This appeal presents, in yet another form, the chronic controversy generated by the tension between efforts by the Commissioner of Correction (commissioner) to manage our prison system, and claims by prisoners for protection from alleged violations of their constitutional and statutory rights.4 This clash also arises, as here, in efforts to reconcile the interests served by punishment: deterrence, isolation and incapacitation, retribution and moral reinforcement, and reformation. See Cepulonis v. Commonwealth, 384 Mass. 495, 499 (1981), citing Commonwealth v. O’Neal, 369 Mass. 242, 251 & n.11 (1975) (Tauro, C.J., concurring). See also Fried, Reflections on Crime and Punishment, 30 Suffolk U. L. Rev. 681 (1997).
At issue is whether the defendants — the commissioner and the superintendent of the Massachusetts Correctional Institution at Cedar Junction (Cedar Junction) (superintendent) — can ignore regulations, duly enacted and still in effect, which govern the placement of prisoners in segregated confinement for nondisciplinary reasons.
Litigation, commenced in 1985, resulted in a single justice of this court ordering the adoption of regulations that require procedural protections before a prisoner can be isolated for nondisciplinary reasons. See Hoffer vs. Fair, No. SJ-85-0071 (Mar. 3, 1988). See also 103 Code Mass. Regs. §§ 421.00 (1993). In 1995, the commissioner attempted to repeal those regulations in the wake of a lockdown of Cedar Junction following a disturbance. The commissioner was unsuccessful, and a single justice enjoined the repeal of the regulations on September 26, 1995. Notwithstanding the 1995 injunction, the commissioner and the superintendent thereafter implemented certain operational changes at Cedar Junction, the effect of which was to place a substantially increased number of prisoners in segregated *739confinement for nondisciplinary reasons under conditions substantially similar to those that existed in 1985, without complying with the applicable regulations. For reasons we shall explain, the prisoners now in or who may be in such confinement, although more in number, are entitled to the protections contained in the regulations promulgated in response to the 1988 order unless and until the applicable regulations are amended or repealed. Amendment or repeal would not be warranted unless the defendants assert meritorious grounds different from those presented to the single justice in 1995. The defendants did not seek any such relief in this action.
I
The plaintiffs are a certified class of “all prisoners who are now confined or may at some point be confined” at Cedar Junction “in any housing unit other than the Departmental Disciplinary Unit” (DDU). Prisoners are housed in the DDU for disciplinary reasons, and we are concerned here only with those prisoners who are segregated unrelated to any reason of discipline.5 The plaintiffs challenge the severely restrictive conditions of their confinement in the East Wing of Cedar Junction, alleging violations of various regulations and statutes, as well as of the equal protection and due process provisions of the Massachusetts and United States Constitutions. They claim that their nondisciplinary segregation in the so-called East Wing of the prison, tantamount to indefinite solitary confinement in many cases, constitutes confinement comparable to that in the former departmental segregation unit (DSU), and that they are, therefore, entitled to the procedural due process protections applicable to prisoners segregated for nondisciplinary reasons, including those housed in the former DSU. See 103 Code Mass. Regs. §§ 421.00.
The defendants contend that the DSU at Cedar Junction has been abolished and the DSU regulations are therefore no longer of any force or effect. They further argue that the plaintiffs’ liberty interests are adequately protected by a six-month “clas*740sification” review every prisoner in every prison under the jurisdiction of the Department of Corrections (department) receives pursuant to 103 Code Mass. Regs. §§ 420.00 (1995).
A judge in the Superior Court, acting on cross motions for summary judgment, allowed the plaintiffs’ motion with respect to their due process claim. After thoroughly reviewing the record evidence, the motion judge, in a carefully reasoned memorandum of decision and order, concluded that there were no disputed issues of material fact and that (1) the conditions in the East Wing imposed an “atypical and significant hardship,” Sandin v. Conner, 515 U.S. 472, 484 (1995), on the prisoners confined there; (2) the conditions of confinement in the East Wing are substantially similar to the conditions in the former DSU; and (3) the DSU regulations “must be fully complied with before inmates may be subjected to the restrictive conditions” of the East Wing. The judge later stayed the effectiveness of the third item pending appellate review.
For the reasons set forth below, we reject the defendants’ claims and affirm, in substantial part, the allowance of summary judgment because the record does not disclose any disputes of material fact concerning the plaintiffs’ due process claim. We do so, however, for reasons different from those relied on by the Superior Court judge. We agree with the judge that the conditions of nondisciplinary segregation about which the plaintiffs complain are substantially similar to the conditions in the former DSU. The regulations that govern placement in such restrictive conditions, 103 Code Mass. Regs. §§ 421.00, have not been repealed, and have the full force of law. Royce v. Commissioner of Correction, 390 Mass. 425, 427 (1983). Those regulations must therefore be complied with before any prisoner is placed for nondisciplinary reasons in the East Wing under the segregation conditions of confinement operative there. It is accordingly not necessary to reach the constitutional claims or to apply the analysis of Sandin v. Conner, supra, as the motion judge did.
n
A
The disposition of this case necessitates a thorough recitation *741of the background to the litigation, the operation of Cedar Junction, and the conditions of confinement in the East Wing. We summarize the undisputed material facts on the summary judgment record.
