concurring in the judgment.
Today’s decision reaffirms that “[cjourts certainly have a responsibility to scrutinize claims of cruel and unusual confinement.” Ante, this page. With that I agree. I also agree that the District Court’s findings in this case do not support a judgment that the practice of double celling in the South*353ern Ohio Correctional Facility is in violation of the Eighth Amendment. I write separately, however, to emphasize that today’s decision should in no way be construed as a retreat from careful judicial scrutiny of prison conditions, and to discuss the factors courts should consider in undertaking such scrutiny.
I
Although this Court has never before considered what prison conditions constitute “cruel and unusual punishment” within the meaning of the Eighth Amendment, see ante, at 344^345, such questions have been addressed repeatedly by the lower courts. In fact, individual prisons or entire prison systems in at least 24 States have been declared unconstitutional under the Eighth and Fourteenth Amendments,1 with litiga*354tion underway in many others.2 Thus, the lower courts have learned from repeated investigation and bitter experience that judicial intervention is indispensable if constitutional dictates — not to mention considerations of basic humanity — are to be observed in the prisons.
No one familiar with litigation in this area could suggest that the courts have been overeager to usurp the task of running prisons, which, as the Court today properly notes, is entrusted in the first instance to the “legislature and prison administration rather than a court.” Ante, at 349. And certainly, no one could suppose that the courts have ordered creation of “comfortable prisons,” ibid., on the model of country clubs. To the contrary, “the soul-chilling inhumanity of conditions in American prisons has been thrust upon the judicial conscience.” Inmates of Suffolk County Jail v. Eisenstadt, 360 F. Supp. 676, 684 (Mass. 1973).
Judicial opinions in this area do not make pleasant reading.3 For example, in Pugh v. Locke, 406 F. Supp. 318 (MD *355Ala. 1976), aff’d as modified, 559 F. 2d 283 (CA5 1977), rev’d in part on other grounds, 438 U. S. 781 (1978) (per curiam), Chief Judge Frank Johnson described in gruesome detail the conditions then prevailing in the Alabama penal system. The institutions were “horrendously overcrowded,” 406 F. Supp., at 322, to the point where some inmates were forced to sleep on mattresses spread on floors in hallways and next to urinals. Id., at 323. The physical facilities were “dilapidated]” and “filthy,” the cells infested with roaches, flies, mosquitoes, and other vermin. Ibid. Sanitation facilities were limited and in ill repair, emitting an “overpowering odor”; in one instance over 200 men were forced to share one toilet. Ibid. Inmates were not provided with toothpaste, toothbrush, shampoo, shaving cream, razors, combs, or other such necessities. Ibid. Food was “unappetizing and unwholesome,” poorly prepared and often infested with insects, and served without reasonable utensils. Ibid. There were no meaningful vocational, educational, recreational, or work programs. Id., at 326. A United States health officer described the prisons as “wholly unfit for human habitation according to virtually every criterion used for evaluation by public health inspectors.” Id., at 323-324. Perhaps the worst of all was the “rampant violence” within the prison. Id., at 325. Weaker inmates were “repeatedly victimized” by the stronger; robbery, rape, extortion, theft, and assault were “everyday occurrences among the general inmate population.” Id., at 324. *356Faced with this record, the court — not surprisingly — found that the conditions of confinement constituted cruel and unusual punishment, and issued a comprehensive remedial order affecting virtually every aspect of prison administration.4
Unfortunately, the Alabama example is neither abberational nor anachronistic. Last year, in Ramos v. Lamm, 639 F. 2d 559 (1980), cert. denied, 450 U. S. 1041 (1981), for example, the Tenth Circuit declared conditions in the maximum-security unit of the Colorado State Penitentiary at Canon City unconstitutional. The living areas of the prison were “unfit for human habitation,” 639 F. 2d, at 567; the food unsanitary and “grossly inadequate,” id., at 570; the institution “fraught with tension and violence,” often leading to injury and death, id., at 572; the health care “blatant[ly] inadequate]” and “appalling,” id., at 574; and there were various restrictions of prisoners’ rights to visitation, mail, and access to courts in violation of basic constitutional rights, id., at 578-585. Similar tales of horror are recounted in dozens of other cases. See, e. g., cases cited in n. 1, supra.
