In a ruling that is likely to have a significant impact on all types of class-action lawsuits, in American Honda Motor Co. v. Allen, No. 09-8051, the US Court of Appeals for the Seventh Circuit vacated an order certifying a class action because the district court had not ruled on the merits of the defendant’s motion to strike the report of the plaintiff’s class certification expert. The Seventh Circuit held that when an expert’s testimony is critical to class certification, a district court must adjudicate any challenge to the expert’s qualifications or submissions—including a challenge to the reliability of the expert’s methodology under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)—before resolving the motion for class certification.


This case involves a products liability lawsuit against Honda on behalf of a putative class of purchasers of certain Honda motorcycles. In moving for class certification, the plaintiffs relied on an expert report to demonstrate the existence of common issues regarding an alleged design defect. In response, Honda moved to strike the expert report as unreliable under Daubert. The district court acknowledged reservations about the expert’s report, but nonetheless certified the putative class and denied the motion to strike without prejudice to its being renewed before trial.


The Seventh Circuit vacated and remanded, holding that the district court was required to address Honda’s motion to strike. The court’s decision confirms that class action plaintiffs may not escape challenges to the experts they employ at the class certification stage by arguing that evidentiary objections should be deferred until the motions in limine before trial. As the Seventh Circuit noted, many district courts had expressed uncertainty about whether Daubert challenges to class certification experts must be resolved before analyzing class certification itself. And as the court pointed out, other federal appellate courts had not directly addressed the issue. In the wake of American Honda v. Allen, it is critical that defendants consider and prepare for the use of Daubert challenges to plaintiffs’ class certification experts at the early stages of a class-action lawsuit.

For more information about the matters raised in this Alert, please contact Archis Parasharami and Kevin Ranlett.

Learn more about Mayer Brown’s Antitrust & Competition and Consumer Litigation & Class Actions practices.