The plaintiffs commenced this litigation on June 30, 1995, in the wake of two changes the defendants made in the operation of Cedar Junction during a lockdown of the prison.6 The first change occurred when the commissioner notified prisoners that those deemed “members” or a “leader” of “security threat groups” (gangs), or those “involved in a security threat group incident” would be “subject to transfer to restrictive housing at MCI-Cedar Junction.”7 The plaintiffs claim that the defendants’ application of this gang policy resulted in racially discriminatory long-term segregation placements in violation of the equal protection clause. The plaintiffs’ equal protection claim is not before us.8
Second, the superintendent notified all prisoners at Cedar Junction that the prison was undergoing “a number of changes both physically and operationally,” and that the housing units in the prison would be divided into two “phases” that are now known as the “East Wing” and the “West Wing.” The conditions of confinement in the East Wing would be significantly more restrictive than those in the West Wing. The defendants’ placement of prisoners in the East Wing gave rise to the *742plaintiffs’ due process claim, which is now before us on the allowance of the plaintiffs’ motion for summary judgment.9
B
Cedar Junction is a maximum security prison, the only one in the Commonwealth. It has long consisted of two physically distinct “wings,” both of which house prisoners under conditions of maximum security. The West Wing is comprised of three housing units, each containing seventy-two one-man cells. The East Wing contains eight housing units, each having forty-five one-man cells. Four of the eight East Wing units are called “Plymouth” units and now house prisoners who have been labeled as gang members under the department’s gang policy. Thus, in 1995, when this litigation commenced, this maximum security prison housed some 858 of the 10,835 prisoners in the department’s custody, by definition the most violent and dangerous, presenting the most difficult and oftentimes hazardous challenges of prison management.10 Both the East and West Wings also contain an identified “segregation unit,” where prisoners are placed for various reasons, such as discipline or pending the *743outcome of an investigation or a disciplinary hearing.11 The conditions in the segregation units and in the DDU are not at issue here.12
In connection with the 1995 policy changes, the physical configuration of the two wings was not changed. Rather, the defendants implemented what they term operational changes directed at the prisoners themselves. The parties do not dispute that, for prisoners in the East Wing, conditions are now vastly more restrictive than those in the West Wing. Prisoners in the East Wing experience nondisciplinary segregated conditions that are essentially solitary confinement, while housed in the same one-man cells that existed before the department’s 1995 operational changes. In the Plymouth units, for example, prisoners are released from their cells for only sixty minutes each day, while those in the other East Wing units receive only ninety minutes of “out of cell” time each day. During their out-of-cell time, East Wing prisoners must, for example, schedule all showers and telephone calls, affording them almost no opportunities for interaction with other prisoners.13
In contrast, prisoners housed in the West Wing are not segregated. While all of the prisoners in the West Wing have been determined to require confinement under conditions of maximum security, they are allowed out of their cells for as much as fifteen hours each day, and all day on weekends, and interact with other prisoners throughout those times. East Wing prisoners also eat alone: while they collect their meals outside of their cells, they must return to their cells to eat alone, while *744prisoners in the West Wing eat their meals in a “chow hall.” Canteen privileges14 for prisoners in the East Wing are forty per cent less than canteen privileges for those in the West Wing.
Moreover, segregated confinement in the East Wing may be for long periods. The average continuous period of confinement in the East Wing for the entire plaintiff class is 270 days.15 In some cases prisoners are segregated in the East Wing for the duration of their sentence. Since the operational changes implemented in 1995, prisoners in the East Wing are locked up in the near-solitary confinement conditions described above effectively indefinitely, for reasons not related to any disciplinary problems and contingent solely on the defendants’ subjective evaluation of the prisoners. Thus, except as stated in note 13, supra, for either twenty-three hours or twenty-two and one-half hours a day, a prisoner may be housed in solitary confinement solely at the superintendent’s discretion.
C
In Hoffer vs. Fair, No. SJ-85-0071 (Mar. 3, 1988), a single justice of this court addressed a complaint brought by prisoners in the DSU at Cedar Junction and Massachusetts Correctional Institution at Norfolk. They sought relief for the procedures by which they were placed and held in nondisciplinary segregation. The single justice ordered that changes be made to the then-existing version of the DSU regulations.
The modified DSU regulations issued in response to that decision are now codified at 103 Code Mass. Regs. §§ 421.00. The DSU regulations apply to all State correctional facilities and are issued pursuant to G. L. c. 124, § 1 (b) & (q), and G. L. c. 127, § 39. See 103 Code Mass. Regs. §§ 421.02 & 421.04. The purpose of the regulations is “to establish rules whereby an inmate may be confined to a Departmental Segregation Unit because his continued presence in a general institution population would be detrimental to the program of the institution” *745(emphasis added). 103 Code Mass. Regs. § 421.01. The regulations make clear that a prisoner may not be segregated and denied interaction with other prisoners in the institution for nondisciplinary reasons without receiving certain procedural due process protections. See 103 Code Mass. Regs. § 421.07.16 Rather, a prisoner may be isolated from other prisoners for nondisciplinary reasons to prevent him from injuring others, damaging property, or interrupting the safe operation of the correctional facility only in accordance with the regulations. See 103 Code Mass. Regs. § 421.09. See also Hoffer v. Commissioner of Correction, 412 Mass. 450, 455 n.6 (1992).
In July, 1995, following the lockdown that precipitated this action, the commissioner “closed” the DSU at Cedar Junction and initiated the administrative process to repeal the regulations governing the placement of prisoners in the DSU. See G. L. c. 30A, § 3. It is noteworthy that the commissioner’s affidavit of August 25, 1995, submitted to the single justice in support of the repeal of the DSU regulations, relied on the same grounds asserted here: “a number of large-scale prison disturbances and incidents of unusual violence” during 1992 and 1993 in Massachusetts prisons.
Notwithstanding the commissioner’s submission concerning the increased levels of violence at Cedar Junction and elsewhere, on September 26, 1995, a single justice of this court allowed a motion by the plaintiff-prisoners in the Hoffer case, to enjoin the repeal of the DSU regulations. The facts on which the commissioner relied and his arguments before the single justice all but mirror the claims made by the defendants in this case. For example, in 1995, the commissioner maintained before the *746single justice that “the DSU had outlived its usefulness” because “the climate in the state prison system had become more dangerous, due no doubt in part to severe overcrowding, inmates serving longer sentences, increased racial friction and a growing number of volatile, often gang-affiliated, younger inmates.” The same claim is made here. The commissioner argued before the single justice that ordering the defendants to provide certain due process procedures and substantive protections is no longer of “any practical effect” because “there are no DSU prisoners and the Commissioner has no intention of ‘designating’ any in the future.” The same claim is made here. None of these or related claims persuaded the single justice, and the regulations applicable to conditions of nondisciplinary segregation remained in effect. The commissioner did not appeal from the decision of the single justice, nor has the commissioner ever sought a reconsideration of that decision on the basis of any further or different information available to him.
