opinion: Justice Powell
  announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I, II, III-B, III-C, and IV, and an opinion with respect to Part III-A, in which The Chief Justice, Justice White, and Justice O’Connor join.
  The question presented in this case is whether and to what extent a State’s interest in the confidentiality of its investigative files concerning child abuse must yield to a criminal defendant’s Sixth and Fourteenth Amendment right to discover favorable evidence.
  I
  As part of its efforts to combat child abuse, the Commonwealth of Pennsylvania has established Children and Youth Services (CYS), a protective service" agency charged with investigating cases of suspected mistreatment and neglect. In 1979, respondent George Ritchie was charged with rape, involuntary deviate sexual intercourse, incest, and corruption of a minor. The victim of the alleged attacks was his 13-year-old daughter, who claimed that she had been assaulted by Ritchie two or three times per week during the previous four years. The girl reported the incidents to the police, and the matter then was referred to the CYS.
  During pretrial discovery, Ritchie served CYS with a subpoena, seeking access to the records concerning the daughter. Ritchie requested disclosure of the file related to the immediate charges, as well as certain records that he claimed were compiled in 1978, when CYS investigated a separate report by an unidentified source that Ritchie’s children were being abused. CYS refused to comply with the subpoena, claiming that the records were privileged under Pennsylvania law. The relevant statute provides that all reports and other information obtained in the course of a CYS investigation must be kept confidential, subject to 11 specific exceptions. One of those exceptions is that the agency may disclose the reports to a “court of competent jurisdiction pursuant to a court order.” Pa. Stat. Ann., Tit. 11, §2215(a)(5) (Purdon Supp. 1986).
  Ritchie moved to have CYS sanctioned for failing to honor the subpoena, and the trial court held a hearing on the motion in chambers. Ritchie argued that he was entitled to the information because the file might contain the names of favorable witnesses, as well as other, unspecified exculpatory evidence. He also requested disclosure of a medical report that he believed was compiled during the 1978 CYS investigation. Although the trial judge acknowledged that he had not examined the entire CYS file, he accepted a CYS representative’s assertion that there was no medical report in the record. The judge then denied the motion and refused to order CYS to disclose the files. See App. 72a.
  At trial, the main witness against Ritchie was his daughter. In an attempt to rebut her testimony, defense counsel cross-examined the girl at length, questioning her on all aspects of the alleged attacks and her reasons for not reporting the incidents sooner. Except for routine evidentiary rulings, the trial judge placed no limitation on the scope of cross-examination. At the close of trial Ritchie was convicted by a jury on all counts, and the judge sentenced him to 3 to 10 years in prison.
  On appeal to the Pennsylvania Superior Court, Ritchie claimed, inter alia, that the failure to disclose the contents of the CYS file violated the Confrontation Clause of the Sixth Amendment, as applied to the States through the Due Process Clause of the Fourteenth Amendment. The court agreed that there had been a constitutional violation, and accordingly vacated the conviction and remanded for further proceedings. 324 Pa. Super. 557, 472 A. 2d 220 (1984). The Superior Court ruled, however, that the right of confrontation did not entitle Ritchie to the full disclosure that he sought. It held that on remand, the trial judge first was to examine the confidential material in camera, and release only the verbatim statements made by the daughter to the CYS counselor. But the full record then was to be made available to Ritchie’s lawyer, for the limited purpose of allowing him to argue the relevance of the statements.. The court stated that the prosecutor also should be allowed to argue that the failure to disclose the statements was harmless error. If the trial judge determined that the lack of information was prejudicial, Ritchie would be entitled to a new trial. Id., at 567-568, 472 A. 2d, at 226.
  On appeal by the Commonwealth, the Supreme Court of Pennsylvania agreed that the conviction must be vacated and the case remanded to determine if a new trial is necessary. 509 Pa. 357, 502 A. 2d 148 (1985). But the court did not agree that the search for material evidence must be limited to the daughter’s verbatim statements. Rather, it concluded that Ritchie, through his lawyer, is entitled to review the entire file to search for any useful evidence. It stated: “When materials gathered become an arrow of inculpation, the person inculpated has a fundamental constitutional right to examine the provenance of the arrow and he who aims it.” Id., at 367, 502 A. 2d, at 153. The Pennsylvania Court concluded that by denying access to the file, the trial court order had violated both the Confrontation Clause and the Compulsory Process Clause. The court was unpersuaded by the Commonwealth’s argument that the trial judge already had examined the file and determined that it contained no relevant information. It ruled that the constitutional infirmity in the trial court’s order was that Ritchie was unlawfully denied the opportunity to have the records reviewed by “the eyes and the perspective of an advocate,” who may see relevance in places that a neutral judge would not. Ibid.
