being the claim on the merits and the other being the claim that he is entitled to represent a class. "The denial of class certification stands as an adjudication of one of the issues litigated," Roper, ante, at 336, and in determining whether the plaintiff may continue to press the class certification claim after the claim on the merits "expires," the nature of the "personal stake" in the class certification claim must be examined. P. 402.

(b) The imperatives of a dispute capable of judicial resolutionsharply presented issues in a concrete factual setting and self-interested parties vigorously advocating opposing positions-can exist with respect to the class certification issue notwithstanding that the named plaintiff's claim on the merits has expired. Such imperatives are present in this case where the question whether class certification is appropriate remains as a concrete, sharply presented issue, and respondent continues vigorously to advocate his right to have a class certified. Pp. 403-404.

(c) Respondent was a proper representative for the purpose of appealing the ruling denying certification of the class that he initially defined, and hence it was not improper for the Court of Appeals to consider whether the District Court should have granted class certification. P. 407.

(d) The Court of Appeals' remand of the case for consideration of subclasses was a proper disposition, except that the burden of constructing subclasses is not upon the District Court but upon the respondent. Pp. 407-408.

579 F.2d 238, vacated and remanded.

BLACKMUN, J., delivered the opinion of the Court, in which BRENNAN, WHITE, MARSHALL, and STEVENS, JJ., joined. POWELL, J., filed a dissenting opinion, in which BURGER, C. J., and STEWART and REHNQUIST, JJ., joined, post, p. 409.

Kent L. Jones argued the cause pro hac vice for petitioners. With him on the briefs were Solicitor General McCree, Assistant Attorney General Heymann, Deputy Solicitor General Easterbrook, Jerome M. Feit, and Elliott Schulder.

Kenneth N. Flaxman argued the cause for respondent. With him on the brief was Thomas R. Meites.*

*Robert J. Hobbs filed a brief for the National Client Council, Inc., et al. as amici curiae urging affirmance.

Opinion of the Court

445 U.S. MR. JUSTICE BLACKMUN delivered the opinion of the Court. This case raises the question whether a trial court's denial of a motion for certification of a class may be reviewed on appeal after the named plaintiff's personal claim has become "moot." The United States Court of Appeals for the Third Circuit held that a named plaintiff, respondent here, who brought a class action challenging the validity of the United States Parole Commission's Parole Release Guidelines, could continue his appeal of a ruling denying class certification even though he had been released from prison while the appeal was pending. We granted certiorari, 440 U. S. 945 (1979), to consider this issue of substantial significance, under Art. III of the Constitution, to class-action litigation,' and to resolve the conflict in approach among the Courts of Appeals.'

1 The grant of certiorari also included the question of the validity of the Parole Release Guidelines, an issue left open in United States v. Addonizio, 442 U. S. 178, 184 (1979). We have concluded, however, that it would be premature to reach the merits of that question at this time. See infra, at 408.

While the petition for a writ of certiorari was pending, respondent Geraghty filed a motion to substitute as respondents in this Court five prisoners, then incarcerated, who also were represented by Geraghty's attorneys. In the alternative, the prisoners sought to intervene. We deferred our ruling on the motion to the hearing of the case on the merits. 440 U. S. 945 (1979). These prisoners, or most of them, now also have been released from incarceration. On September 25, 1979, a supplement to the motion to substitute or intervene was filed, proposing six new substitute respondents or intervenors; each of these is a presently incarcerated federal prisoner who, allegedly, has been adversely affected by the guidelines and who is represented by Geraghty's counsel.

Since we hold that respondent may continue to litigate the class certification issue, there is no need for us to consider whether the motion should be granted in order to prevent the case from being moot. We conclude that the District Court initially should rule on the motion.

2 See, e. g., Armour v. City of Anniston, 597 F. 2d 46, 48-49 (CA5 1979); Susman v. Lincoln American Corp., 587 F. 2d 866 (CA7 1978), cert. pending, No. 78-1169; Goodman v. Schlesinger, 584 F. 2d 1325, 1332-1333 (CA4 1978); Camper v. Calumet Petrochemicals, Inc., 584

In 1973, the United States Parole Board adopted explicit Parole Release Guidelines for adult prisoners. These guidelines establish a "customary range" of confinement for various classes of offenders. The guidelines utilize a matrix, which combines a "parole prognosis" score (based on the prisoner's age at first conviction, employment background, and other personal factors) and an "offense severity" rating, to yield the "customary" time to be served in prison.

