In the
United States Court of Appeals
For the Seventh Circuit
No. 09-8051
A MERICAN H ONDA M OTOR C OMPANY, INC., et al.,
Petitioners,
v.
R ICHARD A LLEN, et al.,
Respondents.
Petition for Leave to Appeal from the
United States District Court for the
Northern District of Illinois, Eastern Division.
No. 06 CV 5932—Nan R. Nolan, Magistrate Judge.
S UBMITTED D ECEMBER 30, 2009—D ECIDED A PRIL 7, 2010
Before P OSNER, E VANS, and T INDER, Circuit Judges.
P ER C URIAM. American Honda Motor Company and
Honda of America Manufacturing (collectively “Honda”)
seek leave to appeal the district court’s grant of class
certification pursuant to Federal Rule of Civil Procedure
23(f). Specifically, Honda asks us to resolve whether
the district court must conclusively rule on the admissi-
bility of an expert opinion prior to class certification in
2 No. 09-8051
this case because that opinion is essential to the certifica-
tion decision. Since this is the type of question that
Rule 23(f) was designed to address, and because the
district court’s analysis was incomplete, we accept the
appeal. See Allen v. Int’l Truck & Engine Corp., 358 F.3d 469,
470 (7th Cir. 2004) (“The parties’ comprehensive sub-
missions show not only that immediate review would
promote the development of the law . . . but also that
the district court committed an error best handled by a
swift” action.).
Plaintiffs are purchasers of Honda’s Gold Wing GL1800
motorcycle; they allege that the motorcycle has a design
defect that prevents the adequate dampening of “wob-
ble,” that is, side-to-side oscillation of the front steering
assembly about the steering axis. In other words, they
claim that the defect makes the steering assembly shake
excessively and they want Honda to fix the problem.
Plaintiffs moved for class certification pursuant to Rule
23(b)(3). To demonstrate the predominance of common
issues, they relied heavily on a report prepared by
Mark Ezra, a motorcycle engineering expert. Ezra’s
report opined that motorcycles should “by [their] design
and manufacture exhibit[] decay of any steering oscilla-
tions sufficiently and rapidly so that the rider neither
reacts to nor is frightened by such oscillations.” Assuming
that human reaction time to wobble is ½ to ¾ of a second,
Ezra opined that wobble should decay, or dissipate, to
37% of its original amplitude within ¾ of a second to
ensure that riders do not perceive and react to the oscilla-
tions. This standard, which Ezra devised himself and char-
acterizes as “reasonable,” was published in the June 2004
No. 09-8051 3
edition of the Journal of the National Academy of Forensic
Engineers. After testing one used GL1800 serviced to
factory condition, Ezra concluded that it failed to meet his
wobble decay standard. He also concluded that his stan-
dard could be achieved in the GL1800 motorcycle by
replacing the regular ball bearings in the steering as-
sembly with tapered ones.
Honda moved to strike the report pursuant to Daubert
v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993), arguing
that Ezra’s wobble decay standard was unreliable be-
cause it was not supported by empirical testing, was not
developed through a recognized standard-setting proce-
dure, was not generally accepted in the relevant scientific,
technical, or professional community, and was not the
product of independent research. In the alternative,
Honda argued that even if the standard was reliable, Ezra
did not reliably apply it to this case because he only
tested one motorcycle and did not account for variables
that could affect the wobble decay rate.
The district court concluded that it was proper to
decide whether the report was admissible prior to certi-
fication because “most of Plaintiffs’ predominance argu-
ments rest upon the theories advanced by Mr. Ezra.” Allen
v. Am. Honda Motor Co., 264 F.R.D. 412, 425 (N.D. Ill. 2009).
