But I thought there was a question of proving a rape for the purpose of the
sentence being a mandatory life as opposed to a kidnapping where there would not
be a mandatory life. Am I correct?
Government: No, Your Honor . . . The sexual assault is not an
element of the kidnapping . . .
Court: No, it isn't. I agree with you. That's where I was under the
misapprehension, and I thought there was - - that you had a burden - - I don't
know where I got this from. . . .
Court: All right. Then I had the wrong impression, but, again,

98
district court even admitted as much.10 Needless to say, the Government, in its

closing statement, stressed the importance of the testimony of Lanning and Onorato

that the lack of forensic evidence did not mean that the rape––and, hence, the

kidnapping––did not occur. The Government also mentioned the scientific

“studies” that it required of Tressel but not of its own experts.11 The defense, on

that's part of the fallacy of - - this is my first contact with the case. Unlike the
Magistrate is the one who has had dealings with it, I don't even know that I have
actually seen the indictment. In fact I don't think I have.
All right. The rape then is not an essential element of the crime, right?
Defense: It's not an essential element of the crime, but it's a central
part of [the victim's] allegation that she was kidnapped, and certainly as a defense
lawyer whether or not there was a sexual assault is absolutely critical to my
impeaching her credibility on the kidnapping itself. . . .
Defense: And I think pretty much whether or not there actually was
a kidnapping is based almost entirely on [the victim's] testimony, and that's why
her description of what happened, and if this focal point of her story is not to be
believed by the jury, then I have, again as Mr. Frazier's lawyer, a very strong
argument to the jury that all of her testimony including the kidnapping portion of
her testimony should be disregarded, as well.
Court: All right. I am beginning to focus on the issues and the
relevance now. . . .
Court: I think I am getting focused because I only got your brief
that was filed just today just a few minutes before I came in . . .
R5 at 52-54, 56-57 (emphasis mine).
10
Defense counsel advised the court that whether a sexual assault occurred is “absolutely
critical to . . . impeaching [the victim's] credibility on the kidnapping itself,” id. at 54, and that, if
the jury did not believe the victim, the defense would have “a very strong argument . . . that all of
[the victim's] testimony including the kidnapping portion of her testimony should be
disregarded,” id. at 56. The court acknowledged that expert testimony would be relevant to the
sexual assault issue, see id. at 56-67, and, after eviscerating Tressel's proposed testimony,
acknowledged that the Defense had no further use for Tressel, id. at 65-66.
11
In its closing argument, the Government stated:
Now, you heard a lot of testimony today and the defense has
presented evidence to you trying to get you to focus on evidence of the
rape examination kit and the examination clothes, and wanted to point out

99
the other hand, without any experts to quote or studies on which to rely, could only

make the bald argument that the lack of forensic evidence did not support the

victim's account of the events.12

to you that no hair was found and no semen was found. And they want to
take your attention away from what happened to [the victim] and focus on
this so that you will conclude, we assume, that well, no - - no hair was
found and no semen was found, and we point to a couple of other
problems, and based on that, you need to conclude, I think they are going
to argue, that you can't believe [the victim] about the sexual assault. And
if you can't believe her about the sexual assault, you can't believe her about
the kidnapping. Well, that's not true. . . .
First of all, the fact that no hair is found doesn't mean anything. As
you heard from the studies involved there are lots of cases where no hairs
are found. A majority - - large majority of cases where no hair is
found. . . .
The witness testified, Mr. Onorato just a few minutes ago, that in
the rape kits he does, perhaps 20 or 25 percent of the time he doesn't find
any.
R9 at 407-09 (emphasis mine).
12
During its closing argument, the defense stated:
The whole purpose of the government's case, their whole scenario
is that Mr. Frazier kidnapped [the victim] to rape her. And, if you listen to
[the victim's] story, the focal point of this whole story is the rape. If the
sexual assault did not occur, then I submit that you have to - - that so
impacts [the victim's] credibility that you cannot convict him of
[kidnapping]. . . .
[B]efore you can convict somebody of something as serious as kidnapping
or anything, really, but certainly in this case, you have got to look at the extent to
which you can corroborate what [the victim] says or does the evidence say that
she is not being truthful about something? And that's the significance - - that is
why the rape in this case becomes so significant because it's such a large portion
of what she describes. . . .
[T]here is no hair. No, no hair, no semen, no liquid, forget the semen.
Why is there - - we've got all of this - - this activity, movement back and forth in
the car, and you know, look at him. He's a hairy man. We don't have any hair
falling off into the car?
And we have the FBI collecting all of this evidence. Are they going to
now say, oh, well, we're really pretty shoddy at this. No. We know they have

100
 Frazier appealed, arguing that the district court abused its discretion when it

limited Tressel's testimony under the guise of Daubert, thereby eviscerating his

only viable defense.

II. DISCUSSION

In this section, I will (a) state the proper standard of review, (b) discuss the

district court's erroneous Daubert rulings, and (c) discuss the effect of this ruling on

Frazier's ability to present a meaningful defense.

