                 FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


PHYLLIS GRODZITSKY, on behalf of          No. 18-55417
themselves and all others similarly
situated; JEREMY BORDELON, on                D.C. No.
behalf of themselves and all others       2:12-cv-01142-
similarly situated; STEPHANIE               SVW-PLA
MANZO, on behalf of themselves and
all others similarly situated; SOHAL
SHAH, on behalf of themselves and           OPINION
all others similarly situated; JOYCE
YOUNG; CHARITY ANYIAM; DENNIS
MASON; JONATHAN PENDARVIS,
                 Plaintiffs-Appellants,

                  v.

AMERICAN HONDA MOTOR CO.,
INC.,
            Defendant-Appellee.


      Appeal from the United States District Court
          for the Central District of California
      Stephen V. Wilson, District Judge, Presiding

           Argued and Submitted April 8, 2019
                  Pasadena, California

                   Filed April 29, 2020
2       GRODZITSKY V. AMERICAN HONDA MOTOR CO.

    Before: Johnnie B. Rawlinson and Mary H. Murguia,
     Circuit Judges, and Jed S. Rakoff,* District Judge.

                  Opinion by Judge Rawlinson;
                   Dissent by Judge Murguia


                            SUMMARY**


             Expert Opinion / Class Certification

    The panel affirmed the district court’s order excluding
plaintiff’s expert opinion, and denying class certification in
a design defect case concerning 2003–2008 Honda Pilot
vehicles.

    The proposed class were purchasers and lessees of Honda
Pilots who alleged that the vehicles were defectively designed
when the regulators failed to properly support the side
windows, rendering the windows inoperable. Plaintiff’s
expert Glenn Akhavein opined that the window regulators
were not sufficiently durable when exposed to vibrations at
certain frequencies. The district court excluded the opinion as
deficient under Daubert v. Merrell Dow Pharms., Inc., 509
U.S. 579 (1993).




    *
     The Honorable Jed S. Rakoff, United States District Judge for the
Southern District of New York, sitting by designation.
    **
       This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                 3

    The panel held that the district court properly excluded
Akhavein’s opinion under Daubert. The district court
properly held that Akhavein’s opinion was unreliable due to:
Akhavein’s failure to utilize a workable standard supporting
his design defect theory; the lack of supporting studies or
testing to demonstrate a common design defect; and
deficiencies in Akhavein’s methodology. The panel further
held that in the absence of the expert report, the plaintiffs
failed to demonstrate commonality for a putative class action,
as the remaining evidence consisted solely of highly
individualized complaints.

    Judge Murguia dissented. Although she agreed that the
district court acted within its discretion in excluding certain
parts of Akhavein’s expert testimony, she would hold that the
district court abused its discretion when it excluded the
testimony in its entirety, and she would reverse the district
court’s order excluding Akhavein’s expert testimony. Judge
Murguia would also reverse the district court’s denial of class
certification and remand so that the district court could
reconsider plaintiffs’ motion in light of the admissible
portions of Akhavein’s testimony.


                         COUNSEL

Jonathan D. Selbin (argued) and Annika K. Martin, Lieff
Cabraser Heimann & Bernstein LLP, New York, New York;
Mark P. Chalos and Andrew R. Kaufman, Lieff Cabraser
Heimann & Bernstein LLP, Nashville, Tennessee; Marc
Godino, Glancy Prongay & Murray LLP, Los Angeles,
California; Jon A. Tostrud, Tostrud Law Group P.C., Los
Angeles, California; J. Barton Goplerud, Shindler &
4     GRODZITSKY V. AMERICAN HONDA MOTOR CO.

Anderson Goplerud & Weese P.C., West Des Moines, Iowa;
for Plaintiffs-Appellants.

Michael L. Mallow (argued), David Carpenter, and Rachel A.
Straus, Sidley Austin LLP, Los Angeles, California; Paul G.
Cereghini and Robert L. Wise, Bowman and Brooke LLP,
Torrance, California; for Defendant-Appellee.


