Rule 23 Class Actions: The 1L Framework

A class is certified only if it satisfies all four prerequisites in Rule 23(a) and also fits within one of the three categories in Rule 23(b). Both steps are mandatory, and the second is where most proposed classes die. Students flatten this into a single list of requirements and then cannot explain why a class with obvious common questions still failed.

Say the structure out loud before analyzing anything: Rule 23(a) asks whether this group can be represented at all — numerosity, commonality, typicality, adequacy. Rule 23(b) asks what kind of class this is and whether the class device is the right tool for that kind of case. A class that clears 23(a) but fits no 23(b) category is not certified.

One more framing point from Wal-Mart Stores, Inc. v. Dukes (2011): Rule 23 is not a mere pleading standard. The party seeking certification must affirmatively demonstrate compliance with the rule, and the court must conduct a rigorous analysis, which will frequently overlap with the merits of the underlying claim. Certification is not decided on the allegations alone.

All four must be satisfied; failing any one ends the inquiry. Numerosity asks whether the class is so numerous that joinder of all members is impracticable. Note the word: impracticable, not impossible. There is no magic number in the rule, and courts weigh geographic dispersion, the size of individual claims, and the ability to identify members alongside raw headcount.

Commonality requires questions of law or fact common to the class. This is the element Dukes redefined, and it gets its own section below.

Typicality asks whether the claims or defenses of the representative parties are typical of those of the class. The representative does not need identical damages, but must have been injured by the same course of conduct and must be advancing the same legal theory. Typicality fails when the named plaintiff is subject to a unique defense — an individual arbitration agreement, a limitations problem, a release — that would consume the litigation.

Adequacy asks whether the representative parties will fairly and adequately protect the interests of the class. It has two components: no conflict of interest between the representative and the absent members, and competent, adequately resourced counsel. Rule 23(g) governs the appointment of class counsel separately, which is why adequacy of counsel is usually litigated under 23(g) rather than 23(a)(4).

Typicality and adequacy overlap and are often argued together, but keep them distinct on an exam: typicality is about the shape of the claim, adequacy is about the loyalty and competence of the person and lawyer pressing it.

After Dukes, identifying a common question is not enough. The Court held that class members must have suffered the same injury and that their claims must depend on a common contention of such a nature that it is capable of classwide resolution — meaning that determining its truth or falsity will resolve an issue central to the validity of each claim in one stroke.

The line to memorize is the Court's framing of what actually matters: not the raising of common questions, even in droves, but the capacity of a classwide proceeding to generate common answers apt to drive the resolution of the litigation. Any group of employees can raise the question "were we discriminated against?" That question is common in the trivial sense. What Dukes requires is a common answer — some glue holding the alleged reasons for the challenged decisions together.

The practical test is to ask what a single trial would actually decide. If the defendant applied one uniform policy, one uniform disclosure, or one uniform contract term to everyone, resolving its lawfulness resolves the core issue for everyone at once, and commonality is comfortably met. If the alleged wrong is that thousands of separate decision-makers each exercised discretion in a discriminatory way, there is no single contention whose resolution decides all the claims.

Commonality remains a low bar in one specific sense: a single common contention capable of classwide resolution can satisfy it. The rule says "questions," but one qualifying question suffices. Dukes did not raise the count; it raised the quality.

Having satisfied 23(a), the proposed class must fit one of three categories, and they are not interchangeable. Rule 23(b)(1) covers two risk scenarios. Under (b)(1)(A), separate individual actions would risk inconsistent or varying adjudications that would establish incompatible standards of conduct for the party opposing the class — think a utility that cannot simultaneously be ordered to use two different rate structures. Under (b)(1)(B), individual adjudications would as a practical matter be dispositive of absent members' interests or substantially impair their ability to protect them — the classic limited fund, where a pool of money is too small to pay everyone and early claimants would exhaust it.

Rule 23(b)(2) applies when the party opposing the class has acted or refused to act on grounds generally applicable to the class, so that final injunctive relief or corresponding declaratory relief is appropriate respecting the class as a whole. The key phrase is "as a whole": the remedy must be indivisible, a single injunction that necessarily benefits every member at once. Dukes held that (b)(2) does not authorize certification when each member would be entitled to an individualized award of money damages, which is why plaintiffs cannot route a damages case through (b)(2) to avoid predominance and opt-outs.

Rule 23(b)(3) is the damages class. It requires that questions of law or fact common to class members predominate over questions affecting only individual members, and that a class action be superior to other available methods for fairly and efficiently adjudicating the controversy. The rule lists matters pertinent to that finding, including class members' interests in individually controlling separate actions, the extent and nature of litigation already begun, the desirability of concentrating the litigation in the forum, and the likely difficulties in managing a class action.

Commonality asks whether there is at least one common contention capable of classwide resolution. Predominance asks a comparative question: do the common questions outweigh the individual ones across the case as a whole? The Supreme Court has described predominance as far more demanding than commonality, and the two are not satisfied by the same showing.

The clearest way to see the gap is to imagine a class that passes one and fails the other. Suppose every member bought the same product with the same allegedly false label. Whether the label was misleading is a common contention — one answer resolves it for everyone, so commonality is met. But if each member must separately prove that they saw the label, relied on it, and suffered a different amount of loss, individual questions may swamp the common one and predominance fails even though commonality was satisfied.

A related point that recurs on exams: individualized damages calculations do not automatically defeat predominance. Where liability turns on common proof and damages are a mechanical computation — a flat overcharge multiplied by the number of purchases — courts routinely certify. Predominance becomes a real problem when the individual issues go to liability itself: reliance, causation, consent, knowledge, or the enforceability of member-specific contract terms.