A. Standard of Review

problems at the lab, but there is no indications we have any problems in this case
with the collection of evidence. You saw it, you heard it, you see it, they rip the
car apart and send it to the lab. No, not one speck of hair from this. And we're
not, again, I think the lack of pubic hair is pretty significant when you've got all of
this activity on the front seat of the car.
Id. at 417, 419, 428-29.
The search warrant described the “activity” in the Ford Escort as follows:
[The victim] stated that . . . [ ] Frazier, while having [the victim] at knife point,
told [the victim] to take her pants and panties off, at which she did. [The victim]
stated that [ ] Frazier put his hand in her vagina and began rubbing it. [The victim]
stated that [ ] Frazier then took his clothes off and asked [the victim] if the seat
reclined. [The victim] stated that she told Frazier that they did not recline back.
[The victim] stated that [ ] Frazier had sex with her on the bottom and [ ] Frazier
on the top. [The victim] stated that [ ] Frazier got up and told her to get on top,
which she did. [The victim] stated that after that [ ] Frazier told her to, “suck my
dick”, in which she complied. [The victim] stated that [ ] Frazier told her to get on
her hands and knees, which she did and [ ] Frazier inserted his penis into her anus.
[The victim] stated that [ ] Frazier had sex with her again.
Def. Ex. 5, Attach. A.

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 We review a district court's exclusion of expert testimony under the federal

rules of evidence for an abuse of discretion. United States v. Paul, 175 F.3d 906,

909 (11th Cir. 1999). As for the district court's interpretation of Federal Rule of

Evidence 702, our review is plenary. Id. No error regarding the admission or

exclusion of evidence is reversible “unless a substantial right of the party is

affected.” Fed. R. Evid. 103(a).

B. The District Court's Daubert Rulings

Rule 702 of the Federal Rules of Evidence allows “a witness qualified as an

expert by knowledge, skill, experience, training, or education” to testify “in the

form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts

or data, (2) the testimony is the product of reliable principles and methods, and (3)

the witness has applied the principles and methods reliably to the facts of the case,”

provided that the “scientific, technical, or other specialized knowledge will assist

the trier of fact to understand the evidence or to determine a fact in issue.” In

Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 113 S. Ct. 2786 (1993), the

Supreme Court “assign[ed] to the trial judge the task of ensuring that an expert’s

testimony both rests on a reliable foundation and is relevant to the task at hand.”

Id. at 597, 113 S. Ct. at 2799.

102
 Faced with a proffer of expert scientific testimony, then, the trial judge
must determine at the outset, pursuant to Rule 104(a), whether the
expert is proposing to testify to (1) scientific knowledge that (2) will
assist the trier of fact to understand or determine a fact in issue. This
entails a preliminary assessment of whether the reasoning or
methodology underlying the testimony is scientifically valid and of
whether that reasoning or methodology properly can be applied to the
facts in issue.

Id. at 592, 113 S. Ct. at 2796 (footnotes omitted). Thus, for proffered expert

testimony to be admissible, a court must determine that:

(1) the expert is qualified to testify competently regarding the matters
he intends to address; (2) the methodology by which the expert
reaches his conclusions is sufficiently reliable as determined by the
sort of inquiry mandated in Daubert; and (3) the testimony assists the
trier of fact, through the application of scientific, technical, or
specialized expertise, to understand the evidence or to determine a fact
in issue.

City of Tuscaloosa v. Harcros Chem., Inc., 158 F.3d 548, 562 (11th Cir. 1998).

But while “[t]he judge’s role is to keep unreliable and irrelevant information

from the jury,” it “is not intended to supplant the adversary system or the role of the

jury.” Allison v. McGhan Med. Corp., 184 F.3d 1300, 1311-12 (11th Cir. 1999).

The admissibility standard is a liberal one, United States v. Hankey, 203 F.3d 1160,

1168 (9th Cir. 2000), and “[a] review of the caselaw after Daubert shows that the

rejection of expert testimony is the exception rather than the rule.” Fed. R. Evid.

702 advisory committee notes, 2000 amends. (emphasis mine).
103
 Courts have found that an abuse of discretion occurs when under
Daubert the admissibility bar is too high. . . . “Trial judges must
exercise sound discretion as gatekeepers of expert testimony under
Daubert. . . . [We must not] elevate them to the role of St. Peter at the
gates of heaven, performing a searching inquiry into the depth of an
expert witness’s soul—separating the saved from the damned.”

Allison, 184 F.3d at 1321 (citation omitted) (quoting McCullock v. H.B. Fuller Co.,

61 F.3d 1038, 1045 (2d Cir. 1995)).

Because the district court forbade Tressel from testifying to two key

propositions, I address each proposition in turn and then discuss how the district

court's ruling was incorrectly and inconsistently applied.

1. Tressel's Opinion on the Import of the Lack of Forensic Evidence

The district court would not allow Tressel to draw any inferences that the

lack of forensic evidence did not substantiate the victim's claim of rape because it

would invade the jury's province and usurp its role in deciding the penultimate

issue of whether rape actually occurred. However, “it is part of the normal role of

the expert not merely to describe patterns of conduct in the abstract, but to connect

actions in a specific case to those patterns—sometimes even to the point of

testifying that the defendant was [or was not] involved in criminal conduct.”