The court then discussed Honda’s Daubert arguments. It
noted that it was concerned that, among other things,
Ezra’s wobble decay standard may not be supported by
empirical evidence, the standard has not been generally
accepted by the engineering community, and Ezra’s test
sample of one may be inadequate to conclude that the
4 No. 09-8051
entire fleet of GL1800s is defective. The court then con-
cluded, “Viewing all of the arguments together, the court
has definite reservations about the reliability of Mr. Ezra’s
wobble decay standard. Nevertheless, the court declines
to exclude the report in its entirety at this early stage of
the proceedings.” Id. at 428. The court denied Honda’s
motion to exclude “without prejudice,” id. at 437, and
granted Plaintiffs’ motion for class certification in part,
certifying two classes of individuals who purchased
GL1800s.
In Szabo v. Bridgeport Machs., Inc., 249 F.3d 672, 676 (7th
Cir. 2001), we held that a district court must make what-
ever factual and legal inquiries are necessary to ensure
that requirements for class certification are satisfied
before deciding whether a class should be certified, even
if those considerations overlap the merits of the case. And
in West v. Prudential Sec., Inc., 282 F.3d 935, 938 (7th Cir.
2002), we held that a plaintiff cannot obtain class certifica-
tion just by hiring a competent expert. We emphasized, “A
district judge may not duck hard questions by observing
that each side has some support. . . . Tough questions
must be faced and squarely decided, if necessary by
holding evidentiary hearings and choosing between
competing perspectives.” Id. But we have not yet specifi-
cally addressed whether a district court must resolve a
Daubert challenge prior to ruling on class certification if
the testimony challenged is integral to the plaintiffs’
satisfaction of Rule 23’s requirements.
Plaintiffs argue that we do not need to accept this ap-
peal because district courts in this circuit generally agree
that a Daubert challenge must be resolved prior to class
No. 09-8051 5
certification. This is true, though the courts have relied
on different authority, including other district court
decisions, to reach their conclusion. See, e.g., Reed v.
Advocate Health Care, No. 06 C 3337, 2009 WL 3146999, at
*21 (N.D. Ill. Sept. 28, 2009); In re Ready-Mixed Concrete
Antitrust Litig., 261 F.R.D. 154, 162 (S.D. Ind. 2009); Srail v.
Village of Lisle, 249 F.R.D. 544, 557, 560-61 (N.D. Ill. 2008); cf.
Szabo, 249 F.3d at 675 (accepting an appeal pursuant to
Rule 23(f) in part because the district court relied largely
on decisions by other district judges “[a]t critical junc-
tures”). Further, in many of these cases, including the
case at hand, this issue was heavily contested. Finally,
other appellate courts have not directly addressed whether
challenges to experts must be resolved prior to certifica-
tion. See, e.g., In re Hydrogen Peroxide Antitrust Litig., 552
F.3d 305, 315 n.13 (3d Cir. 2008) (noting that parties
agreed that lower court properly addressed admission of
expert testimony); Dukes v. Wal-Mart, Inc., 509 F.3d 1168,
1174, 1179 (9th Cir. 2007) (withdrawing and superceding
prior opinion, 474 F.3d 1214, which held that full
Daubert examination should not be conducted at class
certification stage), reh’g granted, 556 F.3d 919 (9th Cir.
2009); In re Initial Public Offering Sec. Litig., 471 F.3d 24, 42
(2d Cir. 2006) (disavowing suggestion that expert’s testi-
mony may establish component of class certification
“simply by being not fatally flawed”). Given the uncer-
tainty surrounding the propriety of conducting a Daubert
analysis at the class certification stage, and the fre-
quency with which this issue arises, we find the question
to be one appropriate for resolution under Rule 23(f).
See Blair v. Equifax Check Servs., Inc., 181 F.3d 832, 835 (7th
Cir. 1999).
6 No. 09-8051
We hold that when an expert’s report or testimony is
critical to class certification, as it is here, see Allen, 264
F.R.D. at 420 (“Mr. Ezra’s wobble decay standard . . . forms
the basis of Plaintiffs’ theory of defect.”), a district
court must conclusively rule on any challenge to the
expert’s qualifications or submissions prior to ruling on
a class certification motion. That is, the district court
must perform a full Daubert analysis before certifying
the class if the situation warrants. If the challenge is to
an individual’s qualifications, a court must make that
determination “by comparing the area in which the
witness has superior knowledge, skill, experience, or
education with the subject matter of the witness’s testi-
mony.” Carroll v. Otis Elevator Co., 896 F.2d 210, 212 (7th
Cir. 1990). The court must also resolve any challenge to
the reliability of information provided by an expert if
that information is relevant to establishing any of the
Rule 23 requirements for class certification.
