Filing a Class Action Lawsuit: Requirements and Process

CPLR 901(a) requires numerosity, predominance of common questions, typicality, adequate representation, and superiority. These requirements determine whether representative litigation is appropriate rather than merely whether several people experienced similar conduct.

New York does not impose a fixed minimum number of class members. Courts have recognized that relatively small classes can qualify when joinder is impracticable. Although decisions often cite 40 members as a level at which numerosity may be presumed, the Court of Appeals has noted that the Legislature contemplated classes involving as few as 18 members under appropriate circumstances.

Rule 23(a) requires numerosity, commonality, typicality, and adequacy. The proposed class must also satisfy one of the categories in Rule 23(b).

For many damages actions, Rule 23(b)(3) is central. The court must find that common questions predominate over individual questions and that class treatment is superior to other available methods. These federal requirements should not be treated as identical to CPLR Article 9, even though the two frameworks overlap.

The proposed class must be large or dispersed enough that joining every member individually would be impracticable. There is no automatic New York rule requiring exactly 40 members.

The case must also present questions of law or fact common to the class that predominate over questions affecting only individual members. Different damage amounts do not necessarily defeat certification when a central liability issue can be resolved with common proof.

The named plaintiff's claims or defenses must be typical of those belonging to the proposed class. A representative whose claim depends on materially different facts may have difficulty satisfying this requirement.

The representative must also fairly and adequately protect class interests. Courts examine potential conflicts and whether the proposed representation can protect absent members throughout the litigation.

CPLR 901 also requires a class action to be superior to other available methods for fairly and efficiently resolving the controversy.

Under CPLR 902, the court additionally considers factors such as class members' interest in controlling individual actions, the efficiency of separate cases, existing related litigation, the desirability of concentrating the dispute in the selected forum, and likely management difficulties.

These considerations make the certification motion a significant stage of the broader civil litigation process.

Before filing, counsel generally reviews contracts, transaction records, communications, product information, employment records, or other evidence relevant to the alleged common conduct. The proposed class should be defined by objective criteria that allow the court to determine who falls within it.

The named plaintiff then files the summons and complaint in a court with jurisdiction over the claims and defendants. Filing does not itself create a certified class. At this stage, the lawsuit remains a proposed or putative class action.

Proper jurisdiction, pleading, service, and motion practice remain part of ordinary civil lawsuit procedure, while Article 9 adds requirements specific to representative litigation.

For a New York state class action, CPLR 902 provides an important deadline. The plaintiff must move for a determination on class treatment within 60 days after the time to serve a responsive pleading has expired for all named defendants.

The certification record should address each CPLR 901 requirement and the additional CPLR 902 considerations. Courts do not have to accept conclusory assertions that many people were affected; factual support for the proposed class and common issues matters.

Federal Rule 23 uses a different timing standard. A federal court must determine certification at an early practicable time after a person sues or is sued as a class representative rather than following CPLR 902's specific 60-day formula.

If a New York court permits the case to proceed as a class action, CPLR 903 requires the certification order to describe the class. When appropriate, the court may limit the class to members who do not request exclusion within the period specified after notice.

CPLR 904 generally requires reasonable notice in class actions other than those brought primarily for injunctive or declaratory relief. The court controls the manner and content of notice. For primarily injunctive or declaratory actions, notice is not automatically required.

Federal Rule 23(b)(3) imposes its own notice rule. Class members must receive the best notice practicable under the circumstances, including individual notice to members identifiable through reasonable effort, and must be told how and when they may request exclusion.

Under 28 U.S.C. § 1332(d), CAFA generally provides federal jurisdiction when the aggregated amount in controversy exceeds $5 million, the proposed plaintiff classes contain at least 100 members in the aggregate, and minimal diversity exists between at least one class member and at least one defendant.

CAFA also contains statutory exceptions and provisions that may require or permit a federal court to decline jurisdiction when a dispute is strongly concentrated in the state where it was filed. Meeting the headline thresholds therefore does not automatically settle every jurisdictional question.

Once a class action is properly before a federal district court, certification is governed by Rule 23 rather than CPLR 901 and 902.

New York CPLR 908 provides that a class action cannot be dismissed, discontinued, or compromised without court approval. The court also directs notice of a proposed dismissal, discontinuance, or compromise to class members.

Federal Rule 23(e) separately governs settlements, voluntary dismissals, or compromises that would bind a certified class or a class proposed for settlement certification. A binding class settlement requires judicial review, and the court may approve it only after the required procedures and findings are satisfied.