D
All prisoners entering Cedar Junction are initially housed in the East Wing, including those who have failed in lower security institutions and are, as a result, being returned to Cedar Junction and prisoners who are initially classified to a maximum security institution — for example, those serving fife sentences.
The East Wing also houses prisoners transferred from the West Wing. A prisoner is moved from the West Wing to the East Wing solely at the discretion of the superintendent or his designee. According to the deposition testimony of Mark J. Powers, the superintendent’s designee at the times relevant to these cases, among the factors used in determining whether to transfer a prisoner from the West Wing to the East Wing are his disciplinary history, over-all adjustment, and “enemy” issues — i.e., concerns that prisoners housed in the same block might not get along well. He testified that the transfer of a prisoner from the West Wing to the East Wing is for reasons “usually surrounding disciplinary reports,” although it is undisputed that the transfer to the East Wing is not imposed for the commission of a disciplinary offense. A prisoner transferred from the West Wing to the East Wing receives no notice or hearing incident to the transfer.
*747E
As the motion judge found, the conditions of confinement in the East Wing are substantially similar to those that existed in the former DSU at Cedar Junction. While in the East Wing, prisoners are housed in isolation for extended periods each day, confined to their single-man cells except for brief specified periods when they may leave for a particular purpose. Prisoners housed in the East Wing do not interact with other prisoners and do not participate in collective activities. Prisoners in the East Wing receive ninety minutes of out-of-cell time seven days a week, while those prisoners in the former DSU received sixty minutes of outdoor recreation five days a week. But prisoners in the East Wing must use their out-of-cell “recreation” time for showers and telephone calls.17 The result is that prisoners in the East Wing do not receive significantly different out-of-cell time for exercise than those in the former DSU. Prisoners in both the former DSU and in the East Wing eat their meals in their cells and receive the same library and visitation privileges.
As to other restrictive conditions, the record reveals that there are no differences in issued clothing, religious services, educational opportunities, or programming between the former DSU and the East Wing. Prisoners in the former DSU received a greater canteen allowance ($50 a week) than prisoners in the East Wing ($30 a week). Work opportunities for prisoners in the East Wing do not match those in the DSU: there are almost no job opportunities in the East Wing; only three jobs per forty-five-man block exist in the East Wing. There were no such restrictions in the DSU.18
F
Prisoners housed in both the East Wing and the West Wing *748are entitled, as are all other prisoners housed by the department in any facility in the Commonwealth, no matter the level of security, to receive a review of their status every six months pursuant to 103 Code Mass. Regs. §§ 420.00.19 Beyond this postplacement, six-month classification review, the defendants do not provide any procedural protections before a prisoner is housed in the East Wing, or while he remains there. Notwithstanding the significant differences in restrictive conditions between the East and West Wings that have now been implemented, the classification reviews are the same for prisoners housed in both wings: the classification determines only in which level of security a prisoner is to be housed. If the prisoner is classified as requiring maximum security confinement, he is sent to Cedar Junction, space permitting. Beyond that, the decision to isolate some prisoners from the general population of those other prisoners also classified to maximum security is the entirely subjective and discretionary function of the prison authorities.
Moreover, the plaintiffs submitted an uncontroverted affidavit from a correctional expert, William H. Dallman, a former maximum security prison warden in Ohio with twenty-two years of correctional experience. Dallman, who has never before testified on behalf of prisoner-plaintiffs, reviewed the records containing the information on which the defendants relied in deciding which Cedar Junction prisoners to segregate in the East Wing. The motion judge found, based on Dallman’s unchallenged testimony, that the defendants do not comply with their own classification procedures. For example, fewer than fifteen per cent of prisoners are reviewed within one year of their initial placement in the East Wing.
Dallman’s unrebutted analysis of a representative sampling of 486 prisoners also showed that the defendants often failed to employ or ignored the results of their own system of classification. The defendants did not compile a classification *749score in 200 out of 486 cases, and in those cases in which scoring had been completed, the defendants ignored the results one-half of the time. Dallman concluded that sixty per cent of randomly selected prisoners and 140 of the 200 prisoners at Cedar Junction whose records he reviewed “were inappropriately placed in segregation” — i.e., were inappropriately confined in the East Wing according to the defendants’ own procedures, not his own subjective evaluation. Eighty-five per cent of prisoners in the nonrandom sampling did “not even arguably warrant segregation placement,” according to the defendants’ own procedures. Nearly one-half the records Dallman reviewed lacked not only justification for segregation, but lacked a basis for confining the prisoner to maximum security.
m
A
As noted earlier, the judge considered the plaintiffs’ due process claim under Sandin v. Conner, 515 U.S. 472 (1995), in which the United States Supreme Court recognized that under the Federal Constitution, a prisoner may have a “state-created” liberty interest only in remaining free from “restraint which . . . imposes atypical and significant hardship on the inmate in relation to the ordinary incidents of prison life.” Id. at 484.20 The Court held in that case that a prisoner’s confinement in segregation for thirty days because of a disciplinary violation “did not present the type of atypical, significant deprivation in which a State might conceivably create a liberty interest.” Id. at 486.
In this case, the motion judge concluded that the circumstances of the plaintiff-prisoner class are “entirely different” from those of the inmate in Sandin v. Conner, supra. He pointed out that no prisoner is assigned to the East Wing for disciplinary reasons, that prisoners in the East Wing “spend an indefinite *750period of time under essentially the same conditions as those facing disciplinary charges,” and concluded that the conditions in the East Wing are “nearly indistinguishable from a disciplinary sanction” and beyond the “range of confinement to be normally expected,” even at a maximum security facility. The judge contrasted the indefinite confinement of those in the East Wing, conceivably “through the entire length of their incarceration,” as compared to the fixed period of the thirty days at issue in the Sandin case.