Here, the district court started off on the right foot by
beginning to undertake what might have become a fairly
extensive Daubert analysis. Cf. Naeem v. McKesson Drug
Co., 444 F.3d 593, 608 (7th Cir. 2006) (noting that there is
no need for a court to perform the Daubert analysis in any
particular or mechanical way). It noted its role as “gate-
keeper” and its duty to “determine reliability in light of
the proposed expert’s full range of experience and
training as well as the methodology used to arrive at a
particular conclusion.” Allen, 264 F.R.D. at 423 (quotations
omitted). The district court acknowledged Honda’s
concerns about the reliability of Ezra’s testimony and
largely agreed with them. It expressed reservations
No. 09-8051 7
about Ezra’s failure to “establish the minimal amplitude
required for a rider to detect an oscillation,” id. at 426, his
failure to “verif[y] whether a lesser or greater percentage
of decay would also provide an appropriate margin of
safety,” id. at 427, the fact that his wobble decay standard
was developed “to assist with a lawsuit and was not
conceived through the logical flow of independent re-
search,” id., the questionable peer-review process that his
article underwent, see id., the engineering community’s
lack of acceptance of his proposed standard, id., and his
test sample size of one used GL1800, see id. at 427-28. Yet
the district court ultimately declined, without further
explanation, “to exclude the report in its entirety at this
early stage of the proceedings.” Id. at 428.
“We give the court great latitude in determining not only
how to measure the reliability of the proposed expert
testimony but also whether the testimony is, in fact,
reliable, but the court must provide more than just
conclusory statements of admissibility to show that it
adequately performed the Daubert analysis.” United States
v. Pansier, 576 F.3d 726, 737 (7th Cir. 2009) (citation omit-
ted). The court’s effective statement of admissibility here
is not even conclusory; it leaves open the questions of
what portions of Ezra’s testimony it may have decided
(or will decide) to exclude, whether Ezra reliably applied
the standard to the facts of the case, and, ultimately,
whether Plaintiffs have satisfied Rule 23(b)(3)’s predomi-
nance requirement. As a result, the district court never
actually reached a conclusion about whether Ezra’s expert
report was reliable enough to support Plaintiffs’ class
certification request. Instead it denied Honda’s motion
8 No. 09-8051
to exclude without prejudice and noted that the case was
in an “early stage of the proceedings.” This was not
sufficient. Indeed, it was an abuse of discretion. See Night-
ingale Home Healthcare, Inc. v Anodyne Therapy, LLC, 589
F.3d 881, 883 (7th Cir. 2009) (“It is an abuse of discretion
not to exercise discretion.”); Smith v. Ford Motor Co., 215
F.3d 713, 717 (7th Cir. 2000) (“We review for abuse of
discretion the district court’s choice of factors to include
within [the Daubert] framework as well as its ultimate
conclusions regarding the admissibility of expert testi-
mony.”).
As we have explained, a district court must make
the necessary factual and legal inquiries and decide all
relevant contested issues prior to certification. See West,
282 F.3d at 938; Szabo, 249 F.3d at 676. The district court’s
actions here were more akin to the “provisional” approach
that we rejected in Szabo. 249 F.3d at 676. Ezra’s testimony
is necessary to show that Plaintiffs’ claims are capable of
resolution on a class-wide basis and that the common
defect in the motorcycle predominates over the class
members’ individual issues. Therefore, by failing to clearly
resolve the issue of its admissibility before certifying
the class, the district court erred. Cf. West, 282 F.3d at
938 (“A district judge may not duck hard questions by
observing that each side has some support . . . . Tough
questions must be faced and squarely decided . . . .”(em-
phasis added)).