                         OPINION

RAWLINSON, Circuit Judge:

    In this design defect case, Appellant Phyllis Grodzitsky
(Grodzitsky), the class representative for a proposed class of
purchasers and lessees of 2003–2008 Honda Pilot vehicles,
appeals the district court’s order excluding her expert’s
opinion and denying class certification. Grodzitsky alleged
that window regulators inside Honda Pilot vehicles were
defectively designed because the regulators failed to properly
support the side windows, rendering the windows inoperable.
Plaintiff’s expert Glenn Akhavein (Akhavein) opined that
Honda window regulators were not sufficiently durable when
exposed to vibrations at certain frequencies. We affirm the
district court’s order excluding Grodzitsky’s expert and
denying class certification.

I. BACKGROUND

    In her third amended class action complaint, Grodzitsky
alleged that the window regulators installed by Honda were
defective because they caused windows to fall into the
doorframes, which increased the likelihood of injuries or
accidents. Based on the alleged defect, Grodzitsky alleged
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                    5

causes of action for: (1) violations of California’s Consumer
Legal Remedies Act, Cal. Civ. Code § 1750 et seq.; and
(2) violations of California’s Unfair Competition Law, Cal.
Bus. & Prof. Code § 17200 et seq.

    Grodzitsky initially sought certification of a class of “[a]ll
persons in the United States who purchased or leased [one of
seven Honda models, for model years 2000–2011, including
the Honda Pilot] with the Window Regulator,” as well as
various subclasses based on the residencies of the vehicle
owners. During the course of the litigation, Grodzitsky
narrowed the proposed class to include only individuals who
leased or owned 2003–2008 Honda Pilots.

     In her renewed motion for class certification, Grodzitsky
described the asserted design defect as window regulators in
Honda Pilot vehicles that were “insufficiently strong and
insufficiently durable to withstand the forces required to
perform [their] intended function.” In support of her motion,
Grodzitsky relied in part on Akhavein’s expert opinion. In
his report, Akhavein, an engineer, explained that “[a] window
regulator, including a Honda Pilot regulator, has a primary
purpose of moving the window glass from where it is to
where the user wants [it] to go and stay there.” Akhavein
conveyed that static loading, which occurs “when the load or
force on an object is constant,” and dynamic loading,
involving changes in force on an object, may impact the
efficacy of a window regulator. Akhavein opined that,
“[b]ased on [his] comprehensive review of the failed Honda
Pilot regulators, all appear to have failed at the ferrule-carrier
interface, that is the portion of the carrier that supports the
cable ferrule.”
6     GRODZITSKY V. AMERICAN HONDA MOTOR CO.

     According to Akhavein, dynamic loading affected the
window regulators due to the force exerted when the vehicle
was in motion. Akhavein stated that “[a] significant design
mistake made by Honda, and missed or ignored by [Honda’s
expert], is just how quickly a high number of cycles is applied
to the carrier due to the dynamic vibrational loading that
occurs in the Vehicle Moving state.” In other words, the
internal mechanisms of the window regulators were
ultimately unable to withstand the vibrations caused by the
vehicle’s movement. Akhavein opined that “Honda did not
adequately design the Window Regulators to be strong and
durable enough to withstand this high-cycle dynamic
loading.” Akhavein also explained that “[f]atigue, in this
case caused by vibration exposure, is important as it has been
estimated that 90% of all mechanical service failures can be
attributed to fatigue.”

    Akhavein determined that Honda’s testing of its window
regulators was deficient. Akhavein faulted Honda for only
testing dynamic loading at a single, constant frequency, as
opposed to subjecting the window regulators to a range of
vibrational frequencies. Akhavein stated that “[t]his is crucial
because a mechanical object can function perfectly when
vibrated at one frequency but will tear itself apart if vibrated
at or near its natural frequency.” Akhavein concluded that
“[t]he Pilot Window Regulators were not adequately designed
to [be] strong and durable enough to withstand the continual
affects [sic] that vibration induced metal fatigue had upon the
metal portion of the carrier to ferrule interface which is what
supports the window.”