The judge further held that the State had “create[dj” a liberty interest that triggered due process protections in the regulations applicable to the former DSU because “the conditions in the East Wing and Plymouth units are substantially the same as those which were present in the former DSU.” He specifically rejected the defendants’ claim that conditions in the East Wing are “less restrictive” than those in the former DSU. The judge also rejected the defendants’ claim that the East Wing is the “general population” of Cedar Junction as the sort of “pretextual semantic change aimed at avoiding compliance with regulations” we have criticized in the past. See Longval v. Commissioner of Correction, 404 Mass. 325, 328-329 (1989).
After concluding that there were no disputed material issues of fact and granting the plaintiffs’ motion for summary judgment as to their due process claim, the motion judge allowed the defendants’ motion for entry of separate and final judgment under Mass. R. Civ. P. 54 (b), 365 Mass. 820 (1974), as to that claim and stayed the aspect of the judgment requiring compliance with the DSU regulations pending appeal. The defendants have appealed, and we granted their application for direct appellate review.21
*751B
On appeal, the defendants assert that the due process mandated by 103 Code Mass. Regs. §§ 421.00 before subjecting prisoners to certain restrictive conditions of confinement “rests on outdated notions of liberty and due process rights of prisoners” and that the six-month classification review of all prisoners pursuant to 103 Code Mass. Regs. §§ 420.00 is adequate. They assert that the changes over the past twenty-five years in the operation of Cedar Junction have been for the purpose, of effectively managing a maximum security prison that houses a violent prisoner population. According to the superintendent’s affidavit, the “successful prosecution of gang affiliated crimes” has caused the prisoner population in the department to change “dramatically”: it is younger and more prone to “volatile and frequently gang-affiliated incidents.”
With the minor exception described above concerning recreation time, see note 17, supra, and accompanying text, the defendants do not dispute the facts concerning the conditions of confinement in the various housing areas of Cedar Junction or in the former DSU. Rather, they contend that the conditions of confinement in the East Wing are not the “functional equivalent” of confinement to the former DSU. To this end, they point out that, although it is undisputed that ninety-three per cent of the prisoners confined in the East Wing are not permitted to work, work for all prisoners is at the discretion of the commissioner, and that, under the DSU regulations, employment is also discretionary. The defendants also note small differences in the manner in which prisoners in the East Wing and the former DSU take their meals, exercise, and move outside of their cells.
The plaintiffs, relying on the defendants’ own documentatian,*75222 contend that the East Wing is a de facto DSU, and therefore the regulations governing the placement of prisoners into the DSU and its operation, which are still in effect despite the official closure of the DSU, should apply to prisoners housed in or transferred to the East Wing. They argue that the defendants’ position is consistent with a pattern of circumvention of the due process protections that prisoners subjected to restrictive confinement must be afforded under the Massachusetts and Federal Constitutions.
The plaintiffs claim that the conditions of confinement in the East Wing also constitute an “atypical and significant hardship” under Sandin v. Conner, 515 U.S. 472 (1995), based on the duration and the nature of the restrictive conditions to which they are subjected. In support of their claim, the plaintiffs offered the unrebutted affidavit of Dr. Stuart Grassian, a psychiatrist, that:
“ [Prolonged solitary confinement is highly toxic to psychological functioning. Inmates go into a kind of stupor, and some even become actively psychotic, agitated and paranoid. Difficulties with concentration and memory, and even overt confesional symptoms, are quite common. Intense anxiety, agitation, and panic attacks occur frequently. Many inmates become overtly paranoid — fearful and preoccupied with the ominous significance of every noise he hears and every shadow that passes his cell. Some inmates become unable to form any coherent string of thoughts; others become progressively, and obsessively, preoccupied with a particular thought or fear, entirely unable to quiet the thought or pay attention to anything else. Many inmates develop severe perceptual disturbances, including perceptual distortions and overt hallucinations.”
According to Dr. Grassian, a prisoner confined alone in a cell for extended periods is forced into idleness and restricted in his environment and social stimulation. There are extremely limited, if any, opportunities for educational, occupational, recreational, or social activities, and little opportunity to interact with or *753observe the outside world or to maintain family contacts. These hallmarks of solitary confinement, say the plaintiffs, are precisely the conditions that are present in the East Wing at Cedar Junction, and that were present in the former DSU.
IV
A
With this background, we address the parties’ cross motions for summary judgment. We have reviewed all of the evidentiary materials submitted in conjunction with those motions and agree with the carefully reached conclusion of the Superior Court judge that there is no genuine issue as to any material fact. Mass. R. Civ. P. 56 (c), 365 Mass. 824 (1974). See Attorney Gen. v. Bailey, 386 Mass. 367, 370, cert. denied sub nom. Bailey v. Bellotti, 459 U.S. 970 (1982); Beatty v. NP Corp., 31 Mass. App. Ct. 606, 607-608, 613 (1991), and cases cited.
We have considered, for example, in the light most favorable to the defendants, the material submitted regarding the amount of time East Wing prisoners are confined to their cells, out-of-cell time, exercise and recreation, meals (including how prisoners obtain and where they eat their meals), showers, telephone time, library access, employment opportunities, canteen privileges, opportunities to earn good time credits, access to educational and other programming, visits, and the availability of religious services. We have also considered the conditions of confinement in, and the regulations governing, the former DSU, and have compared these conditions with the conditions of confinement in the East Wing. We sometimes noted minor discrepancies, not only between certain statements provided on behalf of the parties, but also among statements submitted by each party. Nevertheless, not one of the differences creates a genuine issue of material fact. See Beatty v. NP Corp., supra at 608 (substantive law will identify which facts are material).
