Class Action Lawsuit Criteria: What a Court Requires Before a Case Can Proceed as a Class
Reference Guide
The class action lawsuit criteria in federal court are written down in one place: Rule 23 of the Federal Rules of Civil Procedure. A judge must find four things — enough people, a shared question, representatives whose claims are typical, and representatives who will protect everyone else — and, for a money case, that the shared questions dominate. The Supreme Court has tightened that test several times, most recently by leaving an open question in June 2025. You do not need to meet any of this yourself to be paid; the court decides it.
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The Four Requirements in Rule 23(a)
Under Federal Rule of Civil Procedure 23(a), one or more people may sue on behalf of a whole group only if:
1. Numerosity — the class is “so numerous that joinder of all members is impracticable.” The rule names no number. The Second Circuit has said numerosity is presumed at a level of 40 members (Consolidated Rail Corp. v. Town of Hyde Park, 47 F.3d 473, 1995); other courts look at the facts rather than a headcount.
2. Commonality — there are questions of law or fact common to the class.
3. Typicality — the representatives’ claims are typical of the class’s claims.
4. Adequacy — the representatives “will fairly and adequately protect the interests of the class.”
Then the case must also fit one of the Rule 23(b) types. Most consumer cases seeking money use Rule 23(b)(3): common questions must predominate over individual ones, and a class action must be superior to other ways of resolving the dispute. Cases seeking only a court order to stop a practice use Rule 23(b)(2).
Case details
Four Supreme Court decisions explain how strictly judges apply these criteria:
Wal-Mart Stores, Inc. v. Dukes, No. 10-277, decided June 20, 2011. A proposed class of some 1.5 million female employees was decertified. The Court held the claims “must depend upon a common contention” capable of classwide resolution — one answer that resolves the issue for everyone “in one stroke.”
Amchem Products, Inc. v. Windsor, No. 96-270, decided June 25, 1997. A nationwide asbestos settlement class failed because “the predominance criterion is far more demanding” than commonality. Individual asbestos claims are handled differently today — see our Texas mesothelioma page.
Comcast Corp. v. Behrend, No. 11-864, decided March 27, 2013. Certification is proper only after “a rigorous analysis,” which may overlap with the merits.
TransUnion LLC v. Ramirez, No. 20-297, decided June 25, 2021. “Every class member must have Article III standing in order to recover individual damages.” Of a class of 8,185 people, only the 1,853 whose misleading credit reports went to third parties could recover; the other 6,332 could not.
Separately, the Class Action Fairness Act (28 U.S.C. § 1332(d)) lets federal courts hear class actions where the combined claims exceed $5,000,000 and at least one class member is a citizen of a different state from any defendant — but not where the proposed classes total fewer than 100 people.
Status: The Open Question After Labcorp v. Davis
In practice this means the answer can depend on the federal circuit where a case is filed. For readers, the practical point is the one TransUnion already set: to recover damages, each class member must have suffered a concrete injury, so read a class definition closely.
Do You Have to Meet These Criteria to Get Paid?
No. The criteria above apply to the case and to the named representatives, not to you. Once a judge certifies a class, you are in it if you fit the class definition in the court’s order — usually a description like “all persons in the United States who bought X between two dates.”
For a Rule 23(b)(3) class, the court must send “the best notice that is practicable,” including individual notice to every member who can be identified through reasonable effort. The notice must tell you how to exclude yourself (opt out) and by when. If you do nothing, you stay in the class and are bound by the result.
Your own test is simpler: read the class definition in the notice or on the settlement website, and check whether you fit its dates, product and location. Our claim ID lookup guide explains how to match a notice to a real settlement.
What Class Members Typically Receive
The best public data on payouts is a September 2019 FTC staff report on 149 consumer class action settlements. Median compensation was $69; about a quarter paid $22 or less, and the top quarter paid $200 or more. The median claims rate was 9%. Lawyers’ fees come out of the case only as the court awards them (Rule 23(h)). Our payout calculator shows how fund size and claim rates set a per-person share; personal-injury settlements work differently, as our talcum powder per-person page shows.
How the Class Action Criteria Developed
January 16, 1974 — American Pipe v. Utah
The Supreme Court holds that filing a class action suspends the statute of limitations for all asserted class members while certification is pending.