    During Akhavein’s deposition, Honda asked several
questions concerning his standard for the effective
performance of window regulators. In response, Akhavein
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                  7

stated that window regulators “shouldn’t fail ever,” and
agreed that, if someone owned a vehicle for thirty years, the
“window regulator assembly should work the same way it
worked when it was brand new . . . [i]f the car is still
running.” Akhavein further asserted that the window
regulator “should work for the life of the car.” Akhavein
articulated that “[t]here’s no universal reason that a window
regulator should fail.” Akhavein explained that the window
regulators had a common defect because they were not
“durable enough,” and that the standard for durability was
that a window regulator “should last the life of the vehicle.”
Akhavein acknowledged that there was no industry standard
establishing that a window regulator should last for the life of
the vehicle. Akhavein stated that his testing protocol was
“just a real world driving around test,” and that he did not
identify “a common solution” for resolving the defect in the
window regulators. Akhavein did not have an opinion
concerning the proper method that Honda should have
utilized in designing its window regulators. Akhavein also
acknowledged that the vibrational testing he conducted
indicated the manner in which the window regulators
responded to various frequencies, but there was “no direct
correlation” with how long the part should last or whether it
was “durable enough to perform its function[.]”

    Honda filed a motion to exclude Akhavein’s expert
opinion, which the district court granted. The district court
determined that Akhavein’s opinion was deficient under
Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579 (1993),
reasoning that Akhavein’s opinion was premised on “half-
baked, warmed-over conclusions” that Honda window
regulators were defective “because they do not last the life of
the vehicle, which [Akhavein] define[d] as the entire duration
8     GRODZITSKY V. AMERICAN HONDA MOTOR CO.

the vehicle is on the road.” The district court excluded that
opinion because:

       (1) Akhavein provide[d] no industry standards
       for window regulator replacement rates;
       (2) Akhavein relie[d] on no peer-reviewed
       literature relating to window regulator
       durability; (3) Akhavein provide[d] no
       information on average window regulator
       replacement rates; and ([4]) Akhavein
       provide[d] no consumer studies to substantiate
       his claim that consumers expect a window
       regulator to last forever.

The district court observed that Grodzitsky attempted to
recast Akhavein’s opinion by asserting that the window
regulators were “defective from the moment they are
installed, and that Akhavein’s claims that they should last
forever [were] therefore irrelevant.” The district court
rejected Grodzitsky’s attempt because “[w]ithout some
objective basis to indicate how long the regulators should last,
alleging that they are defective as soon as they are installed
is simply circular – the window regulators are defective
because they do not last as long as they should, therefore they
are defective.”

   The district court was also unpersuaded by Akhavein’s
opinion that the internal cable or ferrule interfaces for the
regulators were defective. The district court opined that the
methodology employed by Akhavein to reach this opinion
was deficient because:

       (1) he examined an extremely small sample
       size of window regulators; (2) he does not
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                9

       know who made the regulators he examined;
       and (3) of the failed window regulators he
       inspected, he does not know if the failures
       were attributable to Plaintiffs’ theory of
       liability.

The district court emphasized that:

       Mr. Akhavein inspected a total of 26
       regulators over the course of his investigation.
       Of these, three were sent to him by Plaintiffs
       on the instruction of Plaintiffs’ counsel, eight
       were inspected in Plaintiffs’ vehicles, ten
       came from junkyards Mr. Akhavein visited,
       and three regulators came from a test vehicle.
       Not all of these regulators had failed when
       Mr. Akhavein inspected them. In fact, only
       roughly a dozen had failed. . . . This means
       Mr. Akhavein has no information whatsoever
       regarding why the other failed regulators in
       class vehicles failed. He is essentially
       extrapolating from the 12 failed regulators he
       inspected to draw conclusions about the
       441,600 regulators installed in class vehicles.
       This is insufficient.