Moreover, as noted above, while the defendants submitted detailed information about the changing racial composition of the prisoner population (increases in African-Americans, Hispanics, and others who are labeled gang members), their assertions regarding an increase in violence in the prison do not *754contain any comparable level of detail. In fact, their assertions are mostly generalized statements about changes in conditions within the entire prisoner population housed by the department in all prisons in the Commonwealth, and are noticeably devoid of specific details of changes that have occurred at Cedar Junction itself. They are, in short, conclusory as to the legal issue at the core of the plaintiffs’ claim: the nondisciplinary segregation of some, but not all, prisoners classified as requiring maximum security housing. See Ng Bros. Constr., Inc. v. Cranney, 436 Mass. 638, 648 (2002) (“An adverse party may not manufacture disputes by conclusory factual assertions; such attempts to establish issues of fact are not sufficient to defeat summary judgment”); Polaroid Corp. v. Rollins Envtl. Servs. (NJ), Inc., 416 Mass. 684, 696 (1993) (affidavit must set forth specific facts showing genuine issue for trial; bare assertions and conclusions not enough to withstand well-pleaded motion for summary judgment). In the absence of a genuine issue as to any material fact, we consider whether the plaintiffs are entitled to judgment as a matter of law.
B
The prisoners claim that they are being confined in conditions so similar to those of the DSU that they are entitled to the protections of the DSU regulations. See Longval v. Commissioner of Correction, 404 Mass. 325 (1989). The Appeals Court recently termed the question whether prisoners in the East Wing are being housed in DSU-like conditions without being afforded the procedures mandated by DSU regulations as “particularly troubling.” Gilchrist v. Commissioner of Correction, 48 Mass. App. Ct. 60, 65 (1999). See note 4, supra. The isolation of prisoners in segregated confinement, including for nondisciplinary purposes, has been the source of constant appellate litigation.
In Longval v. Commissioner of Correction, supra, a prisoner challenged on constitutional and other grounds his transfer on two occasions to an administrative segregation unit (ASU) at the Massachusetts Correctional Institute at Concord (Concord) without a hearing and without the authorization of the commissioner. Id. at 327. Among other things, the prisoner *755argued that his placement in the ASU was the substantial equivalent of his being placed in a DSU because the conditions in the two segregation units were virtually identical. Id. at 328. We vacated the grant of summary judgment for the prisoner because there was in that case a dispute of material fact concerning the substantial similarity between the ASU and the DSU, and whether the ASU at Concord was “in practical effect” a DSU. Id. at 330. Although we remanded the case to the trial court to resolve these disputed factual issues, we cautioned that “the department and the commissioner may not sidestep statutory and regulatory provisions stating the rights of an inmate as to his placement in a DSU by assigning as a pretext another name to such a unit.” Id. at 328-329. See Royce v. Commissioner of Correction, 390 Mass. 425, 429-430 (1983) (prison administrators “may not abuse their discretion ... by using awaiting action status as a means to accomplish an unlimited punishment immune to the procedures set forth in the rules and regulations”).
The Appeals Court has reaffirmed that the commissioner may not place prisoners in segregation for nondisciplinary reasons with conditions as severe as those of a DSU without the procedural protections afforded by 103 Code Mass. Regs. §§ 421.00. See, e.g., Martino v. Hogan, 37 Mass. App. Ct. 710, 721 (1994) (“where the conditions in a segregation unit, however named by the correction officials, were as severe as those at the DSU, the unit should be dealt with, at least for such purposes as requirements of hearings and so forth, as a DSU”). See also Gilchrist v. Commissioner of Correction, 48 Mass. App. Ct. 60, 64 (1999), quoting Longval v. Commissioner of Correction, supra at 328 (whether plaintiff “was entitled to the procedural protections set out in the regulations governing DSUs depended upon whether his ‘placement in [restrictive confinement] . . . was shown to be the substantial equivalent of his being placed in a . . . DSU’ ”). In several such cases, disputes as to material facts precluded the entry of summary judgment. See, e.g., Gilchrist v. Commissioner of Correction, supra at 64-66; DeLong v. Commissioner of Correction, 46 Mass. App. Ct. 353, 357 (1999) (record lacked “factual wherewithal” for comparing conditions suffered by plaintiff “with existing condi*756tians of the general population, of other forms of segregation, and of the range of confinement expected for inmates serving the same sentence as the plaintiff”).
In this case the record is fully developed, and there are no disputes as to material facts. The motion judge had available to him the decision of the Appeals Court in Gilchrist v. Commissioner of Correction, supra, and was careful to specify with particularity his reasons for determining that there were no disputed issues of material fact and that “[t]he evidence in the record demonstrates that the conditions of confinement in the East Wing and Plymouth units are substantially the same as those found in the former DSU . . . .’’On our own review of the record we reach the same conclusion.
In determining whether the conditions in the East Wing are as severe as those in the DSU such that due process protections are warranted, we pay particular attention to those deprivations that were the essence of confinement for nondisciplinary reasons in the DSU: the segregation of a prisoner in near solitary confinement, for no specified period.23 As discussed in detail above, the degree of segregated confinement experienced by prisoners in the East Wing in every material respect is every bit as harsh — both in extent and duration — as confinement in the DSU. Despite the defendants’ claim that there are differences in the conditions of confinement between the East Wing and in the former DSU, such differences are insignificant, while the essence of confinement is the same in each unit.24 Prisoners are placed in segregation for an indefinite period of time, not for *757any specific disciplinary reason (for which they would be sent to the DDU and afforded the procedural protections in 103 Code Mass. Regs. §§ 430.00), but rather because of the prison authorities’ subjective evaluation of their behavior in general. Differences in the specific amount of time a prisoner spends out of his one-man cell for particular purposes (showers or telephone calls), or the manner in which he receives his food or goes to the library, are insignificant where the explicit nature of the housing is segregation from the general prison population and constitutes, in effect, solitary confinement.
