of Appeals therefore held that it had jurisdiction to hear the appeal and, on the merits, reversed the order decertifying the class. Livesay v. Punta Gorda Isles, Inc., 550 F. 2d 1106.

Federal appellate jurisdiction generally depends on the existence of a decision by the District Court that "ends the litigation on the merits and leaves nothing for the court to do but execute the judgment." Catlin v. United States, 324 U. S. 229, 233. An order refusing to certify, or decertifying, a class does not of its own force terminate the entire litigation because the plaintiff is free to proceed on his individual claim. Such an order is appealable, therefore, only if it comes within an appropriate exception to the final-judgment rule. In this

where most defendants reside. Moreover, the allegations regarding the prospectus and financial statements will likely require expert testimony at trial.

"After considering all the relevant information in the record, we are convinced that plaintiffs have sustained their burden of showing that they will not pursue their individual claim if the decertification order stands. Although plaintiffs' total net worth could absorb the cost of this litigation, ‘it [takes] no great understanding of the mysteries of high finance to make obvious the futility of spending a thousand dollars to get a thousand dollars or even less.' Douglas, Protective Committees in Railroad Reorganizations, 47 Harv. L. Rev. 565, 567 (1934). We conclude we have jurisdiction to hear the appeal." Livesay v. Punta Gorda Isles, Inc., 550 F.2d 1106, 1109-1110.

8 For a unanimous Court in Cobbledick v. United States, 309 U. S. 323, 325, Mr. Justice Frankfurter wrote:

"Since the right to a judgment from more than one court is a matter of grace and not a necessary ingredient of justice, Congress from the very beginning has, by forbidding piecemeal disposition on appeal of what for practical purposes is a single controversy, set itself against enfeebling judicial administration. Thereby is avoided the obstruction to just claims that would come from permitting the harassment and cost of a succession of separate appeals from the various rulings to which a litigation may give rise, from its initiation to entry of judgment. To be effective, judicial administration must not be leaden-footed. Its momentum would be arrested by permitting separate reviews of the component elements in a unified cause."

case respondents rely on the "collateral order" exception articulated by this Court in Cohen v. Beneficial Industrial Loan Corp., 337 U. S. 541, and on the "death knell" doctrine adopted by several Circuits to determine the appealability of orders denying class certification.

I

In Cohen, the District Court refused to order the plaintiff in a stockholder's derivative action to post the security for costs required by a New Jersey statute. The defendant sought immediate review of the question whether the state statute applied to derivative suits in federal court. This Court noted that the purpose of the finality requirement "is to combine in one review all stages of the proceeding that effectively may be reviewed and corrected if and when final judgment results." Id., at 546. Because immediate review of the District Court's order was consistent with this purpose, the Court held it appealable as a "final decision" under § 1291. The ruling had "settled conclusively the corporation's claim that it was entitled by state law to require the shareholder to post security for costs... [and] concerned a collateral matter that could not be reviewed effectively on appeal from the final judgment.">

To come within the "small class" of decisions excepted from the final-judgment rule by Cohen, the order must conclusively determine the disputed question, resolve an important issue completely separate from the merits of the action, and be effectively unreviewable on appeal from a final judgment.1o Abney v. United States, 431 U. S. 651, 658; United States v.

• Eisen v. Carlisle & Jacquelin, 417 U. S. 156, 171. 10 As the Court summarized the rule in Cohen:

"This decision appears to fall in that small class which finally determine claims of right separable from, and collateral to, rights asserted in the action, too important to be denied review and too independent of the cause itself to require that appellate consideration be deferred until the whole case is adjudicated." 337 U. S., at 546.

MacDonald, 435 U. S. 850, 855. An order passing on a request for class certification does not fall in that category. First, such an order is subject to revision in the District Court. Fed. Rule Civ. Proc. 23 (c) (1).11 Second, the class determination generally involves considerations that are "enmeshed in the factual and legal issues comprising the plaintiff's cause of action." Mercantile Nat. Bank v. Langdeau, 371 U. S. 555, 558.22 Finally, an order denying class certification is subject to effective review after final judgment at the behest of the named plaintiff or intervening class members. United Airlines, Inc. v. McDonald, 432 U. S. 385. For these reasons, as the Courts of Appeals have consistently recognized,13 the collateral-order doctrine is not applicable to the kind of order involved in this case.