United States v. Boney, 977 F.2d 624, 629 (D.C. Cir. 1992). “Rule 702 does not

bar an expert from drawing conclusions in a specific case . . . [and] does not require

104
that any inferences from the facts in the specific case be left to the jury.” Id. Thus,

experts may “take the further step of suggesting the inference which should be

drawn from applying the specialized knowledge to the facts.” Fed. R. Evid. 702

advisory committee notes, 1972 Proposed Rules. This is true even if the testimony

“merely assist[s] the jury in interpreting the significance of the evidence,” United

States v. Brown, 7 F.3d 648, 654 (7th Cir. 1993), draws on “common sense,”

United States v. Glover, 265 F.3d 337, 345 (6th Cir. 2001), or, while helpful, is

nonetheless “obvious,” United States v. Sellers, 566 F.2d 884, 886 (4th Cir. 1977).

Indeed, “whether the specific expert testimony focuses upon specialized

observations, the specialized translation of those observations into theory, a

specialized theory itself, or the application of such a theory in a particular case, the

expert’s testimony often will rest ‘upon an experience confessedly foreign in kind

to [the jury’s] own.’” Kumho Tire Co. v. Carmichael, 526 U.S. 137, 149, 119 S.

Ct. 1167, 1174 (1999) (citation omitted) (emphasis mine).

In Brown, for instance, the defendant had been convicted of possession with

intent to distribute cocaine base. 7 F.3d at 649. On appeal, “the issue was whether

[he] possessed the twenty-five rocks of crack cocaine for distribution or for

personal use.” Id. at 652. The government’s expert identified certain indices that

are commonly associated with drug dealers. “He also described the typical

105
paraphernalia associated with street-level crack distributors and compared that with

the paraphernalia and behavior patterns usually associated with those possessing

crack only for personal use.” Id. at 650. From this information, the expert

concluded that the crack cocaine seized from the defendant was not intended for

personal consumption, but for distribution. Id. The defendant objected, arguing

that the jury could draw its own inferences from the habits and practices testimony

of the expert. Id. at 652. The Seventh Circuit affirmed the district court’s refusal

to exclude the testimony on the ultimate issue, reasoning that “the average juror

might be unable to determine whether the absence of certain drug paraphernalia

typically associated with crack cocaine is significant.” Id. (emphasis mine); see

also Erickson v. Baxter Healthcare, Inc., 131 F. Supp. 2d 995, 1001 (N.D. Ill.

2001) (permitting medical expert to testify that information contained in the

plaintiff’s medical records did not support one of her allegations).

In the same way, Tressel’s conclusion in this case—that the absence of any

forensic evidence did not substantiate the claim of rape—would have helped the

jury to understand the significance of the negative implication to be drawn; what

the prosecution even referred to as the “import” of the lack of evidence. R9 at

363. Its exclusion by the district court was therefore an abuse of its discretion.

Tressel’s proffered testimony did not state a legal conclusion as to Frazier’s guilt or

106
innocence, and it did not “tell the jury what result to reach.” Montgomery v. Aetna

Cas. & Sur. Co., 898 F.2d 1537, 1541 (11th Cir.1990). His analysis was clear and

was supported by undisputed factual findings as to the evidence retrieved from the

alleged crime scene. No mere “oath-helper,” Hanson v. Waller, 888 F.2d 806, 811

n.2 (11th Cir. 1989), Tressel’s testimony would have assisted the average juror,

unqualified “to determine intelligently and to the best possible degree,” United

States v. Lankford, 955 F.2d 1545,1558 (11th Cir. 1992) (Hoffman, J., dissenting),

what to make of the fact that not a single shred of physical evidence was presented

to link Frazier to the alleged victim qua victim in this case. His testimony would

have assured against any tendency to over- or underestimate the value of this

finding; indeed, the lack of forensic evidence could neither exonerate nor condemn

Frazier of the rape, but only failed to substantiate it. To exclude such helpful

testimony on the inappropriate ground relied on by the district court was manifestly

reversible error.

2. Tressel's Opinion on the Evidence He Would Expect to Find in
This Case

The trial court also refused Tressel's proffered testimony that “it would be

expected that some transfer or either hairs or seminal fluid would occur in this

case” because it found this testimony unreliable for lack of scientific data. R5 at

107
24, Ex. 2 at 2. In particular, the district court faulted Tressel for not having rested

his conclusion on any empirical study and disfavored his testimony because it was

couched in qualitative terms rather than hard numbers or statistical data. See note

3, infra. This ruling was based on an incomplete understanding of the background

required of an expert witness.

The text of Rule 702 dictates that expert status may be based on experience,

and the Advisory Committee Notes dictate that experience alone “may . . . provide

a sufficient foundation for expert testimony.” Rule 702 cmt. at 290. Without

doubt, the Supreme Court’s ruling in Daubert imposes difficult gatekeeping duties

on trial courts, one of which involves an exacting assault to the foundation of any

proposed expert testimony to determine whether it is plumb or stands out of true,

resting on shaky and unreliable ground. To survive this juridic ordeal and meet the

standard of evidentiary reliability, expert testimony must be (1) “ground[ed] in the

methods and procedures of science,” (2) authenticated by “more than subjective

belief or unsupported speculation,” and (3) “supported by appropriate

validation—i.e., ‘good grounds,’ based on what is known.” Daubert, 509 U.S. at

590, 113 S. Ct. at 2795. “[T]he trial court must scrutinize not only the principles

and methods used by the expert, but also whether those principles and methods

have been properly applied to the facts of the case.” Fed. R. Evid. 702 advisory

108
committee’s note, 2000 amends. While the court must focus “solely on principles

and methodology, not on the conclusions that they generate,” Daubert, 509 U.S. at

594, 113 S. Ct. at 2797, “conclusions and methodology are not entirely distinct

from one another,” and “nothing . . . requires a district court to admit opinion

evidence that is connected to existing data only by the ipse dixit of the expert. A

court may conclude that there is simply too great an analytical gap between the data

and the opinion proffered.” Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146, 118 S. Ct.

