Numerosity

Numerosity is the class action requirement that a proposed group be large enough to make joining every member individually in the lawsuit impracticable. Joining people individually, called joinder, means making them parties to the case rather than having named representatives act for a class.

Federal Rule of Civil Procedure 23(a)(1) establishes this requirement without setting a minimum headcount. The Supreme Court explained in General Telephone Co. of the Northwest v. EEOC that numerosity depends on the particular facts. A number mentioned in one court decision is not an automatic pass or fail for every proposed class.

The practical question is whether bringing all members into the case individually would be workable. A large number of people reporting the same problem may support the argument, but the court still needs a basis for finding that the proposed class meets the requirement. Numerosity is about how the lawsuit proceeds, rather than how many people eventually request payment.

You may encounter the term in a class certification motion or order. It is one part of the court’s review, alongside other requirements for class treatment. A settlement can be proposed before a class is finally certified, but an agreement alone does not satisfy certification requirements, as the Supreme Court explained in Amchem Products v. Windsor.

For you as a potential claimant, numerosity is not a payment tier or a document you need to submit. Your inclusion depends on the class definition, and any settlement payment depends on the applicable benefit and claim requirements. A finding that numerosity is satisfied does not establish your individual eligibility or a particular payout.