In a wage and hour class action that was tried to a plaintiffs’ verdict, but decertified by the court of appeal, the California Supreme Court held that “a class action trial management plan must permit the litigation of relevant affirmative defenses, even when these defenses turn on individual questions.” Duran v. U.S. Bank Nat’l Ass’n, No. S200923 (May 29, 2014). It affirmed the court of appeal’s holding that the defendant’s due process rights were violated when sampling was used to determine liability, and the defendant was not allowed to present facts establishing that a large number of individuals outside the sample did not have valid claims.

The Court emphasized that trial courts “must pay careful attention to manageability when deciding whether to certify a class action.” On remand, the trial court could entertain a class certification motion, but the Court cautioned that “[a] trial plan that relies on statistical sampling must be developed with expert input and must afford the defendant an opportunity to impeach the model or otherwise show liability is reduced.” The sampling method previously used by the trial court was flawed because the sample size was too small, not random, and resulted in an intolerably large margin of error.