Justice Rehnquist
delivered the opinion of the Court.
Respondent Aaron Helms was serving a term in the State Correctional Institution at Huntingdon, Pa. (SCIH), which was administered by petitioners. He sued in the United States District Court for the Middle District of Pennsylvania, claiming that petitioners’ actions confining him to administrative segregation within the prison violated his rights under the Due Process Clause of the Fourteenth Amendment to the United States Constitution. The District Court granted petitioners’ motion for summary judgment, but the Court of Appeals for the Third Circuit reversed. 655 F. 2d 487 (1981). We granted certiorari, 455 U. S. 999 (1982), to consider what limits the Due Process Clause of the Fourteenth Amendment places on the authority of prison administrators to remove inmates from the general prison population and confine them to a less desirable regimen for administrative reasons.
In the early evening of December 3, 1978, a prisoner in the state penitentiary at Huntingdon, assaulted two guards. The prisoner was subdued with the assistance of other guards, but one guard received a broken nose, and another a broken thumb. Later in the evening, the violence erupted into a riot during which a group of prisoners attempted to seize the institution’s “control center.” One group of inmates attacked a prison guard and a trainee, using table legs, the guard’s flashlight, barbells, and whatever else came to hand. On another floor, three inmates were subdued while trying to attack a sergeant of the prison guard with a flashlight, and it was necessary to forcibly subdue them and handcuff them to pipes. Inmates in one of the prison blocks tried to break a grille to enter the prison’s control center, but they were held back. One of the assaulted guards suffered cuts and bruises on the face and leg areas, and another reported a possible skull fracture, broken jaw, broken teeth, and an injured collarbone.
This uprising was eventually quelled, but only with the assistance of state police units, local law enforcement officers, and off-duty prison guards whose aid was summoned. Several hours after the riot ended, respondent Helms was removed from his cell and the general prison population for questioning by the state police. Following the interview, he was placed in restrictive confinement, and the state police and prison authorities began an investigation into his role in the riot.
On December 4, 1978, Helms was given a “Misconduct Report” charging him with “Assaulting Officers and Conspiracy to Disrupt Normal Institution Routine by Forcefully Taking Over the Control Center.” The report briefly described the factual basis for the charge and contained a lengthy recitation of the procedures governing the institution’s disciplinary hearing. On December 8, 1978, a “Hearing Committee,” consisting of three prison officials charged with adjudicating alleged instances of misconduct by inmates, was convened to dispose of the charges against Helms. Following a review of the misconduct report, the panel summarized its decision as “[n]o finding as to guilt reached at this time, due to insufficient information,” and ordered that Helms’ confinement in restricted housing be continued.
While as a matter of probabilities it seems likely that Helms appeared personally before the December 8 Hearing Committee, we agree with the Court of Appeals that the record does not allow definitive resolution of the issue on summary judgment. Helms signed a copy of the misconduct report stating that “[t]he circumstance of the charge has been read and fully explained to me,” and that “I have had the opportunity to have my version reported as part of the record.” App. 41a. Likewise, he admitted in an affidavit filed during this litigation that he was “informed by an institutional hearing committee” of the disposition of the misconduct charge against him. Id., at 33a. The same affidavit, however, asserted that no “hearing” was conducted on December 8, suggesting that respondent did not appear before the Committee. The State did not file any affidavit controverting Helms’ contention.
On December 11, 1978, the Commonwealth of Pennsylvania filed state criminal charges against Helms, charging him with assaulting Correction Officer Rhodes and with riot. On January 2, 1979, SCIH’s Program Review Committee, which consisted of three prison officials, was convened. The Committee met to review the status of respondent’s confinement in administrative segregation and to make recommendations as to his future confinement. The Committee unanimously concluded that Helms should remain in administrative segregation; affidavits of the Committee members said that the decision was based on several related concerns. Helms was seen as “a danger to staff and to other inmates if released back into general population,” id., at 11a; he was to be arraigned the following day on state criminal charges, id., at 24a; and the Committee was awaiting information regarding his role in the riot, id., at 16a. The Superintendent of SCIH personally reviewed the Program Review Committee’s determination and concurred in its recommendation. Id., at 15a, 18a.
