7.2 Rule 23 Class Certification Requirements

Updated 2014 by Sarah Somers

Rules 23(a) and (b) of the Federal Rules of Civil Procedure govern the requirements for class certification. Rule 23(a) sets forth four threshold requirements for class certification, each of which must be met: (1) the class is so numerous that joinder of class members is impracticable (numerosity); (2) there are questions of law or fact common to the class (commonality); (3) the claims or defenses of the class representatives are typical of those of the class (typicality); and (4) the class representatives will fairly and adequately protect the interests of the class (adequacy).

To certify a class, a court must also find that one of the following requirements, set forth in Rule 23(b), are met: (1) that prosecution of separate actions risks either inconsistent adjudications which would establish incompatible standards of conduct for the defendant or would as a practical matter be dispositive of the interests of others; (2) that defendants have acted or refused to act on grounds generally applicable to the class; or (3) that there are common questions of law or fact that predominate over any individual class member’s questions and that a class action is superior to other methods of adjudication.

Before filing a case as a class action, counsel should analyze carefully if and how the case meets the Rule 23(a) and (b) requirements. The complaint should plead specifically each of the Rule 23 requirements rather than merely parrot the language of Rule 23. Indeed, many local rules require that class action allegations contain specific information regarding the class, such as an estimate of the number of persons in the class./1/ In addition to Rule 23(a) and (b), as explained below, courts have added implicit requirements for class certification. The courts require (1) that a definable class exists, (2) the named representatives are members of that class, and (3) the claim of the class is live, rather than moot. 

The Supreme Court has recently made it clear that plaintiffs must not merely plead the existence of the Rule 23 requirements, but prove them./2/ As a result, district courts must perform a "rigorous" analysis to determine whether the Rule 23(a) prerequisites are satisfied./3/ In Wal-Mart Stores, the Court cast aside the frequently cited proposition that courts are not to consider the merits of the plaintiff’s underlying claim in the analysis,/4/ and observed that the rigorous analysis required frequently will evaluate the merits of the claims presented./5/ Thus, in Wal-Mart Stores, the Court considered the merits of the plaintiffs' Title VII claims because of the overlap of commonality and allegations of a pattern and practice of discrimination./6/ Subsequently, however, in Amgen, Inc. v. Connecticut Retirement Plans and Trust Funds, the Court cautioned that “free-ranging merits inquiries” are not appropriate under Rule 23 and that “[m]erits questions may be considered to the extent—but only to the extent—that they are relevant to determining whether the Rule 23 prerequisites for class certification are satisfied.”/7/

The plaintiff has the burden of proving that the requirements of Rule 23 are met./8/ Factual determinations necessary to the certification ruling must be proven by a preponderance of the evidence./9/ The district court’s decision to certify or to deny certification of the class is subject to review based on a "limited" abuse of discretion standard./10/ A court abuses its discretion if its certification order is premised on legal error./11/ Courts are less deferential to the denial of certifications than they are to the granting of them./12/

7.2.A. Rule 23(a) Requirements

The four preliminary requirements for class certificationnumerosity, commonality, typicality and adequacy of representationmust all be met.

7.2.A.1. Numerosity

The numerosity requirement of Rule 23 does not focus exclusively on the number of members of the putative class, but, instead, on the impracticality of individual joinder./13/ The courts apply no strict numerical test for determining impracticality of joinder, although, as a general benchmark, classes of less than 20 are insufficiently numerous and classes of 40 or more satisfy the numerosity requirement./14/ Rather than relying only on numbers, courts must examine the specific facts of each case./15/

Although a large number of putative class members may suffice to prove numerosity, other factors are considered in determining whether joinder is impracticable./16/ These factors include the ease of identifying and finding individual class members, geographical separation, fluid composition of class population, size of individual claims, individual ability and motivation to bring separate actions, and the nature of the claims raised and relief sought.

In some cases, class size may be proven by appending to the motion for class certification public documents, census data, or responses to Freedom of Information Act requests. In other cases, affidavits can establish the number of class members. If plaintiffs lack information regarding the size of the class, consideration should be given to filing a discovery request at the same time or soon after the filing of the complaint. If the exact number of class members cannot be proven, the court can use common sense and draw inferences about the class size,/17/ but will not resort to speculation./18/ If the size and impracticality of joinder appear to be a problem in a given case, adjusting the class definition may resolve the issue by, for example, eliminating subclasses (each subclass must independently meet the numerosity requirements) or including persons who will be affected in the future./19/

7.2.A.2. Commonality

Plaintiffs’ grievances generally must share a common question of law or fact./20/ Rule 23 does not require that all questions of law or all questions of fact be common to all class members./21/ In fact, only one question of law or fact must be common to the proposed class./22/ Some factual differences among class members do not defeat commonality./23/ Class actions that seek class-wide injunctive or declaratory relief "by their very nature present common questions of law and fact."/24/  

However, allegations that the common question of law or fact is tied to systemic violations of law have recently drawn closer scrutiny./25/ In Lightfoot v. District of Columbia, for example, the plaintiff class alleged that the government and its contractor terminated the benefits of disabled city workers without providing them a pre-deprivation opportunity to challenge the termination. The court decertified the class following receipt of voluminous summary judgment filings when it concluded the procedural due process violations were the result of different practices which did not uniformly pervade the class as a whole. The court held that plaintiffs were required to identify more specifically a particular policy or custom that both violates due process and is common to the class./26/

The Supreme Court addressed a similar commonality issue in the Title VII context in Wal-Mart Stores v. Dukes./27/  In Wal-Mart Stores, as framed by the majority, the plaintiffs contended that local managers wielded substantial discretion over pay and promotion that had a disparate impact on women because this discretion was exercised within a corporate culture of discrimination of which Wal-Mart was aware but did nothing to stop.  This common discriminatory practice adversely affected all female employees. The Court took issue with defining commonality at a high level of generality:

Quite obviously, the mere claim by employees of the same company that they have suffered a Title VII injury, or even a disparate-impact Title VII injury, gives no cause to believe that all their claims can productively be litigated at  once. Their claims must depend upon a common contention—for example, the assertion of discriminatory bias on the part of the same supervisor. That common contention, moreover, must be of such a nature that it is capable of classwide resolution—which means that determination of its truth or falsity will resolve an issue that is central to the validity of each one of the claims in one stroke./28/

The Court found that the plaintiffs had established the existence of a corporate policy: delegating to local managers decisionmaking authority over pay and promotions.  But, it essentially concluded that such delegation was at odds with commonality.  What was required was a showing that local managers exercised this discretion in a common way.  National and regional disparities in pay and promotion between men and women fell short of that because they failed to show the store-by-store differences.  In short, the plaintiffs failed to demonstrate commonality because they could point to no specific employment practice that directly affected all women at Wal-Mart./29/ As anticipated, Wal-Mart Stores has set a higher bar for establishing commonality./30/

Commonality may be demonstrated by expert opinion and statistical evidence.  However, Wal-Mart Stores may have made doing so more difficult. The Court demanded "significant proof" of a policy of discrimination and was quite critical of the plaintiff's expert who attempted to supply such proof, while expressing a view that such experts must meet the requirements of Daubert v. Merrell Dow./31/ Affidavits from class members containing anecdotal evidence of harm may also be used to support commonality, but there, too, Wal-Mart set a high bar: the Court found insufficient 120 affidavits which represented a very small percentage of class members and only a portion of the nation./32/ If the proposed class definition fails to establish commonality, the court may redefine or limit the class,/33/ or create subclasses./34/

7.2.A.3. Typicality

While commonality and typicality "tend to merge,"/35/ the commonality requirement focuses on the common thread among all class members, and the typicality requirement focuses on the named plaintiff. In the leading case in this area, General Telephone Company of the Southwest v. Falcon, the Supreme Court held that the class representative had to “possess the same interest and suffer the same injury as the class members.”/36/ The typicality requirement centers on “whether the class representative’s claims have the same essential characteristics as those of the putative class. If the claims arise from a similar course of conduct and share the same legal theory, factual differences will not defeat typicality.”/37/

Put another way, typicality can be determined by whether there is a sufficient nexus between the claims of the named representatives and those of the class./38/ As with commonality, factual differences do not defeat typicality if the course of conduct and the claims are based on the same legal theory./39/

However, typicality is not present when a class representative's claim may be challenged by a unique defense, which may preoccupy the putative class representative and potentially place her interests ahead of those of the class./40/ In addition, typicality generally requires at least one named plaintiff to have claims against each defendant./41/ There are two exceptions to this principle: when the defendants conspired to harm the class representative and when the defendants are "juridically linked" in the sense that a class action is preferred over multiple actions./42/

7.2.A.4. Adequacy of Representation—Class Representatives and Counsel

Rule 23 (a)(4) requires a class representative to represent fairly and adequately the interests of absent class members. As with other aspects of Rule 23, due process governs the determination of adequacy of representation./43/ By assuring adequacy of representation, Rule 23 permits class judgments to bind absent class members./44/ The requirement of adequate representation applies to both the plaintiffs and counsel. The 2003 Amendments, which added subsection (g) to Rule 23, have changed somewhat the inquiry into adequate representation of counsel.

First, the court asks whether the named plaintiffs will serve as adequate class representatives. By separating the inquiry into adequacy of representation from the issues of commonality and typicality, the rule requires a critical assessment of issues on which the named plaintiffs and any part of the class might disagree./45/ Class certification is improper when the interests of the representative party and the class conflict, although they need not be identical. In a leading Supreme Court case in this area, a class was decertified upon a finding that the claims of the named representatives were not aligned with those of the other class members. In that case, putative class members were all exposed to asbestos, but many members suffered injuries completely different than those suffered by other class members./46/ Defendants often attempt to defeat class certification by making allegations of antagonistic interests between the named representatives and the remainder of the class.

Conflicts can usually be averted by counsel vigilantly assessing all interests involved on a regular basis, informing the court of any potential conflicts when they arise, and asking the court to certify subclasses and appoint independent counsel to represent the varying interests in the conflict./47/ In addition, a judge may order notice to all class members informing them of the right to intervene to oppose the named plaintiff’s position./48/ Or, the court may define the class in a more limited way to avoid conflicts./49/

In addition to showing a lack of conflict with class members, the named plaintiff must also evidence a willingness to prosecute the class claims actively. Thus, in a case in which the named plaintiff failed to file for class certification for two and a half years, the court found that she failed to protect the interests of the proposed class./50/ Adequate representation by the named plaintiff generally should not, however, include an assessment of plaintiff’s financial resources, unless lack of financial resources is relevant to the named plaintiff’s willingness or ability to fund the litigation or represent the class./51/

The 2003 amendments to Rule 23 added subsection (g), which requires the court to appoint class counsel and now explicitly mandates that counsel fairly and adequately represent the class. Under Rule 23(g), certification of the class precedes appointment of adequate counsel./52/ Rule 23(g)(1)(c) lists the factors that the court must consider in appointing class counsel. They include pre-filing investigation, experience, knowledge of law, and resources that counsel will commit to representing the class./53/

When evaluating adequate representation of counsel, zeal and competency of counsel are important factors. Zeal and competency of counsel for the class are initially determined on the basis of the experience of the lawyer or the legal organization for whom the lawyer works and the quality of initial pleadings./54/ Indeed, the court examines the conduct of counsel in the case to date and in other class actions to determine if the representation is adequate./55/ For example, failing to move promptly for class certification could be viewed as evidence of lack of adequate class representation./56/

Having more than one counsel in class actions is advisable as a rule. If one has not handled a class action, then co-counseling with experienced counsel is necessary. Although an initial determination of counsel’s adequacy to represent the class aggressively is necessary to certify the class, the court has flexibility to decertify the class later based on evidence of inadequate representation in discovery./57/

7.2.B. Implicit Requirements

The courts have added some “implicit” requirements for the putative class to meet in order to obtain class certification: (1) a definable class exists, (2) the named representatives have standing, and (3) the claim of the class is live, not moot.

