What is predominance requirement?

Predominance is the Rule 23(b)(3) requirement that questions of law or fact common to the class outweigh questions affecting only individual members before a court will certify a class seeking money damages. It is typically the most heavily litigated certification element, because it forces a court to weigh how much of the case can be proven with class-wide evidence versus person-by-person proof.

Defendants frequently argue predominance fails when damages, reliance, or causation would require individualized inquiry into each class member's circumstances — for example, in cases where consumers were exposed to different advertising or paid different prices. Plaintiffs counter with common proof such as a uniform written policy, standardized disclosure, or an expert damages model that can calculate harm class-wide. Losing on predominance does not end an individual's claim, but it typically prevents the case from proceeding as a class.

Last reviewed 2026-08-22.