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May 08, 2018 Articles

California Appellate Court Holds that Expert Evidence Submitted in Support of Certification Must Be Admissible

Practitioners should be cognizant of the Apple decision and prepared to meet the evidentiary requirements of Sargon at the class certification stage.

By Robert J. Herrington

Addressing a matter of first impression, the California Court of Appeal recently held that a trial must determine, at the class certification stage, whether expert opinions offered in support of certification are admissible. Apple Inc. v. Superior Court, 19 Cal. App. 5th 1101, 1106 (2018) (“A trial court may consider only admissible expert opinion evidence on class certification, and there is only one standard for admissibility of expert opinion evidence in California.”).

The case involved an alleged defect in the power button on certain iPhone models. In support of their motion for class certification, plaintiffs offered opinions from several experts regarding the defect rate and models for calculating damages and restitution on a class-wide basis. The defendant opposed this evidence, arguing that it was inadmissible under the California Supreme Court’s decision in Sargon Enterprises, Inc. v. Univ. of S. Cal., 55 Cal. 4th 747, 753 (2012) (“We conclude that the trial court has the duty to act as a ‘gatekeeper’ to exclude speculative expert testimony.”). The trial court granted certification, concluding that the admissibility of expert opinion was for trial.

The California Court of Appeal reversed, seeing “no reason why Sargon should not apply equally in the context of class certification motions.” Apple, 19 Cal. App. 5th at 1119. Starting with the principle that courts “may consider only admissible expert opinion evidence at class certification,” the court explained that “certifying a proposed class based on inadmissible expert opinion evidence would merely lead to its exclusion at trial, imperiling continued certification of the class and wasting the time and resources of the parties and the court.” Id. at 1117. “Although class certification is merely a procedural device, and not a determination on the merits, it has profound consequences for the trial court's management of the litigation and the rights of the parties.” Id. at 1119. “The corrosive effects of improper expert opinion testimony may be felt with substantial force at class certification, just as at summary judgment or at trial.” Id.

The court emphasized that “a trial court applying the Sargon standard at class certification should be cognizant of limited scope of its inquiry at that stage, when compared with the inquiry at trial.” Id. at 1120. In some cases, a court may not need to rule on the admissibility of expert opinions because those opinions are irrelevant or not necessary for its decision on certification. “But where, for example, expert opinion evidence provides the basis for a plaintiff's arguments regarding numerosity, ascertainability, commonality, or superiority (or a defendant's opposition thereto), a trial court must assess that evidence under Sargon.” Id.

Practitioners should be cognizant of the Apple decision and prepared to meet the evidentiary requirements of Sargon at the class certification stage.


Robert J. Herrington is a partner with Greenberg Traurig in Los Angeles, California.

Robert J. Herrington – May 8, 2018