7.2.B.1. Existence of a Definable Class

In order to obtain certification, a class must be sufficiently definable./58/ The court must determine that defining the class is both possible and feasible. This means that a court must be able to identify all members of the class by using objective criteria./59/ If a class is defined in terms of vague or subjective criteria, such as the members’ states of mind, the court has no objective means with which to identify the members of the class and therefore will not certify the class./60/ Even if the class is defined in terms of objective criteria, those criteria may be too difficult for the court to apply feasibly and the court may refuse to certify the class./61/

If a class is so broad that it includes members who would not have standing to bring an action individually, the court will not certify the class. For example, in an action by Latino inmates against a prison for not providing Spanish-speaking staff, the court would not certify a class comprised of all of the Latino inmates. Some of those Latino inmates spoke English and would not have suffered any injury; thus, they did not have standing to sue./62/

Although members of a class must be easily identifiable for the court, a class may be certified even though the court cannot identify every potential member of the class at the moment of certification. Thus, a class may obtain certification even if it is of such a nature that it will inevitably need to add or drop members during the course of the action./63/

Upon finding that a class is not sufficiently definable, the court may limit or redefine the class using its authority under Rule 23(c)(4),/64/ or it can deny class certification and allow the named members to proceed individually./65/ A precisely defined class is necessary in order to analyze whether that class meets the other requirements for certification under Rule 23. Further, a court must have a precise class definition in order to be able to determine which individuals are entitled to notice or relief as well as which individuals will be bound by a judgment.

7.2.B.2. Class Representatives Must Be Part of the Defined Class

In order to obtain certification, the named representatives must be class members. That is, each named representative must have proper standing/66/ and must have the same interest and injury as other members of the class. For example, plaintiffs in an employment discrimination suit would need to be qualified for the job positions at issue in order to act as named representatives of the people against whom an employer has allegedly discriminated./67/

7.2.B.3. A Live Claim

In order for the class to obtain certification, courts require a claim to be live, not moot. If it is not a live claim, the court will dismiss the suit unless a new class representative with a live claim steps forward. However, under certain circumstances, an individual with a moot claim may still serve as a class representative. For example, if a class representative’s claim becomes moot after a class is certified, the entire class action does not become moot as a result./68/ If the court denies class certification and the named representative’s claim later becomes moot, the class representative may still appeal the denial of certification./69/

An individual whose claim is moot may also serve as a class representative if the individual’s claim is “capable of repetition yet evading review.” In such cases an individual with a moot claim may serve as a class representative even if the claim became moot before class certification./70/

7.2.C. Rule 23(b) Requirements

In addition to meeting all four Rule 23(a) requirements, a class action must meet one of the three requirements of Rule 23(b).

7.2.C.1. Rule 23(b)(1) Classes

A Rule 23(b)(1)(A) action is intended to protect the defendants from inconsistent adjudications imposing incompatible obligations that might result from independent actions brought by individual plaintiffs. The Advisory Committee explained:  "One person may have rights against, or be under duties toward, numerous persons constituting a class and be so positioned that conflicting or varying adjudications in lawsuits with individual members of the class might establish incompatible standards to govern his conduct. The class action device can be used effectively to obviate the actual or virtual dilemma which would thus confront the party opposing the class."/71/ It offered an example:

Separate actions by individuals against a municipality to declare a bond issue invalid or condition or limit it, to prevent or limit the making of a particular appropriation or to compel or invalidate an assessment, might create a risk of inconsistent or varying determinations. In the same way, individual litigations of the rights and duties of riparian owners, or of landowners’ rights and duties respecting a claimed nuisance, could create a possibility of incompatible adjudications. Actions by or against a class provide a remedy and fair means of achieving unitary adjudication./72/

Generally, the prospect of inconsistent injunctive relief satisfies this rule while the possibility of varying monetary awards does not./73/

By contrast, a Rule 23(b)(1)(B) action is designed to protect absent class members from litigation that could impair “their ability to protect their interests.” The Advisory Committee explained that:

In various situations an adjudication as to one or more members of the class will necessarily or probably have an adverse practical effect on the interests of other members who should therefore be represented in the lawsuit. This is plainly the case when claims are made by numerous persons against a fund insufficient to satisfy all claims. A class action by or against representative members to settle the validity of the claims as a whole, or in groups, followed by separate proof of the amount of each valid claim and proportionate distribution of the fund, meets the problem./74/

The Supreme Court’s most recent word on Rule 23(b)(1)(B) class actions in the limited fund context is Ortiz v. Fibreboard Corporation./75/ The Court held that certification under this provision requires that 1) the fund is inadequate to pay all claims, 2) all the fund is to be devoted to paying the claims and 3) the class members are treated equitably among themselves./76/ These requirements are difficult to satisfy; an excellent recent example is Katrina Canal Breaches Litigation v. Board of Commissioners, in which the Fifth Circuit reversed the certification of a limited fund class for settlement purposes in a Katrina-related case, holding that the settlement was not fair or reasonable and did not equitably distribute funds among class members./77/

7.2.C.2. Rule 23(b)(2) Classes

Class certification under Rule 23(b)(2) is far more common than (b)(1) classes and the traditional class action tool for poverty lawyers. Under Rule 23(b)(2), the class must show that the defendant acted in a way “generally applicable” to class members, making classwide declaratory and injunctive relief appropriate. In Wal-Mart Stores, the Court held that Rule 23(b)(2) is only satisfied when 

a single injunction or declaratory judgment would provide relief to each member of the class. It does not authorize class certification when each individual class member would be entitled to a different injunction or declaratory judgment against the defendant./78/

Unlike with the commonality requirement of Rule 23(a), factual differences between the named plaintiffs following the classwide injunctive relief may sometimes defeat certification./79/ While manageability is not explicitly required in a Rule 23(b)(2) class, courts sometimes consider it nonetheless./80/ Certification is unlikely if the putative class seeks particularized relief for each class member.