The indefinite term of a prisoner’s segregation in the East Wing is one other, critical similarity between the East Wing and the former DSU. As we noted in Hoffer v. Commissioner of Correction, 412 Mass. 450, 456 (1992), a prison resident who is not provided with a conditional release date from segregated confinement and with conditions by which to guide his behavior “is possibly subjected to arbitrary treatment.”25 Moreover, “[wjithout the benefit of knowing what is expected of him while segregated, the resident is denied the opportunity to work toward improving his situation.” Id. Because the prisoner does not know when or how his confinement in segregation will end, he is denied “a meaningful incentive to modify his behavior and conform to prison regulations.” Id.
The thrust of the defendants’ response to the overwhelming factual record that conditions in the East Wing are in substantial measure identical to those in the DSU is to argue that prison conditions have changed since the order of the single justice in 1988 requiring the process set out in the DSU regulations. As we noted earlier, it is the defendants’ actions at Cedar Junction that are at issue in this case, and there is scant record support *758for any significant changes in that institution. As we explained earlier, in 1995 the commissioner attempted to repeal the DSU regulations, but his attempt to do so was enjoined by a single justice of this court.26 The commissioner did not appeal from the order of the single justice, nor does the record reflect that he has made any subsequent attempt to modify or repeal the regulations. The defendants would ignore that the regulations have the full force of law. See Kenney v. Commissioner of Correction, 393 Mass. 28, 34 (1984); Royce v. Commissioner of Correction, 390 Mass. 425, 427 (1983). See also Purity Supreme, Inc. v. Attorney Gen., 380 Mass. 762, 768-769 (1980), quoting DaLomba’s Case, 352 Mass. 598, 603 (1967) (rules promulgated pursuant to legislative grant of power “generally have the force of law”).27
The dissent states that there is “overwhelming support in the record for the conclusion that the reconfiguration [of Cedar Junction] was necessary to secure the safety of prisoners and staff alike, in the context of an unprecedented influx of violent gang members.” Post at 765. That generalized statement glosses over the real deficiencies in the defendants’ factual submissions. What is challenged in this lawsuit is the actions of the defendants concerning some, but not all, prisoners who are classified as requiring maximum security and are thus housed in Cedar Junction. Absent from the record is evidence of any changes in the numbers of prisoners convicted of gang-related crimes who are incarcerated at Cedar Junction rather than other prisons, evidence of changes in the number of prisoners housed at Cedar Junction who have some gang affiliation, or evidence of overcrowding at this maximum security prison as opposed to other prisons, to name but a few examples. The evidence of the defendants on these points is “overwhelming” only in that *759generalized conclusions, unsupported by facts as to conditions at Cedar Junction, are oft repeated in the affidavits and deposition testimony of the defendants.
The dissent also cites to evidence in the summary judgment record concerning the increase in over-all size of the Massachusetts prisoner population, at the same time that the number of correction officers decreased. Post at 774-775. There is little if anything in the record linking these global changes to Cedar Junction. There is no claim of overcrowding at Cedar Junction itself. There is nothing in the record concerning a change in the ratio of guards to prisoners at Cedar Junction. While there is record support for the number of incidents during in 1995 in which guards used force against the prisoners at Cedar Junction, the record contains no evidence of comparable numbers in other years. The dissent’s description of “an unprecedented influx of violent gang members,” post at 765, is simply not supported as to the prison at issue in this litigation.28
Even if, by the summer of 1995 when the defendants embarked on the operational changes at issue here, “the climate in the state prison system had become more dangerous,” and even if the defendants were confronted by “severe overcrowding, inmates serving longer sentences, increased racial friction and a growing number of volatile, often gang-affiliated younger inmates,” as one of the defense affiants stated, the defendants’ response to the problem — the placement of some prisoners classified to Cedar Junction into segregated confinement in near solitary conditions — violates a regulatory framework that mandates that prisoners segregated for nondisciplinary reasons are entitled to the procedural protections of due process. That regulatory framework was specifically promulgated to deal with, in part, those violent prisoners who are assigned to Cedar Junction.
The defendants’ suggestion that the procedural protections contained in 103 Code Mass. Regs. §§ 421.00 are applicable *760only to those housing placements that the commissioner may choose to label as “departmental segregation units” has been rejected, more than once. See, e.g., Longval v. Commissioner of Correction, 404 Mass. 325 (1989); Martino v. Hogan, 37 Mass. App. Ct. 710, 721 (1994). The regulations are applicable to all placements of prisoners in segregated confinement for nondisciplinary reasons for an indefinite period of time; in other words, those prisoners whom prison authorities determine will interfere with the management of the prison unless they are segregated from the general prison population. The procedures are tailored to address precisely such housing placements: the inquiry focuses not on whether a prisoner has committed a specific infraction for which discipline may be warranted for a particular period, but on whether his conduct generally warrants long-term segregation.29 Those procedural protections “reflect the understanding that commitment of a resident to a segregation unit results in a significant reduction of that resident’s liberties.” Hoffer v. Commissioner of Correction, 412 Mass. 450, 455 (1992).
We also reject the defendants’ claim, as did the motion judge, that the prisoners in the East Wing comprise the “general population” of Cedar Junction. We agree with the motion judge that such labeling is nothing more than a “pretextual semantic change.”30 Nor is there merit to the dissent’s position that to conclude that the East Wing is substantially similar to the DSU *761requires a finding that there is a single general population in Cedar Junction and that the general population consists only of the prisoners housed in the West Wing. Post at 769-771. Title 103 Code Mass. Regs. § 423.06, provides that the East Wing and the West Wing are the “general population” of Cedar Junction: neither is a special management unit, health service unit, DSU, DDU, or protective custody unit.31 The regulatory scheme contained in 103 Code Mass. Regs. §§ 421.00 precludes the defendants from subjecting some prisoners confined to this maximum security institution to segregation for nondisciplinary reasons without due process. In short, the defendants may not circumvent the applicable regulations by labeling assignment to nonsegregated conditions in the West Wing “an incentive and reward for the positive behavior of prisoners,” in the words of the dissent. Post at 767. Nothing in the regulations precludes prison authorities from rewarding those prisoners actually convicted of gang-related crimes if they participate in the *762department’s Security Threat Group Program.32 Nothing precludes the department from segregating from the general population those prisoners who it is determined, consistent with due process, must be segregated to prevent injury to others or the interruption of the safe operation of the prison. Nothing prevents the defendants from undertaking “major operational changefs]” at Cedar Junction. Post at 766. But all such changes must conform to regulatory and constitutional requirements. It is the unreviewable, subjective selection of only some maximum security prisoners to be housed in severe and segregated conditions that gives rise to the constitutional problem. That problem is not “resolved” by dramatically increasing the number of prisoners who are treated in this manner.33 The plaintiffs have established that the basis of their assignment to isolated conditions is seriously flawed, their tenure in segregation indefinite and dependent only on the defendants’ subjective discretion, not subject to review. The existing regulatory scheme does not permit the defendants to act in that manner.