512, 519 (1997).

This pre-trial by fire “applies not only to testimony based on ‘scientific’

knowledge, but also to testimony based on ‘technical’ and ‘other specialized’

knowledge.” Kumho Tire, 526 U.S. at 141, 119 S. Ct. at 1171. Thus, all expert

opinion “must be the product of reliable principles and methods that are reliably

applied to the facts of the case.” Fed. R. Evid. 702, advisory committee notes,

2000 amends. “The trial judge in all cases of proffered expert testimony must find

that it is properly grounded, well-reasoned, and not speculative before it can be

admitted. The expert’s testimony must be grounded in an accepted body of

learning or experience in the expert’s field, and the expert must explain how the

conclusion is so grounded.” Id. (emphasis mine).

109
 This uncompromising emphasis on reliability does not mean, however, that

the personal experience or knowledge of the expert alone is not to be trusted. “To

the contrary, the text of Rule 702 expressly contemplates that an expert may be

qualified on the basis of experience. In certain fields, experience is the

predominant, if not sole, basis for a great deal of reliable expert testimony.” Id.

(emphasis mine). Indeed, “there are many different kinds of experts, and many

different kinds of expertise.” Kumho Tire, 526 U.S. at 150, 119 S. Ct. at 1175.

Even after Kumho Tire, “there is no question that an expert may still properly base

his testimony on ‘professional study or personal experience.’” Maiz v. Virani, 253

F.3d 641, 668-69 (11th Cir. 2001) (holding that expert testimony on the “passport-

stamping practices of Mexican immigration officials . . . based largely on [the

expert’s] personal experience rather than verifiable testing or studies” was

admissible) (emphasis mine).

However, this type of expert testimony generates certain difficulties in

evaluating its reliability: “Some types of expert testimony will not rely on anything

like a scientific method, and so will have to be evaluated by reference to other

standard principles attendant to the particular area of expertise.” Fed. R. Evid. 702

advisory committee notes, 2000 amends. “[A]n expert’s qualifications and the

reliability of his testimony do not always separate into a clear dichotomy,” United

110
States v. Jones, 107 F.3d 1147, 1160 (6th Cir. 1997), and, in fact, are often blurred

in the case of experience-based expert testimony. Where “the relevant reliability

concerns may focus upon personal knowledge or experience,” Kumho Tire, 526

U.S. at 150, 119 S. Ct. at 1175, “inquiries into an expert’s qualifications, the

reliability of his proffered opinion and the helpfulness of that opinion” frequently

overlap to a significant degree. Quiet Tech. DC-8, Inc. v. Hurel-Dubois UK Ltd.,

326 F.3d 1333, 1341 (11th Cir. 2003).

Even so, these “are distinct concepts that courts and litigants must take care

not to conflate.” Id. “The trial court’s gatekeeping function requires more than

simply taking the expert’s word for it.” Fed. R. Evid. 702 advisory committee

notes, 2000 amends. (citation and internal quotation marks omitted). All experts,

“whether basing testimony upon professional studies or personal experience, [must]

employ[] in the courtroom the same level of intellectual rigor that characterizes the

practice of an expert in the relevant field.” Kumho Tire, 526 U.S. at 152, 119 S.

Ct. at 1176. Courts must be creative when applying this panoptic principle, more

accommodating in theory than in practice. While the Court in Daubert developed

four, non-exhaustive measures of reliability,13 it emphasized that “[t]he inquiry

13
These are whether proffered scientific knowledge can be (and has been) tested, whether
a theory or technique has been subjected to peer review or publication, whether the “known or
potential rate of error” of a scientific technique is within acceptable bounds for the particular

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envisioned by Rule 702 is . . . a flexible one.” 509 U.S. at 594, 113 S. Ct. at 2797.

“[T]hose factors do not all necessarily apply even in every instance in which the

reliability of scientific testimony is challenged.” Kumho Tire, 526 U.S. at 151, 119

S. Ct. at 1175. Whether they do “depend[s] on the nature of the issue, the expert’s

particular expertise, and the subject of his testimony.” Id. at 150, 119 S. Ct. at

1175 (citation and internal quotation marks omitted).14 In short, while adapting the

reliability inquiry to the nature of the testimony proffered, courts must still look

long and hard at the expert’s principles and methods:

For example, when a law enforcement agent testifies regarding the use
of code words in a drug transaction, the principle used by the agent is
that participants in such transactions regularly use code words to
conceal the nature of their activities. The method used by the agent is

discipline, and to what extent the evidence has been accepted within the “relevant scientific
community.” 509 U.S. at 593-94, 113 S. Ct. at 2796-97.