In requesting Rule 23(b)(2) certification for injunctive relief, the named plaintiffs must have standing for each type of relief requested./81/ Thus, when a named plaintiff does not have standing to seek injunctive relief, Rule 23(b)(2) class certification is denied./82/ Rule 23(b)(2) class members require no notice (although the court may direct notice in unusual cases) and have no opt-out rights./83/

In cases where compensatory damages as well as injunctive or declaratory relief are sought, courts have struggled with determining whether (b)(2) certification is appropriate. This is particularly significant in employment discrimination cases. Since the 1991 amendments to the Civil Rights Act, Title VII plaintiffs have been permitted to recover compensatory damages./84/ These damages include relief for a wide range of losses including future pecuniary losses, emotional pain, suffering, nonpecuniary damages (Section 1981a(b)(3)); and punitive damages (Section 1981a(b)(1)(2)). In Wal-Mart Stores v. Dukes, the Court resolved that issue in large part by holding that a Rule 23(b)(2) class is not appropriate when the class seeks individualized monetary damages for class members./85/ Further, the Court rejected the notion that Rule 23(b)(2) classes are appropriate so long as monetary relief does not "predominate" over injunctive or declaratory relief./86/

The Court noted, with apparent approval, the holding in Allison v. Citgo Petroleum Corporation/87/ that Rule 23(b)(2) certification was appropriate only if compensatory relief was merely "incidental" to the equitable relief sought in Title VII cases./88/ Such would be the case if "damages . . . flow directly from liability to the class as a whole on the claims forming the basis of the injunctive or declaratory relief."/89/ This was appropriate because such "incidental damage should not require additional hearings to resolve the disparate merits of each individual's case; it should neither introduce new substantial legal or factual issues, nor entail complex individualized determinations."/90/ The Court in Wal-Mart said that it did not have to decide whether the award of such incidental damages could comport with Due Process because the plaintiffs did not and could not argue that the monetary relief sought satisfied the "incidental" test./91/ In the Title VII context, the Court held that principles of Due Process require individualized hearings on eligibility for backpay./92/

 Increasingly, courts are finding an implicit "cohesiveness" requirement in Rule 23(b)(2)./93/ The Lightfoot v. District of Columbia case fell victim to such a requirement, found nowhere in the Rule.  There, the court found that differences in the amounts of time class members had between notice and termination, all alleged to be constitutionally insufficient, yielded a conclusion that the class was not sufficiently cohesive to warrant class certification./94/ The irony of such a cohesiveness requirement in Rule 23(b)(2) cases is seemingly arbitrary deviations from a common unwritten custom and practice can preclude class certification.

7.2.C.3. Rule 23(b)(3) Classes

Rule 23(b)(3) permits certification under subdivision (b)(3) when the primary relief sought is damages. In such a case, Rule 23(b)(3) requires that the common questions of law and fact predominate over any individual questions and that a class action be superior to other methods for fair and efficient resolution of the conflict./95/ The district court has broad discretion in determining whether common questions predominate and whether a class action is manageable, using the factors set forth in Fed. R. Civ. P. 23(b)(3)(A-D).

Rule 23(b)(3) class actions are expensive and time-consuming, requiring notice to all class members;/96/ opportunity for opt-out; more expensive and extensive discovery; and individual representation post-judgment. As such, counsel should carefully consider the resources required for litigation before undertaking representation of a Rule 23(b)(3) class. Whenever possible, certification should be sought under subdivision (b)(1) or (b)(2).


1. E.g., L.R. 23.1 (A)(2) (N.D. Fla.) and L.R. 23.1 (b)(2)(A) (E.D. Pa.). Local rules may also have other specific and/or additional requirements regarding class actions.

2. Wal-Mart Stores, Incorporated v. Dukes, 131 S. Ct. 2541, 2551 (2011).

3. Id. (citing  General Tel. Co. of Sw. v. Falcon, 457 U.S. 147, 161 (1982)).

4. Wal-Mart Stores, 131 S. Ct. at 2552 n.6 (citing Eisen v. Carlisle and Jacquelin, 417 U.S. 156, 177-78 (1974)).

5. Wal-Mart Stores, 131 S. Ct. at 2551-52. The 2003 rule changes allow for a slightly later determination of class certification and eliminate the possibility of “conditional” class certification; some courts have understood such rule changes as compelling a more thorough evaluation at the class certification stage, including a limited review of the merits. For cases predating Wal-Mart Stores, see In re Hydrogen Peroxide Antitrust Litigation, 552 F.3d 305, 307, 317 (3d Cir. 2008); In re Initial Public Offering Securities Litigation, 471 F.3d 24 (2d Cir. 2006), clarified on reh'g, 483 F.3d 70 (2d Cir. 2007); Fener v. Operating Engineers Construction Industry and Miscellaneous Pension Fund (Local 66), 579 F.3d 401 (5th Cir. 2009) (class certification denied because plaintiffs failed to prove at certification stage that alleged action, in fact, caused stock prices to fall).

6. Wal-Mart Stores, 131 S. Ct. at 2552.

7. 133 S. Ct. 1184, 1194-95 (2013). See also Messner v. Northshore University HealthSystem, 669 F.3d 802, 811 (7th Cir. 2012) (cautioning that district courts may not “turn the class certification proceedings into a dress rehearsal for the trial on the merits.”).