Overcrowding and cramped living conditions are particularly pressing problems in many prisons. Out of 82 court orders in effect concerning conditions of confinement in federal and state correctional facilities as of March 31, 1978, 26 involved the issue of overcrowding. 3 American Prisons and Jails 32. Two-thirds of all inmates in federal, state, and local correctional facilities were confined in cells or dormitories providing less than 60 square feet per person — the minimal standard deemed acceptable by the American Public Health Association, the Justice Department, and other authorities.5
*357The problems of administering prisons within constitutional standards are indeed “ 'complex and intractable,’ ” ante, at 351, n. 16, quoting Procunier v. Martinez, 416 U. S. 396, 404 (1974), but at their core is a lack of resources allocated to prisons. Confinement of prisoners is unquestionably an expensive proposition: the average direct current expenditure at adult institutions in 1977 was $5,461 per inmate, 3 American Prisons and Jails 115; the average cost of constructing space for an additional prisoner is estimated at $25,000 to' $50,000. Id., at 119. Oftentimes, funding for prisons has been dramatically below that required to comply with basic constitutional standards. For example, to bring the Louisiana prison system into compliance required a supplemental appropriation of $18,431,622 for a single year’s operating expenditures, and of $105,605,000 for capital outlays. Williams v. Edwards, 547 F. 2d 1206, 1219-1221 (CA5 1977) (Exhibit A).
Over the last decade, correctional resources, never ample, have lagged behind burgeoning prison populations. In Ruiz v. Estelle, 503 F. Supp. 1265 (SD Tex. 1980), for example, the court stated that an “unprecedented surge” in the number of inmates has “undercut any realistic expectation” of eliminating double and triple celling, despite construction of a new $43 million unit. Id., at 1280-1281. The number of inmates in federal and state correctional facilities has risen 42% since 1975, and last year grew at its fastest rate in three years. Krajick, The Boom Resumes, 7 Corrections Magazine 16-17 (Apr. 1981) (report of annual survey of prison populations).6 A major infusion of money would be required merely to keep pace with prison populations.
*358Public apathy and the political powerlessness of inmates have contributed to the pervasive neglect of the prisons. Chief Judge Henley observed that the people of Arkansas “knew little or nothing about their penal system” prior to the Holt litigation, despite “sporadic and sensational” exposes. Holt v. Sarver, 309 F. Supp. 362, 367 (ED Ark. 1970). Prison inmates are “voteless, politically unpopular, and socially threatening.” Morris, The Snail’s Pace of Prison Reform, in Proceedings of the 100th Annual Congress of Corrections of the American Correctional Assn. 36, 42 (1970). Thus, the suffering of prisoners, even if known, generally “moves the community in only the most severe and exceptional cases.” Ibid. As a result even conscientious prison officials are “[c] aught in the middle,” as state legislatures refuse “to spend sufficient tax dollars to bring conditions in outdated prisons up to minimally acceptable standards.” Johnson v. Levine, 450 F. Supp. 648, 654 (Md.), aff’d in part, 588 F. 2d 1378 (CA4 1978).7 After extensive exposure to this *359process, Chief Judge Pettine came to view the “barbaric physical conditions” of Rhode Island’s prison system as “the ugly and shocking outward manifestations of a deeper dysfunction, an attitude of cynicism, hopelessness, predatory selfishness, and callous indifference that appears to infect, to one degree or another, almost everyone who comes in contact with the [prison].” Palmigiano v. Garrahy, 443 F. Supp. 956, 984 (RI 1977), remanded, 599 F. 2d 17 (CA1 1979).
