Litigation: Are plaintiffs required to submit admissible evidence in support of class certification?

In Comcast Corp. v. Behrend, the Supreme Court could raise the evidentiary bar for plaintiffs attempting to demonstrate “commonality”

Last year, the Supreme Court issued its landmark decision in Wal-Mart Stores, Inc. v. Dukes, ruling that an “expansive” class of plaintiffs could not pursue their employment discrimination claims collectively against Wal-Mart. In so holding, the court explained that in a class action, “a party seeking class certification must affirmatively demonstrate his compliance with [Federal Rule of Civil Procedure 23],” including being able “to prove that there are in fact… common questions of law or fact” capable of class-wide resolution.

In a pair of cases this term, the court continues to focus on the contours of Rule 23’s class-certification requirements. One of those cases, Comcast Corp. v. Behrend, takes up an important question left open by Dukes: whether the district court must decide, at the class-certification stage, whether plaintiffs’ expert testimony purporting to demonstrate “common questions of law or fact” is admissible—and, specifically, whether such expert testimony must be subjected to a full analysis under Daubert v. Merrell Dow Pharmaceuticals, Inc. As the court stated in its reformulation of the question presented, the Comcast decision will address whether “a district court may certify a class action without resolving whether the plaintiff class has introduced admissible evidence, including expert testimony, to show that the case is susceptible to awarding damages on a class-wide basis.”

Regardless of how the court answers the question presented, the Comcast decision will likely provide important guidance regarding the burdens on plaintiffs’ counsel to demonstrate “commonality” at the class-certification stage. Comcast may also significantly alter class-action litigants’ settlement calculations insofar as a district court’s class-certification decision is typically a significant milestone in a case. 

The plaintiffs in Comcast brought the case on behalf of a putative class of Philadelphia-area subscribers to a Comcast premium service. Plaintiffs alleged that Comcast perpetrated an anticompetitive “clustering scheme” in violation of the Sherman Act, excluding competition from the region by “swapping” with other providers or purchasing their systems outright. In an attempt to establish that common issues predominate, one of the requirements for certifying a class under Rule 23(b)(3), the plaintiffs’ expert presented a model purporting to calculate damages on a class-wide basis. The district court certified the class, finding, pursuant to Dukes, that the expert’s model provided “common evidence… to measure and quantify damages on a class-wide basis.” The court did not, however, undertake an analysis to determine whether the testimony offered by the plaintiffs’ expert would be admissible under Daubert.

Affirming certification, the 3rd Circuit held not only that a Daubert analysis was unnecessary, but that Comcast’s arguments were “attacks on the merits of the [expert’s] methodology that have no place in the class certification inquiry.” The 3rd Circuit went on to explain its view that Dukes “require[s] a district court to evaluate whether an expert is presenting a model which could evolve to become admissible evidence,” but does not require a determination that the “model is perfect at the certification stage.” The court observed that this interpretation of Dukes “is consistent with our jurisprudence… [under which] we evaluate expert models to determine whether the theory of proof is plausible.”

The Supreme Court granted certiorari (and reformulated the question presented) to resolve whether the evidence offered by plaintiffs to show common questions of law or fact—and, in particular, the expert’s damages model—must be admissible at the class-certification stage. During oral argument, the court demonstrated an interest in developing a workable rule for determining the sufficiency of plaintiffs’ evidence in support of class certification. When pressed to explain what rule the court should adopt, Comcast proposed a two-step approach in which the district court first decides whether the expert’s methodology “sufficiently fits the facts and is reliable based on a scientific method,” and then determines whether the plaintiff “has discharged his duty under [the Supreme] Court’s cases to come forward with evidence that is persuasive” as to whether class treatment is proper. Plaintiffs, in contrast, urged the court to adopt the 3rd Circuit’s approach and rule that the evidence of commonality need only be plausible at the class-certification stage. Plaintiffs further argued that a district court could defer the Daubert question at the certification stage and decide only whether the evidence was “reliable.”

Whether the court will adopt any of these competing approaches remains to be seen. And because much of the argument focused on whether Comcast had waived its objection to the admissibility of plaintiffs’ expert’s damages model, the ultimate outcome of the litigation may be decided on remand. As the Chief Justice stated, “one option for the Court, since we did reformulate the question, is to answer the question and then send it back for the court to determine whether or not the parties adequately preserved the [Daubert] option or not.” 

Contributing Author

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Matthew Brown

Matthew D. Brown is a partner in Cooley LLP’s Litigation Department in San Francisco and a member of the firm’s Privacy, Commercial Class Action Litigation,...

Additional Contributors: Christopher Durbin, Abby Pringle

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