The Advisory Committee Notes to Rule 702 delineate five additional factors in
determining reliability: (1) Whether the testimony “grow[s] naturally and directly out of research
[experts] have conducted independent of the litigation, or whether they have developed their
opinions expressly for purposes of testifying”; (2) “Whether the expert has unjustifiably
extrapolated from an accepted premise to an unfounded conclusion”; (3) “Whether the expert has
adequately accounted for obvious alternative explanations”; (4) “Whether the expert is being as
careful as he would be in his regular professional work outside his paid litigation consulting”;
and (5) “Whether the field of expertise claimed by the expert is known to reach reliable results
for the type of opinion the expert would give.” Fed R. Evid. 702 advisory committee's notes,
2000 amends. (citations and internal quotation marks omitted).
14
For example, “[i]f the witness is relying solely or primarily on experience, then the
witness must explain how that experience leads to the conclusion reached, why that experience is
a sufficient basis for the opinion, and how that experience is reliably applied to the facts.” Fed.
R. Evid. 702 advisory committee's notes, 2000 amends.

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 the application of extensive experience to analyze the meaning of the
conversations. So long as the principles and methods are reliable and
applied reliably to the facts of the case, this type of testimony should
be admitted.

Fed. R. Evid. 702 advisory committee's notes, 2000 amends.

Case law is replete with judicially-sanctioned instances of this type of

deductive reasoning. For instance, physicians and other professionals,15 valuation

experts,16 experts on industry customs and practices,17 and handwriting analysts18

15
See, e.g., McGuire v. Davis, 437 F.2d 570, 572 (5th Cir. 1971) (recognizing “the well-
settled proposition that a physican who has examined an injured party may describe what he has
seen and give his expert inferences therefrom”); Smith v. BMW N. Am., Inc., 308 F.3d 913, 919
(8th Cir. 2002) (concluding that a physician’s testimony as to the cause of the plaintiff’s injuries
is admissible where “[h]e applied his medical knowledge and his experience to the physical
evidence and came to a conclusion as to the cause of Smith’s neck injury”); Heller v. Shaw
Indus., Inc., 167 F.3d 146, 154 (3d Cir. 1999) (concluding that a physician is not required “to
rely on definitive published studies before concluding that exposure to a particular object or
chemical was the most likely cause of a plaintiff’s illness”); United States v. Pollard, 128 F.
Supp. 2d 1104, 1123 (E.D. Tenn. 2001) (finding that a physician’s testimony as to the age of
young girls in a pornographic videotape is admissible where it is based only “upon multiple
personal viewings of the video and the correlation of his observations to a lengthy clinical
experience in assessing chronologic age based on physical and sexual development” because he
was “properly qualified and possess[ed] valid scientific and/or technical knowledge”);
Protocomm Corp. v. Novell Advanced Servs., Inc., 171 F. Supp. 2d 473, 479-80 (E.D. Penn.
2001) (finding the conclusions of a forensic accountant reliable because he “based his opinions
on personal knowledge and experience, as well as a seemingly copious review of a multitude of
relevant business documents”).
16
See, e.g., United States v. Conn, 297 F.3d 548, 556-57 (7th Cir. 2002) (recognizing that,
just as experienced law enforcement agents may apply “knowledge gained through years of
experience” to the facts in a particular case, a gun expert may “appraise, on the basis of his past
experience and training, the value of . . . firearms found in [a criminal defendant’s] residence”).
17
See, e.g., Maiz, 253 F.3d at 668-69 (holding that expert testimony based on personal
experience was admissible to establish “the passport-stamping practices of Mexican immigration
officials” even in the absence of any “verifiable testing or studies”); Marx & Co., Inc. v. Diner’s

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are often permitted to derive their conclusions in this fashion. After all, “[e]xperts

of all kinds tie observations to conclusions through the use of what Judge Learned

Hand called ‘general truths derived from . . . specialized experience,’” id. at 148,

119 S. Ct. at 1174 (citation omitted), and “no one denies that an expert might draw

a conclusion from a set of observations based on extensive and specialized

experience.” Id. at 156, 119 S. Ct. at 1178.

Considering the four, non-exhaustive measures of reliability developed by

the Daubert Court, “[g]eneral acceptance in the community is an important factor in

evaluating an expert’s methodology and courts particularly emphasize this Daubert

factor when reliability focuses on experience.” Groobert v. President & Dirs. of

Georgetown Coll., 219 F. Supp. 2d 1, 8 (D.C. 2002). The other Daubert factors

often recede in importance.19 “The more subjective and controversial the expert’s

Club, Inc., 550 F.2d 505, 509 (2d Cir. 1977) (“Testimony concerning the ordinary practices of
those engaged in the securities business is admissible under the same theory as testimony
concerning the ordinary practices of physicians or concerning other trade customs.”).
18
See, e.g., United States v. Paul, 175 F.3d 906, 909-10 (11th Cir. 1999) (upholding
district court’s admission of handwriting expert’s testimony based on personal experience and
knowledge of general principles in the field over an unreliability objection); Jones, 107 F.3d at
1160-61 (upholding district court’s decision to admit handwriting expert’s testimony based on
his “various training experiences, his job responsibilities, his years of practical experience, and
the detailed nature of his testimony”).
19
See, e.g., City of Tuscaloosa, 158 F.3d at 566 n.25 (recognizing that testability is not a
proper measure of reliability for economic or statistical analyses of allegedly collusive markets
“because each such case is widely different from other such cases and because such cases cannot
be made the subject of repeated experiments”); Hankey, 203 F.3d at 1169 (“The Daubert factors .