Under these circumstances, the courts have emerged as a critical force behind efforts to ameliorate inhumane conditions. Insulated as they are from political pressures, and charged with the duty of enforcing the Constitution, courts are in the strongest position to insist that unconstitutional conditions be remedied, even at significant financial cost. Justice Blackmun, then serving on the Court of Appeals, set the tone in Jackson v. Bishop, 404 F. 2d 571, 580 (CA8 1968): “Humane considerations and constitutional requirements are not, in this day, to be measured or limited by dollar considerations . . . .”
Progress toward constitutional conditions of confinement in the Nation’s prisons has been slow and uneven, despite judicial pressure. Nevertheless, it is clear that judicial intervention has been responsible, not only for remedying some of the worst abuses by direct order, but also for “forcing the legislative branch of government to reevaluate correction policies and to appropriate funds for upgrading penal systems.” 3 American Prisons and Jails 163. A detailed study of four prison conditions cases by the American Bar Association concluded:
“The judicial intervention in each of the correctional *360law cases studied had impact that was broad and substantial. . . . For the most part, the impact of the judicial intervention was clearly beneficial to the institutions, the correctional systems, and the broader community. Dire consequences predicted by some correctional personnel did not accompany the judicial intervention in the cases studied. Inmates were granted greater rights and protections, but the litigation did not undermine staff authority and control. Institutional conditions improved, but facilities were not turned into 'country clubs.’ The courts intervened in correctional affairs, but the judges did not take over administration of the facilities.” M. Harris & D. Spiller, After Decision: Implementation of Judicial Decrees in Correctional Settings 21 (National Institute of Law Enforcement and Criminal Justice, 1977).
Even prison officials have acknowledged that judicial intervention has helped them to obtain support for needed reform. GAO, Comptroller General, Report to Congress: The Department of Justice Can Do More to Help Improve Conditions at State and Local Correctional Facilities 12-13 (GGD-80-77, 1980). The Commissioner of Corrections of New York City, a defendant in many lawsuits challenging jail and prison conditions, has stated: “Federal courts may be the last resort for us ... . If there’s going to be change, I think the federal courts are going to have to force cities and states to spend more money on their prisons. ... I look on the courts as a friend.” Gettinger, “Cruel and Unusual” Prisons, 3 Corrections Magazine 3, 5 (Dec. 1977). In a similar vein, the Commissioner of the Minnesota Department of Corrections testified before a congressional Committee that lawsuits brought on behalf of prison inmates
“have upgraded correctional institutions and the development of procedural safeguards regarding basic constitutional rights. There is no question in my mind that *361had such court intervention not taken place, these fundamental improvements would not have occurred.
“While I do not intend to imply here that I sit expectantly at my desk each week awaiting news of another impending suit, I do recognize that unless my agency consistently deals fairly with those incarcerated in our institutions we will be held judicially accountable.” Civil Rights of Institutionalized Persons, Hearings on S. 1393 before the Subcommittee on the Constitution of the Senate Committee on the Judiciary, 95th Cong., 1st Sess., 409-410 (1977) (testimony of Kenneth F. Schoen).8
II
The task of the courts in cases challenging prison conditions is to “determine whether a challenged punishment comports with human dignity.” Furman v. Georgia, 408 U. S. 238, 282 (1972) (Brennan, J., concurring). Such determinations are necessarily imprecise and indefinite, Trop v. Dulles, 356 U. S. 86, 100-101 (1958); Wilkerson v. Utah, 99 U. S. 130, 135-136 (1879); they require careful scrutiny of challenged conditions, and application of realistic yet humane standards.