  In light of the substantial and conflicting interests held by the Commonwealth and Ritchie, we granted certiorari. 476 U. S. 1139 (1986). We now affirm in part, reverse in part, and remand for proceedings not inconsistent with this opinion.
  J-H HH
  Before turning to the constitutional questions, we first must address Ritchie’s claim that the Court lacks jurisdiction, because the decision below is not a “final judgment or decree.” See 28 U. S. C. § 1257(3); Market Street R. Co. v. Railroad Comm’n of California, 324 U. S. 548, 551 (1945). Normally the finality doctrine contained in § 1257(3) is not satisfied if the state courts still must conduct further substantive proceedings before the rights of the parties as to the federal issues are resolved. Ibid.; Radio Station WOW, Inc. v. Johnson, 326 U. S. 120, 123-127 (1945). Ritchie argues that under this standard the case is not final, because there are several more proceedings scheduled in the Pennsylvania courts: at a minimum there will be an in camera review of the file, and the parties will present arguments on whether the lack of disclosure was prejudicial; after that, there could be a new trial on the merits. Ritchie claims that because the Sixth Amendment issue may become moot at either of these stages, we should decline review until these further proceedings are completed.
  Although it is true that this Court is without jurisdiction to review an interlocutory judgment, it also is true that the principles of finality have not been construed rigidly. As we recognized in Cox Broadcasting Corp. v. Cohn, 420 U. S. 469 (1975), there are at least four categories of cases in which jurisdiction is proper even when there are further proceedings anticipated in the state court. One of these exceptions states that the Court may consider cases:
  “[WJhere the federal claim has been finally decided, with further proceedings on the merits in the state courts to come, but in which later review of the federal issue cannot be had, whatever the ultimate outcome of the case. . . . [I]n these cases, if the party seeking interim review ultimately prevails on the merits, the federal issue will be mooted; if he were to lose on the merits, however, the governing state law would not permit him again to present his federal claims for review.” Id., at 481.
  We find that the case before us satisfies this standard because the Sixth Amendment issue will not survive for this Court to review, regardless of the outcome of the proceedings on remand. If the trial court decides that the CYS files do not contain relevant information, or that the nondisclosure was harmless, the Commonwealth will have prevailed and will have no basis to seek review. In this situation Ritchie’s conviction will be reinstated, and the issue of whether defense counsel should have been given access will be moot. Should Ritchie appeal the trial court’s decision, the Commonwealth’s only method for preserving the constitutional issue would be by cross-claims. Thus the only way that this Court will be able to reach the Sixth Amendment issue is if Ritchie eventually files a petition for certiorari on the trial court’s adverse ruling, and the Commonwealth files a cross-petition. When a case is in this procedural posture, we have considered it sufficiently final to justify review. See, e. g., New York v. Quarles, 467 U. S. 649, 651, n. 1 (1984); South Dakota v. Neville, 459 U. S. 553, 558, n. 6 (1983).
  Alternatively, if Ritchie is found to have been prejudiced by the withholding and is granted a new trial, the Commonwealth still will be unable to obtain a ruling from this Court. On retrial Ritchie either will be convicted, in which case the Commonwealth’s ability to obtain review again will rest on Ritchie’s willingness to appeal; or he will be acquitted, in which case the Commonwealth will be barred from seeking review by the Double Jeopardy Clause. See ibid.; California v. Stewart, 384 U. S. 436, 498, n. 71 (1966) (decided with Miranda v. Arizona, 384 U. S. 436 (1966)). Therefore, if this Court does not consider the constitutional claims now, there may well be no opportunity to do so in the future.