V
We recognize the obligation of the commissioner and other officials of our prison system to maintain security in all institutions under their jurisdiction, and to ensure the safety of all who work there, as well as the prisoners themselves. Prison overcrowding, longer prison sentences, and the prosecution of gang-related crimes have made prison management throughout our prison system more difficult. But the solution cannot be found in violation of a constitutionally required regulatory scheme, one that continues to have the force of law. The commissioner has not challenged the testimony of the prisoners’ expert that a substantial number of the certified class are inap*763propriately segregated from other prisoners and that the records of others lack any basis for confinement in a maximum security institution in the first place.34 The purpose of the DSU regulations was to “establish rules” whereby an inmate may be placed in segregation “because his continued presence in a general institution population would be detrimental to the program of the institution,” such that improper subjective evaluation of individual prisoners would be subject to review. 103 Code Mass. Regs. § 421.01. The regulations must be complied with. See Longval v. Commissioner of Correction, supra at 328-329.
We affirm the decision of the motion judge that the procedural protections contained in 103 Code Mass. Regs. §§ 421.00 must be afforded to all prisoners before they are housed in DSU-like conditions operating today in the East Wing, subject only to the exception next described: all prisoners entering Cedar Junction, including some for whom there is no expectation that they will remain at that facility, apparently are first placed in the East Wing. Some are then quickly classified to other institutions, or are moved into the West Wing, perhaps in a matter of days.35 For those prisoners whose stay in the East Wing is intended to be, and is, brief, the procedural protections are not required because their placement in the East Wing implicates a lesser deprivation of individual liberty than it does for the prisoners whose confinement to the East Wing is lengthy or indefinite.
Accordingly, we affirm the grant of summary judgment on the plaintiffs’ due process claim to the extent that it applies to those prisoners who are (1) transferred to the East Wing from the West Wing; (2) labeled as gang members and placed in the Plymouth or other units of the East Wing; (3) returned to Cedar Junction; or (4) remain in the East Wing for longer than a brief period for “booking” or similar reasons. For these prisoners, the procedural protections set forth in 103 Code Mass. Regs. *764§§ 421.00 are required. We vacate so much of the order as may apply to prisoners sent to the East Wing of Cedar Junction initially on confinement in the expectation that their stay there will be brief.36
The policy of the department to place certain prisoners at Cedar Junction in segregated conditions for nondisciplinary reasons has been in effect since at least 1995, and there are now several hundred prisoners housed in the East Wing in such conditions. The judge in the Superior Court stayed his injunction against such segregated confinement pending this appeal. To ensure that the defendants may effectuate the injunction in an orderly and safe manner, the case is remanded to the Superior Court judge for further proceedings consistent with this, opinion, and to determine the timing and manner of implementing the provisions of 103 Code Mass. Regs. §§ 421.00 at Cedar Junction.
So ordered.
See, e.g., Hudson v. Commissioner of Correction, 431 Mass. 1 (2000); Torres v. Commissioner of Correction, 427 Mass. 611 (1998); Hastings v. Commissioner of Correction, 424 Mass. 46 (1997); Longval v. Commissioner of Correction, 404 Mass. 325 (1989); Kenney v. Commissioner of Correction, 393 Mass. 28 (1984); Royce v. Commissioner of Correction, 390 Mass. 425 (1983); Puleio v. Commissioner of Correction, 52 Mass. App. Ct. 302 (2001); Drayton v. Commissioner of Correction, 52 Mass. App. Ct. 135 (2001); DeLong v. Commissioner of Correction, 46 Mass. App. Ct. 353 (1999); Martino v. Hogan, 37 Mass. App. Ct. 710 (1994).
On November 15, 1995, a judge in the Superior Court certified an open class of plaintiff-prisoners as defined above. The representative class is 536 prisoners as of October 13, 1999.
The lockdown began on April 3, 1995, in the wake of a disturbance. During the lockdown, prisoners were kept almost continuously in their cells for more than four months: they were allowed out of their cells only for twenty to thirty minutes, twice each week.
On April 19, 1995, the commissioner informed all prisoners housed by the department that “inmates who are members of security threat groups win not be permitted to transfer below medium security” and that a prisoner who is a “leader of any of these groups or any inmate involved in a security threat group incident will be subject to transfer to restrictive housing at MCI-Cedar Junction.”
The motion judge found that, although only twenty per cent of the prison population is Hispanic, ninety per cent of all prisoners labeled as gang members are Hispanic. The motion judge held that this disparity combined with a “pervasive atmosphere of racism” at Cedar Junction established a prima facie case of intentional discrimination. Nevertheless, the judge denied the plaintiffs’ motion for summary judgment on the equal protection claim and ordered that claim to trial, finding that the defendants’ denial of improper racial animus, however “limited,” raised disputed issues of material fact as to the implementation of the department’s gang policy.