In performing this responsibility, this Court and the lower *362courts have been especially deferential to prison authorities “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); see also ante, at 351, n. 16; Jones v. North Carolina Prisoners’ Labor Union, 433 U. S. 119, 128 (1977); Cruz v. Beto, 405 U. S. 319, 321 (1972). Many conditions of confinement, however, including overcrowding, poor sanitation, and inadequate safety precautions, arise from neglect rather than policy. See supra, at 358-359. There is no reason of comity, judicial restraint, or recognition of expertise for courts to defer to negligent omissions of officials who lack the resources or motivation to operate prisons within limits of decency. Courts must and do recognize the primacy of the legislative and executive authorities in the administration of prisons; however, if the prison authorities do not conform to constitutional minima, the courts are under an obligation to take steps to remedy the violations. Procunier v. Martinez, 416 U. S., at 405.9
The first aspect of judicial decisionmaking in this area is scrutiny of the actual conditions under challenge. It is important to recognize that various deficiencies in prison conditions “must be considered together.” Holt v. Sarver, 309 F. Supp., at 373. The individual conditions “exist in combination; each affects the other; and taken together they [may] have a cumulative impact on the inmates.” Ibid. Thus, a court considering an Eighth Amendment challenge to condi*363tions of confinement must examine the totality of the circumstances.10 Even if no single condition of confinement would be unconstitutional in itself, “exposure to the cumulative effect of prison conditions may subject inmates to cruel and unusual punishment.” Laaman v. Helgemoe, 437 F. Supp. 269, 322-323 (NH 1977).
Moreover, in seeking relevant information about conditions in a prison, the court must be open to evidence and assistance from many sources, including expert testimony and studies on the effect of particular conditions on prisoners. For this purpose, public health, medical, psychiatric, psychological, peno-logical, architectural, structural, and other experts have proved useful to the lower courts in observing and interpreting prison conditions. See, e. g., Palmigiano v. Garrahy, 443 F. Supp., at 960 (commenting that the court’s “task was made easier by the extensive assistance of experts”).11
More elusive, perhaps, is the second aspect of the judicial inquiry: application of realistic yet humane standards to the conditions as observed. Courts have expressed these standards in various ways, see, e. g., M. C. I. Concord Advisory Bd. v. Hall, 447 F. Supp. 398, 404 (Mass. 1978) (“contemporary standards of decency”); Palmigiano v. Garrahy, supra, at 979 (conditions so bad as to “shock the conscience of any reasonable citizen”); Estelle v. Gamble, 429 U. S. 97, 102 (1976) (“ ‘broad and idealistic concepts of dignity, civilized standards, humanity, and decency,’ ” quoting Jackson v. Bishop, 404 F. *3642d, at 579). Each of these descriptions has its merit, but in the end, the court attempting to apply them is left to rely upon its own experience and on its knowledge of contemporary standards.12 Coker v. Georgia, 433 U. S. 584, 597 (1977) (plurality opinion).
In determining when prison conditions pass beyond legitimate punishment and become cruel and unusual, the “touchstone is the effect upon the imprisoned.” Laaman v. Helgemoe, 437 F. Supp., at 323. The court must examine the effect upon inmates of the condition of the physical plant (lighting, heat, plumbing, ventilation, living space, noise levels, recreation space); sanitation (control of vermin and insects, food preparation, medical facilities, lavatories and showers, clean places for eating, sleeping, and working) ; safety (protection from violent, deranged, or diseased inmates, fire protection, emergency evacuation); inmate needs and services (clothing, nutrition, bedding, medical, dental, and mental health care, visitation time, exercise and recreation, educational and rehabilitative programming); and staffing (trained and adequate guards and other staff, avoidance of placing inmates in positions of authority over other inmates). See ibid.; Ramos v. Lamm, 639 F. 2d, at 567-581. When “the cumulative impact of the conditions of incarceration threatens the physical, mental, and emotional health and well-being of the inmates and/or creates a probability of recidivism and future incarceration,” the court must conclude that the conditions violate the Constitution. Laaman v. Helgemoe, supra, at 323.