Note also that predominance and superiority appear only in (b)(3). A (b)(1) or (b)(2) class never has to establish predominance. That asymmetry is precisely why plaintiffs try to characterize damages cases as injunctive ones, and why Dukes closed that route for individualized monetary relief.

Only a (b)(3) class carries mandatory notice and a right to opt out. Rule 23(c)(2)(B) requires the court to direct to class members the best notice practicable under the circumstances, including individual notice to all members who can be identified through reasonable effort, and the notice must state in plain language what the class is, what the claims are, that a member may enter an appearance through counsel, that a member may request exclusion and how, and the binding effect of a class judgment.

For (b)(1) and (b)(2) classes, Rule 23(c)(2)(A) says the court may direct appropriate notice. It is discretionary, and there is no exclusion right. These are mandatory classes: members are bound whether or not they wanted to participate.

The reason for the split is what is at stake. A (b)(3) class adjudicates each member's damages claim — a property interest of their own — so due process concerns push toward individual notice and a chance to walk away and sue alone. A (b)(2) class seeks relief that is indivisible; there is no coherent way for one member to opt out of an injunction that necessarily governs the defendant's conduct toward everyone.

The consequence for absent members is the same in both directions: a class member who does not opt out of a (b)(3) class is bound by the judgment and cannot relitigate the class claims later. This is where class actions connect to preclusion — the whole point of certification is that the judgment will bind people who never appeared.

Suppose an online retailer adds an undisclosed flat processing fee at checkout over a two-year period. Every customer saw the identical checkout screen, and the fee appeared nowhere in the disclosures. A named plaintiff sues for the fee on behalf of everyone who paid it, seeking damages.

Run 23(a). Numerosity: a customer base large enough that joining each purchaser individually is impracticable — satisfied. Commonality: the contention is that this one checkout screen failed to disclose the fee adequately. Determining the truth of that contention resolves a central issue for every member in one stroke, which is exactly what Dukes requires — satisfied. Typicality: the named plaintiff paid the same fee through the same screen on the same legal theory — satisfied. Adequacy: no conflict with absent members, and competent counsel appointed under 23(g) — satisfied.

Now 23(b). The claim seeks money, so (b)(2) is unavailable for individualized monetary relief and (b)(1) does not fit — there is no limited fund and no risk of incompatible standards of conduct. That leaves (b)(3). Predominance: the disclosure was uniform, so liability rests entirely on common proof, and damages are the flat fee multiplied by each customer's order count, a mechanical computation. Superiority: individual claims worth a few dollars would never be brought alone, which is the paradigm superiority case. Certified as a (b)(3) class, with mandatory best-practicable notice and opt-out rights.

Change one fact: during the second year, the retailer used a different checkout screen for some customers that did disclose the fee, and some customers agreed to individual arbitration clauses at various times. Commonality may still survive — the adequacy of the first screen is still one contention resolvable classwide. But predominance is now in serious trouble, because determining which screen each customer saw and whether each customer's arbitration clause is enforceable are individual liability questions. This is the distinction in action: same facts, commonality holds, predominance collapses.

Change it again: the plaintiff drops damages and seeks only an injunction requiring disclosure of the fee going forward. That is a (b)(2) class — the defendant acted on grounds generally applicable to the class and a single injunction provides indivisible relief respecting the class as a whole. No predominance requirement, no mandatory notice, no opt-out. Ask for the injunction plus individualized refunds, though, and Dukes says (b)(2) is not the vehicle.

Class claims cannot be settled the way ordinary claims can. Under Rule 23(e), the claims, issues, or defenses of a certified class — or of a class proposed to be certified for purposes of settlement — may be settled, voluntarily dismissed, or compromised only with the court's approval. The court must direct notice in a reasonable manner to all class members who would be bound, hold a hearing, and find the proposal fair, reasonable, and adequate. Class members may object.

The reason is structural: the named plaintiff and class counsel are negotiating away the rights of absent people who have no seat at the table, and their incentives can diverge from the class's. Judicial approval is the check. Rule 23(e)(4) also lets the court refuse approval of a (b)(3) settlement unless it gives members a new opportunity to opt out.

Certification decisions are ordinarily interlocutory and therefore not immediately appealable, but Rule 23(f) creates a discretionary exception: a court of appeals may permit an appeal from an order granting or denying class certification if a petition for permission is filed within a short window — 14 days after entry of the order under the current rule. Permission is discretionary; the court of appeals can simply decline.

Rule 23(f) exists because certification is often case-dispositive in practice. A denial can end a case whose individual claims are too small to pursue; a grant can create settlement pressure large enough that the defendant never tests the merits. Immediate review is the safety valve.

First, treating Rule 23 as one list. It is two gates. Write the 23(a) analysis, then separately identify which 23(b) category the class fits and prove it. An answer that never names a (b) category has not certified anything.

Second, satisfying commonality by reciting a shared question. After Dukes the question must be one whose resolution generates a common answer that drives the litigation. Ask what a single trial would actually decide for everyone.

Third, blurring commonality and predominance. Commonality needs one qualifying common contention. Predominance is comparative and far more demanding, and it applies only in (b)(3). Using them interchangeably is the single most common error in this unit.

Fourth, attaching notice and opt-out rights to every class. Mandatory best-practicable notice and the right to request exclusion belong to (b)(3) alone. Classes under (b)(1) and (b)(2) are mandatory, and notice there is discretionary.

Fifth, running a damages case through (b)(2) because there is also an injunction in the prayer for relief. Dukes forecloses (b)(2) certification for individualized monetary awards. As always, this is a study guide to the framework courts apply, not advice about a live case — certification practice varies considerably by circuit and by subject matter.