The district court articulated that, although Grodzitsky
maintained that statistical significance was irrelevant in
design defect actions, Akhavein framed his opinion in terms
of probabilities without an adequate methodology supporting
his assessment that it was “more likely than not that a failed
Honda regulator . . . failed because of this design defect.”
10    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

    The district court similarly rejected Akhavein’s opinion
that Honda’s vibration testing was defective because it was
conducted at only one frequency. The district court
determined that Akhavein’s vibration testing did not support
his opinion because “he conducted no durational testing to
confirm that these additional frequencies cause the regulators
to fail when they are exposed to those frequencies over time.”
The district court opined that Akhavein failed to demonstrate
that his testing would have identified the defect relative to the
tests performed by Honda.

    Finally, the district court held that “[t]he exclusion of
Mr. Akhavein’s testimony [was] fatal to Plaintiffs’ motion for
class certification,” because “without this testimony Plaintiffs
[were] unable to meet the requirements of Rule 23.” The
district court reasoned that, without Akhavein’s opinion, the
plaintiffs were unable to demonstrate the requisite
commonality because “[a]ll they have is a series of window
regulators that may or may not have broken before they were
supposed to, and these breakages may or may not have been
caused by a common defect which may or may not exist.”

    We granted Grodzitsky’s petition for permission to appeal
the district court’s order.

II. STANDARDS OF REVIEW

    We review the district court’s exclusion of Akhavein’s
expert opinion and the resulting denial of class certification
for an abuse of discretion. See Crowley v. Epicept Corp.,
883 F.3d 739, 752 (9th Cir. 2018) (expert opinion); see also
Sandoval v. Cnty. of Sonoma, 912 F.3d 509, 515 (9th Cir.
2018) (denial of class certification).
       GRODZITSKY V. AMERICAN HONDA MOTOR CO.                 11

    “A class certification order is an abuse of discretion if the
district court applied an incorrect legal rule or if its
application of the correct legal rule was based on a factual
finding that was illogical, implausible, or without support in
inferences that may be drawn from the facts in the
record. . . .” Sandoval, 912 F.3d at 515 (citation and internal
quotation marks omitted).

III.    DISCUSSION

    Grodzitsky contends that the district court erred in
excluding Akhavein’s expert opinion because his opinion was
reliable, relevant, and comported with the admissibility
standards established in Daubert.

    The district court did not abuse its discretion in excluding
Akhavein’s opinion. “[I]n evaluating challenged expert
testimony in support of class certification, a district court
should evaluate admissibility under the standard set forth in
Daubert. . . .” Sali v. Corona Reg’l Med. Ctr., 909 F.3d 996,
1006 (9th Cir. 2018), as amended (citation omitted). Under
Daubert, “the district court judge must ensure that all
admitted expert testimony is both relevant and reliable.”
Wendell v. GlaxoSmithKline LLC, 858 F.3d 1227, 1232 (9th
Cir. 2017) (citation omitted). “Scientific evidence is reliable
if the principles and methodology used by an expert are
grounded in the methods of science.” Id. (citation and
internal quotation marks omitted). “The focus of the district
court’s analysis must be solely on principles and
methodology, not on the conclusions that they generate,” and
“the court’s task is to analyze not what the experts say, but
what basis they have for saying it.” Id. (citations, alteration,
and internal quotation marks omitted). In conducting this
analysis, the district court may consider “whether the theory
12    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

or technique employed by the expert is generally accepted in
the scientific community; whether it’s been subjected to peer
review and publication; whether it can be and has been tested;
and whether the known or potential rate of error is
acceptable.” Id. (citation omitted).

     The district court properly excluded Akhavein’s opinion
under Daubert. Although Grodzitsky vigorously attempts to
disassociate her design defect claim from the standard
utilized by Akhavein during his deposition, Grodzitsky’s
recasting of Akhavein’s opinion is unavailing. In his
deposition, Akhavein faulted Honda’s design for its window
regulators because the window regulators “shouldn’t fail
ever.” This was not a passing observation by Akhavein.
Instead, he stated that “a window regulator assembly should
work the same way it worked when it was brand new,” the
window regulator “should work for the life of the car,” there
was “no universal reason that a window regulator should
fail,” if an owner operated the vehicle for thirty years, the
“window regulator assembly should work the same way it
worked when it was brand new,” the window regulators had
a common defect because they were not “durable enough,”
and the applicable standard for durability was that the
regulators “should last the life of the vehicle.” Although
Grodzitsky maintains that Akhavein’s opinion was premised
on his determination that the regulators were defective
because they lacked the requisite strength and durability to
withstand force produced during the vehicle’s operation, this
assertion elides the life-of-the-vehicle defect design theory
permeating Akhavein’s deposition testimony.

