Before a lawsuit may proceed as a class action, the proposed class must satisfy several certification requirements. One of the first is numerosity: the class must be so numerous that joining every member as an individual plaintiff would be impracticable.
Numerosity is required in both federal class actions and cases filed under New Jersey’s class-action rules. However, there is no automatic minimum number of plaintiffs that guarantees certification.
Federal Rule of Civil Procedure 23 does not identify a specific number. Courts evaluate the circumstances of each case rather than applying a strict mathematical test.
In the Third Circuit, which includes New Jersey, a proposed class containing more than 40 members will generally satisfy numerosity. This is a practical guidepost, not an absolute rule.
A class with fewer than 40 members may still qualify, while a larger proposed class may fail if the plaintiff relies only on assumptions and does not provide reliable evidence that the class actually exists.
Impracticable does not mean that joining every class member would be completely impossible. The question is whether individual joinder would be inefficient, burdensome, or unrealistic under the circumstances.
Courts may consider:
For example, a geographically dispersed group of 35 consumers with relatively small individual losses may present a stronger numerosity argument than 35 sophisticated businesses with large claims and a clear incentive to sue separately.
The plaintiff seeking class certification carries the burden of establishing numerosity. A court generally will not accept speculation that a product was widely sold or that many people were probably affected.
Evidence may include sales records, customer databases, billing information, employment records, transaction reports, government data, or testimony explaining how the class estimate was calculated.
The plaintiff may not need to identify every class member by name before certification. However, the estimate must have a reasonable factual basis.
An exact count is not always available at the beginning of a case. Relevant information may be controlled by the defendant and obtained only through discovery.
A plaintiff may rely on reasonable estimates, but those estimates should be supported by documents or a reliable methodology. Courts may reject calculations that depend on unsupported assumptions or fail to distinguish between people who meet the class definition and those who do not.
The proposed class definition is therefore critical. It must identify the group clearly enough for the court to evaluate whether a sufficiently numerous class exists.
No. Numerosity is only one requirement. The proposed class must also satisfy requirements involving common questions, typicality, adequate representation, and the applicable form of class relief.
A court may find hundreds of potential members but still deny certification because individual issues overwhelm the common questions or because the proposed representative’s claim is materially different from the claims of other members.
Numerosity should be evaluated before a class-certification motion is filed. Attorneys may need to obtain records, analyze databases, define the proposed class, and retain experts to establish a reliable estimate.
A carefully supported numerosity argument can demonstrate why one coordinated class action is more practical than dozens or thousands of separate lawsuits. The final determination, however, depends on the size and characteristics of the particular class rather than any single numerical threshold.
