In the case of Dukes v. Wal-Mart Stores, Inc., 603 F.3d 571 (9th Cir. 2010), the Ninth Circuit lowered the standards for class certification under Rule 23 of the Federal Rules of Civil Procedure. The court announced a more lenient standard of proof at the certification stage and eased restrictions on expert testimony and statistical evidence. This article, which first appeared in the ABA's Section of Litigation, Consumer & Civil Rights Newsletter in February 2011, discusses the significance of the ruling, not only for parties in the case, but for employers and class action litigants generally.