The district court was reluctant to exclude Ezra’s re-
port “in its entirety at this early stage of the proceedings,”
Allen, 264 F.R.D. at 428, but our examination of the
No. 09-8051 9
record reveals that exclusion is the inescapable result
when the Daubert analysis is carried to its conclusion.
Under the Daubert framework, a district court must
determine “whether a given expert is qualified to testify
in the case in question and whether his testimony is
scientifically reliable.” Gayton v. McCoy, 593 F.3d 610,
616 (7th Cir. 2010). Ezra’s qualifications are not at issue
here; the reliability of his testimony is what Honda con-
tests. But even the most “supremely qualified expert
cannot waltz into the courtroom and render opinions
unless those opinions are based upon some recognized
scientific method and are reliable and relevant under
the test set forth by the Supreme Court in Daubert.” Clark
v. Takata Corp., 192 F.3d 750, 759 n.5 (7th Cir. 1999).
Daubert sets forth a non-exhaustive list of guideposts to
consult in assessing the reliability of expert testimony:
(1) whether the scientific theory can be or has been tested;
(2) whether the theory has been subjected to peer review
and publication; and (3) whether the theory has been
generally accepted in the relevant scientific, technical, or
professional community. Daubert, 509 U.S. at 593-94. In
addition to these guideposts, the 2000 Advisory Commit-
tee’s Notes to Rule 702 suggest other benchmarks for
gauging expert reliability, including whether the testi-
mony relates to “matters growing naturally and directly
out of research they have conducted independent of the
litigation, or whether they have developed their opinions
expressly for purposes of testifying”; “[w]hether the
expert has adequately accounted for obvious alternative
explanations”; and “[w]hether the expert is being as
careful as he would be in his regular professional
10 No. 09-8051
work outside his paid litigation consulting.” Fed. R. Evid.
702 Advisory Committee’s Notes (2000 Amends.); see
also Fuesting v. Zimmer, Inc., 421 F.3d 528, 534-35 (7th Cir.
2005), vacated in part on other grounds, 448 F.3d 936 (7th Cir.
2006).
The “theory” here is Ezra’s wobble decay standard, and,
as the district court thoroughly enumerated, there are
many reasons to harbor “definite reservations” about its
reliability. Allen, 264 F.R.D. at 428. Ezra originally devel-
oped the standard for use in a mid-1980s lawsuit
in which he testified as an expert against Honda and
subsequently published it in a journal article aimed at
forensic engineers who testify as experts on motorcycle
instability, see Mark A.M. Ezra, Forensic Engineering Investi-
gation of Motorcycle Instability Induced Crashes, 21 J. Nat’l
Acad. Forensic Eng’rs 69, 80-84 (2004) (discussing seven
common “attacks by opposing counsel,” including “You
Did What While Testing the Motorcycle?!”, and instructing
future experts to “be ready to defend in simple lay terms
the standard [they have] proposed and relied upon in
evaluating the motorcycle and its reasonableness”). Despite
its publication, there is no indication that Ezra’s wobble
decay standard has been generally accepted by anyone
other than Ezra. See Porter v. Whitehall Labs., Inc., 9 F.3d 607,
613 (7th Cir. 1993) (“A known technique that has gained
only a minimal following may be viewed with some
skepticism.”). Indeed, Ezra’s article merely “suggested” a
standard for wobble decay; it acknowledged that he was
“unaware of any governmental, industry or [Society of
Automotive Engineers] standards determining acceptable
response characteristics for [motorcycles] . . . in . . . wobble
No. 09-8051 11
mode[],” Ezra, supra, at 78, and noted that “it is up to the
investigating forensic engineer to define a reasonable
standard that he may defend in the legal forum before
opposing council [sic] or a jury,” id. at 79.
Even if we were to assume that Ezra’s standard is
generally accepted by mere virtue of its publication in a
peer-reviewed journal, its reliability remains in question.
Ezra has never conducted any rider confidence studies
to determine when motorcycle riders perceive wobble,
or performed any tests to determine the minimal
wobble amplitude at which riders detect oscillation.