*365III
A reviewing court is generally limited in its perception of a case to the findings of the trial court. I have not seen the Southern Ohio Correctional Facility at Lucasville, nor have I directly heard evidence concerning conditions there. From the District Court opinion, I know that the prison is a modern, “top-flight, first-class facility,” built in the early 1970’s at a cost of some $32 million, 434 F. Supp. 1007, 1009 (SD Ohio 1977). Chief Judge Hogan, who toured the facility, described it as “not lacking in color,” and, “generally speaking, . . . quite light and . . . airy, etc.” Id., at 1011. The cells are reasonably well furnished, with one cabinet-type night stand, one wall cabinet, one wall shelf, one wall-mounted lavatory with hot and cold running water and steel mirror, one china commode flushed from inside the cell, one wall-mounted radio, one heating and air circulation vent, one lighting fixture, and one bed or bunkbed. Id., at 1011-1012. Prisoners in each cellblock have frequent access to a dayroom, which is “in a sense part of the cells,” and is “designed to furnish that type of recreation or occupation which an ordinary citizen would seek in his living room or den.” Id., at 1012. Food is “adequate in every respect,” and the kitchens and dining rooms are clean. Id., at 1014. Prisoners are all permitted contact visitation. Ibid. The ratio of inmates to guards is “well within the acceptable ratio,” and incidents of violence, while not uncommon, have not increased out of proportion to inmate population. Id., at 1014-1015, 1016-1018. Plumbing and lighting are adequate. Id., at 1015. The prison has a modern, well-stocked library, with an adequate law library. Id., at 1010, and n. 2. It has eight schoolrooms, two chapels, a commissary, a barbershop, dining rooms, kitchens, and workshops. Ibid. Virtually the only serious complaint of the inmates at the Southern Ohio Correctional Facility is that 1,280 of the 1,620 cells are used to house two inmates.
*366I have not the slightest doubt that 63 square feet of cell space is not enough for two men. I understand that every major study of living space in prisons has so concluded. See id., at 1021; see also n. 5, supra; post, at 371-372, and n. 4 (Marshall, J., dissenting). That prisoners are housed under such conditions is an unmistakable signal to the legislators and officials of Ohio: either more prison facilities should be built or expanded, or fewer persons should be incarcerated in prisons. Even so, the findings of the District Court do not support a conclusion that the conditions at the Southern Ohio Correctional Facility — cramped though they are — constitute cruel and unusual punishment. See Hite v. Leeke, 564 F. 2d 670, 673-674 (CA4 1977); M. C. I. Concord Advisory Bd. v. Hall, 447 F. Supp., at 404-405.13
The “touchstone” of the Eighth Amendment inquiry is “ The effect upon the imprisoned.’ ” Supra, at 364, quoting Laaman v. Helgemoe, 437 F. Supp., at 323. The findings of the District Court leave no doubt that the prisoners are adequately sheltered, fed, and protected, and that opportunities, for education, work, and rehabilitative assistance are available.14 One need only compare the District Court’s descrip*367tion of conditions at the Southern Ohio Correctional Facility with descriptions of other major state and federal facilities, see supra, at 354-356, to realize that this prison, crowded though it is, is one of the better, more humane large prisons in the Nation.15
The consequence of the District Court’s order might well be to make life worse for many Ohio inmates, at least in the short run. As a result of the order, some prisoners have been transferred to the Columbus Correctional Facility, a deteriorating prison nearly 150 years old, itself the subject of litigation over conditions of confinement and under a preliminary order enjoining racially segregative and punitive practices. See Stewart v. Rhodes, 473 F. Supp. 1185 (SD Ohio 1979).
The District Court may well be correct in the abstract that prison overcrowding and double celling such as existed at the Southern Ohio Correctional Facility generally results in serious harm to the inmates. But cases are not decided in the abstract. A court is under the obligation to examine the actual effect of challenged conditions upon the well-being of the prisoners.16 The District Court in this case was unable to identify any actual signs that the double celling at the *368Southern Ohio Correctional Facility has seriously harmed the inmates there;17 indeed, the court’s findings of fact suggest that crowding at the prison has not reached the point of causing serious injury. Since I cannot conclude that the totality of conditions at the facility offends constitutional norms, and am of the view that double celling in itself is not per se impermissible, I concur in the judgment of the Court.