The preliminary hearing on the state criminal charges against Helms was postponed on January 10, 1979, apparently due to a lack of evidence. On January 19, 1979, a second misconduct report was given to respondent; the report charged Helms with assaulting a second officer during the December 3 riot. On January 22 a Hearing Committee composed of three prison officials heard testimony from one guard and Helms. Based on this, the Committee found Helms guilty of the second misconduct charge and ordered that he be confined to disciplinary segregation for six months, effective December 3, 1978. The Committee also decided to drop the earlier misconduct charge against respondent, without determining guilt. On February 6, 1979, the State dropped criminal charges relating to the prison riot against Helms.
The Court of Appeals, reviewing these facts, concluded that Helms had a protected liberty interest in continuing to reside in the general prison population. While the court seemed to doubt that this interest could be found in the Constitution, it held that Pennsylvania regulations governing the administration of state prisons created such an interest. It then said that Helms could not be deprived of this interest without a hearing, governed by the procedures mandated in Wolff v. McDonnell, 418 U. S. 539 (1974), to determine whether such confinement was proper. Being uncertain whether the hearing conducted on December 8 satisfied the Wolff requirements, see supra, at 464-465, the Court of Appeals remanded the case to the District Court for an eviden-tiary hearing regarding the character of that proceeding. On these same facts, we agree with the Court of Appeals that the Pennsylvania statutory framework governing the administration of state prisons gave rise to a liberty interest in respondent, but we conclude that the procedures afforded respondent were “due process” under the Fourteenth Amendment.
While no State may “deprive any person of life, liberty, or property, without due process of law,” it is well settled that only a limited range of interests fall within this provision. Liberty interests protected by the Fourteenth Amendment may arise from two sources — the Due Process Clause itself and the laws of the States. Meachum v. Fano, 427 U. S. 215, 223-227 (1976). Respondent argues, rather weakly, that the Due Process Clause implicitly creates an interest in being confined to a general population cell, rather than the more austere and restrictive administrative segregation quarters. While there is little question on the record before us that respondent’s confinement added to the restraints on his freedom, we think his argument seeks to draw from the Due Process Clause more than it can provide.
We have repeatedly said both that prison officials have broad administrative and discretionary authority over the institutions they manage and that lawfully incarcerated persons retain only a narrow range of protected liberty interests. As to the first point, we have recognized that broad discretionary authority is necessary because the administration of a prison is “at best an extraordinarily difficult undertaking,” Wolff v. McDonnell, supra, at 566, and have concluded that “to hold . . . that any substantial deprivation imposed by prison authorities triggers the procedural protections of the Due Process Clause would subject to judicial review a wide spectrum of discretionary actions that traditionally have been the business of prison administrators rather than of the federal courts.” Meachum v. Fano, supra, at 225. As to the second point, our decisions have consistently refused to recognize more than the most basic liberty interests in prisoners. “Lawful incarceration brings about the necessary withdrawal or limitation of many privileges and rights, a retraction justified by the considerations underlying our penal system.” Price v. Johnston, 334 U. S. 266, 285 (1948). Thus, there is no “constitutional or inherent right” to parole, Greenholtz v. Nebraska Penal Inmates, 442 U. S. 1, 7 (1979), and “the Constitution itself does not guarantee good-time credit for satisfactory behavior while in prison,” Wolff v. McDonnell, supra, at 557, despite the undoubted impact of such credits on the freedom of inmates. Finally, in Meachum v. Fano, supra, at 225, the transfer of a prisoner from one institution to another was found unprotected by “the Due Process Clause in and of itself,” even though the change of facilities involved a significant modification in conditions of confinement, later characterized by the Court as a “grievous loss.” Moody v. Daggett, 429 U. S. 78, 88, n. 9 (1976). As we have held previously, these decisions require that “[a]s long as the conditions or degree of confinement to which the prisoner is subjected is within the sentence imposed upon him and is not otherwise violative of the Constitution, the Due Process Clause does not in itself subject an inmate’s treatment by prison authorities to judicial oversight.” Montanye v. Haymes, 427 U. S. 236, 242 (1976). See also Vitek v. Jones, 445 U. S. 480, 493 (1980).
It is plain that the transfer of an inmate to less amenable and more restrictive quarters for nonpunitive reasons is well within the terms of confinement ordinarily contemplated by a prison sentence. The phrase “administrative segregation,” as used by the state authorities here, appears to be something of a catchall: it may be used to protect the prisoner’s safety, to protect other inmates from a particular prisoner, to break up potentially disruptive groups of inmates, or simply to await later classification or transfer. See 37 Pa. Code §§95.104 and 95.106 (1978), and n. 1, supra. Accordingly, administrative segregation is the sort of confinement that inmates should reasonably anticipate receiving at some point in their incarceration. This conclusion finds ample support in our decisions regarding parole and good-time credits. Both these subjects involve release from institutional life altogether, which is a far more significant change in a prisoner’s freedoms than that at issue here, yet in Greenholtz and Wolff we held that neither situation involved an interest independently protected by the Due Process Clause. These decisions compel an identical result here.