  The Sixth Amendment issue has been finally decided by the highest court of Pennsylvania, and unless we review that decision, the harm that the Commonwealth seeks to avoid— the disclosure of the entire confidential file — will occur regardless of the result on remand. We thus cannot agree with the suggestion in Justice Stevens’ dissent that if we were to dismiss this case and it was resolved on other grounds after disclosure of the file, “the Commonwealth would not have been harmed.” Post, at 74. This hardly could be true, because of the acknowledged public interest in ensuring the confidentiality of CYS records. See n. 17, infra. Although this consideration is not dispositive, we have noted that “statutorily created finality requirements should, if possible, be construed so as not to cause crucial collateral claims to be lost and potentially irreparable injuries to be suffered.” Mathews v. Eldridge, 424 U. S. 319, 331, n. 11 (1976). We therefore reject Ritchie’s claim that the Court lacks jurisdiction, and turn to the merits of the case before us.
  HH HH 1 — I
  The Pennsylvania Supreme Court held that Ritchie, through his lawyer, has the right to examine the full contents of the CYS records. The court found that this right of access is required by both the Confrontation Clause and the Compulsory Process Clause. We discuss these constitutional provisions in turn.
  A
  The Confrontation Clause provides two types of protections for a criminal defendant: the right physically to face those who testify against him, and the right to conduct cross-examination. Delaware v. Fensterer, 474 U. S. 15, 18-19 (1985) (per curiam). Ritchie does not allege a violation of the former right. He was not excluded from any part of the trial, nor did the prosecutor improperly introduce out-of-court statements as substantive evidence, thereby depriving Ritchie of the right to “confront” the declarant. See Ohio v. Roberts, 448 U. S. 56 (1980). Cf. United States v. Inadi, 475 U. S. 387 (1986). Instead, Ritchie claims that by denying him access to the information necessary to prepare his defense, the trial court interfered with his right of cross-examination.
  Ritchie argues that he could not effectively question his daughter because, without the CYS material, he did not know which types of questions would best expose the weaknesses in her testimony. Had the files been disclosed, Ritchie argues that he might have been able to show that the daughter made statements to the CYS counselor that were inconsistent with her trial statements, or perhaps to reveal that the girl acted with an improper motive. Of course, the right to cross-examine includes the opportunity to show that a witness is biased, or that the testimony is exaggerated or unbelievable. United States v. Abel, 469 U. S. 45, 50 (1984); Davis v. Alaska, 415 U. S. 308, 316 (1974). Because this type of evidence can make the difference between conviction and acquittal, see Napue v. Illinois, 360 U. S. 264, 269 (1959), Ritchie argues that the failure to disclose information that might have made cross-examination more effective undermines the Confrontation Clause’s purpose of increasing the accuracy of the truth-finding process at trial. See United States v. Inadi, supra, at 396.
  The Pennsylvania Supreme Court accepted this argument, relying in part on our decision in Davis v. Alaska, supra. In Davis the trial judge prohibited defense counsel from questioning a witness about the latter’s juvenile criminal record, because a state statute made this information presumptively confidential. We found that this restriction on cross-examination violated the Confrontation Clause, despite Alaska’s legitimate interest in protecting the identity of juvenile offenders. 415 U. S., at 318-320. The Pennsylvania Supreme Court apparently interpreted our decision in Davis to mean that a statutory privilege cannot be maintained when a defendant asserts a need, prior to trial, for the protected information that might be used at trial to impeach or otherwise undermine a witness’ testimony. See 509 Pa., at 365-367, 502 A. 2d, at 152-153.
  If we were to accept this broad interpretation of Davis, the effect would be to transform the Confrontation Clause into a constitutionally compelled rule of pretrial discovery. Nothing in the case law supports such a view. The opinions of this Court show that the right to confrontation is a trial right, designed to prevent improper restrictions on the types of questions that defense counsel may ask during cross-examination. See California v. Green, 399 U. S. 149, 157 (1970) (“[I]t is this literal right to ‘confront’ the witness at the time of trial that forms the core of the values furthered by the Confrontation Clause”); Barber v. Page, 390 U. S. 719, 725 (1968) (“The right to confrontation is basically a trial right”). The ability to question adverse witnesses, however, does not include the power to require the pretrial disclosure of any and all information that might be useful in contradicting unfavorable testimony. Normally the right to confront one’s accusers is satisfied if defense counsel receives wide latitude at trial to question witnesses. Delaware v. Fensterer, 474 U. S., at 20. In short, the Confrontation Clause only guarantees “an opportunity for effective cross-examination, not cross-examination that is effective in whatever way, and to whatever extent, the defense might wish.” Id., at 20 (emphasis in original). See also Ohio v. Roberts, supra, at 73, n. 12 (except in “extraordinary cases, no inquiry into ‘effectiveness’ [of cross-examination] is required”).
