Jamien Jensen v. Exc Incorporated

FOR PUBLICATION

UNITED STATES COURT OF APPEALS
FOR THE NINTH CIRCUIT

JAMIEN RAE JENSEN, individually No. 20-15908
and as parent and next friend of minor
D.J. and as Personal Representative of D.C. No.
the Wrongful Death Estate of unborn 3:15-cv-08019-
child C.J.; CHAVIS JOHNSON, SPL
individually and as Personal
Representative of the Wrongful Death
Estate of Butch Corey Johnson; OPINION
MARGARET JOHNSON; FRANK
JOHNSON; FRANCESCA
JOHNSON; JUSTIN JOHNSON;
HOLLY JOHNSON; DOMINIQUE
JOHNSON; RAYMOND JENSEN,
Sr.; LOUISE R. JENSEN; KATRINA
JENSEN; RAYMOND JENSEN, Jr.;
MURPHY JENSEN; NICOLE
JENSEN; RYAN JENSEN; JUSTIN
JENSEN,

Plaintiffs-Appellants,

v.

EXC, INC., DBA D.I.A. Express,
Inc., DBA Express Charters, a
Nevada corporation; CONLON
GARAGE, INC., a Colorado
2 JENSEN V. EXC INC.

corporation; GO AHEAD
VACATIONS, INC., a Massachusetts
corporation; RUSSELL J. CONLON,
individually; NATIONAL
INTERSTATE INSURANCE CO.,

Defendants-Appellees.

Appeal from the United States District Court
for the District of Arizona
Steven P. Logan, District Judge, Presiding

Argued and Submitted May 11, 2021
San Francisco, California

Filed September 22, 2023

Before: WALLACE and COLLINS, Circuit Judges, and
RAKOFF,* District Judge.

Opinion by Judge Collins;
Partial Concurrence and Partial Dissent by Judge Wallace

*
The Honorable Jed S. Rakoff, United States District Judge for the
Southern District of New York, sitting by designation.
 JENSEN V. EXC INC. 3

SUMMARY**

Evidence / Arizona and Tribal Law / Negligence

In a diversity action involving personal injury and
wrongful death claims arising from a collision between a
sedan and a tour bus on a U.S. highway within the
boundaries of the Navajo Nation reservation, the panel
affirmed the district court’s judgment in favor of defendants
to the extent that it dismissed all claims that had been
asserted solely under Navajo law; reversed the district
court’s judgment on the claims that were submitted for trial
because the district court erroneously allowed the
introduction of hearsay opinions of a non-testifying putative
expert; and remanded for a new trial.
The panel held that the district court abused its discretion
in allowing, under the guise of impeachment evidence
against plaintiffs’ expert witnesses, defendants’ counsel to
elicit the opinions expressed in a police report prepared by
the Arizona Department of Public Safety as to the cause of
the accident. An opinion rendered by a person of unknown
qualifications and contained in a report that, without any
other explanation, relies uncritically on the hearsay
statements of only selected witnesses and that does not
expressly take account of, or address, any other relevant
considerations, does not bear sufficient indicia of reliability
and trustworthiness to be admitted as a competing expert
“opinion” that a testifying expert may be required to address

**
This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
4 JENSEN V. EXC INC.

on cross-examination. The panel held that the error was not
harmless, and reversed and remanded for a new trial.
Next, the panel affirmed the district court’s conclusion
that Arizona law applied and its resulting dismissal of all
claims that were asserted only under Navajo law. In
determining what law governed the case, the panel applied
Arizona substantive law. Arizona courts generally follow
the Second Restatement of Conflict of Laws in determining
the applicable law in a tort case. Applying the relevant
factors set forth in the Restatement, the panel agreed with the
district court that Arizona law applied rather than Navajo
law.
Finally, plaintiffs challenged the district court’s refusal
to hold that, as a matter of law, defendant Russell Conlon’s
negligence proximately caused the accident. As a threshold
issue, the panel held that it could not review the district
court’s denial of summary judgment on the causation issue
where an actual trial has intervened between the summary
judgment ruling and the final judgment on appeal. The panel
was limited to reviewing only the denial of plaintiffs’
comparable arguments in its Fed. R. Civ. P. 50 motions for
judgment as a matter of law at trial. The panel held that the
district court properly denied plaintiffs’ motions for
judgment as a matter of law because, under Arizona law, a
reasonable jury could find that Conlon’s negligence was not
the proximate cause of the accident.
Concurring in part and dissenting in part, Judge Wallace
would affirm the district court in all respects. He concurred
with the majority that Arizona state law governed this action
and that the district court did not err in denying plaintiffs’
motion for judgment as a matter of law. He dissented from
the majority’s resolution of the evidentiary question, and he
 JENSEN V. EXC INC. 5

would hold that the district court did not abuse its discretion
in permitting defendants’ counsel to ask the plaintiffs’
experts about the police officer’s report and conclusions
because the report was sufficiently reliable to be considered
and to be the subject of limited cross-examination.

COUNSEL

Geoffrey R. Romero (argued), Law Offices of Geoffrey R.
Romero, Albuquerque, New Mexico; John P. Lavelle,
University of New Mexico, Albuquerque, New Mexico;
Thomas A. Biscup, Zebrowski Law, Shelby Township,
Michigan; for Plaintiffs-Appellants.
Eileen D. GilBride (argued), John T. Masterson, Elizabeth
A. Gilbert, and Brandi C. Blair, Jones Skelton & Hochuli
PLC, Phoenix, Arizona, for Defendants-Appellees.

OPINION

COLLINS, Circuit Judge:
This diversity suit involves personal injury and wrongful
death claims arising from a collision between a sedan and a
tour bus on a U.S. highway within the boundaries of the
Navajo Nation reservation. Before trial, the district court
held that Arizona law applies to the accident, and it therefore
dismissed all claims based on Navajo law. At trial, the jury
rejected all remaining claims asserted by the sedan’s
surviving passengers and by the estate of the sedan’s driver,
and the district court entered judgment in favor of the tour
bus driver, the tour organizer, and other related corporations.
6 JENSEN V. EXC INC.

We affirm the dismissal of all claims that were based on
Navajo law. However, we conclude that the district court
erroneously permitted defense counsel to introduce, and to
rely upon at trial, the hearsay opinions of a non-testifying
putative expert, namely, the state trooper who investigated
the crash and who expressed an opinion as to how it
occurred. We therefore affirm in part, reverse in part, and
remand for a new trial.
I
A
On the night of September 20, 2004, a group of tourists
participating in a National Parks tour organized by Go
Ahead Vacations, Inc. (“Go Ahead Vacations”) stayed at a
Hampton Inn on Highway 160 in Kayenta, Arizona, within
the Navajo reservation. Go Ahead Vacations had chartered
a bus for the tour from EXC, Inc. (“EXC”), which provided
a 2004 Van Hool 57-seat motor coach driven by Russell
Conlon. At around 8:00 AM on the morning of September
21, Conlon, together with a tour guide and 38 passengers,
boarded the bus to head out to the Grand Canyon. The
Hampton Inn from which they departed is located on the
north side of U.S. Highway 160, which is an east-west road
that “is open to the public and maintained by the State of
Arizona under a federally granted right-of-way over Navajo
Nation land.” EXC Inc. v. Jensen, 2012 WL 3264526, at *1
(D. Ariz. Aug. 9, 2012), aff’d, 588 F. App’x 720 (9th Cir.
2014), cert. denied, 579 U.S. 941 (2016). Driving the tour
bus, Conlon turned to the right out of the Hampton Inn’s
driveway, and the bus began heading westbound on
Highway 160.
At the point at which the tour bus entered Highway 160
in front of the Hampton Inn, the highway has two westbound
 JENSEN V. EXC INC. 7

travel lanes. However, shortly down the road to the west,
those two lanes merge into one. Just before he turned
westbound onto Highway 160, Conlon looked to the east and
saw a Chevy Tahoe (driven by Bert Wisner) turn out of a
nearby Burger King into the left-most westbound lane of
Highway 160. Despite seeing the Tahoe turn into the left-
most lane, Conlon turned onto the highway and then
proceeded to move into that very same left-most lane before
the Tahoe had passed the bus. Presumably annoyed that the
slow-moving 40,000-lb. bus had turned directly in front of
him in the left lane rather than stay in the right lane, Wisner
moved his vehicle into the right lane and began catching up
to the bus.
At the same time, a Pontiac Sunfire sedan driven by
Butch Corey Johnson was proceeding eastbound on
Highway 160. In the front passenger seat of the sedan was
his wife, Jamien Rae Jensen, who was holding their one-
year-old son D.J. and who was also pregnant with their
unborn second child. The front left of Johnson’s sedan
collided with the front left of the tour bus. Johnson died as
a result of the crash, Jensen and their son D.J. suffered
injuries, and Jensen’s unborn child was killed. At the time
of the collision, Wisner’s Tahoe was next to the bus. Both
vehicles veered to the right, following roughly parallel paths
until they came to rest off the north side of the westbound
highway, about 20 to 25 feet apart from each other.
At the time of the accident, Highway 160 had just been
resurfaced and the lanes were marked with temporary yellow
tabs instead of painted lines. The parties agree that the
accident occurred in the vicinity of the left-most westbound
lane, but they disagree about most other major points about
exactly what happened. Plaintiffs’ theory at trial was that
Johnson was driving in the lane immediately to the south of
8 JENSEN V. EXC INC.

the left-most westbound lane (which was either a center,
universal turn lane or was the left-most eastbound lane); that
Conlon, distracted by Wisner’s nearby vehicle, entered
Johnson’s lane; and that Conlon veered to the right shortly
before the impact. Defendants’ theory was that Johnson
crossed into the westbound lanes and collided with the bus.
B
The ensuing tort litigation was first filed in the courts of
the Navajo Nation in 2006, but we ultimately held in
December 2014 that the tribal court lacked jurisdiction. See
EXC, Inc., 588 F. App’x at 722. Two months later, this
lawsuit was filed in federal court by Jensen, suing
individually and on behalf of D.J., and by Johnson’s brother
Chavis Johnson, as the representative of Johnson’s wrongful
death estate (collectively, “Plaintiffs”). Named as
Defendants were Conlon, EXC, Go Ahead Vacations, and
another corporation related to Conlon (collectively,
“Defendants”). Asserting that Navajo law applied and
permitted additional persons to sue for damages arising from
Johnson’s death, the original complaint named, as additional
plaintiffs, the wrongful death estate of Jensen’s unborn child
and several additional family members other than Jensen and
D.J. The complaint also asserted, based on Navajo law,
direct claims against EXC’s insurer. However, the district
court subsequently granted Defendants’ motion for
judgment on the pleadings and held that Arizona law, not
Navajo law, governed this case. Accordingly, the court held
that “Plaintiffs and Defendants that have been made party to
this suit pursuant only to Navajo and customary law are
dismissed with prejudice.”
Plaintiffs then filed their operative First Amended
Complaint. That complaint asserted two causes of action:
 JENSEN V. EXC INC. 9

