One or more members of a class may sue or be sued as representative parties on behalf of all only if (1) the class is so numerous that joinder of all members is impracticable, (2) there are questions of law or fact common to the class, (3) the claims or defenses of the representative parties are typical of the claims or defenses of the class, and (4) the representative parties will fairly and adequately protect the interests of the class.
Section 9-7.Class Actions; Prerequisites to Class Actions
Current through August 12, 2025 (2026 Practice Book edition) · Last verified July 9, 2026
In one sentenceConnecticut allows a lawsuit to proceed as a class action only when the class is too large to join every member individually, the members share common legal or factual questions, the representatives’ claims match the class’s, and those representatives will protect the class’s interests adequately.
Full Text of Section 9-7
Amendment History
(P.B. 1978-1997, Sec. 87.)
Plain-English Summary
Section 9-7 sets the four gatekeeping requirements a lawsuit must meet before one or more people can sue or be sued as representatives for an entire class. The class must be so large that requiring every member to join individually would be impracticable, and the case must raise questions of law or fact common to the whole class. The representative parties’ claims or defenses must be typical of the class’s claims or defenses, and those representatives must be able to protect the class’s interests adequately.
These four elements — numerosity, commonality, typicality, and adequacy of representation — work as a threshold test. A court must find all four before moving on to the additional requirements in Section 9-8 that determine whether the case can proceed as a class action.
Frequently Asked Questions
What four requirements must a proposed class action meet in Connecticut?
Section 9-7 requires numerosity (joinder of all members would be impracticable), commonality (shared questions of law or fact), typicality (the representatives’ claims or defenses match the class’s), and adequacy of representation.
How large does a class need to be under Section 9-7?
The rule does not set a number. It asks only whether the class is so numerous that joining every member individually would be impracticable.
Do the representative plaintiffs need claims identical to every class member?
No. Section 9-7 requires the representatives’ claims or defenses to be typical of the class, not identical to each member’s.
Is satisfying Section 9-7 enough to get a class certified?
No. Section 9-7 is a threshold test. The case must also satisfy one of the additional categories set out in Section 9-8.
Source & verification. The section text is reproduced verbatim from the
official Connecticut Practice Book (Conn. Practice Book § 9-7). Prescribed by the Judges of the Superior Court of Connecticut (Conn. Gen. Stat. Section 51-14). The plain-English summary is original and written by us. Last verified July 9, 2026. ·
Official source
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