114
inquiry, the more likely the testimony should be excluded as unreliable.” Fed. R.

Evid. 702 advisory committee notes, 2000 amends. By the same token, the less

controversial a conclusion, the more likely it is reliable. For example, it may “be

useful to ask even of a witness whose expertise is based purely on experience, say,

a perfume tester able to distinguish among 140 odors at a sniff, whether his

preparation is of a kind that others in the field would recognize as acceptable.”

Kumho Tire, 526 U.S. at 151, 119 S. Ct. at 1176. Therefore, “that an expert’s

opinion is not based on statistical studies does not render that opinion inadmissible,

provided that . . . the testimony is based on reasoning or methodology generally

. . simply are not applicable to [criminal practices] testimony whose reliability depends heavily
on the knowledge and experience of the expert, rather than the methodology or theory behind
it.”).

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accepted within a particular profession or discipline.”20 Katt v. City of New York,

151 F. Supp. 2d 313, 356 (S.D.N.Y. 2001).

This is all the more true, as in this case, where probative quantitative studies

are unavailable. For instance, one court refused to admit a physician’s statistical

testimony based on general experience. “To allow doctors to testify about specific

statistical or medical questions and base their testimony only on general experience

would be to say that doctors are qualified experts on every medical subject merely

because they wear white coats.” Erickson, 131 F. Supp. 2d at 999. But the same

court permitted similarly based qualitative testimony:

Although mere experience in the field is not a reliable basis for . . .
specific statistical . . . opinions . . . , here [the] opinion does not
concern a specific statistic, but instead concerns the common

20
The district court's rulings suggest that, if only Tressel had been willing to testify with
the careless grace of the government’s witnesses, providing the court with slapdash, but facially
numerical, guesstimations, his testimony may have been admitted. R5 at 68-70; see also Maj.
Op. at * 43-45 (characterizing Tressel's testimony as unreliable because he could not quantify the
word “expect” or describe a sufficient number of sexual assault investigations to support his
conclusions). To favor this brand of off-the-cuff approximations over well-settled, qualitative
principles published in numerous editions of the field’s leading textbook is hardly, to put it
mildly, the hallmark of sound judicial practice. Not only does it create a perverse incentive for
experts to fortify overstated conclusions in a manner largely unverifiable by the courts, it
circumvents the spirit and letter of Daubert’s principles. As one court so tersely put it, “a number
pulled out of the air is not ‘scientific knowledge.’” Erickson, 131 F. Supp. 2d at 1000. Rather
than resort to farcical solutions to difficult problems, courts should recognize that the contest
between valid qualitative and quantitative data is properly one for the jury. See Daubert, 509
U.S. at 596, 113 S. Ct. at 2798 (“Vigorous cross-examination, presentation of contrary evidence,
and careful instruction on the burden of proof are the traditional and appropriate means of
attacking shaky but admissible evidence.”).

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 knowledge in the field at the time. Experts have knowledge of the
standards that govern their fields—that is part of what qualifies them
as experts. . . . Although it would be ideal to have a citation to some
medical publication to support th[e] proposition, [an expert] may
testify about the standards or common knowledge of the [relevant
academic] community . . . .

Id. at 1001. The Third Circuit likewise recognized that an expert’s “testimony is

neither conjecture nor speculation” merely because there is no available publication

to substantiate it if the testimony is “well recognized by the scientific community,”

“not a novel scientific theory,” and “supported by widely accepted scientific

knowledge,” and the expert “relied on general experience and readings, general

medical knowledge, standard textbooks, and standard references.” Kannankeril v.

Terminix Internat’l, Inc., 128 F.3d 802, 809 (3d Cir. 1997). Thus, expert opinion is

not inherently unreliable merely for want of empirical studies if the information is

commonplace in the field and “[s]tatistical methods are . . . not invariably used in

such research.” Katt, 151 F. Supp. 2d at 357. Where “experience-based studies are

generally accepted in the industry,” a “court cannot penalize [a litigant] for the lack

of scientific or academic studies and public reports on the topic. . . .” Groobert,

219 F. Supp. 2d at 9, 11; accord Benedi v. McNeil-P.P.C., Inc., 66 F.3d 1378, 1385

(4th Cir. 1995) (holding that a “defendant should not be allowed ‘to escape liability

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simply because . . . there are, as yet, no . . . studies concerning [the specific subject

area]’”) (citation omitted).

A useful construct is to imagine these two factors—whether the principle is

common knowledge in the field and whether quantitative studies are available—as

positioned within a four-part box. Just as no trial court would abuse its discretion

by refusing to admit expert testimony considered experimental or speculative in the

field for which quantitative studies were available,21 a trial court would most

certainly abuse its discretion in many instances––like this one––by refusing to

admit qualitative testimony for want of statistical support where the analytic

assumptions were widely-held and relevant and probative statistical data

unavailable.

The district court in this case did not question Tressel’s experience—his

participation in 150 sexual assault cases and thousands of crime scene

investigations—or the application of that experience to the undisputed facts of the

case—the absence of any physical evidence to link Frazier to the crime of rape.

The court instead forbade his testimony because it was stated qualitatively, not

quantitatively, and not because he failed to cite any authority in the field for the

21
See, e.g., Boncher v. Brown County, 272 F.3d 484, 486-87 (7th Cir. 2001) (upholding
district court’s rejection of expert testimony that the number of jail suicides in the instant case
was “unusually high,” where studies on jail suicide rates were presumably available).