    Moreover, the methodological flaws in Akhavein’s
opinion were not limited to his overly expansive standard for
a design defect. Indeed, Akhavein admitted that he failed to
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                13

identify a common solution to the defect, but relied on “just
a real world driving around test.” Additionally, Akhavein
explained in his rebuttal report that he examined only twenty-
six Honda Pilot window regulators. Akhavein stated that:

       Of the 26 regulators that [he had] seen, . . .
       [f]our of them were sent to [him] directly by
       the named Plaintiffs . . . 9 of them were on
       Plaintiffs’ Vehicles whose inspection pictures
       [he] reviewed, 10 of them are Regulators [he]
       removed from Class Vehicles [he] found at
       random in Florida salvage yards, and 4 are
       Regulators from the test vehicles used by
       Honda’s expert[.]

In addition to utilizing this small sample size to prove a
common defect in over 400,000 window regulators for class
vehicles, Akhavein acknowledged that there was “no direct
correlation” between his vibrational testing and failure of the
window regulators. Akhavein further conceded that he did
not conduct a comparison with window regulators from other
manufacturers, and did not review any industry data
concerning replacement rates for window regulators. Finally,
Akhavein confirmed that he did not “have an opinion on what
[Honda] should have done” in designing a proper window
regulator.

    The dissent fully acknowledges that the district court
properly excluded Akhavein’s opinion that the regulators
should have lasted the life of the vehicle, the crux of
Akhavein’s defect theory, and that Akhavein entirely failed
to cite industry standards, peer-reviewed literature, or even
“test a statistically significant number of regulators to opine
on the probabilities that any given Honda Pilot regulator
14    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

failed because of the alleged defect.” Dissenting Opinion,
p. 18. Nevertheless, the dissent unsuccessfully attempts to
salvage Akhavein’s deeply flawed opinion by artificially
separating Akhavein’s fatally flawed opinion into a series of
opinions, including some based on “first-hand observations
and testing.” Id. at p. 19. However, as the district court
noted, Akhavein articulated no scientific basis for his
observations. And the only testing he performed was not
designed to identify any defects, let alone a common defect.
See, e.g., Cates v. Whirlpool Corp., No. 15-CV-5980, 2017
WL 1862640 at *12 (N.D. Ill. May 9, 2017) (excluding an
expert opinion in the class certification context based on the
expert’s “merely point[ing] to an undifferentiated mass of
potential problems”). In other words, identification of
general “potential problems” in the absence of the
identification of a specific defect present in all the regulators
did not constitute “an opinion that fits Plaintiffs’ class-
certification argument.” Id. (citation omitted). See Ellis v.
Costco Wholesale Corp., 657 F.3d 970, 982 (9th Cir. 2011)
(explaining that “Daubert does not require a court to admit or
to exclude evidence based on its persuasiveness; rather it
requires a court to admit or exclude evidence based on its
scientific reliability and relevance. Thus, an expert’s
inference or assertion must be derived by the scientific
method to be admissible.”) (citations and internal quotation
marks omitted). The dissent’s reliance on Akhavein’s
generalized opinion, while ignoring its acknowledged flaws,
does not comport with our standards for assessing expert
opinions. See id.

    According to the dissent, if Akhavein could cobble
together some form of generalized opinion, even one riddled
with scientific and methodological flaws, the district court
would abuse its discretion in not accepting that opinion. See
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                15

Dissenting Opinion, pp. 19–21. Relying on this premise, the
dissent contends that the district court should reconsider its
denial of class certification based on “the admissible portions
of Akhavein’s testimony.” Id. at p. 22. However, we have
recognized that a district court errs when it “limit[s] its
analysis of whether there was commonality to a determination
of whether Plaintiffs’ evidence on that point was admissible.”
Ellis, 657 F.3d at 982. Instead, the district court must engage
in a “rigorous analysis” of commonality, rather than “merely
conclud[ing] that, because . . . evidence was admissible, a
finding of commonality was appropriate.” Id. at 984.