Despite this, respondent points out that the Court has held that a State may create a liberty interest protected by the Due Process Clause through its enactment of certain statutory or regulatory measures. Thus, in Wolff, where we rejected any notion of an interest in good-time credits inherent in the Constitution, we also found that Nebraska had created a right to such credits. 418 U. S., at 556-557. See also Greenholtz v. Nebraska Penal Inmates, supra (parole); Vitek v. Jones, supra (transfer to mental institution). Likewise, and more relevant here, was our summary affirmance in Wright v. Enomoto, 462 F. Supp. 397 (ND Cal. 1976), summarily aff’d, 434 U. S. 1052 (1978), where the District Court had concluded that state law created a liberty interest in confinement to any sort of segregated housing within a prison. Hughes v. Rowe, 449 U. S. 5 (1980) (per curiam), while involving facts similar to these in some respects, was essentially a pleading case rather than an exposition of the substantive constitutional issues involved.
Respondent argues that Pennsylvania, in its enactment of regulations governing the administration of state prisons, has created a liberty interest in remaining free from the restraints accompanying confinement in administrative segregation. Except to the extent that our summary affirmance in Wright v. Enomoto, supra, may be to the contrary, we have never held that statutes and regulations governing daily operation of a prison system conferred any liberty interest in and of themselves. Meachum v. Fano, 427 U. S. 215 (1976), and Montanye v. Haymes, supra, held to the contrary; in Wolff, supra, we were dealing with good-time credits which would have actually reduced the period of time which the inmate would have been in the custody of the government; in Greenholtz, supra, we dealt with parole, which would likewise have radically transformed the nature of the custody to which the inmate was subject; and in Vitek, supra, we considered the transfer .from a prison to a mental institution.
There are persuasive reasons why we should be loath to transpose all of the reasoning in the cases just cited to the situation where the statute and regulations govern the day-to-day administration of a prison system. The deprivations imposed in the course of the daily operations of an institution are likely to be minor when compared to the release from custody at issue in parole decisions and good-time credits. Moreover, the safe and efficient operation of a prison on a day-to-day basis has traditionally been entrusted to the expertise of prison officials, see Meachum v. Fano, supra, at 225. These facts suggest that regulations structuring the authority of prison administrators may warrant treatment, for purposes of creation of entitlements to “liberty,” different from statutes and regulations in other areas. Nonetheless, we conclude in the light of the Pennsylvania statutes and regulations here in question, the relevant provisions of which are set forth in full in the margin, that respondent did acquire a protected liberty interest in remaining in the general prison population.
Respondent seems to suggest that the mere fact that Pennsylvania has created a careful procedural structure to regulate the use of administrative segregation indicates the existence of a protected liberty interest. We cannot agree. The creation of procedural guidelines to channel the decision-making of prison officials is, in the view of many experts in the field, a salutary development. It would be ironic to hold that when a State embarks on such desirable experimentation it thereby opens the door to scrutiny by the federal courts, while States that choose not to adopt such procedural provisions entirely avoid the strictures of the Due Process Clause. The adoption of such procedural guidelines, without more, suggests that it is these restrictions alone, and not those federal courts might also impose under the Fourteenth Amendment, that the State chose to require.
Nonetheless, in this case the Commonwealth has gone beyond simple procedural guidelines. It has used language of an unmistakably mandatory character, requiring that certain procedures “shall,” “will,” or “must” be employed, see n. 6, supra, and that administrative segregation will not occur absent specified substantive predicates — viz., "the need for control,” or “the threat of a serious disturbance.” Petitioners argue, with considerable force, that these terms must be read in light of the fact that the decision whether to confine an inmate to administrative segregation is largely predictive, and therefore that it is not likely that the State meant to create binding requirements. But on balance we are persuaded that the repeated use of explicitly mandatory language in connection with requiring specific substantive predicates demands a conclusion that the State has created a protected liberty interest.