8. Stirman v. Exxon Corp., 280 F.3d 554, 562 (5th Cir. 2002).

9. Hydrogen Peroxide, 552 F.5d at 320.

10Paton v. N. M. Highlands Univ., 275 F.3d 1274, 1277 (10th Cir. 2002); See also Amchem Prods. v. Windsor, 521 U.S. 591, 630 (1997) (Breyer, J., dissenting).

11. Hawkins v. Comparet-Cassani, 251 F.3d 1230, 1237 (9th Cir. 2001).

12. Millowitz v. Citigroup Global Markets, Inc. (In re Salomon Analyst Metromedia Litigation), 544 F.3d 474, 480 (2d Cir. 2008). 

13. “Numerosity” is the term generally used to identify this requirement. However, classes of various numbers have been certified. This requirement might be more appropriately termed “impracticality.” See, e.g., Anderson v. Dep’t of Pub. Welfare, 1 F. Supp. 2d 456, 461 (E.D. Pa. 1998); 1 William Rubenstein, Alba Conte & Herbert B. Newberg, Newberg on Class Actions § 3:3 (4th ed. and Supp. 2010). 

14. See Gen. Tel. Co. of the NW. v. EEOC, 446 U.S. 318, 330 (1980) (suggesting 15 is too few); Hayes v. Wal-Mart Stores, Incorporated, 725 F.3d 349, 357 (3d Cir. 2013) (presuming numerosity at 40); Consol. Rail Corp. v. Town of Hyde Park, 47 F.3d 473, 483 (2d Cir. 1995) (same). There are, of course, exceptions. Clark v. State Farm Mut. Auto. Ins. Co., 245 F.R.D. 478 (D. Colo. 2007) (rejecting class of 115); Peoples v. Sebring Capital Corp., 209 F.R.D. 428 (N.D. Ill. 2002) (certifying a class of eleven individuals); Grant v. Sullivan, 131 F.R.D. 436 (M.D. Pa. 1990) (noting that in some cases, particularly where declaratory and injunctive relief is sought classes as small as fourteen may be certified); Hernandez v. Alexander, 152 F.R.D. 192 (D. Nev. 1993) (indicating that a class of fifty-two might meet numerosity requirements but declined to certify because of failure to show “impracticability” of individual joinder).

15. Gen. Tel. Co. of the NW. v. EEOC, 446 U.S. 318, 330 (1980); Rannis v. Recchia, 380 F. App'x 646, 651 (9th Cir. 2010); Stewart v. Abraham, 275 F.3d 220, 226-27 (3d Cir. 2001); In re Am. Med. Sys., Inc., 75 F.3d 1069, 1079 (6th Cir. 1996); Robidoux v. Celani, 987 F.2d 931, 935-36 (2d Cir. 1993); 5 James Wm. Moore, et al., Moore's Federal Practice at § 23.33[1][a];1 Rubenstein, Conte & Newberg, supra note 13, § 3:6.

16. 7AA Charles A. Wright et al., Federal Practice and Procedure § 1762, at 176 (3d ed. 2005 & Supp. 2010); 5 Moore et al., supra note 15, § 23.05[3] at 23-156. See Robidoux, 987 F.2d at 935-36.

17. See Evans v. U.S. Pipe & Foundry, 696 F.2d 925, 930 (11th Cir. 1983); Sullivan v. Kelly Servs., Inc., 268   F.R.D. 356, 362 (N.D. Cal. 2010); Neese v. Johanns, 2006 U.S. Dist. LEXIS 25344, at *15, 2006 WL 1169800, at *5 (W.D. Va. May 2, 2006); Talbott v. GC Servs., Ltd. Pshp., 191 F.R.D. 99 (W.D. Va. 2000); McGlothlin v. Connors, 142 F.R.D. 626, 632 (W.D. Va. 1992). 

18. Vega v. T-Mobile USA, Inc., 564 F.3d 1256, 1267-68 (11th Cir. 2009); Golden v. City of Columbus, 404 F.3d 950, 966 (6th Cir. 2005) .

19Courts have struggled to produce a rule governing the inclusion of future adversely affected persons within a class. Although those already injured by an unlawful practice can be identified, knowing how many will be injured if the practice is continued is inherently impossible. Accordingly, some courts routinely include future victims of the challenged conduct within the class definition. See e.g., Pederson v. La. State Univ., 213 F.3d 858, 868 n.11 (5th Cir. 2000). Such inclusion of future victims does not render the class definition too vague for certification. Rodriguez v. Hayes, 591 F.3d 1105, 1118 (9th Cir. 2010); Probe v. State Teachers’ Ret. Sys., 780 F.2d 776, 780 (9th Cir. 1986); Williams v. City of Antioch, No. 90, 2010 WL 3632197, at *6, 2010 U.S. Dist. LEXIS 97829, at *21 (N.D. Cal. Sept. 2, 2010).

20 Fed. R. Civ. P. 23(a)(2); Wal-Mart Stores, 131 S. Ct. at 2556; Baby Neal v. Casey, 43 F.3d 48, 56 (3d Cir. 1994). See also Marisol A. v. Giuliani, 126 F.3d 372, 376 (2d Cir. 1997).

21. See, e.g., Wal-Mart Stores, 131 S. Ct. at 2556; Parra v. Bashas', Inc., 536 F.3d 975 (9th Cir. 2008), cert. denied, 129 S. Ct. 1050 (2009); Thomas v. Albright, 139 F.3d 227, 236 (D.C. Cir. 1998).

22. Wal-Mart Stores, 131 S. Ct. at 2556.  See Jamie S. v. Milwaukee Public Schools, 668 F.3d 481, 497 (7th Cir. 2012); D.G. ex rel. Stricklin v. DeVaughn, 594 F.3d 1188, 1198 (10th Cir. 2010); In Re Am. Med. Sys. Inc., 75 F.3d at 1080; Baby Neal, 43 F.3d at 56; Lightfoot v. District of Columbia, 246 F.R.D. 326, 337 (D.D.C. 2007).