Among the States in which prisons or prison systems have been placed under court order because of conditions of confinement challenged under the Eighth and Fourteenth Amendments are: Alabama, see Pugh v. Locke, 406 F. Supp. 318 (MD Ala. 1976), aff’d as modified, 559 F. 2d 283 (CA5 1977), rev’d in part on other grounds, 438 U. S. 781 (1978) (per curiam); Arizona, see Harris v. Cardwell, No. CIV-75-185-PHX-CAM (DC Ariz., Oct. 14, 1980) (consent decree); Arkansas, see Finney v. Mabry, 458 F. Supp. 720 (ED Ark. 1978) (consent decree); Colorado, see Ramos v. Lamm, 639 F. 2d 559 (CA10 1980), cert. denied, 450 U. S. 1041 (1981); Delaware, see Anderson v. Redman, 429 F. Supp. 1105 (Del. 1977); Florida, see Costello v. Wainwright, 397 F. Supp. 20 (MD Fla. 1975), aff’d, 525 F. 2d 1239 (CA5), vacated on rehearing on other grounds, 539 F. 2d 547 (CA5 1976) (en banc), rev’d, 430 U. S. 325, aff’d on remand, 553 F. 2d 506 (CA5 1977) (en banc) (per curiam); Georgia, see Guthrie v. Caldwell, No. 3068 (SD Ga., Dec. 1, 1978) (consent decree); Illinois, see Lightfoot v. Walker, 486 F. Supp. 504 (SD Ill. 1980); Iowa, see Watson v. Ray, 90 F. R. D. 143 (SD Iowa 1981); Kentucky, see Kendrick v. Bland, No. 76-0079-P (WD Ky., Oct. 24, 1980) (consent decree); Louisiana, see Williams v. Edwards, 547 F. 2d 1206 (CA5 1977); Maryland, see Johnson v. Levine, 450 F. Supp. 648 (Md.), aff’d in part, 588 F. 2d 1378 (CA4 1978), and Nelson v. Collins, 455 F. Supp. 727 (Md.), aff’d in part, 588 F. 2d 1378 (CA4 1978); Mississippi, see Gates v. Collier, 501 F. 2d 1291 (CA5 1974); Missouri, see Burks v. Teasdale, 603 F. 2d 59 (CA8 1979); New Hampshire, see Laaman v. Helgemoe, 437 F. Supp. 269 (NH 1977); *354New Mexico, see Duran v. Apodaca, No. Civil 77-721-C (DC NM, July 17, 1980) (consent decree); New York, see Todaro v. Ward, 565 F. 2d 48 (CA2 1977); Ohio, see (in addition to this case) Stewart v. Rhodes, 473 F. Supp. 1185 (ED Ohio 1979); Oklahoma, see Battle v. Anderson, 564 F. 2d 388 (CA10 1977); Oregon, see Capps v. Atiyeh, 495 F. Supp. 802 (Ore. 1980); Pennsylvania, see Hendrick v. Jackson, 10 Pa. Commw. 392, 309 A. 2d 187 (1973); Rhode Island, see Polmigiano v. Garrahy, 443 F. Supp. 956 (RI 1977), remanded, 599 F. 2d 17 (CA1 1979); Tennessee, see Trigg v. Blanton, No. A-6047 (Ch. Ct., Davidson Cty., Aug. 23, 1978), vacated (Tenn. App., May 1, 1980) (for consideration of changes in conditions), appeal pending (Tenn. Sup. Ct.); Texas, see Ruiz v. Estelle, 503 F. Supp. 1265 (SD Tex. 1980). See also Feliciano v. Barcelo, 497 F. Supp. 14 (PR 1979); Barnes v. Government of Virgin Islands, 415 F. Supp. 1218 (V. I. 1976).
There are over 8,000 pending cases filed by inmates challenging prison conditions. 3 National Institute of Justice, American Prisons and Jails 34 (1980) (hereafter American Prisons and Jails).