  We reaffirmed this interpretation of the Confrontation Clause last Term in Delaware v. Fensterer, supra. In that case, the defendant was convicted in part on the testimony of the State’s expert witness, who could not remember which scientific test he had used to form his opinion. Although this inability to recall frustrated defense counsel’s efforts to discredit the testimony, we held that there had been no Sixth Amendment violation. The Court found that the right of confrontation was not implicated, “for the trial court did not limit the scope or nature of defense counsel’s cross-examination in any way.” 474 U. S., at 19. Fensterer was in full accord with our earlier decisions that have upheld a Confrontation Clause infringement claim on this issue only when there was a specific statutory or court-imposed restriction at trial on the scope of questioning.
  The lower court’s reliance on Davis v. Alaska therefore is misplaced. There the state court had prohibited defense counsel from questioning the witness about his criminal record, even though that evidence might have affected the witness’ credibility. The constitutional error in that case was not that Alaska made this information confidential; it was that the defendant was denied the right “to expose to the jury the facts from which jurors . . . could appropriately draw inferences relating to the reliability of the witness.” 415 U. S., at 318. Similarly, in this case the Confrontation Clause was not violated by the withholding of the CYS file; it only would have been impermissible for the judge to have prevented Ritchie’s lawyer from cross-examining the daughter. Because defense counsel was able to cross-examine all of the trial witnesses fully, we find that the Pennsylvania Supreme Court erred in holding that the failure to disclose the CYS file violated the Confrontation Clause.
  B
  The Pennsylvania Supreme Court also suggested that the failure to disclose the CYS file violated the Sixth Amendment’s guarantee of compulsory process. Ritchie asserts that the trial court’s ruling prevented him from learning the names of the “witnesses in his favor,” as well as other evidence that might be contained in the file. Although the basis for the Pennsylvania Supreme Court’s ruling on this point is unclear, it apparently concluded that the right of compulsory process includes the right to have the State’s assistance in uncovering arguably useful information, without regard to the existence of a state-created restriction — here, the confidentiality of the files.
  1
  This Court has had little occasion to discuss the contours of the Compulsory Process Clause. The first and most celebrated analysis came from a Virginia federal court in 1807, during the treason and misdemeanor trials of Aaron Burr. Chief Justice Marshall, who presided as trial judge, ruled that Burr’s compulsory process rights entitled him to serve a subpoena on President Jefferson, requesting the production of allegedly incriminating evidence. United States v. Burr, 25 F. Cas. 30, 35 (No. 14,692d) (CC Va. 1807). Despite the implications of the Burr decision for federal criminal procedure, the Compulsory Process Clause rarely was a factor in this Court’s decisions during the next 160 years. More recently, however, the Court has articulated some of the specific rights secured by this part of the Sixth Amendment. Our cases establish, at a minimum, that criminal defendants have the right to the government’s assistance in compelling the attendance of favorable witnesses at trial and the right to put before a jury evidence that might influence the determination of guilt.
  This Court has never squarely held that the Compulsory Process Clause guarantees the right to discover the identity of witnesses, or to require the government to produce exculpatory evidence. But cf. United States v. Nixon, 418 U. S. 683, 709, 711 (1974) (suggesting that the Clause may require the production of evidence). Instead, the Court traditionally has evaluated claims such as those raised by Ritchie under the broader protections of the Due Process Clause of the Fourteenth Amendment. See United States v. Bagley, 473 U. S. 667 (1985); Brady v. Maryland, 373 U. S. 83 (1963). See also Wardius v. Oregon, 412 U. S. 470 (1973). Because the applicability of the Sixth Amendment to this type of case is unsettled, and because our Fourteenth Amendment precedents addressing the fundamental fairness of trials establish a clear framework for review, we adopt a due process analysis for purposes of this case. Although we conclude that compulsory process provides no greater protections in this area than those afforded by due process, we need not decide today whether and how the guarantees of the Compulsory Process Clause differ from those of the Fourteenth Amendment. It is enough to conclude that on these facts, Ritchie’s claims more properly are considered by reference to due process.
