In the Wal-Mart stores , Inc. v. Dukes case of 2011, the U.S. Supreme Court ruled against allowing a class-action suit alleging gender discrimination by female employees on grounds of non-compliance with the rule of commonality in the law. In a class-action suit, according to Rule 23(a)(2) of the Federal Rules of Civil Procedure, members must have common questions of fact or of law central to their claims. The Court, in a 5-4 decision authored by Justice Scalia, determined that the plaintiffs who argued Wal-Mart’s decentralization of corporate culture resulted in gender discrimination in pay and promotion—could not establish such commonality. The Court’s basis was that because Wal-Mart entrusted local managers with broad discretion over employment issues, there was no uniform company-wide policy or practice leading to discrimination. Without a central system (e.g., discriminatory corporate policy), the alleged harms were too scattered throughout the decisions of thousands of individual managers to be a common legal question. The ruling reinterpreted commonality as demanding a certain, tangible policy or practice that applied to all class members in the same way, rather than statistical disparities from decentralized decision making.

This raised the bar for certification of mass class-action cases, particularly employment discrimination cases, by demanding plaintiffs demonstrate systematic bias arises from a coordinated corporate act, and not from managers’ subjective decisions. Justice Ginsburg, dissenting, refuted that Wal-Mart’s delegation of free-wheeling discretion to managers was a policy supporting bias with a gender differential footing nationwide. But the majority dismissed that as too broad. The decision significantly narrowed the scope of class-action lawsuits, making it harder for large groups to sue over systemic inequalities without direct proof of a centralized discriminatory policy.