That being the case, we must then decide whether the process afforded respondent satisfied the minimum requirements of the Due Process Clause. We think that it did. The requirements imposed by the Clause are, of course, flexible and variable dependent upon the particular situation being examined. E. g., Greenholtz v. Nebraska Penal Inmates, 442 U. S., at 12; Morrissey v. Brewer, 408 U. S. 471, 481 (1972). In determining what is “due process” in the prison context, we are reminded that “one cannot automatically apply procedural rules designed for free citizens in an open society ... to the very different situation presented by a disciplinary proceeding in a state prison.” Wolff v. McDonnell, 418 U. S., at 560. “Prison administrators . . . should be accorded wide-ranging deference in the adoption and execution of policies and practices that in their judgment are needed to preserve internal order and discipline and to maintain institutional security.” Bell v. Wolfish, 441 U. S. 520, 547 (1979). These considerations convince us that petitioners were obligated to engage only in an informal, non-adversary review of the information supporting respondent’s administrative confinement, including whatever statement respondent wished to submit, within a reasonable time after confining him to administrative segregation.
. Under Mathews v. Eldridge, 424 U. S. 319, 335 (1976), we: consider the private interests at stake in a governmental decision, the governmental interests involved, and the value of procedural requirements in determining what process is due under the Fourteenth Amendment. Respondent’s private interest is not one of great consequence. He was merely transferred from one extremely restricted environment to an even more confined situation. Unlike disciplinary confinement the stigma of wrongdoing or misconduct does not attach to administrative segregation under Pennsylvania’s prison regulations. Finally, there is no indication that administrative segregation will have any significant effect on parole opportunities.
Petitioners had two closely related reasons for confining Helms to administrative segregation prior to conducting a hearing on the disciplinary charges against him. First, they concluded that if housed in the general population, Helms would pose a threat to the safety of other inmates and prison officials and to the security of the institution. Second, the prison officials believed that it was wiser to separate respondent from the general population until completion of state and institutional investigations of his role in the December 3 riot and the hearing on the charges against him. Plainly, these governmental interests are of great importance. The safety of the institution’s guards and inmates is perhaps the most fundamental responsibility of the prison administration. See Bell v. Wolfish, supra, at 547; Jones v. North Carolina Prisoners’ Labor Union, 433 U. S. 119, 132 (1977); Pell v. Procunier, 417 U. S. 817, 823 (1974); Procunier v. Martinez, 416 U. S. 396, 404 (1974). Likewise, the isolation of a prisoner pending investigation of misconduct charges against him serves important institutional interests relating to the insulating of possible witnesses from coercion or harm, see infra, at 476.
Neither of these grounds for confining Helms to administrative segregation involved decisions or judgments that would have been materially assisted by a detailed adversary proceeding. As we said in Rhodes v. Chapman, 452 U. S. 337, 349, n. 14 (1981), “a prison’s internal security is peculiarly a matter normally left to the discretion of prison administrators.” In assessing the seriousness of a threat to institutional security, prison administrators necessarily draw on more than the specific facts surrounding a particular incident; instead, they must consider the character of the inmates confined in the institution, recent and longstanding relations between prisoners and guards, prisoners inter se, and the like. In the volatile atmosphere of a prison, an inmate, easily may constitute an unacceptable threat to the safety of other prisoners and guards even if he himself has committed no misconduct; rumor, reputation, and even more imponderable factors may suffice to spark potentially disastrous incidents. The judgment of prison officials in this context, like that of those making parole decisions, turns largely on “purely subjective evaluations and on predictions of future behavior,” Connecticut Board of Pardons v. Dumschat, 452 U. S. 458, 464 (1981); indeed, the administrators must predict not just one inmate’s future actions, as in parole, but those of an entire institution. Owing to the central role of these types of intuitive judgments, a decision that an inmate or group of inmates represents a threat to the institution’s security would not be appreciably fostered by the trial-type procedural safeguards suggested by respondent. This, and the balance of public and private interests, lead us to conclude that the Due Process Clause requires only an informal nonadversary review of evidence, discussed more fully below, in order to confine an inmate feared to be a threat to institutional security to administrative segregation.
Likewise, confining respondent to administrative segregation pending completion of the investigation of the disciplinary charges against him is not based on an inquiry requiring any elaborate procedural safeguards. We think the closest case in point dealing with an analogous situation in the world outside of prisons is Gerstein v. Pugh, 420 U. S. 103 (1975). There, in the context of a challenge to the pretrial detainment of persons suspected of criminal acts, we held that States must “provide a fair and reliable determination of probable cause as a condition for any significant pretrial restraint of liberty,” and we required that “this determination must be made by a judicial officer either before or promptly after arrest.” Id., at 125. We explicitly rejected the suggestion, however, that an adversary proceeding, accompanied by traditional trial-type rights, was required, and instead permitted an informal proceeding designed to determine whether probable cause existed to believe that the detained person had committed a crime. Id., at 119-123.
