What is class certification?
Class certification is a court's formal ruling, under Federal Rule of Civil Procedure 23, that a lawsuit may proceed as a class action because it meets requirements including numerosity, commonality, typicality, and adequate representation, plus at least one condition under Rule 23(b) such as predominance of common questions. Certification is not a ruling on the merits — it decides only whether the case can proceed collectively.
Certification is frequently the most contested and expensive phase of a class action, since a defendant that defeats certification usually ends the case as a class matter entirely, leaving only the named plaintiffs' individual claims. A certified class can later be decertified if facts change, and appellate courts can review certification decisions on an expedited basis under Rule 23(f) before the case goes any further. News that a class 'has been certified' means the case can continue as a group action — not that anyone has won or that a settlement exists yet.
Sources
Last reviewed 2026-08-22.