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proposition. See note 2, infra. That certain symptoms are indicative of particular

illnesses, that certain customs and practices are frequently used in particular

industries, legal or illegal, or that certain patterns of handwriting are distinctive

have rarely been challenged as an unreliable basis for expert testimony just because

they are not explicitly validated by quantitative research; even where such

quantitative data could have been collected (e.g., the Government could collect

data as to how drug dealers, money launderers, etc., do business based on collective

data from case studies). Courts recognize that such principles are commonly

known, widely-accepted, and often taken for granted in the relevant academic

community. They need not be substantiated empirically because they have risen to

the rank of platitudes within their respective fields.

This is what the Supreme Court meant when it instructed trial courts to

ensure that an expert relying on personal experience “employs in the courtroom the

same level of intellectual rigor that characterizes the practice of an expert in the

relevant field.” Kumho Tire, 526 U.S. at 152, 119 S. Ct. at 1176. What physician,

for example, would be laughed out of a medical conference for asserting without

supporting statistical data that he would expect the cause of classic flu-like

symptoms to be, of all things, the flu? Yet, this is precisely what the district court

did in response to Mr. Tressel’s testimony based on the rather uncontroversial

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assumption in his field that an experienced forensic investigator would expect to

find hair or semen transfer in a sexual assault of prolonged duration in cramped

quarters where, as here, evidence was gathered from an uncontaminated and

confined crime scene. This ruling––requiring an experience-based expert to

substantiate his conclusions with scientific data or studies––was an abuse of

discretion.

3. The District Court's Daubert Rulings were Inconsistent

The trial court's Daubert error was compounded: it excluded Tressel's

testimony relating to the import of the lack of forensic evidence found at the crime

scene––on the ground that this conclusion was not supported by scientific

data––and yet allowed the Government's witnesses to testify to this very

issue––without similarly requiring scientific support for their conclusions. On

rebuttal, the Government was allowed to convert two defense fact witnesses––the

FBI agents––into experts. Like the defense's proffer of Tressel's testimony, the

Government offered the FBI agents as experience-based experts who would be

asked to testify as to the import of the lack of forensic evidence found at the crime

scene.22 Over the defense's objection, the two agents, not surprisingly, testified that

22
The Government stated: “We proffer that we're going to be asking them about their
experience and qualifications in these matters, and asking them what the import of this testimony
they gave in this case was. To wit, was is the import of the fact that there was nothing found?”

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the lack of forensic evidence matching Frazier did not prove that he had not

committed the alleged sexual assaults. R9-363, 371, 387.

“It is an abuse of discretion ‘to exclude the otherwise admissible opinion of a

party’s expert on a critical issue, while allowing the opinion of his adversary’s

expert on the same issue.’” United States v. Gaskell, 985 F.2d 1056, 1063 (11th

Cir. 1993) (per curiam); accord United States v. Garber, 607 F.2d 92, 95-97 (5th

Cir. 1979) (en banc). This was the district court’s particular transgression here, and

it constituted an abuse of discretion.

In United States v. Gaskell, we held that it was an abuse of discretion for the

district court to allow the Government to present expert testimony on the

determinative issue in that case, while not similarly allowing the defense to present

its expert testimony. 985 F.2d at 1062-64. Gaskell involved a father charged with

murdering his infant daughter by shaking her to death. Id. at 1058. The key issue

was whether this shaking was willful or accidental. Id. at 1062. The Government

was allowed to proffer the testimony of its expert, who stated that, “We are all

taught to support the baby's head. It's fragile. You don't want to shake a baby's

heads [sic].” Id. (citation omitted). The defense was forbidden, however, from

R9 at 363 (emphasis mine).

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proffering the testimony of its expert, who would have testified to “the general lack

of public awareness of the dangers of shaking an infant.” Id. We held that the

exclusion of the defense's expert was an abuse of discretion and that this error was

“compounded” by the allowing the Government to present its experts. Id. at 1063-

64.

In this case, similar to Gaskell, the key issue is the import of the lack of

forensic evidence found in a cramped crime scene after allegedly numerous acts of

sexual activity. Like in Gaskell, the district court allowed the Government to

present the testimony of its expert witness as to the import of this lack of evidence,

but did not similarly allow the defense to present its expert on the issue. The

district court thus abused its discretion by refusing to allow the defense's expert

testimony regarding the import of the lack of forensic evidence, and this error was

compounded when the Government was allowed to present expert testimony on

this same issue.

C. Effect of Daubert Error on Frazier's Defense

While abuse of discretion is undoubtedly the measuring stick we use to

evaluate the evidentiary decisions of trial courts, we cannot apply it in a vacuum.

We must never forget that, in criminal cases, the life and freedom of a real

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individual are at stake. “[T]here are certain immutable principles of justice, which

inhere in the very idea of free government, which no member of the Union may

disregard, as that no man shall be condemned in his person or property without due

notice, and an opportunity of being heard in his defense.” Holden v. Hardy, 169

U.S. 366, 389-90, 18 S. Ct. 383, 387 (1898). “[B]y ‘the law of the land’ is intended

‘a law which hears before it condemns.’” Powell v. Alabama, 287 U.S. 45, 68, 53

S. Ct. 55, 64 (1932) (citation omitted).

A person’s right to reasonable notice of a charge against him, and an
opportunity to be heard in his defense—a right to his day in court—are
basic in our system of jurisprudence; and these rights include, as a
minimum, a right to examine the witnesses against him, to offer
testimony, and to be represented by counsel.