(1) a claim for personal injuries and related damages caused
by negligence, negligence per se, and aggravated
negligence; and (2) a claim, based on similar alternative
theories of negligence, for wrongful death. The case
ultimately proceeded to a jury trial. After the district court
denied Plaintiffs’ motion for judgment as a matter of law
under Federal Rule of Civil Procedure 50(a), the case was
submitted to the jury, which rendered a special verdict
finding that Defendants were not at fault for the death of
Johnson or for the injuries to Jensen and D.J. The clerk
entered judgment on the jury verdict for Defendants in
December 2019, and Plaintiffs thereafter filed a timely
renewed motion for judgment as a matter of law under Rule
50(b). The district court denied that motion in April 2020,
and Plaintiffs timely appealed. See FED. R. APP. P.
4(a)(4)(A)(i).
II
Plaintiffs argue that the district court erred in allowing,
under the guise of impeachment evidence against Plaintiffs’
expert witnesses, the introduction of inadmissible evidence
from a police report prepared by the Arizona Department of
Public Safety (“ADPS” or “DPS”). We review a district
court’s admission of evidence, including purported
impeachment evidence, for abuse of discretion. See, e.g.,
United States v. Osazuwa, 564 F.3d 1169, 1173 (9th Cir.
2009). We conclude that the district court abused its
discretion and that the error was not harmless. Therefore,
we remand for a new trial.
A
Prior to trial, Plaintiffs filed a motion in limine
concerning the accident reports that had been prepared by
the ADPS and by the Kayenta Police Department. In their
10 JENSEN V. EXC INC.

motion, Plaintiffs conceded that the portions of the police
reports that contained “personal knowledge, photos, and
measurements taken by the investigating officers” were
admissible under Federal Rule of Evidence 803(8)(A)’s
hearsay exception for public records. But to the extent that
the reports contained “discussions, opinions, and
conclusions about what allegedly happened based on
interviews and other inadmissible sources,” Plaintiffs
contended that the reports were inadmissible hearsay under
Rule 802 and also that they were unduly prejudicial under
Rule 403. Therefore, Plaintiffs requested that the district
court exclude “any evidence, testimony, reference, or
argument related to investigation of the accident, including
any conclusions or opinions, that are not based solely on
personal knowledge and measurements.” In their response
to this motion, Defendants stated that they did “not object to
. . . preclusion of hearsay contained within police reports,
coroner’s reports, and medical records that are not subject to
a hearsay exception.” The district court granted Plaintiffs’
motion in limine. In doing so, the court agreed that
Defendants could still “introduce statements in the police
reports that are made by the officer and based on personal
knowledge and observation,” but the court cautioned that,
before seeking to introduce any such statements, Defendants
should first request a “sidebar” to “raise the issue with the
Court.”
On the second day of trial, Plaintiffs called Robert
Turner, whom the district court found to be qualified to
testify as an expert “in commercial vehicle code enforcement
and training.” During his brief direct examination, Turner
testified that, by moving into the left-most westbound lane
of Highway 160 when he exited the Hampton Inn parking
lot, Conlon had violated Arizona Revised Statutes § 28-721,
 JENSEN V. EXC INC. 11

which he said generally required the bus to stay in the right-
most lane. See ARIZ. REV. STAT. § 28-721 (2004 ed.).1 On
cross-examination, Turner further opined that Conlon
“should have waited until the Tahoe had passed” before
turning into the highway and that, in his view, the “main
cause” of the accident “was the fact that the bus” moved “out
of its lane” and “was to the left of the lane.” Defense counsel
elicited from Turner that he had reviewed the ADPS report
about the accident, and counsel then asked if “that was one
of the materials or documents [Turner] relied upon in
preparing [his] opinions as an expert witness.” Turner
responded, “It all contributed. I read it all and evaluated it.”
Turner also confirmed that it would be “customary” and
“reasonable” for an expert in his field to review such reports.
Defense counsel then asked for a sidebar, which the court
allowed. Counsel stated that he “want[ed] to be careful
because of a motion in limine,” and he explained that he was
“intending to ask the witness about information he reviewed
in the Arizona Department of Public Safety report that
includes witness statements, statements from the driver, and
actual information provided by the DPS officer in that report
that this witness just testified he relied upon in preparing his
opinions.” Defense counsel argued that he should be
allowed to ask about those items to show “bias of this
witness, because what he’s doing is he’s disregarding every
single witness and every single finding other than” the
findings of another of Plaintiffs’ experts (Gabriel
Alexander). Defense counsel specifically stated that he
wanted to ask Turner about the ADPS report’s conclusion
“that there was no improper driving by the bus.” Plaintiffs’
counsel objected, stating that only the officers’ own
“measurements” and observations should be admitted and
1
The text of that statute is quoted and discussed below. See infra note 9.
12 JENSEN V. EXC INC.

not the “ultimate conclusions by the officers.” Plaintiffs’
counsel also objected that the “opinion by the officer is not
expert testimony opinion.” Defense counsel responded by
arguing that it is proper to ask an expert witness about what
he “read and relied upon in preparing his opinions.” The
court ruled that, because it had “agreed that [Turner] should
be considered as an expert,” it would allow “that limited
question.”
Defense counsel then engaged in the following
questioning:

Q. When you read the Arizona Department of
Public Safety report, you noted in the report
that vehicle number one—excuse me, sir—or
traffic unit number one is the white car driven
by Butch Johnson. Do you recall that?
A. I remember, yes.
Q. And traffic unit two or vehicle number two
is the bus, right?
A. Yes.
Q. And as you recall that the Department of
Public Safety police report indicated that
with respect to vehicle number two, the bus,
there was no improper action, right?
A. I vaguely remember that.
Q. Okay.
A. It’s been awhile since I reviewed that
report.
Q. And in the DPS report, the DPS officer
who investigated the accident who was
 JENSEN V. EXC INC. 13

actually out at the scene of the accident,
investigated the accident, took the
measurements, talked to all the witnesses,
also determined that the car driven by Mr.
Johnson was traveling at a speed too fast for
conditions, correct?
A. That may have been in the report, yes.
Q. And the Department of Public Safety
police report shows that vehicle number one,
the car driven by Mr. Johnson, engaged in
unsafe passing?
A. In unsafe passing?
Q. Yes, sir.
A. Like I say, it’s been awhile since I read the
report, so—
Q. Would you disagree with me if I tell you
it says that?
A. I’d have to look at it.
Q. Well, you do agree that the report says
there was no improper action by the bus,
right?
A. I remember some of that, yes.
Q. And you do agree with me that the DPS
report states that the car driven by Mr.
Johnson was traveling at a speed too fast for
conditions, right?
A. Well, if the report says that and it conflicts
with the—if it conflicts—
14 JENSEN V. EXC INC.

Q. Well, ley me stop you, sir, because my
question was only doesn’t the report say that?
A. Does it say that? Yes.
Q. Okay. So the Arizona Department of
Public Safety—And that’s the Highway
Patrol, right, the state police?
A. Right.
Q. They went out to the scene of the accident,
investigated the accident, made
measurements, took photos, correct?
A. Yes.
Q. Talked to witnesses at the scene who saw
the accident, correct?
A. Yes.
Q. And they were out there the same day as
the accident, right?
A. Yes.
Q. And the Arizona Department of Public
Safety report says, with respect to the bus,
there was no improper action, right?
A. Yes.
Q. And says the white car driven by Mr.
Johnson was driving too fast?
A. Could I speak to that?
Q. Well, is the answer yes?
A. Yes.
 JENSEN V. EXC INC. 15

Plaintiffs also called Gabriel Alexander, whom the
district court found was qualified to testify as an expert on
“accident reconstruction.” On direct examination,
Alexander opined that, based on the position of the bus’s tire
skid marks, he believed that the bus was over the line of the
left-most westbound lane at the time of the accident.
Alexander’s view was that, because Conlon was aware that
Wisner was trying to pass him on the right before the two
westbound lanes merged down to one, Conlon moved
leftward to allow Wisner to pass and ended up going over
the line into the eastbound lane. Although the point was
sharply disputed at trial, Alexander testified that he believed
that the arrangement of temporary tabs marking the lanes did
not provide for a center, universal turn lane—meaning in his
view that, when Conlon assertedly crossed over the line, the
bus was in the eastbound lanes rather than a center turn lane.
Alexander estimated that, “[p]rior to impact, [Conlon] was
about five feet” over the line. Alexander’s opinion was that,
in reaction to seeing the bus come over the line, Johnson then
veered to his left; that Conlon simultaneously veered back to
his right; and that the two vehicles then collided. Alexander
also opined that Conlon must have been over the center line
because, if he had instead begun moving right from the
westbound lanes, he would have hit Wisner’s vehicle, which
would have been too close to the bus to react in time. The
fact that Wisner had time to react and to stay parallel to the
bus as it drove off the road on the right suggested to
Alexander that the bus had been further to the left from
Wisner when it first began moving over to the right.
On cross-examination, Alexander acknowledged that his
expert report had not claimed that there was no center
universal turn lane and that, during his deposition, he had
agreed that there was such a lane. Alexander further
16 JENSEN V. EXC INC.

acknowledged that his own diagram showed that there was a
center turn lane further east, in front of the Hampton Inn and
the Burger King. Alexander also admitted that, in his
deposition, he had agreed that, at the time of impact, no part
of Johnson’s vehicle was in the eastbound lanes but was
instead “completely in the universal turn lane or even
partially within the westbound lane.” On redirect, Alexander
noted that he had also stated during his deposition that only
one side of what would have been the universal turn lane had
double yellow tabs, meaning that, from Johnson’s
perspective, the lane would appear to be an eastbound lane.
During cross-examination, Alexander was also asked
about his assumption that there had been no contact between
the bus and Wisner’s Tahoe. Although the parties had
formally stipulated that “[t]here was no contact between the
bus and Mr. Wisner’s SUV,” Wisner actually testified at his
deposition that the bus hit his “left-hand mirror,” but no
other part of his vehicle. The relevant deposition excerpts
were presented to the jury, and defense counsel asked
Alexander whether Wisner’s testimony was consistent with
his theory. Alexander responded that he did not “see how it
could have happened” that way, and he agreed that, if Wisner
said that, he was “just wrong.”
At one point in the cross-examination, Defense counsel
confirmed that Alexander had reviewed and relied upon the
ADPS report, and counsel then engaged in the following
colloquy with Alexander:

Q. And the Arizona Department of Public
Safety did investigate this accident, right?
A. Yes.
 JENSEN V. EXC INC. 17

Q. And a state trooper went out to the scene
of the accident on the day of the accident and
took photographs and measurements and
talked to witnesses and prepared the report
that you reviewed, right?
A. Well, I’m going to assume that.
Q. Okay. And then based upon the
investigation conducted by the state trooper
at the scene of the accident on the day of the
accident, a report was prepared, correct?
A. That’s correct.
Q. And the report and—and you reviewed the
report—says that traffic unit one, Johnson,
was traveling eastbound on U.S. 160 when it
crossed the center line and collided into
traffic unit two, correct?
A. Yes.
Q. And it also says, with respect to vehicle
number two, the bus, there was no improper
action, correct?
A. That’s correct.
Q. And the Arizona Department of Public
Safety report, the investigating officer also
checked the box that indicates that vehicle
number one, the Johnson car, was traveling at
a speed too fast for conditions, correct?
A. That’s correct.

Defense counsel subsequently mentioned the ADPS
report during his closing argument. After first noting that all
18 JENSEN V. EXC INC.

of the eyewitnesses to the accident testified that Johnson
drove into the bus, defense counsel stated:

The Department of Public Safety
highway patrol officer who was at the scene
of the accident who investigated the accident
on the same day of the accident designated
the Johnson vehicle [as] vehicle number one.
What does that mean?
Well, Mr. Alexander told you that DPS
officers will determine who they think is at
fault, and they will designate that vehicle [as]
vehicle number one. So the DPS officer who
was at the scene of the accident that day,
investigated the accident, talked to witnesses,
took photographs, took measurements, made
the decision that Mr. Johnson’s vehicle was
the at-fault vehicle, vehicle number one.
And the DPS officer went further. The
DPS officer who investigated the accident,
who was at the scene of the accident, who
took photographs, who took statements, who
took measurements stated that the Johnson
vehicle was traveling eastbound on U.S. 160
when it crossed the center line and collided
into traffic unit number two. Traffic unit
number two is the bus.
And the DPS report prepared by the
officer who was at the scene, who
investigated the accident, who took
measurements, who took photographs, who
talked to witnesses and prepared a report
 JENSEN V. EXC INC. 19

said, with respect to vehicle number two, the
bus, there was no improper action.
And he also noted that the Johnson
vehicle was traveling at a speed too fast for
conditions, in other words, that he was
speeding.

Defense counsel then argued that Alexander’s opinion
concerning the accident was not credible because Alexander
had changed his view about whether there was a universal
turn lane and because Alexander’s opinion was inconsistent
with all of the eyewitness testimony, with Wisner’s
testimony about his left mirror being hit by the bus, and with
the ADPS report.
B
On appeal, Plaintiffs renew their objections, made in
their pretrial motion in limine and during the sidebar at trial,
that (1) no portion of the ADPS police report should have
been admitted other than the officers’ own “measurements”
and observations; and (2) in particular, the “opinion by the
officer” concerning the accident “is not expert testimony”
and the “ultimate conclusions by the officers” should have
been excluded. We conclude that, on this record, the district
court abused its discretion in allowing Defendants’ counsel
to elicit the opinions expressed in the ADPS report as to the
cause of the accident.
As a general matter, hearsay is an out-of-court statement
offered “to prove the truth of the matter asserted in the
statement,” FED. R. EVID. 801(c)(2), and it is “not
admissible” unless otherwise provided by federal statute or
rules, FED. R. EVID. 802. Among the exceptions provided in
the Federal Rules of Evidence is the exception for public
20 JENSEN V. EXC INC.

records, which states that the rule against hearsay does not
exclude a “record or statement of a public office” that “sets
out . . . a matter observed while under a legal duty to report,
but not including, in a criminal case, a matter observed by
law-enforcement personnel.” FED. R. EVID. 803(8)(A)(ii).2
This public-records hearsay exception applies only if “the
opponent [of admission] does not show that the source of
information or other circumstances indicate a lack of
trustworthiness.” FED. R. EVID. 803(8)(B). We have held
that, under the public-records exception, “entries in a police
report which result from the officer’s own observations and
knowledge may be admitted” in a civil case. United States
v. Morales, 720 F.3d 1194, 1202 (9th Cir. 2013) (emphasis
added) (citation omitted). By contrast, any statements from
third parties that are recounted in a police report involve an
additional layer of hearsay that must be separately justified
by another exception to the hearsay rule. See FED. R. EVID.
805; see also Morales, 720 F.3d at 1202 (stating that “the
exception allowing for a ‘matter observed while under a
legal duty to report’ in Rule 803(8) ‘generally does not pave
the way for official records to prove conclusions resting on
statements by outsiders or to prove what such outsider
statements themselves assert’ unless ‘the outsider’s
statement itself fits an exception’” (citation omitted)).
Contrary to what Plaintiffs suggest, this latter restriction
against the admission, for their truth, of the contents of third-
party statements recounted in police reports was not violated

2
The evidence rules also contain a separate hearsay exception for
business records, see FED. R. EVID. 803(6), but we have held that “this
exception does not apply to records of government agencies, which are
public records for purposes of Rule 803.” United States v. Morales, 720
F.3d 1194, 1201 (9th Cir. 2013); see also United States v. Orozco, 590
F.2d 789, 793–94 (9th Cir. 1979).
 JENSEN V. EXC INC. 21

in this case. As our earlier verbatim excerpts of the relevant
questioning and arguments make clear, defense counsel did
not disclose or elicit anything about the actual substance of
any witness statements recounted in the police report.
Instead, he elicited that the officer at the scene took various
witness statements—whose content was not disclosed—and
that the officer then reached a conclusion, based on all of the
information gathered (including those statements), as to how
the accident occurred. See supra at 12–19.
The central question, instead, is whether the district court
properly admitted, in cross-examination of Plaintiffs’
experts, the police report’s conclusions as to how the
accident transpired. That question implicates, in the first
instance, a different provision of the public-records
exception to the hearsay rule, viz., a portion of Rule 803(8)
that allows the admission—absent a showing of lack of
trustworthiness—of a “record or statement of a public
office” that sets out, “in a civil case or against the
government in a criminal case, factual findings from a
legally authorized investigation.” FED. R. EVID.
803(8)(A)(iii); see also FED. R. EVID. 803(8)(B). The
Supreme Court has held that the “factual findings” covered
by this hearsay exception include a “conclusion” or
“opinion” in such a report that “is based on a factual
investigation” as described in the rule and that “satisfies the
Rule’s trustworthiness requirement.” Beech Aircraft Corp.
v. Rainey, 488 U.S. 153, 170 (1988) (construing the same
hearsay exception, which was then in Rule 803(8)(C)). That
construction of the rule would extend to a police report’s
conclusions as to the manner in which a traffic accident
occurred. See, e.g., Simmons v. Chicago & Nw. Transp. Co.,
993 F.2d 1326, 1327–28 (8th Cir. 1993).
22 JENSEN V. EXC INC.

In moving in limine to exclude the police report,
Plaintiffs argued that the report’s conclusions were
untrustworthy and were therefore inadmissible under Rule
803(8). In their response to the in limine motion, Defendants
did not contest that point, and the district court granted the
motion. In later seeking admission of additional portions of
the report, Defendants did not rely on Rule 803(8), nor did
they contend that Plaintiffs had failed to show “a lack of
trustworthiness.” FED. R. EVID. 803(8)(B). At the sidebar,
after Plaintiffs’ counsel reiterated that the court’s in limine
ruling had excluded the “opinion[s]” and “conclusions” of
the officers as hearsay, and Defendants’ counsel again did
not dispute that point. Instead, Defendants’ counsel’s
position was that his proposed line of questioning did not
“really involve[] the motion in limine,” because his purpose
was to “show[] [the] bias” of Plaintiffs’ expert by cross-
examining him about “what he analyzed” and “what he
disregarded.” Moreover, in response to Plaintiffs’ reliance,
in their appellate opening brief, on caselaw construing the
limitations on admission of police reports under Rule 803(6)
and 803(8), Defendants’ answering brief never argued that
the report’s conclusions were admissible under Rule
803(8)(A)(iii). We therefore deem any reliance upon Rule
803(8) to be forfeited, and we proceed on the basis that the
opinions expressed in the report were hearsay that is not
covered by any exception.3

3
In any event, for the reasons discussed below, we conclude that the
police report’s opinion as to the cause of the accident lacked sufficient
independent indicia of trustworthiness to be admissible in the absence of
an adequate foundation as to the expert qualifications of the report’s
author and the methods and reasoning used to reach those conclusions.
See infra at 24–32. These same considerations confirm that, had
Defendants sought to rely on Rule 803(8), the district court would have
abused its discretion had it invoked that rule here.
 JENSEN V. EXC INC. 23

Defendants nonetheless contend that the questioning
constituted permissible cross-examination under Rules 703
and 705, which address the extent to which an expert may be
questioned about the bases for his or her opinion. Rule 703
generally allows experts to rely on otherwise inadmissible
evidence in formulating their opinions “[i]f experts in the
particular field would reasonably rely on those kinds of facts
or data in forming an opinion on the subject.” FED. R. EVID.
703. However, the “proponent of the opinion” may not
disclose such otherwise-inadmissible “facts or data” to the
jury unless “their probative value in helping the jury evaluate
the opinion substantially outweighs their prejudicial effect.”
Id. (emphasis added). By contrast, Rule 705 then broadly
allows the opposing party, on cross-examination, to elicit
any “underlying facts or data” on which the opinion was
based. FED. R. EVID. 705. Defendants argue that, because
Plaintiffs’ experts both stated that they had reviewed and
relied on the police report, Rule 705 allowed Defendants to
cross-examine the experts about the report’s contrary
opinion concerning the cause of the accident. We disagree.
In evaluating this argument, we begin with the full text
of Rule 705, which states:

Unless the court orders otherwise, an expert
may state an opinion—and give the reasons
for it—without first testifying to the
underlying facts or data. But the expert may
be required to disclose those facts or data on
cross-examination.