23. D.G., 594 F.3d at 1195; Lightfoot, 246 F.R.D. at 337; Bynum v. District of Columbia, 214 F.R.D. 27, 32 (D.D.C. 2003). 

24. Disability Rights Council of Greater Washington v. WMATA, 239 F.R.D. 9, 26 (D.D.C. 2007) (quoting 7A Wright, et al., supra note 16, § 1763.).

25. D.G., 594 F.3d at 1195; Lightfoot v. District of Columbia, No. 01-01484 (D.D.C. Jan. 10, 2011). 

26Lightfoot, No. 01-01484.

27Wal-Mart Stores v. Dukes, 131 S. Ct. 2541 (2011).

28. Id. at 2551.

29. Id. at 2551-57 .

30. See, e.g., DL v. District of Columbia, 713 F.3d 120, 126 (D.D.C. 2013) (vacating certification of class of Individuals with Disabilities Education Act (IDEA)-eligible children for failure to satisfy commonality, citing Wal-Mart Stores’ change of the landscape, collecting cases); M.D. ex re. Stukenberg v. Perry, 675 F.3d 832, 840-41 (5th Cir. 2012) (vacating class certification based on failure to establish commonality, citing “heightened” standard established by Wal-Mart Stores); Jamie S., 668 F.3d at 498 (vacating certification of class of IDEA-eligible children and order approving subsequent settlement based on lack of commonality).

31. Id. at 2555.

32Id. at 2556.

33. Fed. R. Civ. P. 23(c)(4); See, e.g., Rodriguez v. Hayes, 591 F.3d 1105, 1123 (9th Cir. 2010); Gunnells v. Healthplan Servs., Inc., 348 F.3d 417, 439 (4th Cir. 2003); Robinson v. Metro-North Commuter R.R. Co., 267 F.3d 147, 167 (2d Cir. 2001), cert. denied, 535 U.S. 951 (2002).

34.  Fed. R. Civ. P. 23(c)(5). See e.g., In re Ins. Brokerage Antitrust Litig., 579 F.3d 241, 271 (3d Cir. 2009); McDonough v. Toys "R" Us, Inc., 638 F. Supp. 2d 461, 473–74 (E.D. Pa. 2009).

35. General Tel. Co. of Sw. v. Falcon, 457 U.S. 147, at 157, n.13 (1982).

36. Id. at 156. 

37. Stirman v. Exxon Corp., 280 F.3d 554, 562 (5th Cir. 2002); Stewart v. Abraham, 275 F.3d 220, 227-28 (3d Cir. 2001) (certifying class challenging city’s re-arrest policy). See also Piazza v. Ebsco Industries Inc., 273 F.3d 1341, 1351 (11th Cir. 2001) (strong similarity of legal theories satisfies typicality despite substantial factual differences)

38. Prado-Steiman v. Bush, 221 F.3d 1266, 1278-79 (11th Cir. 2000). 

39. D.G. ex rel. Stricklin, 594 F.3d at 1199; Beck v. Maximus, Inc., 457 F.3d 291, 296 (3d Cir. 2004); Bynum, 214 F.R.D. at 34.

40. See Brown v. Kelly, 609 F.3d 467, 480 (2d Cir. 2010).

41. See, e.g., In re Franklin Mutual Funds Fee Litigation, 388 F. Supp. 2d 451, 461 (D.N.J. 2005). 

42. Payton v. County of Kane, 308 F.3d 673, 679 (7th Cir. 2002); La Mar v. H & B Novelty and Loan Co., 489 F.2d 461 (9th Cir. 1973).

43. See generally Rubenstein, Conte & Newberg, supra note 13, § 1.03 (notice and adequacy of representation are touchstones of due process in class actions). See also In re Am. Med. Sys. Inc., 75 F.3d at 1083 and Broussard v. Meineke Disc. Muffler Shops Inc., 155 F.3d 331, 338 (4th Cir. 1998) (explaining the class action premise that, because “litigation by representative parties adjudicates basic due process rights of all class members, named plaintiffs must possess undivided loyalty to absent class members”).

44. Hansberry v. Lee, 311 U.S. 32 (1940). For a good explanation of this case, see Horton v. Goose Creek Indep. Sch. Dist., 690 F.2d 470, 486-87 (5th Cir. 1982). See also Richards v. Jefferson Co., 517 U.S. 793, 800-01 (1996).

45. But see General Tel. Co. of Sw. v. Falcon, 457 U.S. 147 at 157 n.13 (1982) (requirements of commonality and typicality tend to merge and so does adequacy-of-representation requirement, although adequacy of representation raises concerns about competency of class counsel and conflicts of interest).

46. Anchem Prod. Inc. v. Windsor, 521 U.S. 591, 626 (1997). See also Schlaud v. Snyder , 717 F.3d 451, 458 (6th Cir. 2013) (upholding denial of certification of home childcare providers challenging union because proposed class included members who voted for union); Berger v. Compaq Computer Corp., 257 F.3d 475, 480 (5th Cir. 2001) (differences between named plaintiffs and class members render named plaintiffs inadequate only when those differences create conflicts.)

47. See, e.g., Diaz v. Romer, 961 F.2d 1508 (10th Cir. 1992) and cases cited therein (appropriate to certify subclasses due to conflict between those class members who were HIV-positive and those who were HIV-negative). See also Marisol A. v. Giuliani, 126 F.3d 372, at 378-79 (2d Cir. 1997) (affirming class certification but suggesting to district court on remand ways to subdivide the class).

48. Horton v. Goose Creek Indep. Sch. Dist., 690 F.2d 470, 487 (5th Cir. 1982) (explaining options open to a district court).