In re Oliver, 333 U.S. 257, 273, 68 S. Ct. 499, 507-08 (1948). “Judgment without

such citation and opportunity . . . can never be upheld where justice is justly

administered.” Hovey v. Elliott, 167 U.S. 409, 418, 17 S. Ct. 841, 845 (1897)

(citation and internal quotation marks omitted). “A defendant who has been denied

an opportunity to be heard in his defense has [indeed] lost something

indispensable.” Snyder v. Massachusetts, 291 U.S. 97, 116, 54 S. Ct. 330, 336

(1934).

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 “Under the Due Process Clause of the Fourteenth Amendment, criminal

prosecutions must comport with prevailing notions of fundamental fairness. We

have long interpreted this standard of fairness to require that criminal defendants

be afforded a meaningful opportunity to present a complete defense.” California v.

Trombetta, 467 U.S. 479, 485, 104 S. Ct. 2528, 2532 (1984) (emphasis mine);

accord United States v. Beard, 436 F.2d 1084, 1086 (5th Cir. 1971).

The right to offer the testimony of witnesses, and to compel their
attendance, if necessary, is in plain terms the right to present a
defense, the right to present the defendant’s version of the facts as
well as the prosecution’s to the jury so it may decide where the truth
lies. Just as an accused has the right to confront the prosecution’s
witnesses . . . , he has the right to present his own witnesses to
establish a defense. This right is a fundamental element of due
process of law.

Washington v. Texas, 388 U.S. 14, 19, 87 S. Ct. 1920, 1923 (1967). “Few rights

are more fundamental than that of an accused to present witnesses in his own

defense.” Chambers v. Mississippi, 410 U.S. 284, 302, 93 S. Ct. 1038, 1049

(1973). True enough, a defendant has no right to put on inadmissible evidence or

unreliable expert testimony. See Johnson v. Wainwright, 806 F.2d 1479, 1485

(11th Cir. 1986); Phillips v. Wainwright, 624 F.2d 585, 588 (5th Cir. 1980).

Several cases in our own circuit support the proposition that a criminal

defendant must be allowed to present a complete defense. In particular, we have

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reversed lower court rulings that have excluded defense testimony where we

thought a stricter standard of review prudent.

The trial court is vested with broad discretion in ruling upon the
relevancy and admissibility of evidence. Its ruling will not be
disturbed on appeal in the absence of clear abuse of that discretion.
Such discretion does not, however, extend to the exclusion of crucial
relevant evidence necessary to establish a valid defense.

United States v. Kelly, 888 F.2d 732, 743 (11th Cir. 1989) (citation and internal

quotation marks omitted) (emphasis mine). “‘When proffered [defense] evidence is

of substantial probative value, and will not tend to prejudice or confuse, all doubt

should be resolved in favor of admissibility.’” United States v. Terebecki, 692 F.2d

1345, 1351 (11th Cir. 1987) (Hill, J., dissenting) (quoting United States v.

Wasman, 641 F.2d 326, 329 (5th Cir. Unit B Apr. 2, 1981)). There can be no

question but that Frazier’s proffered expert testimony here was fundamental to his

case. Informing the jury in simple, declarative terms that forensic evidence did not

exist to substantiate the claim of rape and that hair or fluid transfer would have

been expected in this type of case, would have allowed it “to hear the whole story.”

United States v. Word, 129 F.3d 1209, 1213 (11th Cir. 1997).

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 In addition, we have also expressly relaxed otherwise strict admissibility

criteria when it is the defendant who seeks to introduce evidence under Rule 404(b)

of the Federal Rules of Evidence. In reversing the district court, we said:

Rule 404(b) is normally used by the government to show evidence of
prior similar offenses committed by the defendant. In such cases,
strict standards for admissibility protect the defendant from prejudice.
But in the case before us it was the defendant who sought to introduce
evidence of the informant’s scheme. His right to present a vigorous
defense required the admission of the proffered testimony.

United States v. McClure, 546 F.2d 670, 673 (5th Cir. 1977); see also Cohen, 888

F.2d at 776 (observing that “the standard for admission is relaxed when [FRE

404(b)] evidence is offered by a defendant”). There is no principled reason to

begrudge a criminal defendant this same remedial benefit for the admissibility of

expert testimony under Daubert.

III. CONCLUSION

I conclude that the district court abused its discretion when, under the guise

of Daubert, it required Tressel, an experience-based expert witness, to support his

conclusions with scientific data or studies. The majority concedes this, but then

ignores it. See Maj. Op. at * 40; note 4, infra. This Daubert error was compounded

when the Government's experience-based expert witnesses were not similarly

required to support their conclusions with any scientific or statistical information.

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The district court's erroneous Daubert ruling, in effect, eviscerated Frazier's

principal and only practical defense. Based on the district court's incorrect Daubert

ruling, and because I am convinced that, in cases like this, the defendant's Sixth

Amendment right to a fair trial should circumscribe an interpretation of the rules of

evidence eviscerating his defense, I must respectfully dissent.

127