  2
  It is well settled that the government has the-obligation to turn over evidence in its possession that is both favorable to the accused and material to guilt or punishment. United States v. Agurs, 427 U. S. 97 (1976); Brady v. Maryland, supra, at 87. Although courts have used different terminologies to define “materiality,” a majority of this Court has agreed, “[ejvidence is material only if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different. A ‘reasonable probability’ is a probability sufficient to undermine confidence in the outcome.” United States v. Bagley, 473 U. S., at 682 (opinion of Blackmun, J.); see id., at 685 (opinion of White, J.).
  At this stage, of course, it is impossible to say whether any information in the CYS records may be relevant to Ritchie’s claim of innocence, because neither the prosecution nor defense counsel has seen the information, and the trial judge acknowledged that he had not reviewed the full file. The Commonwealth, however, argues that no materiality inquiry is required, because a statute renders the contents of the file privileged. Requiring disclosure here, it is argued, would override the Commonwealth’s compelling interest in confidentiality on the mere speculation that the file “might” have been useful to the defense.
  Although we recognize that the public interest in protecting this type of sensitive information is strong, we do not agree that this interest necessarily prevents disclosure in all circumstances. This is not a case where a state statute grants CYS the absolute authority to shield its files from all eyes. Cf. 42 Pa. Cons. Stat. §5945.1(b) (1982) (unqualified statutory privilege for communications between sexual assault counselors and victims). Rather, the Pennsylvania law provides that the information shall be disclosed in certain circumstances, including when CYS is directed to do so by court order. Pa. Stat. Ann., Title 11, §2215(a)(5) (Purdon Supp. 1986). Given that the Pennsylvania Legislature contemplated some use of CYS records in judicial proceedings, we cannot conclude that the statute prevents all disclosure in criminal prosecutions. In the absence of any apparent state policy to the contrary, we therefore have no reason to believe that relevant information would not be disclosed when a court of competent jurisdiction determines that the information is “material” to the defense of the accused.
  We therefore affirm the decision of the Pennsylvania Supreme Court to the extent it orders a remand for further proceedings. Ritchie is entitled to have the CYS file reviewed by the trial court to determine whether it contains information that probably would have changed the outcome of his trial. If it does, he must be given a new trial. If the records maintained by CYS contain no such information, or if the nondisclosure was harmless beyond a reasonable doubt, the lower court will be free to reinstate the prior conviction.
  c
  This ruling does not end our analysis, because the Pennsylvania Supreme Court did more than simply remand. It also held that defense counsel must be allowed to examine all of the confidential information, both relevant and irrelevant, and present arguments in favor of disclosure. The court apparently concluded that whenever a defendant alleges that protected evidence might be material, the appropriate method of assessing this claim is to grant full access to the disputed information, regardless of the State’s interest in confidentiality. We cannot agree.
  A defendant’s right to discover exculpatory evidence does not include the unsupervised authority to search through the Commonwealth’s files. See United States v. Bagley, supra, at 675; United States v. Agurs, supra, at 111. Although the eye of an advocate may be helpful to a defendant in ferreting out information, Dennis v. United States, 384 U. S. 855, 875 (1966), this Court has never held — even in the absence of a statute restricting disclosure — that a defendant alone may make the determination as to the materiality of the information. Settled practice is to the contrary. In the typical case where a defendant makes only a general request for exculpatory material under Brady v. Maryland, 373 U. S. 83 (1963), it is the State that decides which information must be disclosed. Unless defense counsel becomes aware that other exculpatory evidence was withheld and brings it to the court’s attention, the prosecutor’s decision on disclosure is final. Defense counsel has no constitutional right to conduct his own search of the State’s files to argue relevance. See Weatherford v. Bursey, 429 U. S. 545, 559 (1977) (“There is no general constitutional right to discovery in a criminal case, and Brady did not create one”).
  We find that Ritchie’s interest (as well as that of the Commonwealth) in ensuring a fair trial can be protected fully by requiring that the CYS files be submitted only to the trial court for in camera review. Although this rule denies Ritchie the benefits of an “advocate’s eye,” we note that the trial court’s discretion is not unbounded. If a defendant is aware of specific information contained in the file (e. g., the medical report), he is free to request it directly from the court, and argue in favor of its materiality. Moreover, the duty to disclose is ongoing; information that may be deemed immaterial upon original examination may become important as the proceedings progress, and the court would be obligated to release information material to the fairness of the trial.