49. See, e.g., In re Cmty. Bank of N. Va., 622 F.3d 275, 304 ((3d Cir. 2010) (remanded the case to the lower court to decide whether, in view of the intra-class conflict, a subclass should be created); Fabricant v. Sears Roebuck & Co., 202 F.R.D. 306, 308 (S.D. Fla. 2001) (“So long as the exclusions preserve the objective nature of the class definition, persons may be excluded from the class.”)

50Rattray v. Woodbury County, 614 F.3d 831, 836 (8th Cir. 2010); Monroe v. City of Charlottesville, 579 F.3d 380, 385 (4th Cir. 2009) (apparent disinterest in case); cert. denied, 130 S. Ct. 1740 (2010); Harriston v. Chicago Tribune Co., 992 F.2d 697, 704 (7th Cir. 1993).

51. Horton, 690 F.2d at 485 n.26.

52. Sheinberg v. Sorenson, 606 F.3d 130 (3rd Cir. 2010).


54. Marisol A. v. Giuliani, 126 F.3d 372, 378 (2d Cir. 1997) (inquiry into whether named plaintiffs will represent potential class with necessary vigor most often described as turning on questions of “whether plaintiffs’ counsel are qualified, experienced, and generally able to conduct proposed litigation”). See also Berger v. Compaq Computer Corp., 257 F.3d 475, 479 (5th Cir. 2001) (adequacy requirement mandates inquiry into zeal and competence of representatives’ counsel). The adequacy of counsel is generally pled in the motion for class certification and resumes of counsel are attached.

55. See, e.g., Kandel v. Bro. Int'l Corp., 264 F.R.D. 630, 634-35 (C.D. Cal. 2010);  Armstrong v. Chi. Park Dist., 117 F.R.D. 623, 631-34 (N.D. Ill. 1987) (holding inexperience alone may not be sufficient, but examining mistakes in other class actions as well as the one before in denying certification based on mistakes and inexperience). See also Creative Montessori Learning Centers v. Ashford Gear LLC, 662 F.3d 913, 917 (7th Cir. 2011) (vacating order certifying class, holding class counsel was  not adequate due to “lack of integrity” of counsel and court’s lack of conviction that they would represent interests of class); Gomez v. St. Vincent Health, Inc., 649 F.3d 583, 592 (7th Cir. 2011) (finding lower court did not abuse its discretion in finding proposed class counsel inadequate based on lack of diligence and promptness, faulty discovery efforts, and lack of respect for judicial resources).

56. E. Tex. Motor Freight Sys. v. Rodriguez, 431 U.S. 395, 405 (1977); Rattray, 614 F.3d at 836-37. But see In re Arakis Energy Corp. Sec. Litig., No.1:95-civ-3431 (AAR), 1999 WL 1021819, 1999 U.S. Dist. LEXIS 22246 (E.D.N.Y. April 23, 1999) (finding small delay insufficient to deny certification and collecting cases discussing issue).

57E. Tex. Motor Freight Sys., 431 U.S. at 405.

58John v. National Sec. Fire & Cas. Co., 501 F.3d 443, 445 (5th Cir. 2007).

59. See, e.g., Garrish v. UAW, 149 F. Supp. 2d 326 (E.D. Mich. 2001) (finding that union membership was an objective criterion sufficient to define a class); Daniels v. City of N. Y., 198 F.R.D. 409, 414 (S.D.N.Y. 2001) (finding that a proposed class of persons stopped and frisked by a street crimes police unit in the absence of reasonable suspicion was sufficiently definable for certification); Pigford v. Glickman, 182 F.R.D. 341 (D.D.C. 1998) (finding a sufficiently definable class when farmers suing the U.S. Department of Agriculture defined a class as those African American farmers who farmed between certain dates, applied to participate in department programs between those dates, and filed with the department a written complaint alleging a discriminatory response to their applications).

60. Burley v. City of New York, 2005 WL 668789, at *8–9, 2005 U.S. Dist. LEXIS 4439, at *25-28 (S.D.N.Y. Mar. 23, 2005) (class that refers to “arrestees who were subject to excessive handcuffing” not precise enough to be certified); Oldroyd v. Kugler, 352 F. Supp. 27, 31 (D.N.J. 1972) (class not certified where putative class members had a “fear of prosecution” for flag desecration because class defined in terms of subjective criterion of state-of-mind). See also Carrera v. Bayer Corporation , 727 F.3d 300, 304 (3d Cir. 2013) (class not certifiable if it is impossible to identify members without extensive individual fact finding); DeBremaecker v. Short, 433 F.2d 733 (5th Cir. 1970) (class definition “active in peace movement” too vague for objective criteria to identify class).

61. Mueller v. CBS Inc., 200 F.R.D. 227 (W.D. Pa. 2001) (declining to certify class where numerous individual determinations were necessary to identify class members). See generally UAW v. GMC, 235 F.R.D. 383 (E.D. Mich. March 31, 2006), aff'd, 497 F.3d 615 (6th Cir. 2007); see also Rahman v. Chertoff, 530 F.3d 622, 627 (7th Cir. 2008) (resolving definition problem by finding typicality was not satisfied).

62. Pagan v. Dubois, 884 F. Supp. 25 (D. Mass. 1995).

63. See Santillan v. Ashcroft, No. C 04-2686 MHP, 2004 U.S. Dist. LEXIS 20824 (N.D. Cal. Oct. 12, 2004); Probe v. State Teachers’  Ret. Sys., 780 F.2d 776, 780 (9th Cir. 1986). See also 7A Wright et al., supra note 16, § 1760, at 139.

64. In re Monumental Life Ins. Co., 365 F.3d 408, 414 (5th Cir. 2004); Clay v. Am. Tobacco Co., 188 F.R.D. 483, 490 (S.D. Ill. 1999).