     The district court conducted the requisite “rigorous
analysis” in determining that Grodzitsky was unable to
demonstrate commonality.          Contrary to the dissent’s
contention, Akhavein did not proffer an opinion based on
“general product engineering principles” completely
untethered from the scientific and methodological flaws
identified by the district court. Dissenting Opinion, p. 20. In
his own testimony, Akhavein stated that the regulators had a
“common defect” because they were not “durable enough” to
“last the life of the vehicle,” conceded that he was unable to
identify a “common solution” to the purported defects in the
regulators, and confirmed that he had no opinion concerning
the proper manufacturing method that should have been
utilized by Honda. Finally, his vibration testing provided “no
direct correlation” to the durability of the regulators. Due to
these concessions, Akhavein did not and could not provide a
reliable opinion demonstrating a common defect for over
400,000 regulators. See Ellis, 657 F.3d at 982–84; see also
Wendell, 858 F.3d at 1232 (reminding us that the focus is
“solely” on “principles and methodology, not on the
conclusions they generate”) (citation omitted). We “analyze
not what the experts say, but what basis they have for saying
16    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

it.” Wendell, 858 F.3d at 1232 (citation omitted). The district
court in this case properly performed its gatekeeping function
in assessing Akhavein’s proffered opinion and concluding
that the opinion was not predicated on reliable scientific
methodology. See id.

    The dissent’s reliance on McKendall v. Crown Control
Corp., 122 F.3d 803 (9th Cir. 1997) is misplaced. See
Dissenting Opinion, pp. 20–21. In that case, which was a
products liability action “for injuries incurred when a sofa fell
on [the plaintiff] while he was operating [a] forklift,” we held
that the expert’s “testimony, based on his engineering
experience and his having investigated hundreds of fork lift
cases over the past thirty years, that a safety device is
feasible, [was] both facially helpful and relevant and
seemingly reliable.” McKendall, 122 F.3d at 804, 807
(citation and internal quotation marks omitted). We did not
hold that an engineer’s generalized opinion suffering from
severe methodological and scientific flaws was otherwise
reliable.    Moreover, we have since recognized that
McKendall’s holding that “the Daubert factors are relevant
only to testimony bearing on scientific knowledge and did not
apply to an expert testifying on how a product ought to have
been designed” has been overruled. See White v. Ford Motor
Co., 312 F.3d 998, 1007 (9th Cir. 2002). Thus, McKendall
provides little assistance in salvaging Akhavein’s opinion.

    Neither do United States v. Laurenti, 611 F.3d 530 (9th
Cir. 2010) and United States v. Finley, 301 F.3d 1000 (9th
Cir. 2002) compel a finding that the district court abused its
discretion in this case. See Dissenting Opinion, p. 21. In
Laurenti, a criminal prosecution for securities fraud, we
concluded that the district court erred in excluding testimony
concerning National Association of Securities Dealers rules
       GRODZITSKY V. AMERICAN HONDA MOTOR CO.                17

and the expert’s “general knowledge of the industry as a
whole.” 611 F.3d at 548. In Finley, we held that the district
court erred in excluding the entirety of an expert’s testimony
in a criminal case as a discovery sanction under Federal Rule
of Criminal Procedure 16(d)(2). See 301 F.3d at 1018.
Because these cases did not address a deeply flawed and
unsupported expert opinion offered in the context of the
rigorous analysis applied to assess commonality for a putative
class action, they are unpersuasive on this point. Finally, our
opinion in Wolin v. Jaguar Land Rover N. Am., LLC,
617 F.3d 1168 (9th Cir. 2010), lends no assistance to the
dissent’s position. In that case, the existence of a defect was
undisputed. See id. at 1170–71 (focusing on whether the
defect was common rather than on the existence of a defect).