  To allow full disclosure to defense counsel in this type of case would sacrifice unnecessarily the Commonwealth’s compelling interest in protecting its child-abuse information. If the CYS records were made available to defendants, even through counsel, it could have a seriously adverse effect on Pennsylvania’s efforts to uncover and treat abuse. Child abuse is one of the most difficult crimes to detect and prosecute, in large part because there often are no witnesses except the victim. A child’s feelings of vulnerability and guilt and his or her unwillingness to come forward are particularly acute when the abuser is a parent. It therefore is essential that the child have a state-designated person to whom he may turn, and to do so with the assurance of confidentiality. Relatives and neighbors who suspect abuse also will be more willing to come forward if they know that their identities will be protected. Recognizing this, the Commonwealth — like all other States — has made a commendable effort to assure victims and witnesses that they may speak to the CYS counselors without fear of general disclosure. The Commonwealth’s purpose would be frustrated if this confidential material had to be disclosed upon demand to a defendant charged with criminal child abuse, simply because a trial court may not recognize exculpatory evidence. Neither precedent nor common sense requires such a result.
  > I — I
  We agree that Ritchie is entitled to know whether the CYS file contains information that may have changed the outcome of his trial had it been disclosed. Thus we agree that a remand is necessary. We disagree with the decision of the Pennsylvania Supreme Court to the extent that it allows defense counsel access to the CYS file. An in camera review by the trial court will serve Ritchie’s interest without destroying the Commonwealth’s need to protect the confidentiality of those involved in child-abuse investigations. The judgment of the Pennsylvania Supreme Court is affirmed in part and reversed in part, and the case is remanded for further proceedings not inconsistent with this opinion.
  It is so ordered.
  Although the 1978 investigation took place during the period that the daughter claimed she was being molested, it is undisputed that the daughter did not tell CYS about the assaults at that time. No criminal charges were filed as a result of this earlier investigation.
  The statute provides in part:
  “(a) Except as provided in section 14 [Pa. Stat. Ann., Tit. 11, §2214 (Purdon Supp. 1986)], reports made pursuant to this act including but not limited to report summaries of child abuse . . . and written reports ... as well as any other information obtained, reports written or photographs or X-rays taken concerning alleged instances of child abuse in the possession of the department, a county children and youth social service agency or a child protective service shall be confidential and shall only be made available to:
  “(5) A court of competent jurisdiction pursuant to a court order.” Pa. Stat. Ann., Tit. 11, § 2215(a) (Purdon Supp. 1986).
  At the time of trial the statute only provided five exceptions to the general rule of confidentiality, including the exception for court-ordered disclosure. The statute was amended in 1982 to increase the number of exceptions. For example, the records now may be revealed to law enforcement officials for use in criminal investigations. § 2215(a)(9). But, the identity of a person who reported the abuse or who cooperated in the investigation may not be released if the disclosure would be detrimental to that person’s safety. § 2215(c).
  The trial judge stated that he did not read “50 pages or more of an extensive record.” App. 72a. The judge had no knowledge of the case before the pretrial hearing. See id,., at 68a.
  There is no suggestion that the Commonwealth’s prosecutor was given access to the file at any point in the proceedings, or that he was aware of its contents.
  The Sixth Amendment of the United States Constitution protects both the right of confrontation and the right of compulsory process:
  “In all criminal prosecutions, the accused shall enjoy the right... to be confronted with the witnesses against him; [and] to have compulsory process for obtaining witnesses in his favor.”
  Both Clauses are made obligatory on the States by the Fourteenth Amendment. Pointer v. Texas, 380 U. S. 400, 403-406 (1965) (Confrontation Clause); Washington v. Texas, 388 U. S. 14, 17-19 (1967) (Compulsory Process Clause).
  The court noted that the trial court should take “appropriate steps” to guard against improper dissemination of the confidential material, including, for example, “fashioning of appropriate protective orders, or conducting certain proceedings in camera.” 509 Pa., at 368, n. 16, 502 A. 2d, at 153, n. 16. These steps were to be taken, however, subject to “the right of [Ritchie], through his counsel, to gain access to the information.” Ibid.
