One of the least disputed elements of class certification is Rule 23(a)(1) numerosity, and so there is relatively little analysis from the courts about it. Last month, however, a divided panel of the Third Circuit provided a detailed analysis of the purposes of numerosity and the factors that district courts should employ in making numerosity determinations. In doing so, the court has broken new ground, and its decision will likely be cited by other courts and parties for years to come.
Plaintiffs in In re: Modafinil Antitrust Litigation, No. 15-3475, 2016 WL 4757793 (3d Cir. Sept. 13, 2016) were direct wholesale purchasers of Provigil, a wakefulness-promoting agent used to treat narcolepsy and other sleep disorders. Defendant Cephalon owned the patent for modafinil and had FDA approval for the branded version. Plaintiffs alleged an antitrust conspiracy between Cephalon and the four generic modafinil manufacturers for entering into reverse-payment settlements. Plaintiffs also brought a monopoly claim against Cephalon.
The district court