June 25, 1997 — Amchem v. Windsor
An asbestos settlement class is rejected. Predominance under Rule 23(b)(3) is “far more demanding” than commonality, even for settlement-only classes.
June 20, 2011 — Wal-Mart v. Dukes
A class of some 1.5 million employees fails commonality. Claims must turn on a common contention that one answer can resolve for everyone.
March 27, 2013 — Comcast v. Behrend
Class certification is proper only after a rigorous analysis, which will often overlap with the merits of the underlying claims.
June 25, 2021 — TransUnion v. Ramirez
Every class member must have Article III standing to recover damages. Of 8,185 class members, 6,332 could not recover.
June 5, 2025 — Labcorp v. Davis Dismissed
The Court declines to decide whether a damages class may include uninjured members. As of October 2026 the question remains open.
Three Things to Watch For
Questions about who qualifies for a class action are exactly what lead-generation sites and imposters exploit:
“Check if you qualify” quizzes
Many sites ranking for class action questions are ad funnels that collect your phone number and health or financial details for law firms. Qualifying for a certified class depends only on the class definition in the court’s order, which is public on the settlement website.
Fees to “join” a class
You never pay to be in a class. Under Rule 23 you are included automatically if you fit the definition, and lawyers are paid only what the judge awards. A request for a processing fee or gift card is a scam.
Settlement emails with no court behind them
A real settlement has a case name, a court and a docket number, and the judge must approve it after a hearing. If a notice names none of these, look up the case yourself before giving any information.
Class Action Lawsuit Criteria — Questions People Actually Ask
Short answers to the questions people ask most about this case.
What are the criteria for a class action lawsuit?
In federal court, Rule 23(a) requires numerosity (too many people to join individually), commonality (shared questions of law or fact), typicality (the representatives’ claims match the class) and adequacy (the representatives will protect the class). A damages case must also show that common questions predominate and that a class action is superior to other methods.
How many are needed for a class action lawsuit?
Rule 23 sets no minimum number — it requires only that joining everyone individually be impracticable. The Second Circuit has said numerosity is presumed at a level of 40 members. Separately, the federal Class Action Fairness Act does not apply when the proposed classes total fewer than 100 people.
How much should I expect from a class action settlement?
Usually a modest amount. In the FTC’s study of 149 consumer settlements, median compensation was $69; a quarter paid $22 or less and the top quarter paid $200 or more. Your share depends on the fund, the fees the court awards and how many people file claims.
Do I have to meet the criteria myself to get money?
No. The criteria apply to the case and its named representatives. If you fit the class definition in the court’s order, you are a class member. For most settlements you still have to submit a claim form by the deadline printed in the notice.
Can I file a class action lawsuit without a lawyer?
Not as a class. Rule 23(g) says a court that certifies a class must appoint class counsel, and the court must find the representatives will adequately protect the class. You can bring your own individual case — see our guides to filing a lawsuit, small claims court and what it costs to sue.
What happens if a class is denied certification?
The named plaintiffs can usually continue individually, and a party may ask the court of appeals for permission to appeal within 14 days of the order (45 days if the United States is a party). Under American Pipe (1974), the filing of the class action suspended the statute of limitations for class members while certification was pending.
Is a mass tort the same as a class action?
No. Mass torts such as product-injury cases are usually filed as individual lawsuits, often grouped in an MDL, because injuries differ person to person — the predominance problem the Supreme Court identified in Amchem. Each claimant’s recovery is valued separately; see our Tepezza hearing loss calculator for an example.
What should I do if I think I belong to a class?
Find the official notice or settlement website and read the class definition. Note the claim deadline and the opt-out and objection deadlines. Keep receipts, statements or the notice letter. Browse open settlements to see which ones are taking claims now.
About This Information
- Editorially Reviewed — Content reviewed for accuracy using published legal research, government data, and verified court records. See our methodology. Reviewed by Leonard Goldberg, Editor · Last updated
- $236 billion in real payouts analyzed · See what we found
This page is for general information only and is not legal advice. Lawsuit status, eligibility, and compensation can change. Settlement Insight is not a law firm and does not represent any party. Consult a licensed attorney about your specific situation.
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