FED. R. EVID. 705 (emphasis added). With respect to the
particular expert who is being examined on the stand, Rule
705 thus distinguishes between three distinct aspects of the
24 JENSEN V. EXC INC.

expert’s opinion testimony, namely: (1) the ultimate
“opinion” that the expert has been found to be qualified to
render in accordance with the strictures of Rule 702; (2) the
“underlying facts” and “data” on which that opinion is
based4; and (3) the “reasons” why the expert drew that
“opinion” from those “underlying facts” and “data.” Id. In
appropriate cases, the “underlying facts” and “data” on
which an expert’s opinion is based may, in turn, include the
opinion of another expert with respect to a subsidiary issue.
See Westfield Ins. Co. v. Harris, 134 F.3d 608, 612 (4th Cir.
1998). And the underlying facts or data on which the
opinion is based may also include facts that are “unfavorable
to the opinion”—i.e., facts that are among those considered
by the expert but that, for one reason or another, were
discounted in formulating the expert’s opinion. See FED. R.
EVID. 705, advis. comm. note (1972 proposed rule).
The question presented here is how these principles
apply in the unique context of a testifying expert’s review of
a contrary opinion rendered by another person on the very
same issue that is the subject of the testifying expert’s
opinion. Defendants’ position is that, simply because
Plaintiffs’ experts’ read the police report and relied on its
data, that report’s contrary opinion on the cause of the
accident is properly deemed to be among the unfavorable
“facts or data” that may be freely elicited on cross-
examination of those experts under Rule 705. But, as we and
other courts have acknowledged, the unique situation of
4
In referencing “the underlying facts or data,” Rule 705 clearly refers
back to the “facts or data” on which the expert has “base[d]” an
“opinion,” as addressed in Rules 702 and 703. See FED. R. EVID. 702(b)
(stating that, to be admissible, expert testimony must, inter alia, be
“based on sufficient facts or data”); FED. R. EVID. 703 (“An expert may
base an opinion on facts or data in the case that the expert has been made
aware of or personally observed.”).
 JENSEN V. EXC INC. 25

questioning one expert about the competing opinion of a
non-testifying expert on the very same issue is one that raises
special concerns that defy such a simplistic rule.
In Phillips v. E.I. DuPont de Nemours & Co. (In re
Hanford Nuclear Reserv. Litig.), 534 F.3d 986 (9th Cir.
2008), we expressly “agree[d] with the Fifth Circuit that
reports of other experts cannot be admitted even as
impeachment evidence unless the testifying expert based his
opinion on the hearsay in the examined report or testified
directly from the report.” Id. at 1012 (emphasis added)
(citing Bryan v. John Bean Div., 566 F.2d 541, 546–47 (5th
Cir. 1978)). That principle was easily applied in Phillips,
where (unlike in this case) the opposing counsel cross-
examined an expert with opinions expressed in a document
that the testifying expert had not even read. Id. at 1011–12
(noting that the testifying expert had “never read nor relied
on [the non-testifying expert’s] deposition in rendering his
expert opinion”). But our express endorsement of the Fifth
Circuit’s decision in Bryan confirms that the principle
applied in those cases is not so narrow.
In Bryan, the plaintiff, an automobile mechanic, was
grievously injured when a cast-iron tool used in aligning
wheels “broke into pieces under pressure.” 566 F.3d at 543.
He sued John Bean Corp. (“Bean”), which had designed and
distributed the tool, on strict-liability theories of design
defect and manufacturing defect. Id. at 543, 549. Bean in
turn filed a third-party claim against Midland-Ross Corp.
(“Midland-Ross”), which had manufactured the tool for
Bean. Id. In rebutting the claims of manufacturing defect at
trial, Midland-Ross presented testimony from an expert
(“Walters”), who opined that the tool “as manufactured was
sufficiently strong to sustain the stress it would have
encountered in normal use in the proper manner.” Id. at 544.
26 JENSEN V. EXC INC.

In reaching his opinion, Walters had affirmatively relied on
data provided by two non-testifying metallurgical experts,
one of whom had been retained by the plaintiff and the other
by Bean. Id. Given the adversity between Midland-Ross
and both Bean and the plaintiff, there were aspects of these
non-testifying experts’ opinions that were unfavorable to
Midland-Ross, and “[o]n cross-examination of Walters,
plaintiff’s counsel made maximum use of the opinions
expressed in the two reports.” Id. Indeed, the plaintiff’s
counsel “made much greater use of the opinions than of the
data underlying them.” Id. Midland-Ross objected, arguing
that “the facts recited in the reports were admissible but the
opinions of the experts were not.” Id. The district court
rejected this distinction, concluding that “the opinions were
admissible because they were supporting data for Walters’
opinion.” Id.
The Fifth Circuit reversed, holding that the portions of
the non-testifying experts’ opinions elicited by the plaintiff’s
counsel “were improperly admitted either as evidence of the
basis of the testifying expert’s opinion or as impeachment
evidence.” 566 F.2d at 545. The court noted that, through
this cross-examination, the “opinions” of the non-testifying
experts “were brought before the jury without qualifying the
experts who rendered them” in accordance with the
requirements of Rule 702. Id. at 546. As such, “[t]he jury
had no way of determining whether the opinions were
credible or worthy of belief.” Id. Moreover, no hearsay
exception applied, the court concluded, and the limited
excerpts elicited about the non-testifying experts’ opinions
“lacked any independent guarantee of trustworthiness that
would justify dispensing with cross-examination.” Id.
Finally, the court held that Rule 705 did not authorize
bringing out these opinions on cross-examination of
 JENSEN V. EXC INC. 27

Walters, because Walters had not “based his opinion on the
opinion in the examined report,” nor had he “testified
directly from the report.” Id. (emphasis added). Walters
admitted that he used “empirical data contained in the
reports and employed these figures to reach his own
conclusions,” and the court held that such data “were
properly brought out under rule 705.” Id. But the competing
“conclusions reached by the other experts” had not been
relied on by Walters, and they could not impeach his opinion
in the absence of an adequate foundation as to the
“substantive correctness of the other experts’ conclusions.”
Id. (emphasis added). Because no such foundation had been
established, “the conclusions of [the] nontestifying experts
were inadmissible under rule 705 either as the facts and data
on which the testifying expert based his opinion or as
impeachment evidence.” Id. at 547.
We find the reasoning of Bryan, which we endorsed in
Phillips, to be persuasive and dispositive in this case. Here,
“the excerpts proffered by [defense] counsel from the
[police] report[]”—which consisted of the author’s opinion
as to the cause of the accident—“lacked any independent
guarantee of trustworthiness that would justify dispensing
with cross-examination” of the report’s author, and there
was likewise no effort to “qualify[]” as an expert the person
“who rendered” that opinion. 566 F.2d at 546. As Plaintiffs
noted in their motion in limine, the report does not provide
any basis for the conclusions that it reached other than the
statements made by the bus driver (Defendant Conlon) and
one of the bus passengers. Nor does the report provide any
information as to the qualifications of the author to render an
28 JENSEN V. EXC INC.

expert opinion as to the cause of the accident.5 An opinion
rendered by a person of unknown qualifications and
contained in a report that, without any other explanation,
relies uncritically on the hearsay statements of only selected
witnesses and that does not expressly take account of, or
address, any other relevant considerations, does not bear
sufficient indicia of reliability and trustworthiness to be
admitted as a competing expert “opinion” that a testifying
expert may be required to address on cross-examination.
Defendants note that Bryan suggested that a report’s
conclusions might be admissible where “an uninterested,
expert third party prepared the report,” 566 F.2d at 546
(citing Challoner v. Day & Zimmermann, Inc., 512 F.2d 77
(5th Cir.), vacated on other grounds, 423 U.S. 3 (1975)), but
this argument is unavailing. Although the author of the
ADPS report was “uninterested,” there was no basis to
conclude that he was qualified as an “expert.” Moreover,
there is no indication in Challoner that there was any dispute
as to the validity of the underlying methods used by the
government agents who conducted the tests that were
described in the reports at issue in that case. See Challoner,
512 F.2d at 83. Here, as in Bryan, the validity of the
methodology used in the relevant report was disputed and,
in the present case, that validity was not established.
Moreover, as in Bryan, the fact that Walters, the
testifying expert, had read the police report did not provide
sufficient grounds, without more, to cross-examine him
about its competing conclusions. Walters never stated that
“he relied on the conclusions” reached in the report, as

5
The conclusions of the report’s author cannot be deemed to be
admissible lay opinion, because they are not “limited to one that is . . .
rationally based on the [author’s] perception.” FED. R. EVID. P. 701.
 JENSEN V. EXC INC. 29

opposed to the “empirical data contained in the reports.”
Bryan, 566 F.2d at 546 (emphasis added). Nor did Walters
open the door to cross-examination about the report’s
competing conclusions by, for example, affirmatively
bringing up those conclusions and attacking them. Cf.
Vodusek v. Bayliner Marine Corp., 71 F.3d 148, 157 (4th
Cir. 1995) (holding that, where a testifying expert stated on
direct examination that “he had read all of these non-
testifying experts’ depositions and disagreed with the
experts’ opinions,” the district court did not abuse its
discretion in permitting cross-examination “as to why he
rejected those opinions,” even though that introduced “what
otherwise would have been inadmissible hearsay”). Under
these circumstances, the report’s opinions—as opposed to its
underlying factual data based on the officer’s observations—
could only provide proper grist for cross-examination if an
adequate foundation were laid to establish “the substantive
correctness” of those conclusions. Bryan, 566 F.2d at 546
(emphasis added). Here, no such foundation appears in the
record.
In arguing for a contrary conclusion, Defendants relied
heavily on the Eighth Circuit’s opinion in Ratliff v. Schiber
Truck Co., 150 F.3d 949 (8th Cir. 1998). In Ratliff, defense
counsel’s cross-examination of the plaintiff’s expert on
accident reconstruction elicited the fact that the state
trooper’s report of the accident opined that, if the plaintiff
had not been speeding, the accident would not have
occurred. See 150 F.3d at 953. The Eighth Circuit held that
the district court did not abuse its discretion in allowing the
cross-examination. See id. at 955. The court held that it did
not matter whether the author of the police report was
qualified as an expert and that the cross-examination was
proper simply because the testifying expert had “reviewed”
30 JENSEN V. EXC INC.