IV.     CONCLUSION

    The district court did not abuse its discretion in excluding
Akhavein’s expert opinion under Daubert. The district court
properly held that Akhavein’s opinion was unreliable due to
Akhavein’s failure to utilize a workable standard supporting
his design defect theory; the lack of supporting studies or
testing to demonstrate a common design defect; and
deficiencies in Akhavein’s methodology.

   In the absence of the report, the plaintiffs failed to
demonstrate commonality, as the remaining evidence
consisted solely of highly individualized complaints.

      AFFIRMED.
18    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

MURGUIA, Circuit Judge, dissenting:

    Although I agree that the district court acted within its
discretion in excluding certain parts of Akhavein’s expert
testimony, the district court abused its discretion when it
excluded the testimony in its entirety, the admissible portions
of which may have critically supported Plaintiffs’ motion for
class certification. I would therefore reverse the district
court’s order excluding Akhavein’s expert testimony.

    To be sure, for many of the reasons identified by the
majority, the district court did not abuse its discretion in
excluding portions of Akhavein’s testimony. The properly
excluded portions included Akhavein’s opinion that
regulators should last the life of the vehicle, Akhavein’s
views on the probabilities that any given failure is due to the
alleged defect, and Akhavein’s opinion that the alleged defect
in fact caused the regulators he examined to fail. In rendering
these opinions, Akhavein failed to, among other things, cite
any industry standards for normal or expected regulator
replacement rates, cite any peer-reviewed literature regarding
regulator durability, and test a statistically significant number
of regulators to opine on the probabilities that any given
Honda Pilot regulator failed because of the alleged defect.

    The district court, however, abused its discretion when it
failed to separate these opinions from the remainder of
Akhavein’s report, choosing instead to exclude Akhavein’s
testimony in its entirety. See Reed v. Lieurance, 863 F.3d
1196, 1208–09 (9th Cir. 2017) (“While the district court may
have had a proper basis to exclude portions of the expert
report in its discretion, . . . the district court abused its
discretion in excluding the entirety of [the expert’s]
testimony[.]”). There is no dispute that Akhavein—an
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                  19

engineer with twenty-five years of education and training—is
qualified to opine on product design and forensic engineering.
See City of Pomona v. SQM N. Am. Corp., 750 F.3d 1036,
1044 (9th Cir. 2014) (“[Expert testimony] is reliable if the
knowledge underlying it has a reliable basis in the knowledge
and experience of the relevant discipline.” (quoting Primiano
v. Cook, 598 F.3d 558, 565 (9th Cir. 2010))). Nevertheless,
the district court went too far when it excluded even those of
Akhavein’s opinions that were rooted in first-hand
observations and testing—including his opinion that the
regulators were designed in a way that made them susceptible
to failure as well as his basic opinion regarding the
vibrational frequencies that the regulators would be exposed
to with normal vehicle use. These opinions—“conclusion[s]
from a set of observations based on extensive and specialized
experience”—have a reliable basis and would be helpful to a
jury tasked with assessing whether the regulators are
defective. Kumho Tire Co. v. Carmichael, 526 U.S. 137, 156
(1999); see Sali v. Corona Reg’l Med. Ctr., 909 F.3d 996,
1006 (9th Cir. 2018) (“[I]n evaluating challenged expert
testimony in support of class certification, a district court
should evaluate admissibility under the standard set forth in
Daubert.”); City of Pomona, 750 F.3d at 1043–44 (“Under
Daubert and its progeny . . . ‘[t]he district court is not tasked
with deciding whether the expert is right or wrong, just
whether his testimony has substance such that it would be
helpful to a jury.’” (quoting Alaska Rent-A-Car, Inc. v. Avis
Budget Group, Inc., 738 F.3d 960, 969–70 (9th Cir. 2013))).