Subsequently, in 1976, Congress enacted the Parole Commission and Reorganization Act (PCRA), Pub. L. 94-233, 90 Stat. 219, 18 U. S. C. §§ 4201-4218. This Act provided the first legislative authorization for parole release guidelines. It required the newly created Parole Commission to "promulgate rules and regulations establishing guidelines for the powe[r] ... to grant or deny an application or recommendation to parole any eligible prisoner." § 4203. Before releasing a prisoner on parole, the Commission must find, "upon consideration of the nature and circumstances of the offense and the history and characteristics of the prisoner," that release "would not depreciate the seriousness of his offense or promote disrespect for the law" and that it "would not jeopardize the public welfare." § 4206 (a).

Respondent John M. Geraghty was convicted in the United States District Court for the Northern District of Illinois of

F. 2d 70 (CA5 1978); Roper v. Consurve, Inc., 578 F. 2d 1106 (CA5 1978), aff'd sub nom. Deposit Guaranty Nat. Bank v. Roper, ante, p. 326; Satterwhite v. City of Greenville, 578 F. 2d 987 (CA5 1978) (en banc), cert. pending, No. 78-1008; Vun Cannon v. Breed, 565 F. 2d 1096 (CA9 1977); Winokur v. Bell Federal Savings & Loan Assn., 560 F. 2d 271 (CA7 1977), cert. denied, 435 U. S. 932 (1978); Lasky v. Quinlan, 558 F.2d 1133 (CA2 1977); Kuahulu v. Employers Ins. of Wausau, 557 F. 2d 1334 (CA9 1977); Boyd v. Justices of Special Term, 546 F. 2d 526 (CA2 1976); Napier v. Gertrude, 542 F. 2d 825 (CA10 1976), cert. denied, 429 U. S. 1049 (1977).

$38 Fed. Reg. 31942-31945 (1973). The guidelines currently in force appear at 28 CFR § 2.20 (1979).

conspiracy to commit extortion, in violation of 18 U. S. C. § 1951, and of making false material declarations to a grand jury, in violation of 18 U. S. C. § 1623 (1976 ed. and Supp. II). On January 25, 1974, two months after initial promulgation of the release guidelines, respondent was sentenced to concurrent prison terms of four years on the conspiracy count and one year on the false declarations count. The United States Court of Appeals for the Seventh Circuit affirmed respondent's convictions. United States v. Braasch, 505 F. 2d 139 (1974), cert. denied sub nom. Geraghty v. United States, 421 U. S. 910 (1975).

Geraghty later, pursuant to a motion under Federal Rule of Criminal Procedure 35, obtained from the District Court a reduction of his sentence to 30 months. The court granted the motion because, in the court's view, application of the guidelines would frustrate the sentencing judge's intent with respect to the length of time Geraghty would serve in prison. United States v. Braasch, No. 72 CR 979 (ND Ill., Oct. 9, 1975), appeal dism'd and mandamus denied, 542 F. 2d 442 (CA7 1976).

Geraghty then applied for release on parole. His first application was denied in January 1976 with the following explanation:

"Your offense behavior has been rated as very high severity. You have a salient factor score of 11. You have been in custody for a total of 4 months. Guidelines established by the Board for adult cases which consider the above factors indicate a range of 26-36 months to be served before release for cases with good institutional program performance and adjustment. After review of all relevant factors and information presented, it is found

The extortion count was based on respondent's use of his position as a vice squad officer of the Chicago police force to "shake down" dispensers of alcoholic beverages; the false declarations concerned his involvement in this scheme.

that a decision at this consideration outside the guidelines does not appear warranted." App. 5.

If the customary release date applicable to respondent under the guidelines were adhered to, he would not be paroled before serving his entire sentence minus good-time credits. Geraghty applied for parole again in June 1976; that application was denied for the same reasons. He then instituted this civil suit as a class action in the United States District Court for the District of Columbia, challenging the guidelines as inconsistent with the PCRA and the Constitution, and questioning the procedures by which the guidelines were applied to his

case.

Respondent sought certification of a class of "all federal prisoners who are or who will become eligible for release on parole." Id., at 17. Without ruling on Geraghty's motion, the court transferred the case to the Middle District of Pennsylvania, where respondent was incarcerated. Geraghty continued to press his motion for class certification, but the court postponed ruling on the motion until it was prepared to render a decision on cross-motions for summary judgment.

The District Court subsequently denied Geraghty's request for class certification and granted summary judgment for petitioners on all the claims Geraghty asserted. 429 F. Supp. 737 (1977). The court regarded respondent's action as a petition for a writ of habeas corpus, to which Federal Rule of Civil Procedure 23 applied only by analogy. It denied class certification as "neither necessary nor appropriate." 429 F. Supp., at 740. A class action was "necessary" only to avoid mootness. The court found such a consideration not comprehended by Rule 23. It found class certification inappropriate because Geraghty raised certain individual issues and, inasmuch as some prisoners might be benefited by the guidelines, because his claims were not typical of the entire proposed class. 429 F. Supp., at 740-741. On the merits, the court ruled that the guidelines are consistent with the PCRA and