65. Perez v. Metabolife International., Inc., 218 F.R.D. 262, 269 (S.D. Fla. 2003); White v. Williams, 208 F.R.D. 123, 129-30 (D.N.J. 2002)

66. Johnson v. GEICO Cas. Co., 673 F. Supp. 2d 244 (D. Del. 2009); In re Franklin Mut. Funds Fee Litig., 388 F. Supp.2d 451 (D.N.J. 2005).

67. E. Tex. Motor Freight Sys. v. Rodriguez, 431 U.S. 395, 403-04 (1977). See also Kelley v. Galveston Autoplex, 196 F.R.D. 471, 474 (S.D. Tex. 2000); McGlothlin v. Connors, 142 F.R.D. 626, 632 (W.D. Va. 1992).

68. Sosna v. Iowa, 419 U.S. 393 (1975); see Roman v. Korson, 307 F. Supp. 2d 908, 914-15 (W.D. Mich. 2004).

69. U.S. Parole Comm’n v. Geraghty, 445 U.S. 388 (1980). See Chapter 3.3.C of this MANUAL for further guidance on this point.

70. Gerstein v. Pugh, 420 U.S. 103 (1975); see Portis v. City of Chicago, 347 F.Supp. 2d 573 (N.D. Ill. 2004).

71Fed. R. Civ. P. 23(b)(1)(A) advisory committee's notes, 1966 amends.

72 Id.

73. See, e.g., Zinser v. Accufix Research Inst., Inc., 253 F.3d 1180 (9th Cir.), amended by 273 F.3d 1266 (9th Cir. 2001). See also 7AA Wright et al., supra note 16, § 1773, at 13.

74. Fed. R. Civ. P. 23(b)(1)(B) advisory committee’s notes, 1966 amends.

75. Ortiz v. Fibreboard Corp., 527 U.S. 815 (1999).

76Id. at 838-39.

77. In re Katrina Canal Breaches Litigation, Case No. 09-31156 (5th Cir. Dec. 16, 2010).

78. Wal-Mart Stores, 131 S. Ct. at 2557.  See also DL v. District of Columbia, 713 at 125 (vacating class certification order, finding failure to satisfy Rule 23(b)(2)); M.D. v. Perry, 675 F.3d at 845 (same); Jamie S. at 498 (same).

79. Compare Stewart v. Abraham, 275 F.3d 220, 227-28 (3d Cir. 2001) (affirming certification of (b)(2) class despite factual differences since there was at least one question of fact and law common to each class member) and Jordan v. Commonwealth Fin. Sys., 237 F.R.D. 132 (E.D. Pa. 2006) with Shook v. Bd. of County Commissioners, 543 F.3d 597, 604 (10th Cir. 2008) ("In short, under Rule 23(b)(2), the class members' injuries must be sufficiently similar that they can be addressed in a single injunction that need not differentiate between class members.") and Vallerio v. Vandehey, 554 F.3d 1259, 1268 (10th Cir. 2009) (reversing grant of certification under Rule 23(b)(2) because plaintiff did not meet burden of showing that injuries were sufficiently similar and because suit sought to enjoin wide range of conduct).

80. See Shook v. Bd. of County Comm'rs, 543 F.3d 597, 604 (10th Cir. 2008).

81Sosna v. Iowa, 419 U.S. 393, 403 (1975).

82. See O’Shea v. Littleton, 414 U.S. 488, 494 (1974); Hayes v. Wal-Mart Stores, Inc., 725 F.3d 349, 361 (3d Cir. 2013) (noting that question of whether class representative has standing can overlap with question of whether he fits within class definition).

83. However, the 2003 amendment to Rule 23(c), provides that the court “may” direct appropriate notice to the class.

84. 42 U.S.C.§ 1981a(a)(1).

85. Wal-Mart Stores, 131 U.S. at 2557.

86. Id. at 2559.

87. Allison v. Citgo Petroleum Corp., 151 F.3d 402 (5th Cir. 1998).

88. Wal-Mart Stores, 131 U.S. at 2560. See also Reeb v. Ohio Dep't of Rehab. & Corr., 435 F.3d 639, 646-51 (6th Cir. 2006); Murray v. Auslander, 244 F.3d 807, 812 (11th Cir. 2001); Lemon v. Int'l Union of Operating Eng'rs Local No. 139, 216 F.3d 577, 580-81 (7th Cir. 2000).

89. Allison, 151 F.3d at 415.

90. Wal-Mart Stores, 131 U.S. at 2560.

91. Id.

92. Id.

93. See, e.g., Benjamin by and through Yock v. Department of Public Welfare of Pennsylvania, 701 F.3d 938, 950 (3d Cir. 2012); Romberio v. UnumProvident Corporation, 385 Fed. App'x 423, 432 (6th Cir. 2009); Shook, 543 F.3d at 604; In re St. Jude Med., Inc., 425 F.3d 1116, 1121 (8th Cir. 2005); Lemon v. Int'l Union of Operating Engr's', Local No. 139, 216 F.3d 577, 580 (7th Cir. 2000); In re Rezulin Prods. Liab. Litig., 210 F.R.D. 61, 75 (S.D.N.Y. 2002).

94. Lightfoot, No. 01-01484.

95. See generally 7A Wright et al., supra note 16, § 1777. The relevant considerations for so determining are listed in Rule 23(b)(3)(A)-(D). The Supreme Court has recently held that “Rule 23(b)(3)’s predominance criterion is even more demanding” than the rigorous standard for satisfying the requirements of 23(a). Comcast Corporation v. Behrend, 133 S. Ct. 1426, 1432 (2013).

96. The 2003 amendments significantly change the notice requirements in (b)(3) cases: courts now may refuse to approve settlements unless they contain post-settlement opt-out notice to all class members. See Fed. R. Civ. P. 23(e)(3).

 Updated 2014 by Sarah Somers