    The majority argues that these opinions are—like the
others—“riddled with scientific and methodological flaws.”
But the majority fails to convincingly explain why
Akhavein’s observations about the design of Honda Pilot
regulators and the normal-use vibrational frequencies that the
20    GRODZITSKY V. AMERICAN HONDA MOTOR CO.

regulators would be exposed to—which, again, are rooted in
his twenty-five years of education and training in the field of
engineering— are “fatally flawed.” While the majority
contends that these observations had “no scientific basis,” it
notably fails to explain with any level of specificity how it
comes to that conclusion. Rather, the majority comes to its
conclusion by indiscriminately lumping these opinions
together with the above-mentioned defective opinions,
seemingly concluding that a few bad apples must mean that
the whole barrel is rotten. But contrary to the majority’s
contention, there is nothing “artificial” about declining to
exclude an expert’s testimony wholesale simply because
some of his opinions are flawed.

    The majority unpersuasively cites as an example of
Akhavein’s “fatally flawed” opinion Akhavein’s examination
of “only twenty-six Honda Pilot window regulators” “to
prove a common defect in over 400,000 window regulators
for class vehicles[.]” But as the district court explained,
Akhavein’s failure to test a statistically significant number of
regulators posed a problem only to Akhavien’s opinion
regarding the probability that a given regulator failed because
of the alleged defect. That is, Akhavein does not need to test
a statistically significant number of regulators to give his
general observations and conclusions about the design of
Honda Pilot regulators. Additionally, the majority cites
Akhavein’s acknowledgment of the lack of direct correlation
between his vibrational testing and failure of the regulators.
But this does not undermine Akhvein’s opinion that—as a
matter of general product engineering principles—products
should be designed with the vibrational frequencies they are
expected to experience in mind, and that Honda failed to take
this into account. See McKendall v. Crown Control Corp.,
122 F.3d 803, 807 (9th Cir. 1997) (“[The expert] reached his
      GRODZITSKY V. AMERICAN HONDA MOTOR CO.                  21

expert conclusions by drawing upon general engineering
principles and his twenty-two years of experience as an
automotive engineer.” (quoting Compton v. Subaru of Am.,
Inc., 82 F.3d 1513, 1519 (10th Cir. 1996))).

    While Akhavein’s admissible opinions may not alone
definitively establish that the regulators are defective,
Plaintiffs do not need to demonstrate that they will prevail on
the merits to satisfy commonality; they need only show that
a classwide proceeding would “generate common answers apt
to drive the resolution of the litigation.” Torres v. Mercer
Canyons Inc., 835 F.3d 1125, 1133 (9th Cir. 2016) (emphasis
omitted) (quoting Wal-Mart Stores, Inc. v. Dukes, 564 U.S.
338, 350 (2011)); Wolin v. Jaguar Land Rover N. Am., LLC,
617 F.3d 1168, 1172 (9th Cir. 2010) (finding that plaintiffs
“easily satisf[ied] the commonality requirement” because
each class member’s claim involved “the same alleged defect,
covered by the same warranty, and found in vehicles of the
same make and model”).

    For these reasons, the district court abused its discretion
when it excluded the entirety of Akhavein’s expert testimony,
an error that cannot be construed as harmless. United States
v. Laurienti, 611 F.3d 530, 548 (9th Cir. 2010) (finding
district court’s erroneous exclusion of expert testimony
harmless because, “[u]nlike in many cases, where the district
court prohibits all testimony by a proffered expert, the district
court here permitted testimony by [the expert] on a wide
range of topics and sustained objections only to a limited set
of questions”); United States v. Finley, 301 F.3d 1000, 1018
(9th Cir. 2002) (holding that the exclusion of expert
testimony was not harmless because it was “the only evidence
of [defendant’s] diagnosed mental disorder, and the [district]
court excluded the entire testimony”).
22     GRODZITSKY V. AMERICAN HONDA MOTOR CO.

    Finally, because the district court explicitly denied class
certification on the basis that “[w]ithout [Akhavein’s]
testimony, Plaintiffs have no way of demonstrating the
commonality required by Rule 23,” I would also reverse the
district court’s denial of class certification and remand so that
the district court could reconsider Plaintiffs’ motion in light
of the admissible portions of Akhavein’s testimony.

     Therefore, with respect, I dissent.
