The Supreme Court refused to certify a class-action complaint filed by female employees who claimed widespread gender discrimination in salary and promotions in the 2011 Duke v. Wal-Mart Stores, Inc ruling. The concept of “commonality,” which is a prerequisite under Federal Rule of Civil Procedure 23(a)(2) that stipulates that there must be questions of law or fact that are common to the class in order for it to be certified as a class action, was the basis for the Court’s ruling.

According to the Court, the plaintiffs had to show that there were legal or factual issues that were shared by the class in order to satisfy the commonality requirements and potentially result in a class-wide settlement of the dispute. This implies that class members’ claims must be based on a shared argument of a kind that can be decided by the entire class. However, because local managers’ individual hiring decisions varied widely throughout the company, the Court determined that the respondents’ claims—that Wal-Mart participated in a pattern or practice of discrimination—did not meet this threshold.

The Court’s consideration of the plaintiffs’ evidence served as the foundation for its reasoning. The plaintiffs claimed that gender discrimination was a result of Wal-Mart’s corporate culture, but the court decided that this was insufficient evidence to establish a widespread discriminatory policy within the company. The plaintiffs’ evidence was deemed inadequate by the Court to show a “general policy” as needed under the commonality requirement. It made the point that because Wal-Mart had a wide range of jobs and managers, any asserted discrimination was not consistent and could not meet the requirements for a class action.

Furthermore, the Court ruled that the plaintiffs’ attempts to demonstrate differences using affidavits from a limited number of workers were insufficient and did not support a conclusion that all of the women in the purported class shared characteristics. According to the Court, there must be substantial evidence that the defendant committed systemic discrimination that had a comparable impact on the whole class in order for class certification to be granted.

This decision reaffirmed that the commonality requirement cannot be satisfied by merely asserting discrimination; rather, there must be a solid, supporting body of evidence that demonstrates that there is a common thread that unites all of the claims and eventually leads to a common resolution for the entire class. The decision eventually made it more difficult for big class claims alleging systematic wrongs to be certified by clarifying the criteria for determining commonality in class-action cases.