While Gerstein was grounded in the Fourth Amendment, we think it provides a useful point of departure with respect to the due process question raised here. Mathews v. Eldridge, supra, at 335, again suggests the points at which Gerstein is inapposite in the prison context. As our discussion above suggests, the private interest at stake here is far less weighty than that at issue in Gerstein, which involved removing a suspect from unrestricted liberty in open society and placing him in an institution. In contrast, as noted above, Helms was merely transferred from an extremely restricted environment to an even more confined situation. Under the Mathews formula, respondent has a far less compelling claim to procedural safeguards than did the pretrial detainees in Gerstein. Likewise, weighty governmental interests are at stake. To be sure, Gerstein involved a situation in which a real possibility existed that the suspected criminal would flee from justice; it is unlikely, to say the least, that confinement to administrative segregation is necessary for this purpose where an inmate has been charged with misconduct. Yet the State has other important interests. For example, it must protect possible witnesses— whose confinement leaves them particularly vulnerable — from retribution by the suspected wrongdoer, and, in addition, has an interest in preventing attempts to persuade such witnesses not to testify at disciplinary hearings. These considerations lead us to conclude that while general patterns of the Gerstein procedures should be our guide, some of the elements required in that case are unnecessary in the much more informal context of prison officials who propose to confine an inmate to administrative segregation pending completion of an investigation against him.
We think an informal, nonadversary evidentiary review is sufficient both for the decision that an inmate represents a security threat and the decision to confine an inmate to administrative segregation pending completion of an investigation into misconduct charges against him. An inmate must merely receive some notice of the charges against him and an opportunity to present his views to the prison official charged with deciding whether to transfer him to administrative segregation. Ordinarily a written statement by the inmate will accomplish this purpose, although prison administrators may find it more useful to permit oral presentations in cases where they believe a written statement would be ineffective. So long as this occurs, and the decisionmaker reviews the charges and then-available evidence against the prisoner, the Due Process Clause is satisfied. This informal procedure permits a reasonably accurate assessment of probable cause to believe that misconduct occurred, and the “value [of additional ‘formalities and safeguards’] would be too slight to justify holding, as a matter of constitutional principle” that they must be adopted, Gerstein v. Pugh, supra, at 122.
Measured against these standards we are satisfied that respondent received all the process that was due after being confined to administrative segregation. He received notice of the charges against him the day after his misconduct took place. Only five days after his transfer to administrative segregation a Hearing Committee reviewed the existing evidence against him, including a staff member’s statement that “[t]his inmate was a member of an organized plot and did actively involve himself with at least 10 other inmates in the assault upon 5 corrections officers in ‘C’ Block and attempted to break thru the ‘C’ grill to the Control Center to disrupt the normal institution routine by usurping the authority of institution officials.” App. 38a. While the Court of Appeals may have been correct that the record does not clearly demonstrate that a Wolff hearing was held, it does show that he had an opportunity to present a statement to the Committee. As noted previously, Helms acknowledged on the misconduct form that he “had the opportunity to have [his] version reported as part of the record”; we see no reason to question the accuracy of his statement. This proceeding plainly satisfied the due process requirements for continued confinement of Helms pending the outcome of the investigation.
Accordingly, the judgment of the Court of Appeals is reversed.
It is so ordered.
Pennsylvania has adopted regulations promulgated by the State Bureau of Corrections establishing two basic types of restricted housing in its correctional facilities — disciplinary and administrative segregation. 37 Pa. Code §95.107 (1978). Other jurisdictions follow a similar pattern. See 28 CFR pt. 541 (1982). Confinement in disciplinary segregation is imposed when an inmate has been found to have committed a misconduct violation. 37 Pa. Code § 95.106(2) (1978). Administrative segregation may be imposed when an inmate poses a threat to security, when disciplinary charges are pending against an inmate, or when an inmate requires protection. §95.104. According to the state regulations, administrative segregation is somewhat less restrictive than disciplinary segregation, compare §95.107(a)(2) with § 95.107(b)(2), although, as noted elsewhere, see n. 4, infra, we assume for purposes of this case that the conditions in the two types of confinement are substantially identical.