the police report and the “report” was a “document of the
type reasonably relied upon by accident reconstructionists in
forming their opinions.” Id.
We reject the Eighth Circuit’s undifferentiated analysis,
which ignores the unique concerns that we and the Fifth
Circuit have identified with respect to cross-examining
experts about contrary opinions that are contained in hearsay
documents and that lack any adequate foundation as to their
reliability or validity. The fact that accident
reconstructionists rely on police “reports” does not
automatically mean that everything included in such a report
is, without more, fair game for cross-examination. As Bryan
explains, there is a critical difference between relying on the
“empirical data contained” in a report and relying on the
contrary “conclusions” contained in that report. 566 F.2d at
546. Defense counsel’s cross-examination in the instant
case did not establish that Plaintiffs’ experts had relied on
the opinions in the ADPS report and, on this record, they
could not have established that. See Phillips, 534 F.3d at
1012 (holding that “reports of other experts cannot be
admitted even as impeachment evidence unless the testifying
expert based his opinion on the hearsay in the examined
report or testified directly from the report”).6

6
The dissent makes the same mistake, erroneously concluding that cross-
examination was proper under Rule 705 because Plaintiffs’ experts
supposedly relied on a “competing conclusion that they reviewed and
that is of a kind that is reasonably relied upon by other experts.” See
Dissent at 49 (emphasis added); see also id. at 52 (asserting that the
cross-examination allowed here was proper because “that opinion is of a
kind reasonably relied on by other experts in the field” (emphasis
added)). As we have explained, Defendants’ counsel simply did not
establish that Plaintiffs’ experts had relied on the opinions in the ADPS
 JENSEN V. EXC INC. 31

Moreover, the risk of unfair prejudice is substantial
when, as here, a party is allowed to cross-examine a properly
qualified expert with a contrary opinion rendered by a person
whose qualifications, methods, and reasoning have not been
adequately established. See FED. R. EVID. 403. The careful
strictures that Rule 702 sets on expert testimony would be
substantially undermined if, in cross-examining an expert, a
contrary expert opinion that the testifying expert has read
and rejected can be placed before the jury with insufficient
foundation as to its adequacy. The risk of unfair prejudice
is particularly great where, as here, the contrary opinion was
rendered by a law enforcement or other government official,
inasmuch as—without any adequate foundation—it puts the
imprimatur of the State behind the contrary view. Indeed,
that seemed to be the only purpose served by the cross-
examination here. Nothing in the principles described above
prevented defense counsel from exploring, in appropriate
cross-examination, why the testifying expert rejected other
competing substantive explanations for how the accident
occurred. But it is quite another matter to put before the jury,
without proper foundation, the additional fact that a
particular person who studied the matter reached the
opposite conclusion.7 In such circumstances, the risk of

report, nor did counsel establish that those (unexplained) opinions were
the kind of facts upon which experts would reasonably rely in forming
their own opinions.
7
The dissent is therefore wrong in contending that our decision would
broadly preclude cross-examination as to alternative explanations or
methodologies that were affirmatively considered and rejected by a
testifying expert. See Dissent at 51–52. Here, the ADPS report did not
meaningfully explain its methodology, and it instead appeared to rely on
uncritical acceptance of the statements of Conlon and one passenger. See
supra at 27–28. Plaintiffs’ experts were examined and cross-examined
32 JENSEN V. EXC INC.

unfair prejudice greatly outweighs the meager probative
value of this limited fact.
Accordingly, we hold that the district court abused its
discretion in allowing defense counsel, on cross-
examination of Plaintiffs’ experts, to elicit the contrary
conclusions about the cause of the accident in the ADPS
report.
C
“[W]hen reviewing the effect of erroneous evidentiary
rulings, we will begin with a presumption of prejudice.”
Obrey v. Johnson, 400 F.3d 691,701 (9th Cir. 2005). Here,
Defendants have failed to carry their burden to establish that
“it is more probable than not that the error did not materially
affect the verdict.” United States v. Bailey, 696 F.3d 794,
803 (9th Cir. 2012) (citation omitted); see also id. (stating
that the “burden to show the harmlessness of the error is on
the party benefitting from the error”).
As noted earlier, the central contested issue in the case
concerned how the accident happened, and the parties’
competing experts drew sharply different conclusions as to
the cause of the accident. Moreover, Plaintiffs’ experts’
analysis played an important role in Plaintiffs’ argument as
to why the eyewitness accounts of the bus passengers who
testified were not reliable. And, as we have explained, the
introduction of the fact that the ADPS had sided with the
defense theory—without any foundation as to the
qualifications of the person rendering that opinion, the

as to why they did not accept those witnesses’ statements at face value,
and in that sense the “methodology,” so to speak, of the ADPS report
was explored on cross-examination. But the further, gratuitous fact that
this view had been accepted by the author of the ADPS report added little
(if any) probative value, and it was highly prejudicial.
 JENSEN V. EXC INC. 33

reasoning behind that opinion, or the reliability of the
methods used in reaching it—did nothing more than put the
State’s imprimatur on the defense side. In addition,
Defendants’ counsel exploited the error by making the
ADPS’s endorsement of the defense theory a centerpiece of
his closing argument. Under these circumstances, we cannot
say that the error was more likely than not harmless.
Accordingly, we reverse and remand for a new trial.
III
Although we reverse the judgment rendered after trial,
we must still address Plaintiffs’ argument that the district
court erred in its pretrial ruling dismissing the additional
claims that had been asserted solely under Navajo law,
including claims involving additional parties. The district
court concluded that, because Arizona law governed the
claims arising from the accident, any such claims based on
Navajo law failed as a matter of law. Reviewing de novo,
Rocky Mountain Farmers Union v. Corey, 913 F.3d 940, 949
(9th Cir. 2019), we agree that Arizona law applies rather than
Navajo law.
The Supreme Court has held that, as a matter of federal
law, there are certain limited circumstances in which an
Indian tribe may assert adjudicative jurisdiction and
legislative jurisdiction over the actions of nonmembers of
the tribe within the boundaries of the tribe’s reservation. See
Strate v. A-1 Contractors, 520 U.S. 438, 445–53 (1997);
Montana v. United States, 450 U.S. 544, 565–66 (1981). We
held in our prior ruling in this same matter that the Navajo
Nation lacks adjudicative jurisdiction over Plaintiffs’ claims
against Defendants. 588 F. App’x at 722; see also Strate,
520 U.S. at 454–59 (holding that Indian tribes generally lack
jurisdiction to adjudicate claims against nonmembers arising
34 JENSEN V. EXC INC.

from traffic accidents that occur on state or federal highways
running through an Indian reservation). Because, as a
general matter, a tribe’s “legislative and adjudicative
jurisdiction are coextensive,” Big Horn Cnty. Elec.
Cooperative, Inc. v. Adams, 219 F.3d 944, 950 (9th Cir.
2000), it follows that these federal law principles do not
grant the Navajo Nation jurisdiction to prescribe the
substantive legal rules governing this traffic accident.
Given that the special federal-law rules governing tribal
jurisdiction do not confer legislative jurisdiction on the
Navajo Nation in this case, the governing substantive law in
this diversity suit must be determined under the ordinary
rules applicable under Erie Railroad Co. v. Tompkins, 304
U.S. 64 (1938).8 Accordingly, in determining what law that
governs this case, the district court was required to “apply
the substantive law of the forum in which the court is
located, including the forum’s choice of law rules.”
Insurance Co. of N. Am. v. FedEx Corp., 189 F.3d 914, 919
(9th Cir. 1999) (citing Klaxon Co. v. Stentor Elec. Mfg. Co.,
313 U.S. 487, 496 (1941)). We are aware of no Arizona
authority that has addressed whether the traditional choice-
of-law rules that Arizona applies in determining which
States’ laws should apply to a given dispute may also be
invoked in arguing for application of tribal law. Defendants
argue, and the district court appeared to agree, that
invocation of Arizona choice-of-law rules is inappropriate
8
Contrary to what Plaintiffs contend, nothing in federal law requires a
departure from these principles. Congress’s declaration of purpose in
authorizing funds to construct roads within the Navajo reservation, see
25 U.S.C. § 631 (2012 ed.), does not provide any basis for displacing
state law that would otherwise be applicable under Strate. Nor does this
case involve jurisdiction obtained by a State through coercion of a tribe’s
consent to such jurisdiction. See Three Affiliated Tribes of Fort Berthold
Reservation v. Wold Eng’g, 476 U.S. 877 (1986).
 JENSEN V. EXC INC. 35

vis-à-vis tribal law and that there is therefore no basis for
declining to apply Arizona substantive law here. Plaintiffs
acknowledge the lack of directly controlling caselaw on this
question, but they point to academic commentary endorsing
the notion that “[a]pplication of choice-of-law principles
will sometimes lead state and federal courts to apply tribal
law[ ].” COHEN’S HANDBOOK OF FEDERAL INDIAN LAW
§ 7.06[2] (2012 ed.). We need not resolve this issue. Even
assuming that Arizona choice-of-law principles may be
applied in addressing an argument that tribal law should be
applied rather than Arizona law, those principles favor the
application of Arizona substantive law here.
Arizona courts generally follow the Second Restatement
of Conflict of Laws in determining the applicable law in a
tort case. See Pounders v. Enserch E&C, Inc., 306 P.3d 9,
11 (Ariz. 2013); Bates v. Superior Ct., 749 P.2d 1367, 1369
(Ariz. 1988). Under the Restatement, the applicable law
with respect to “an issue in tort” is that of the jurisdiction
“which, with respect to that issue, has the most significant
relationship to the occurrence and the parties.”
RESTATEMENT (SECOND) OF CONFLICT OF LAWS
(“RESTATEMENT”) § 145(1). In actions for personal injury
or wrongful death, the law of the place “where the injury
occurred determines the rights and liabilities of the parties,
unless, with respect to the particular issue, some other
[jurisdiction] has a more significant relationship . . . to the
occurrence and the parties.” RESTATEMENT §§ 146, 175; see
also Pounders, 306 P.3d at 11; Bates, 749 P.2d at 1369–70.
In assessing which jurisdiction has the more “significant
relationship,” a court applying the Restatement must
consider several factors, including the “place where the
injury occurred”; the “place where the conduct causing the
injury occurred”; the “domicile, residence, nationality, place
36 JENSEN V. EXC INC.