  As Justice Stevens’ dissent points out, post, at 74, there is a third possibility. If the trial court finds prejudicial error and orders a retrial, the Commonwealth may attempt to take an immediate appeal of this order. See Pa. Rule App. Proe. 311(a). Justice Stevens’ dissent suggests that because the Commonwealth can raise the Sixth Amendment issue again in this appeal, respect for the finality doctrine should lead us to dismiss. But even if we were persuaded that an immediate appeal would lie in this situation, it would not necessarily follow that the constitutional issue will survive. The appellate court could find that the failure to disclose was harmless, precluding further review by the Commonwealth. Alternatively, the appellate court could agree that the error was prejudicial, thus permitting the Commonwealth to claim that the Sixth Amendment does not compel disclosure. But as Justice Stevens’ dissent recognizes, the Pennsylvania courts already have considered and resolved this issue in their earlier proceedings; if the Commonwealth were to raise it again in a new set of appeals, the courts below would simply reject the claim under the law-of-the-case doctrine. Law-of-the-case principles are not a bar to this Court’s jurisdiction, of course, and thus Justice Stevens’ dissent apparently would require the Commonwealth to raise a fruitless Sixth Amendment claim in the trial court, the Superior Court, and the Pennsylvania Supreme Court still another time before we regrant certiorari on the question that is now before us.
  The goals of finality would be frustrated, rather than furthered, by these wasteful and time-consuming procedures. Based on the unusual facts of this ease, the justifications for the finality doctrine — efficiency, judicial restraint, and federalism, see Radio Station WOW, Inc. v. Johnson, 326 U. S. 120, 124 (1945); post, at 72 — would be ill served by another round of litigation on an issue that has been authoritatively decided by the highest state court.
  Nothing in our decision in United States v. Ryan, 402 U. S. 530 (1971), requires a different result. In that case the respondent was served with a subpoena requiring him to produce business records for a grand jury. The District Court denied a motion to quash, and respondent appealed. We concluded that the District Court order was not appealable. Id., at 532. We rejected the contention that immediate review was necessary to avoid the harm of disclosing otherwise protected material, noting that parties who face such an order have the option of making the decision “final” simply by refusing to comply with the subpoena.
  Although there are similarities between this case and Ryan, the analogy is incomplete. In Ryan the Court was concerned about the “necessity for expedition in the administration of the criminal law,” id., at 533, an interest that would be undermined if all pretrial orders were immediately ap-pealable. Ryan also rests on an implicit assumption that unless a party resisting discovery is willing to risk being held in contempt, the significance of his claim is insufficient to justify interrupting the ongoing proceedings. That is not the situation before us. Here the trial already has taken place, and the issue reviewed by the Commonwealth appellate courts. The interests of judicial economy and the avoidance of delay, rather than being hindered, would be best served by resolving the issue. Cf. Cox Broadcasting Corp. v. Cohn, 420 U. S., 469, 477-478 (1975) (exceptions to finality doctrine justified in part by need to avoid economic waste and judicial delay).
  We also reject Ritchie’s suggestion that we should dismiss this action and allow the ease to return to the trial court, so that the Commonwealth can formally refuse to comply with the Pennsylvania Supreme Court decision and be held in contempt. Here we are not faced merely with an individual’s assertion that a subpoena is unduly burdensome, but with a holding of a State Supreme Court that the legislative interest in confidentiality will not be given effect. The Commonwealth’s interest in immediate review of this case is obvious and substantial. Contrary to Justice Stevens’ dissent, we do not think that the finality doctrine requires a new round of litigation and appellate review simply to give the Commonwealth “the chance to decide whether to comply with the order.” Post, at 77. See n. 7, supra. To prolong the proceedings on this basis would be inconsistent with the “pragmatic” approach we normally have taken to finality questions. See generally Bradley v. Richmond School Bd., 416 U. S. 696, 722-723, n. 28 (1974) (“This Court has been inclined to follow a ‘pragmatic approach’ to the question of finality”) (citation omitted).
  This is not to suggest, of course, that there are no protections for pretrial discovery in criminal cases. See discussion in Part IH-B, infra. We simply hold that with respect to this issue, the Confrontation Clause only protects a defendant’s trial rights, and does not compel the pretrial production of information that might be useful in preparing for trial. Also, we hardly need say that nothing in our opinion today is intended to alter a trial judge’s traditional power to control the scope of cross-examination by prohibiting questions that are prejudicial, irrelevant, or otherwise improper. See Delaware v. Van Arsdall, 475 U. S. 673, 678 (1986).
