Rule 23: Class Actions

Rule 23 governs class actions — lawsuits where one or a few representative plaintiffs sue on behalf of a large group. The rule imposes rigorous requirements because class members' rights are being adjudicated without their individual participation.

The threshold requirements are the four prerequisites of 23(a): numerosity (enough people that individual joinder is impracticable), commonality (shared legal or factual questions that can generate common answers), typicality (the representatives' claims are typical of the class), and adequacy (the representatives and their lawyers will protect the class's interests). After Wal-Mart v. Dukes, courts must conduct a rigorous analysis of these prerequisites.

Beyond the 23(a) prerequisites, the class must fit into one of three categories under 23(b). The 23(b)(3) category — predominance and superiority — is the most common for damages class actions and requires the most analysis. Unlike 23(b)(1) and 23(b)(2) classes, 23(b)(3) class members must be given notice and an opportunity to opt out. Any settlement of a class action requires court approval.