of incorporation and place of business of the parties”; and
the “place where the relationship, if any, between the parties
is centered.” Bates, 749 P.2d at 1370 (quoting
RESTATEMENT § 145). The application of these factors “is
qualitative, not quantitative.” Id. “The court must evaluate
the contacts ‘according to their relative importance with
respect to the particular issue.’” Id. (quoting RESTATEMENT
§ 145(2)).
The first two factors—the “place where the injury
occurred” and the “place where the conduct causing the
injury occurred”—both favor Arizona law. Although the
accident occurred within the boundaries of the Navajo
reservation, Arizona’s right-of-way over U.S. Highway 160
renders the highway equivalent, “for nonmember
governance purposes, to alienated, non-Indian land.” Strate,
520 U.S. at 454 (footnote omitted). For purposes of a suit
against nonmembers, we therefore deem the location of the
accident and the injuries as being within Arizona’s
jurisdiction and not the Navajo Nation’s. The third factor—
“[t]he domicile, residence, nationality, place of
incorporation and place of business of the parties”—weighs
in favor of Navajo law because Plaintiffs are domiciled in
the Navajo Nation and none of the Defendants are domiciled
in Arizona. Bates, 749 P.2d at 1371. The fourth factor—the
“place where the relationship, if any, between the parties is
centered”—is irrelevant here, because the parties had no pre-
existing relationship. Pounders, 306 P.3d at 15. On balance,
we conclude that these factors weigh in favor of applying
Arizona law.
Consequently, Arizona law applies unless the “general
factors” concerning choice of law that are contained in § 6
of the Restatement warrant a different result. Bates, 749
P.2d at 1371; see also Pounders, 306 P.3d at 15. These
 JENSEN V. EXC INC. 37

factors include (1) “the needs of the interstate and
international systems”; (2) “the relevant policies of the
forum”; (3) “the relevant policies of other interested states
and the relative interests of those states in the determination
of the particular issue”; (4) “the protection of justified
expectations”; (5) “the basic policies underlying the
particular field of law”; (6) “certainty, predictability, and
uniformity of result”; and (7) “ease in the determination and
application of the law to be applied.” RESTATEMENT, § 6(2).
Several of these factors have little, if any, relevance here.
Because the parties have not identified any respect in which
the relationship between the Navajo Nation and Arizona
would be affected by the choice of law, the first factor—the
needs of the interstate system—is neutral. And because
“accidents are not planned,” the fourth and sixth factors—
the “protection of justified expectations” and “certainty,
predictability, and uniformity of result”—are essentially
irrelevant here. Bryant v. Silverman, 703 P.2d 1190, 1195–
96 (Ariz. 1985). The key factors are the remaining ones—
viz., the relevant tort-law policies of Arizona and the Navajo
Nation, their relevant interests in applying their law to this
dispute, and the ease of determining and applying the
relevant law.
Both Arizona law and Navajo law provide compensation
to injured victims and allow punitive damages in negligence
cases. Bryant, 703 P.2d at 1195–96; Cummings v. Yazzie, 7
Navajo Rptr. 479, 484–89 (Navajo D. Ct. 1996). The only
substantive differences that the parties have clearly
identified between Arizona law and Navajo law are that
(1) the latter permits a wider range of plaintiffs to sue for
wrongful death and also permits recovery for the wrongful
death of an unborn child who is not yet “viable,” cf.
Summerfield v. Superior Ct., 698 P.2d 712, 724 (Ariz. 1985)
38 JENSEN V. EXC INC.

(holding that the Arizona wrongful death statute authorizes
a cause of action for a “stillborn, viable fetus” (emphasis
added)); and (2) Navajo law, according to Plaintiffs, permits
direct recovery against insurers. The differences in
substantive law concerning damages weigh in favor of
Navajo law. The Arizona Supreme Court has held that
issues concerning the compensation of an injured tort
plaintiff are “primarily a concern of the [jurisdiction] in
which [the] plaintiff is domiciled.” Bryant, 703 P.2d at
1194. Moreover, Arizona has at best a weak interest in
limiting the liability of non-Arizona defendants who would
face greater liability under the law of another jurisdiction in
which defendants are also not domiciled. Id. at 1196
(holding that Colorado has “no” interest in protecting an
Arizona resident defendant from the law of its Arizona
domicile, even for an accident occurring in Colorado).
By contrast, the difference in the availability of an action
against insurers weighs in favor of Arizona law. As
Plaintiffs acknowledge, the availability of such a claim is not
entirely settled under Navajo law; indeed, Plaintiffs argue
that it might warrant certification to the Navajo Nation
Supreme Court. Moreover, in a footnote in their appellate
brief, Plaintiffs further state that there is uncertainty as to
whether Navajo law would apply a heightened standard of
care in a case such as this one, and concede that this issue
too may warrant certification to the Navajo Supreme Court.
These acknowledged uncertainties as to the content of
Navajo law implicate the Restatement factor addressing the
“ease in the determination and application of the law to be
applied,” and they weigh heavily in favor of applying
Arizona law. RESTATEMENT, § 6(2)(g).
We conclude that, considered as a whole, the general
factors in Restatement § 6 do not warrant reaching a
 JENSEN V. EXC INC. 39

different conclusion from the one that follows from an
evaluation of the specific factors to be considered in tort
cases under § 145 of the Restatement. See Bates, 749 P.2d
at 1371. On this basis, we affirm the district court’s
conclusion that Arizona law applies and its resulting
dismissal of all claims that were asserted below only under
Navajo law.
IV
Finally, Plaintiffs challenge the district court’s refusal to
hold that, as a matter of law, Conlon’s negligence
proximately caused the accident. In ruling on Plaintiffs’
motion for summary judgment, the district court held that,
by “mov[ing] from the right lane to the left lane” of the
westbound portion of Highway 160, Conlon had, “as a
matter of law . . . breached his duty to stay in the right lane
and violated [Arizona Revised Statutes] Section 28-721.”9

9
At the time of the accident, § 28-721 provided:

A. On all roadways of sufficient width, a person shall drive a
vehicle on the right half of the roadway except as follows:
1. When overtaking and passing another vehicle
proceeding in the same direction under the rules
governing the movement.
2. When the right half of a roadway is closed to traffic
while under construction or repair.
3. On a roadway divided into three marked lanes for
traffic under the rules applicable on the roadway.
4. On a roadway designated and signposted for one-
way traffic.
B. On all roadways, a person driving a vehicle proceeding at
less than the normal speed of traffic at the time and place and
40 JENSEN V. EXC INC.

The district court nonetheless denied summary judgment to
Plaintiffs on the further issue of whether that breach was a
proximate cause of the accident, holding that a reasonable
jury could resolve that causation issue in favor of either
party. At trial, Plaintiffs renewed their proximate causation
arguments in seeking judgment as a matter of law under Rule
50(a) and Rule 50(b), but the district court denied those
motions. On appeal, Plaintiffs challenge both the district
court’s denial of summary judgment and the district court’s
denial of judgment as a matter of law.
A
As a threshold matter, we agree with Defendants that,
under Ortiz v. Jordan, 562 U.S. 180 (2011), we may not
review the district court’s denial of summary judgment on
the causation issue and that we are instead limited to
reviewing only the denial of Plaintiffs’ comparable
arguments in its Rule 50 motions at trial.
The normal rule is that, “[o]nce the case proceeds to trial,
the full record developed in court supersedes the record
existing at the time of the summary-judgment motion.”
Ortiz, 562 U.S. at 184. Accordingly, where an actual trial
has intervened between the summary judgment ruling and
the final judgment on appeal, any claim that the evidence is

under the conditions then existing shall drive the vehicle in the
right-hand lane then available for traffic or as close as
practicable to the right-hand curb or edge of the roadway,
except when overtaking and passing another vehicle proceeding
in the same direction or when preparing for a left turn at an
intersection or into a private road or driveway.

ARIZ. REV. STAT. § 28-721 (1996). The district court’s order did not
specify whether it based its finding of negligence per se on paragraph A
or paragraph B.
 JENSEN V. EXC INC. 41

insufficient to support a verdict in one side’s favor “must be
evaluated in light of the character and quality of the evidence
received in court” at that trial. Id.; see also Dupree v.
Younger, 598 U.S. 729, 735–36 (2023) (reaffirming this
aspect of Ortiz and holding that “an appellate court’s review
of factual challenges after a trial is rooted in the complete
trial record, which means that a district court’s factual
rulings based on the obsolete summary-judgment record are
useless”). Accordingly, under Ortiz, we may not review
Plaintiffs’ argument that, in applying Arizona causation
standards at summary judgment, the district court
misapplied those standards “in the context of the relevant
facts.” Instead, we must review these issues in light of the
record developed at trial and in the context of Plaintiffs’
Rule 50 motions raising comparable issues.
Plaintiffs contend that the causation issues that they
raised at summary judgment qualify as “purely legal” issues
that are not subject to Ortiz’s rule under our decision in
Booker v. C.R. Bard, Inc., 969 F.3d 1067, 1072 (9th Cir.
2020). See also Dupree, 598 U.S. at 735, 738 (holding that
“purely legal issues resolved at summary judgment” are not
subject to Ortiz’s rule and instead “merge into the final
judgment, at which point they are reviewable on appeal”).
That is wrong. As Dupree explains, “a purely legal question
is, by definition, one whose answer is independent of
disputed facts” and as to which “factual development at trial
will not change the district court’s answer.” Id. at 737. The
causation issues raised by Plaintiffs at summary judgment
were not clean legal issues that can be meaningfully
separated from one’s understanding of the underlying facts
concerning how the accident occurred. Because the record
concerning those facts changed from summary judgment to
the trial, the factual record at summary judgment is
42 JENSEN V. EXC INC.

