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 admissibility of an expert opinion prior to class certification in this case because that opinion is essential to the certification 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.,
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 “wobble,” 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 oscillations sufficiently and rapidly so that the rider neither reacts to nor is frightened by such oscillations.” Assuming that human reaction time to wobble is to % of a second, Ezra opined that wobble should decay, or dissipate, to 37% of its original amplitude within % of a second to ensure that riders do not perceive and react to the oscillations. This standard, which Ezra devised himself and characterizes as “reasonable,” was published in the June 2004 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 standard could be achieved in the GL1800 motorcycle by replacing the regular ball bearings in the steering assembly with tapered ones.
Honda moved to strike the report pursuant to
Daubert v. Merrell Dow Pharms., Inc.,
The district court concluded that it was proper to decide whether the report was admissible prior to certification because “most of Plaintiffs’ predominance arguments rest upon the theories advanced by Mr. Ezra.”
Allen v. Am. Honda Motor Co.,
In
Szabo v. Bridgeport Machs., Inc.,
Plaintiffs argue that we do not need to accept this appeal because district courts in this circuit generally agree that a
Daubert
challenge must be resolved prior to class 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,
We hold that when an expert’s report or testimony is critical to class certification, as it is here,
see Allen,
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.,
“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,
*817
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,
The district court was reluctant to exclude Ezra’s report “in its entirety at this early stage of the proceedings,”
Allen,
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,
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,
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,
The methodology underlying the tests Ezra conducted to determine whether the GL1800 met his standard also gives us pause. Ezra tested a single, used 2006 GL1800, ridden by a single test rider, and extrapolated his conclusions 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.,
“ ‘[S]haky’ expert testimony may be admissible, assailable by its opponents through cross-examination,”
Gayton,
We therefore Grant Honda’s petition for leave to appeal, Vacate the district court’s denial of Honda’s motion to strike and its order certifying a class, and Remand for proceedings consistent with this opinion.