See Allen, 264 F.R.D. at 426; see also West, 282 F.3d at 939
(expressing skepticism in a model that “has not been
verified empirically”). His report merely deemed “reason-
able” his proposed standard, relying solely on his own
previous (and similarly unsupported) assessment of the
same for support. The “principles and methodology”
underlying his findings, Winters v. Fru-Con, Inc., 498 F.3d
734, 742 (7th Cir. 2007), then, are questionable at best.
And although we do not consider the validity or accuracy
of the conclusions Ezra reached, see id., we note that the
methodological omissions here render the 37% wobble
decay standard Ezra articulated “somewhat speculative,”
Allen, 264 F.R.D. at 427; see Chapman v. Maytag Corp., 297
F.3d 682, 686-87 (7th Cir. 2002) (noting that courts
must consider “whether the testimony has been sub-
jected to the scientific method, ruling out any subjec-
tive belief or unsupported speculation”).
The methodology underlying the tests Ezra conducted
to determine whether the GL1800 met his standard also
12 No. 09-8051
gives us pause. Ezra tested a single, used 2006 GL1800,
ridden by a single test rider, and extrapolated his con-
clusions to the fleet of GL1800s produced from 2001 to
2008. “Determining the minimum sample size from
which reliable extrapolations can be made to the sampled
population is tricky,” DeKoven v. Plaza Assocs., ___ F.3d __,
Nos. 09-2016, 09-2249, 2010 WL 938025, at *4 (7th Cir.
Mar. 17, 2010), but a sample size of one is rarely, if ever,
sufficient. That is especially true when deposition testi-
mony from putative class members reveals that different
GL1800s handle and manifest the wobble problem dif-
ferently, and when the handling—and wobble—of motor-
cycles is known to vary with the rider and road conditions.
The small sample size also highlights the constraints
litigation placed upon Ezra’s methods and professional
judgment; Ezra was not being as thorough as he might
otherwise be due to Plaintiffs’ reluctance to pay for
more testing. See Smith, 215 F.3d at 719 (“The trial court
must . . . ‘make certain that an expert, whether basing
testimony upon professional studies or personal experi-
ence, employs in the courtroom the same level of intellec-
tual rigor that characterizes the practice of an expert in
the relevant field.’ ”(quoting Kumho Tire Co. v. Carmichael,
526 U.S. 137, 152 (1999))).
“ ‘[S]haky’ expert testimony may be admissible, assailable
by its opponents through cross-examination,” Gayton, 593
F.3d at 616, but the testimony proffered here is not
merely shaky: it is unreliable. And expert testimony that
is not scientifically reliable should not be admitted, even
“at this early stage of the proceedings.” Allen, 264 F.R.D. at
428. Without Ezra’s testimony, Plaintiffs are left with too
No. 09-8051 13
little to satisfy Rule 23(b)(3)’s predominance prong. The
named plaintiffs have presented evidence that their
GL1800s wobble, that 49 declarants’ GL1800s also wobble,
that all GL1800s have the same ball bearing, that over
11,000 aftermarket kits containing tapered ball bearings
and marketed to fix the GL1800 wobble have been sold,
and that some plaintiffs and declarants fixed their wobble
problems by replacing the factory-installed ball bearings
with tapered ones. See Pl. Answer to Petition for Leave
to Appeal at 20. Without Ezra’s testimony, which asserts
that the factory-installed ball bearings are responsible
for an “increased wobble mode decay time” in all GL1800s,
Plaintiffs are not only unable to support their theory
that all GL1800 motorcycles use ball bearings that fail
to adequately dampen wobble, they are also unable
to demonstrate that their wobble claim sufficiently pre-
dominates as to warrant class certification under
Rule 23(b)(3).
We therefore G RANT Honda’s petition for leave to
appeal, V ACATE the district court’s denial of Honda’s
motion to strike and its order certifying a class, and
R EMAND for proceedings consistent with this opinion.
4-7-10