“obsolete” and cannot provide the basis for our review of
those issues. Id. at 736. If Plaintiffs are correct in
contending that the issue of proximate causation should have
been resolved in their favor as a matter of law in this case,
that argument can only be assessed, under Ortiz and Dupree,
in the context of the factual record develop at trial and in the
context of the contentions Plaintiffs made in their Rule 50
motions.
B
Despite our decision to reverse the judgment for
Defendants on other grounds, we will proceed to review
Plaintiffs’ arguments concerning their Rule 50 motions. We
do so for two reasons. First, if Plaintiffs are correct that,
notwithstanding any other error, they should have been
granted judgment as a matter of law at the jury trial, then
there should be no remand for a new trial on liability.
Second, the causation issues, which have been fully briefed
in this court, would arise again on any remand, and the
parties and the district court would benefit from our
guidance on those issues. Turning to the merits of those
questions, we hold that the district court properly denied
Plaintiffs’ motions for judgment as a matter of law.
To establish negligence under Arizona law, “a plaintiff
must prove four elements: (1) a duty requiring the defendant
to conform to a certain standard of care; (2) a breach by the
defendant of that standard; (3) a causal connection between
the defendant’s conduct and the resulting injury; and
(4) actual damages.” Gipson v. Kasey, 150 P.3d 228, 230
(Ariz. 2007). “The negligence complained of need not be
the sole cause, but need only be a proximate cause to support
a verdict for the plaintiff.” Ariz. State Highway Dep’t v.
Bechtold, 460 P.2d 179, 183 (Ariz. 1969). “The proximate
 JENSEN V. EXC INC. 43

cause of an injury is that which, in a natural and continuous
sequence, unbroken by any efficient intervening cause,
produces an injury, and without which the injury would not
have occurred.” Robertson v. Sixpence Inns of Am., Inc., 789
P.2d 1040, 1047 (Ariz. 1990) (citations omitted). In denying
Plaintiffs’ Rule 50(b) motion, the district court held that a
reasonable jury could find that Johnson crossed over into
Conlon’s lane and that Johnson’s actions in doing so
constituted an unforeseeable intervening cause that would
permit the jury to find that Conlon’s negligence in driving in
the left lane was not the proximate cause of the accident.
Plaintiffs raise two principal arguments in challenging this
ruling, but neither has merit.
Plaintiffs argue that, contrary to the district court’s
reasoning, Johnson’s asserted action in crossing into the left
westbound lane cannot be deemed to be an “intervening”
cause given that Conlon continued to negligently drive in
that left lane up to the time of impact. See Zelman v. Stauder,
466 P.2d 766, 769 (Ariz. Ct. App. 1970) (stating that “where
defendant’s negligent course of conduct (as distinguished
from the risk of harm created) actively continues up to the
time the injury is sustained, then any outside force which is
also a substantial factor in bringing about the injury is a
concurrent cause of the injury and never an ‘intervening’
force”). As Plaintiffs note, the Arizona statute that was the
basis for the district court’s negligence per se finding
prohibits “driving a vehicle” in the wrong portion of the
road, not merely the initial act of moving into that portion.
This argument fails because it overlooks the competing duty
that arose under Arizona Revised Statues § 28-729(1) when
Wisner’s Chevy Tahoe moved into the right-hand lane next
to Conlon’s bus. That statute requires a driver to stay
“within a single lane” and “not move the vehicle from that
44 JENSEN V. EXC INC.

lane until the driver has first ascertained that the movement
can be made with safety.” ARIZ. REV. STAT. § 28-729(1).
On the record at trial, a reasonable jury could find that, once
the Tahoe moved next to the bus, Conlon could no longer
move with safety into the right lane and that it would then
have been negligent, and a clear violation of § 28-729(1), for
him to have attempted to do so. Under this view of the
evidence, Conlon’s “negligent course of conduct” in
violation of § 28-721 “terminated” once his superseding
duty under § 28-729(1) arose. Zelman, 466 P.2d at 769. On
this basis the jury could permissibly find that Conlon’s
earlier negligence per se had terminated and that Johnson’s
actions therefore constituted an “intervening” cause.
Plaintiffs also argue that even if Johnson’s actions were
an intervening cause, they were not unforeseeable. “Under
Arizona law as developed in negligence cases, an
intervening cause does not relieve an earlier actor of liability
if the intervening cause was reasonably foreseeable.”
d’Hedouville v. Pioneer Hotel Co., 552 F.2d 886, 893 (9th
Cir. 1977). Thus, “an intervening force becomes a
superseding cause only when its operation was both
unforeseeable and when with the benefit of ‘hindsight’ it
may be described as abnormal or extraordinary.” Rossell v.
Volkswagen of Am., 709 P.2d 517, 526 (Ariz. 1985).
Because, according to Plaintiffs, the very purpose of § 28-
721’s stay-on-the-right rule is to avoid head-on collisions
with traffic coming in the other direction, see United
Dairymen of Ariz. v. Fisher-Miller Hay & Dev. Co., 609 P.2d
609, 612 (Ariz. Ct. App. 1980), Johnson’s actions must be
deemed to be reasonably foreseeable as a matter of law. This
argument’s focus is too myopic. Although Conlon’s original
decision to proceed in the left lane was concededly
negligent, a reasonable jury could find that it was not
 JENSEN V. EXC INC. 45

reasonably foreseeable that Johnson’s vehicle would enter
that lane at precisely the moment in which Conlon could not
safely change lanes. The issue of causation was properly
submitted to the jury.
V
For the foregoing reasons, we affirm the judgment in
Defendants’ favor to the extent that it dismissed all claims,
including claims involving additional parties, based on
Navajo law. We reverse the judgment on the remaining
claims that were submitted for trial, and we remand for a new
trial.
AFFIRMED IN PART, REVERSED IN PART, AND
REMANDED.

WALLACE, Circuit Judge, concurring in part and dissenting
in part:
I agree with my colleagues that Arizona state law
governs this diversity action and that the district court did
not err in denying the Plaintiffs’ motion for judgment as a
matter of law. However, I disagree with my colleagues on
their resolution of the evidentiary question. The majority
opinion vacates and remands for a new trial, concluding that
an expert may be cross-examined on conclusions contained
within an inadmissible report that the expert reviewed and
rejected only if those conclusions have an independent,
sufficient guarantee of trustworthiness. For the following
reasons, I respectfully dissent on that issue and would affirm
the district court.
46 JENSEN V. EXC INC.

I.
The proper extent of cross examination of an expert
witness begins with the scope of materials that an expert
reviewed. Federal Rule of Evidence 703 provides that an
expert witness may base his or her opinion on inadmissible
“facts or data,” provided that “experts in the particular field
would reasonably rely on those kinds of facts or data in
forming an opinion.” Fed. R. Evid. 703. The inadmissible
“facts or data” that experts may consider include the reports,
opinions, and conclusions of other non-testifying witnesses.
See Paddack v. Dave Christensen, Inc., 745 F.2d 1254,
1262–63 & n.14 (9th Cir. 1984) (holding that an expert
accountant may base his opinion on facts and conclusions
contained in audit reports that are otherwise inadmissible);
see also Fed. R. Evid. 703 advis. comm. note, 56 F.R.D. 183,
283 (1973) (approving of an expert physician who “bases his
diagnosis on information from numerous sources and of
considerable variety, including statements by patients,
reports and opinions from nurses, technicians, and other
doctors, hospital records, and X rays”). Any facts, data, and
conclusions that an expert considers and relies upon are not
admissible as substantive evidence, but “solely as a basis for
the expert opinion.” United States v. Sims, 514 F.2d 147,
149–50 (9th Cir. 1975); see also Paddack, 745 F.2d at 1262–
63 (holding that materials underlying an expert’s report were
“admissible only for the limited purpose of explaining the
basis of [the expert’s] testimony”).
Trial judges have a limited role in determining whether
the underlying inadmissible facts, data, and conclusions
reviewed were appropriate to consider. Once a court makes
the legal determination that the facts or data are of a “type”
reasonably relied on by other experts, a qualified expert is
left to determine how much weight—if any—to give those
 JENSEN V. EXC INC. 47

facts and data when formulating his or her opinion. See
United States v. W.R. Grace, 504 F.3d 745, 765 (9th Cir.
2007) (“The expert is, in the first instance, the judge of what
resources would help him to form an opinion, and he can
filter out as irrelevant prejudicial information.”); Sims, 514
F.2d at 149 (holding that courts “should . . . leave to the
expert the assessment of the reliability of the statements on
which he bases his expert opinion”). This principle is
premised on the notion that a qualified expert is “fully
capable of judging for himself what is, or is not, a reliable
basis for his opinion.” Sims, 514 F.2d at 149; see also
Manocchio v. Moran, 919 F.2d 770, 780 (1st Cir. 1990)
(“Rule 703 reflects a recognition of the expert’s integrity and
specialized skill, which ‘will keep him from basing his
opinion on questionable matter.’”), quoting Weinstein’s
Evidence § 803(4)[01] at 803-146 (1990). In other words,
Rule 703 trusts primarily the qualified expert to “separate
the wheat from the chaff” and to use only reliable, reputable
sources. Sims, 514 F.2d at 149. No further judicial
guarantee of reliability is required.
Cross-examination is available to question the bases of
the expert witness’s opinion and to test the credibility and
reliability of those bases. Federal Rule of Evidence 705
places the onus on the cross-examining attorney to elicit the
“underlying facts and data” considered by the expert. See
Fed. R. Evid. 705; cf. Daubert v. Merrell Dow Pharm., Inc.,
509 U.S. 579, 596 (1993). This rule further provides for
cross-examination on “unfavorable” facts or opinions that
were considered but ultimately disregarded or discounted by
the expert. See Fed. R. Evid. 705 advis. comm. note, 56
F.R.D. 183, 286 (1973). In essence, the expert witness is
subject to cross-examination to explain how and why he or
she “separate[d] the wheat from the chaff.” Sims, 514 F.2d
48 JENSEN V. EXC INC.