  “See, e. g., Delaware v. Van Arsdall, supra (denial of right to cross-examine to show bias); Davis v. Alaska, 415 U. S. 308 (1974); Chambers v. Mississippi, 410 U. S. 284 (1973) (denial of right to impeach own witness); Smith v. Illinois, 390 U. S. 129 (1968) (denial of right to ask witness’ real name and address at trial); Douglas v. Alabama, 380 U. S. 415 (1965) (denial of right to cross-examine codefendant). Moreover, the Court normally has refused to find a Sixth Amendment violation when the asserted interference with cross-examination did not occur at trial. Compare McCray v. Illinois, 386 U. S. 300, 311-313 (1967) (no Confrontation Clause violation where defendant was denied the chance to discover an informant’s name at pretrial hearing), with Roviaro v. United States, 353 U. S. 53 (1957) (on the facts presented, Government required to disclose informant’s name at trial). See generally Westen, The Compulsory Process Clause, 73 Mich. L. Rev. 71,125-126 (1974) (“The right of confrontation is exclusively a ‘trial right’ .... It does not . . . require the government to produce witnesses whose statements are not used at trial, or to produce the underlying information on which its witnesses base their testimony”) (footnotes omitted) (hereinafter Westen).
  The evidence consisted of a letter that was sent to President Jefferson by General James Wilkinson that allegedly showed that Burr was planning to invade Mexico and set up a separate government under his control. After being ordered to do so, Jefferson eventually turned over an edited version of the letter. For an excellent summary of the Burr case and its implications for compulsory process, see Westen 101-108.
  The pre-1967 eases that mention compulsory process do not provide an extensive analysis of the Clause. See Pate v. Robinson, 383 U. S. 375, 378, n. 1 (1966); Blackmer v. United States, 284 U. S. 421, 442 (1932); United States v. Van Duzee, 140 U. S. 169, 173 (1891); Ex parte Harding, 120 U. S. 782 (1887). See generally Westen 108, and n. 164.
  See, e. g., Chambers v. Mississippi, supra; Cool v. United States, 409 U. S. 100 (1972) (per curiam); Washington v. Texas, 388 U. S. 14 (1967). Cf. Webb v. Texas, 409 U. S. 95 (1972) (per curiam) (decision based on Due Process Clause).
  We express no opinion on whether the result in this case would have been different if the statute had protected the CYS files from disclosure to anyone, including law-enforcement and judicial personnel.
  The Commonwealth also argues that Ritchie is not entitled to disclosure because he did not make a particularized showing of what information he was seeking or how it would be material. See Brief for Petitioner 18 (quoting United States v. Agurs, 427 U. S. 97, 109-110 (1976) (“The mere possibility that an item of undisclosed information might have helped the defense . . . does not establish ‘materiality’ in the constitutional sense”)). Ritchie, of course, may not require the trial court to search through the CYS file without first establishing a basis for his claim that it contains material evidence. See United States v. Valenzuela-Bernal, 458 U. S. 858, 867 (1982) (“He must at least make some plausible showing of how their testimony would have been both material and favorable to his defense”). Although the obligation to disclose exculpatory material does not depend on the presence of a specific request, we note that the degree of specificity of Ritchie’s request may have a bearing on the trial court’s assessment on remand of the materiality of the nondisclosure. See United States v. Bagley, 473 U. S. 667, 682-683 (1985) (opinion of Blackmun, J.).
  See Fed. Rule Crim. Proe. 16(d)(2); Pa. Rule Crim. Proe. 305(E) (“If at any time during the course of the proceedings it is brought to the attention of the court that a party has failed to comply with this rule [mandating disclosure of exculpatory evidence], the court may... enter such... order as it deems just under the circumstances”).
  The importance of the public interest at issue in this case is evidenced by the fact that all 50 States and the District of Columbia have statutes that protect the confidentiality of their official records concerning child abuse. See Brief for State of California ex reí. John K. Van de Kamp et al. as Amici Curiae 12, n. 1 (listing illustrative statutes). See also Besharov, The Legal Aspects of Reporting Known and Suspected Child Abuse and Neglect, 23 Vill. L. Rev. 458, 508-512 (1978).