12

II

14

Several Circuits, including the Court of Appeals in this case, have held that an order denying class certification is appealable if it is likely to sound the "death knell" of the litigation." The "death knell" doctrine assumes that without the incentive of a possible group recovery the individual plaintiff may find it economically imprudent to pursue his lawsuit to a final

11 The Rule provides that an order involving class status may be "altered or amended before the decision on the merits." Thus, a district court's order denying or granting class status is inherently tentative.

12 "Evaluation of many of the questions entering into determination of class action questions is intimately involved with the merits of the claims. The typicality of the representative's claims or defenses, the adequacy of the representative, and the presence of common questions of law or fact are obvious examples. The more complex determinations required in Rule 23 (b)(3) class actions entail even greater entanglement with the merits. . . .' 15 C. Wright, A. Miller, & E. Cooper, Federal Practice and Procedure § 3911, p. 485 n. 45 (1976).

"

13 See, e. g., King v. Kansas City Southern Industries, Inc., 479 F. 2d 1259 (CA7 1973); Williams v. Mumford, 167 U. S. App. D. C. 125, 511 F.2d 363 (1975), cert. denied, 423 U. S. 828.

14 See n. 2, supra.

judgment and then seek appellate review of an adverse class determination. Without questioning this assumption, we hold that orders relating to class certification are not independently appealable under § 1291 prior to judgment.

In addressing the question whether the "death knell" doctrine supports mandatory appellate jurisdiction of orders refusing to certify class actions, the parties have devoted a portion of their argument to the desirability of the small-claim class action. Petitioner's opposition to the doctrine is based in part on criticism of the class action as a vexatious kind of litigation. Respondents, on the other hand, argue that the class action serves a vital public interest and, therefore, special rules of appellate review are necessary to ensure that district judges are subject to adequate supervision and control. Such policy arguments, though proper for legislative consideration, are irrelevant to the issue we must decide.

There are special rules relating to class actions and, to that extent, they are a special kind of litigation. Those rules do not, however, contain any unique provisions governing appeals. The appealability of any order entered in a class action is determined by the same standards that govern appealability in other types of litigation. Thus, if the "death knell" doctrine has merit, it would apply equally to the many interlocutory orders in ordinary litigation-rulings on discovery, on venue, on summary judgment-that may have such tactical economic significance that a defeat is tantamount to a "death knell" for the entire case.

Though a refusal to certify a class is inherently interlocutory, it may induce a plaintiff to abandon his individual claim. On the other hand, the litigation will often survive an adverse class determination. What effect the economic disincentives created by an interlocutory order may have on the fate of any litigation will depend on a variety of factors.15 Under the

15 E. g., the plaintiff's resources; the size of his claim and his subjective willingness to finance prosecution of the claim; the probable cost of the

"death knell" doctrine, appealability turns on the court's perception of that impact in the individual case. Thus, if the court believes that the plaintiff has adequate incentive to continue, the order is considered interlocutory; but if the court concludes that the ruling, as a practical matter, makes further litigation improbable, it is considered an appealable final decision.

The finality requirement in § 1291 evinces a legislative judgment that "[r]estricting appellate review to 'final decisions' prevents the debilitating effect on judicial administration caused by piecemeal appeal disposition of what is, in practical consequence, but a single controversy." Eisen v. Carlisle & Jacquelin, 417 U. S. 156, 170. Although a rigid insistence on technical finality would sometimes conflict with the purposes of the statute, Cohen v. Beneficial Industrial Loan Corp., 337 U. S. 541, even adherents of the "death knell" doctrine acknowledge that a refusal to certify a class does not fall in that limited category of orders which, though nonfinal, may be appealed without undermining the policies served by the general rule. It is undisputed that allowing an appeal from such an order in the ordinary case would run "directly contrary to the policy of the final judgment rule embodied in 28 U. S. C. § 1291 and the sound reasons for it. . . ." 16 Yet several Courts of Appeals have sought to identify on a caseby-case basis those few interlocutory orders which, when viewed from the standpoint of economic prudence, may induce a plaintiff to abandon the litigation. These orders, then, become appealable as a matter of right.

In administering the "death knell" rule, the courts have used two quite different methods of identifying an appealable class ruling. Some courts have determined their jurisdiction

litigation and the possibility of joining others who will share that cost; and the prospect of prevailing on the merits and reversing an order denying class certification.

16 Korn v. Franchard Corp., 443 F. 2d 1301, 1305 (CA2 1971).