at 149. With the benefit of cross-examination on the
expert’s decisional process, the trier of fact is “then capable
of judging the credibility of the [expert] witness.” Id.
There are limitations to cross-examination. A
questioning attorney may only cross examine an expert
witness on (1) subject matter discussed during direct
examination or other “matters affecting the witness’s
credibility,” as well as on (2) the “underlying facts and data”
reviewed and considered by the expert. Fed. R.
Evid. 611(b); Fed. R. Evid. 705; see also Phillips v. E.I.
DuPont de Nemours & Co. (In re Hanford Nuclear Res.
Litig.), 534 F.3d 986, 1012 (9th Cir. 2008) (holding that an
expert witness cannot be impeached with the reports of other
experts “unless the testifying expert based his opinion on the
hearsay in the examined report or testified directly from the
report”). Moreover, the questioning attorney cannot elicit
the inadmissible facts, data, and conclusions considered by
the expert witness to prove substantive evidence, but only to
“help the factfinder understand the expert’s thought process
and determine what weight to give to the expert’s opinion.”
Williams v. Illinois, 567 U.S. 50, 78 (2012). Similarly,
impeachment of the expert witness on the underlying
materials considered “proves only that the declarant lacks
credibility”; it does not prove the truth of the underlying
facts, data, and conclusions. Urooj v. Holder, 734 F.3d
1075, 1078–79 (9th Cir. 2013), quoting Robert E. Jones,
Federal Civil Trials & Evidence § 8:1954 (2013).
II.
With these principles in mind, I would hold that the
district court did not abuse its discretion in permitting the
Defendants’ counsel to ask the Plaintiffs’ experts about the
police officer’s report and conclusions. The experts
 JENSEN V. EXC INC. 49

reviewed the police officer’s report and testified that such a
report is of a kind on which experts in the field reasonably
rely. The Plaintiffs did not argue otherwise at trial. As it is
not disputed that such a report—including its facts and
conclusions—is of a kind reasonably relied on by experts,
and as the Plaintiffs’ experts reviewed the report, it has
sufficient reliability under Rule 703 to be considered and to
be the subject of cross-examination under Rule 705. At least
two other circuits to consider this question agree. See Ratliff
v. Schiber Truck Co., Inc., 150 F.3d 949, 955 (8th Cir. 1998)
(“[The expert] admitted that he had read the report prior to
submitting his own report. Therefore counsel was free to
cross-examine the expert as to all documents he reviewed in
establishing his opinion.”); Vodusek v. Bayliner Marine
Corp., 71 F.3d 148, 157 (4th Cir. 1995) (“Once [the expert]
testified that he had read and rejected the other experts’ out-
of-court opinions on the source of the fire, defendants were
free to explore the basis for that disagreement and to attempt
to discredit [that] conclusion.”). Such questioning was not
admissible to provide the truth of the officer’s report, but
only to test the expert witness’s credibility and decisional
process. See Sims, 514 F.2d at 149–50; Paddack, 745 F.2d
at 1262–63. The evidentiary rules do not demand any
additional guarantees of reliability or trustworthiness at
cross-examination.
III.
The majority appears to agree with much of the general
framework above. The majority accepts that expert
witnesses may review and consider conclusions reached by
other non-testifying individuals. The majority also agrees
that testifying expert witnesses are subject to cross-
examination on “unfavorable” materials that they considered
and rejected. Yet the majority concludes that testifying
50 JENSEN V. EXC INC.

expert witnesses need not explain on cross-examination why
they disagreed with a competing conclusion that they
reviewed and that is of a kind that is reasonably relied upon
by other experts unless the cross-examining attorney
demonstrates that the competing conclusion has “sufficient
indicia of reliability and trustworthiness.” Relying on a Fifth
Circuit opinion to which our court cited once in passing, the
majority holds that trial judges must now decide whether the
bases underlying the competing, out-of-court report, and the
qualifications of its author, pass muster. Only then must a
testifying expert speak to his or her review of and
disagreement with the report’s conclusions.
This holding imposes a heightened judicial reliability
standard beyond what Rule 703 requires. Once the testifying
expert has been qualified, Rule 703 requires merely that a
trial judge inquire into whether the underlying materials are
of a “type” reasonably relied upon; the trial judge does not
review the substantive sufficiency of each material
considered. See Sims, 514 F.2d at 149 (observing that
Rule 703 rejected the previous rule that required
inadmissible hearsay evidence relied upon by experts to be
subject to “verification” before being presented to a trier of
fact); W.R. Grace, 504 F.3d at 765. Determining the
substantive reliability of the underlying materials falls
principally to the expert. See Sims, 514 F.2d at 149 (holding
that courts “should . . . leave to the expert the assessment of
the reliability of the statements on which he bases his expert
opinion”); W.R. Grace, 504 F.3d at 765. The majority’s rule
invades the province of the expert and improperly supplants
the expert with the trial judge.
In reaching this conclusion, the majority conflates non-
substantive cross-examination evidence with substantive
hearsay evidence. The majority, relying on Bryan, requires
 JENSEN V. EXC INC. 51

trial judges to determine the “substantive correctness” of the
competing conclusion’s methodology in order to deem that
out-of-court conclusion “admitted as a competing expert
‘opinion.’” The Fifth Circuit in Bryan justified this rule by
likening Rule 705 to an “exception[] to the hearsay rule,”
thereby requiring the trial judge to “comport[] with the
concerns of the hearsay rule” and ensure sufficient
trustworthiness and reliability before permitting cross-
examination on a competing conclusion considered by the
testifying expert. 566 F.2d 541, 545–46 (5th Cir. 1978).
However, cross-examination and impeachment
regarding an underlying report reviewed and rejected by a
testifying expert does not seek to substantively admit the
out-of-court report as a Rule 702 expert opinion. Rather,
when a cross-examining attorney questions an expert
witness on his or her consideration of the competing
conclusions reached by another, this line of questioning is
admitted only to test “the expert’s thought process” and the
expert’s credibility. Williams, 567 U.S. at 78; Paddack, 745
F.2d at 1262 n.11. By requiring additional guarantees of
reliability, Bryan and the majority’s rule equates the cross-
examination of the bases underlying an expert’s opinion with
the admission of substantive evidence used to prove the truth
of the matter asserted. This court should not restrict
vigorous cross-examination merely because of unrelated and
inapplicable concerns regarding the substantive admission
of hearsay evidence.1

1
The Bryan court’s rule requiring an “independent guarantee of
trustworthiness,” which the majority adopts, bears striking similarity to
Rule 807’s residual exception to the hearsay rules. Compare Bryan, 566
F.2d at 546 with Fed. R. Evid. 807 (requiring “sufficient guarantees of
trustworthiness” under the residual exception to the hearsay rule). This
52 JENSEN V. EXC INC.

The ultimate effect of the majority opinion’s rule is to
disarm cross-examining attorneys and shield testifying
expert witnesses. Rule 705 places “the full burden of
exploration of the facts and assumptions underlying the
testimony of an expert witness squarely on the shoulders of
opposing counsel’s cross-examination.” Smith v. Ford
Motor Co., 626 F.2d 784, 793 (10th Cir. 1980) (internal
quotation marks and citation omitted); Int’l Adhesive
Coating Co., Inc. v. Bolton Emerson Int’l, Inc., 851 F.2d
540, 545 (1st Cir. 1988) (“The burden is on opposing counsel
through cross-examination to explore and expose any
weaknesses in the underpinnings of the expert’s opinion.”).
Under Rule 703, a qualified expert may consider and rely on
the opinion of another, as long as that opinion is of a kind
reasonably relied on by other experts in the field. See
Paddack, 745 F.2d at 1262–63 & n.14. It disarms an
opposing party if an expert could review and discount a
conclusion of another but be shielded on cross-examination
from explaining why that conclusion was reviewed and
rejected.2 See generally United States v. A & S Council Oil
Co., 947 F.2d 1128, 1135 (4th Cir. 1991) (“Rule 703 creates
a shield by which a party may enjoy the benefit of
inadmissible evidence by wrapping it in an expert’s opinion;
Rule 705 is the cross-examiner’s sword, and, within very
broad limits, he may wield it as he likes.”). This in turn
hinders the jury, as the sole trier of fact and credibility, who
is deprived of facts concerning how the testifying expert
further suggests that Bryan conflated the non-hearsay impeachment of
facts and conclusions reviewed by an expert with the substantive
admissibility of hearsay evidence.
2
The majority’s attempt to blunt the impact of its holding, by suggesting
that some of the cross-examination that occurred here was permissible,
merely underscores its intent to saddle the trial judge with additional
gatekeeping responsibilities not contained in Rule 703.
 JENSEN V. EXC INC. 53

“separate[d] the wheat from the chaff.” Sims, 514 F.2d
at 149.
IV.
I turn now to Federal Rule of Evidence 403. As I have
demonstrated, the majority opinion conflicts with generally
applicable evidentiary principles concerning the
impeachment and cross-examination of expert witnesses.
Nonetheless, Rule 403 permits trial courts to exclude
otherwise-permissible questioning if the probative value is
substantially outweighed by the risk of unfair prejudice or
influence. See United States v. Hinkson, 585 F.3d 1247,
1267 (9th Cir. 2009) (en banc). Exclusion under Rule 403 is
an “extraordinary remedy to be used sparingly.” United
States v. Mende, 43 F.3d 1298, 1302 (9th Cir. 1995), quoting
United States v. Patterson, 819 F.2d 1495, 1505 (9th Cir.
1987). This court must give “great deference” to a trial
court’s Rule 403 determination. Hinkson, 585 F.3d at 1267.
I cannot say that the district court abused its discretion
under Rule 403. The district court granted “limited” cross-
examination concerning how the expert arrived at his
opinion following his review of the police report. While the
fact that a police officer reached a competing conclusion
may risk carrying the imprimatur of the State, the Plaintiffs’
experts had ample opportunity to explain the weaknesses of
the officer’s report and the reasons why they disregarded the
report. I agree that the Defendants’ attorney acted
improperly and attempted to put the substantive truth of the
police report’s conclusions before the jury, going so far as
discussing the report’s conclusions during closing argument.
However, the solution to such gamesmanship is for the
opposing party to request a Rule 105 limiting instruction and
to object during closing arguments. See generally W.R.
54 JENSEN V. EXC INC.

Grace, 504 F.3d at 759 n.7. The Plaintiffs did neither. The
Plaintiffs cannot now claim the benefit of their mistake and
be granted a new trial on the theory that the Defendants’
questioning was too prejudicial when they failed to request
a limiting instruction that would have minimized the
prejudicial effect of the questions.
V.
“A district court is vested with broad discretion to
make . . . evidentiary rulings conducive to the conduct of a
fair and orderly trial.” Campbell Indus. v. M/V Gemini, 619
F.2d 24, 27 (9th Cir. 1980). For the above reasons, I
conclude that the district court did not abuse its discretion in
permitting the Defendants’ counsel to cross-examine the
Plaintiffs’ experts on their consideration of a substantively-
inadmissible competing opinion rendered by a police officer.
Once the experts reviewed the officer’s report, and once the
trial judge determined that the report was of a kind
reasonably relied upon by other experts in the field, the
report was sufficiently reliable to be considered and to be the
subject of limited cross-examination. Because I would
affirm the district court in all respects, I respectfully dissent.