It behooves us to remember that
“it is impossible for a written opinion to convey the pernicious conditions and the pain and degradation which ordinary inmates suffer within [un*355constitutionally operated prisons] — the gruesome experiences of youthful first offenders forcibly raped; the cruel and justifiable fears of inmates, wondering when they will be called upon to defend the next violent assault; the sheer misery, the discomfort, the wholesale loss of privacy for prisoners housed with one, two, or three others in a forty-five foot cell or suffocatingly packed together in a crowded dormitory; the physical suffering and wretched psychological stress which must be endured by those sick' or injured who cannot obtain medical care ....
“For those who are incarcerated within [such prisons], these conditions and experiences form the content and essence of daily existence.” Ruiz v. Estelle, supra, at 1391.
This Court has upheld the exercise of wide discretion by trial courts to correct conditions of confinement found to be unconstitutional. Hutto v. Finney, 437 U. S. 678, 687-688 (1978).
See American Public Health Assn., Standards for Health Services in Correctional Institutions 62 (1976); II. S. Dept, of Justice Federal Standards for Prisons and Jails, Standard No. 2.04, p. 17 (1980); see generally 3 American Prisons and Jails 39-50, 85, n. 6.
Among the causes of the rising number of prison inmates are increasing population, increasing crime rates, stiffer sentencing provisions, and more restrictive parole practices. See Krajick, The Boom Resumes, 7 Corrections Magazine 16-17 (Apr. 1981); 3 National Institute of Law Enforcement and Criminal Justice, The National Manpower Survey of the Criminal Justice System 13-14 (1978).
Moreover, part of the problem in some instances is the attitude of politicians and officials. Of course, the courts should not “assume that state legislatures and prison officials are insensitive to the requirements of the Constitution,” ante, at 352 (emphasis added), but sad experience has shown that sometimes they can in fact be insensitive to such requirements. See Civil Rights of the Institutionalized, Hearings on S. 10 before the Subcommittee on the Constitution of the Senate Committee on the Judiciary, 96th Cong., 1st Sess., 28 (1979) (testimony of Assistant Attorney General Drew Days); Palmigiano v. Garrahy, 448 F. Supp. 659, 671 (RI 1978) (prison officials failed to implement court order for reasons unrelated to ability to comply). William G. Nagel, a New Jersey corrections official for 11 years and now a frequent expert witness in prison litigation, testified in 1977 that, in every one of the 17 lawsuits in which he had participated, the government officials worked in a “systematic way” to “impede the fulfillment of constitutionality within our institutions.” Civil Rights of Institutionalized Persons, Hearing on S. 1393 before the Subcommittee on the Constitution of the Senate Committee on the Judiciary, 95th Cong., 1st Sess., 772 (1977). He stated that he had “learned through experience that most States resist correcting their unconstitutional conditions or operations until pressed to do so by threat of a suit or by direc*359tive from the judiciary.” Id., at 779. Indeed, this Court recognized the problem of obstructionist official behavior when it affirmed an award of attorney’s fees against Arkansas prison officials who had failed to comply with a court order, on the ground that the litigation had been conducted in bad faith. Hutto v. Finney, 437 U. S., at 689-693.
After extensive hearings concerning the effect of court litigation on the correction of unconstitutional conditions in state-operated institutions, Congress emphatically endorsed the role of the courts in the area by passing the Civil Rights of Institutionalized Persons Act, Pub. L. 96-247, 94 Stat. 349, 42 U. S. C. § 1997 et seq. (1976 ed., Supp. IV), which authorized the Attorney General to bring suits in federal court on behalf of persons institutionalized by the States under unconstitutional conditions. The Conference Committee noted that, as a result of litigation in which the Justice Department had participated, “conditions have improved significantly in dozens of institutions across the Nation: . . . barbaric treatment of adult and juvenile prisoners has been curbed; . . . and States facing the prospect of suit by the Attorney General have voluntarily upgraded conditions in their institutions ... to comply with previously announced constitutional standards.” H. R. Conf. Rep. No. 96-897, p. 9 (1980).
