Eisen v. Carlisle & Jacqueline

*Supreme Court decision in 1974 holding that a court may not base a determination whether or not to certify a class based on a preliminary assessment of the merits

*In Eisen’s wake, class certification became progressively easier

• Most courts ruled that, on a motion to certify a class, the plaintiffs’ allegations on the merits must be accepted as true

• Many courts went further, holding that “any doubts” had to be resolved “in favor of certifying the class”

• On the often determinative issue of common impact, courts said they “only must find that plaintiffs have set forth a valid methodology for proving antitrust impact common to the class, not that they will prove it.”

• Second, Third, Ninth Circuits even said that challenges to the presentation of the plaintiffs’ expert – often the only source of evidence supporting class certification – were limited to determining whether the expert’s “proposed methods are so insubstantial as to amount to no method at all.”