The misconduct report informed respondent that a hearing would be held as soon as possible, that he could remain silent at the hearing, that he could be represented by an inmate or staff member, and that he could request witnesses who would be permitted to appear if they were found willing, capable of giving relevant testimony, and not a security hazard. App. 38a-39a.
Wolff required that inmates facing disciplinary charges for misconduct be accorded 24 hours' advance written notice of the charges against them; a right to call witnesses and present documentary evidence in defense, unless doing so would jeopardize institutional safety or correctional goals; the aid of a staff member or inmate in presenting a defense, provided the inmate is illiterate or the issues complex; an impartial tribunal; and a written statement of reasons relied on by the tribunal. 418 U. S., at 563-572.
As noted previously, the case is here on motions for summary judgment. Respondent submitted an affidavit that the State did not rebut, claiming that confinement to administrative segregation imposed severe hardships on him. Among other things, he alleged a denial of access to vocational, educational, recreational, and rehabilitative programs, restrictions on exercise, and confinement to his cell for lengthy periods of time.
We held there that it was error to dismiss for failure to state a claim a pro se prisoner’s complaint alleging confinement to restricted quarters without a hearing. Observing that “[w]e [could not] say with assurance that petitioner can prove no set of facts in support of his claim entitling him to relief,” 449 U. S., at 12-13, we expressly stated that “[o]ur discussion of this claim is not intended to express any view on its merits.” Id., at 12. Rowe is likewise factually dissimilar from this case, since in Rowe we also noted that “[tjhere [was] no suggestion in the record that. . . emergency conditions” existed and the prisoner’s “offense did not involve violence.” Id., at 11.
Title 37 Pa. Code § 95.104(b)(1) (1978) provides:
“An inmate who has allegedly committed a Class I Misconduct may be placed in Close or Maximum Administrative Custody upon approval of the officer in charge of the institution, not routinely but based upon his assessment of the situation and the need for control pending application of procedures under § 95.103 of this title.”
Section 95.104(b)(3) of the same Title provides:
“An inmate may be temporarily confined to Close or Maximum Administrative Custody in an investigative status upon approval of the officer in charge of the institution where it has been determined that there is a threat of a serious disturbance, or a serious threat to the individual or others. The inmate shall be notified in writing as soon as possible that he is under investigation and that he will receive a hearing if any disciplinary action is being considered after the investigation is completed. An investigation shall begin immediately to determine whether or not a behavior violation has occurred. If no behavior violation has occurred, the inmate must be released as soon as the reason for the security concern has abated but in all cases within ten days.”
Finally, a State Bureau of Correction Administrative Directive states that when the State Police have been summoned to an institution:
“Pending arrival of the State Police, the institutional representative shall:
“1. Place all suspects and resident witnesses or complainants in such custody, protective or otherwise, as may be necessary to maintain security. A hearing complying with [37 Pa. Code § 95.103 (1972)] will be carried out after the investigation period. Such hearing shall be held within four (4) days unless the investigation warrants delay and in that case as soon as possible.” Pa. Admin. Dir. BC-ADM 004, § IV(B) (1975).
Indeed, we think an administrator’s judgment probably would be hindered. Prison officials, wary of potential legal liability, might well spend their time mechanically complying with cumbersome, marginally helpful procedural requirements, rather than managing their institution wisely.
The proceeding must occur within a reasonable time following an inmate’s transfer, taking into account the relatively insubstantial private interest at stake and the traditionally broad discretion of prison officials.
Of course, administrative segregation may not be used as a pretext for indefinite confinement of an inmate. Prison officials must engage in some sort of periodic review of the confinement of such inmates. This review will not necessarily require that prison officials permit the submission of any additional evidence or statements. The decision whether a prisoner remains a security risk will be based on facts relating to a particular prisoner — which will have been ascertained when determining to confine the inmate to administrative segregation — and on the officials’ general knowledge of prison conditions and tensions, which are singularly unsuited for “proof” in any highly structured manner. Likewise, the decision to continue confinement of an inmate pending investigation of misconduct charges depends upon circumstances that prison officials will be well aware of — most typically, the progress of the investigation. In both situations, the ongoing task of operating the institution will require the prison officials to consider a wide range of administrative considerations; here, for example, petitioners had to consider prison tensions in the aftermath of the December 3 riot, the ongoing state criminal investigation, and so forth. The record plainly shows that on January 2 a Program Review Committee considered whether Helms’ confinement should be continued, App. 13a-15a. This review, occurring less than a month after the initial decision to confine Helms to administrative segregation, is sufficient to dispel any notions that the confinement was a pretext.