See also Cruz v. Beto, 405 U. S. 319, 321 (1972):
“Federal courts sit not to supervise prisons but to enforce the constitutional rights of all ‘persons/ including prisoners. We are not unmindful that prison officials must be accorded latitude in the administration of prison affairs, and that prisoners necessarily are subject to appropriate rules and regulations. But persons in prison, like other individuals, have the right to petition the Government for redress of grievances which, of course, includes ‘access of prisoners to the courts for the purpose of presenting their complaints.’ ”
The Court today adopts the totality-of-the-cireumstances test. See ante, at 347 (Prison conditions “alone or in combination, may deprive inmates of the minimal civilized measure of life’s necessities”) (emphasis added). See also Hutto v. Finney, 437 U. S., at 687 (“We find no error in the court’s conclusion that, taken as a whole, conditions in the isolation cells continued to violate the prohibition against cruel and unusual punishment”) (emphasis added).
I do not understand the Court’s opinion to disparage use of experts to assist the courts in these functions. Indeed, the Court acknowledges that expert opinion may be “helpful and relevant” in some circumstances. Ante, at 348, n. 13.
Again, the assistance of experts can be of great value to courts when evaluating standards for confinement. Although expert testimony alone does not “suffice to establish contemporary standards of decency,” ibid., such testimony can help the courts to understand the prevailing norms against which conditions in a particular prison may be evaluated. In this connection, the work of standard-setting organizations such as the Department of Justice, the American Public Health Association, the Commission on Accreditation for Corrections, and the National Sheriff’s Association is particularly valuable.
The District Court rested its judgment on five considerations: (1) the long-term confinement of the prisoners, (2) the rated capacity of the prison, (3) expert opinion concerning living-space requirements, (4) time spent in the cells, and (5) the permanent character of the double celling. 434 F. Supp. 1007, 1020-1021 (SD Ohio 1977). This led the Court of Appeals to conclude that the District Court had not ruled the practice of double celling “unconstitutional under all circumstances.” App. to Pet. for Cert. A-2. The five considerations cited by the District Court, in my view, are not separate aspects of conditions at the prison; rather, they merely embroider upon the theme that double celling is unconstitutional in itself.
The overcrowding in the cells is mitigated considerably by the freedom of most prisoners to spend time away from their cells, especially in the dayrooms. The inhabitants of 960 of the double-occupant cells were out of the cells some 10 hours a day at school, work, or other activities. 434 F. Supp., at 1013. Of the remainder, all of whom spent six or fewer hours a week out of the cells, some were on short-term “receiving” status, some *367on semiprotected status by choice, and some on “idle” status by choice. Ibid. The remainder were in administrative isolation because of infractions of the rules, determined after a plenary hearing. Ibid.
During trial in this case, and before final judgment by the District Court, the prison implemented a plan limiting double celling to those inmates free to move about the facility 15 hours per day. Brief for Petitioners 27.
If it were true that any prison providing less than 63 square feet of cell space per inmate were a per se violation of the Eighth Amendment, then approximately two-thirds of all federal, state, and local inmates today would be unconstitutionally confined. See supra, at 356.
This is not to say that injury to the inmates from challenged prison conditions must be “demonstrate[d] with a high degree of specificity and certainty.” Ruiz v. Estelle, 503 F. Supp., at 1286. Courts may, as usual, employ common sense, observation, expert testimony, and other practical modes of proof. See id., at 1286-1287.
Cf. Capps v. Atiyeh, 495 F. Supp., at 810-814 (evidence “replete with examples of the deleterious effects of overcrowding on prisoners’ mental and physical health,” including increased health risks, diminished access to essential services, fewer opportunities to engage in rehabilitative programs, levels of privacy and quiet insufficient for psychological well-being, and exacerbated levels of tension, anxiety, and fear); Anderson v. Redman, 429 F. Supp., at 1112-1118 (court found that overcrowding had caused severe physical and psychological damage to inmates, increased the incidence of self-multilation, suicide, attempted suicide, theft, assault, and homosexual rape, destroyed all privacy, overtaxed the sanitary facilities, exacerbated the problems of filth, noise, and vermin, caused serious deterioration in medical care, fostered increased idleness, broke down the classification and incentive systems, and demoralized the staff).