The plaintiffs also sought relief under the Federal and State Constitutions based on the conditions of confinement during the lockdown and for the defendants’ “permitting and encouraging the excessive, malicious, and sadistic use of force” against them. The plaintiffs contended that these issues had become moot since the end of the lockdown, but the motion judge in his memorandum and order on the parties’ cross motions for summary judgment noted that the complaint did not specify when these practices were alleged to have occurred. The judge found that there were genuine issues of material fact regarding these issues and indicated that they would be resolved in an evidentiary hearing. On October 4, 2000, the plaintiffs voluntarily dismissed their “claim of systemic abuse of force” pursuant to Mass. R. Civ. P. 41 (A) (1) (ii), 365 Mass. 803 (1974), and on October 12, 2000, a judgment entered in the Superior Court dismissing these claims pursuant to Mass. R. Civ. P. 58 (a), as amended, 371 Mass. 908 (1977). That claim is not before us.
The dissent characterizes the West Wing as the “minimum wing” and the Bast Wing as the “maximum wing” of Cedar Junction. Post at 765. The entire institution is, and always has been, a maximum security prison. Lest there be no misunderstanding, we recognize that Cedar Junction, the Commonwealth’s only long-time maximum security prison, has always housed the Commonwealth’s most dangerous prisoners. The dissent’s characterization of the prison environment, however, as “unimaginably dangerous,” post at 766, which it has been for decades, see, e.g., Commonwealth v. Brown, 364 Mass. 471, 476 (1973), obscures the issue in this case: whether the defendants can, without any procedural due process protections, select some of these dangerous prison*743ers at Cedar Junction for nondisciplinary segregation in violation of existing regulations.
The East Wing segregation unit and the West Wing segregation unit are located in the same physical spaces at Cedar Junction as the former departmental segregation unit (DSU), described infra. Both units are distinct from the departmental disciplinary unit (DDU), to which prisoners may be confined as a disciplinary sanction in conformance with 103 Code Mass. Regs. §§ 430.00 (1993).
The conditions of confinement are the same in each of the two segregation units: they are more severe than the conditions in the West Wing and substantially similar to conditions in the East Wing.
Prisoners housed in the East Wing, including those in the Plymouth units, also receive two hours of library access and two hours of visitation each week.
The “canteen” is a prison commissary, from which prisoners can purchase various personal hygiene and food items.
An uncontested representative sampling of the plaintiff class shows that the 200 longest stays in the East Wing averaged 456.1 days; the fifty longest, 739.8 days; the twenty longest, 890.5 days; and the ten longest 981.0 days.
The regulations were designed to, and do, cabin the power of the prison officials to isolate any prisoner (including those in maximum security conditions) from other prisoners based solely on the subjective evaluation of the prisoner by the prison authorities. Thus, the regulations provide for, among other things, a written referral summary prior to the hearing before the DSU board, prior written notice of the hearing, the right to be represented at the hearing, the right to request that certain witnesses testify and to cross-examine adverse witnesses, and the right to a record of the hearing. See 103 Code Mass. Regs. §§ 421.10 & 421.11. Each prisoner placed in a DSU receives a review of his states every ninety days, 103 Code Mass. Regs. § 421.18, as well as monthly evaluations summarizing his current behavior and recommendations for releasing him from the DSU. 103 Code Mass. Regs. § 421.19.
Prisoners in the former DSU were allowed three showers a week, which apparently did not count against the time that they had out of their cells for recreation; prisoners in the former DSU could place three telephone calls a week from their cells.
Although the defendants claim that prisoners in the former DSU received “no work opportunities,” the DSU regulations in fact provide for employment programs. See 103 Code Mass. Regs. § 421.21 (3). To the extent that the defendants failed to provide any employment opportunities whatsoever to prisoners in the former DSU, they appear to have been in violation of the DSU regulations.
Title 103 Code Mass. Regs. §§ 420.00 provides generally that a prisoner receives an initial classification hearing, of which he receives notice and in which he has the right to participate, the right to a written summary, the right to appeal to the superintendent, and subsequent classification hearings at least every six months.
The judge did not distinguish between the plaintiffs’ due process claim under the Massachusetts and United States Constitutions, but analyzed the claim through (as he put it) the “lens” of Sandin v. Conner, 515 U.S. 472, 474 (1995), decided under the due process clause of the Fourteenth Amendment to the United States Constitution.
The motion judge’s decision was issued following the decision of the Appeals Court in Gilchrist v. Commissioner of Correction, 48 Mass. App. Ct. 60 (1999). There, the plaintiff-prisoner claimed that his internal move from the West Wing to the East Wing violated his due process rights guaranteed by both the State and Federal Constitutions because he was not afforded the process set forth in 103 Code Mass. Regs. §§ 421.00. The Appeals Court vacated the grant of summary judgment to the prisoner holding that the record did not include sufficient evidence to compare the prisoner’s living conditions in restrictive confinement with conditions present in the DSU. On remand to the Superior Court, the parties filed an agreed motion to consolidate actions *751and stay proceedings, which was allowed on February 16, 2000. The undisputed record evidence once absent is now present. The issues of law presented in the Gilchrist case have been consolidated into this case in accordance with Mass. R. Civ. P. 42 (a), as amended, 423 Mass. 1402 (1996). See note 3, supra.
We are informed that the proceedings in several cases presenting due process claims similar to the one raised here have been stayed pending the outcome of this case.
The motion judge also relied on documents “produced by the Department for dissemination to the inmates for orientation purposes.”
As the motion judge correctly noted, the United States Supreme Court has focused its inquiry on the degree of restriction — e.g., the amount of time a prisoner is confined to his cell — and the length of time the prisoner is subjected to the more restrictive conditions as critical factors in determining whether the prisoner is entitled to due process protections. Sandin v. Conner, 515 U.S. 472, 486 (1995).
The dissent concedes that the conditions of confinement in the East Wing and in the former DSU are “similar in some respects,” with a prisoner’s isolation as the “point of greatest similarity.” Post at 767. It is, of course, the isolation of prisoners that gave rise to the constitutional necessity for the DSU regulations in the first place. As to differences between the DSU and the East Wing, the dissent notes only that prisoners in the former DSU exercised outdoors, alone, in a 350 square foot exercise cage, while prisoners in the East Wing exercise outdoors fifteen at a time in a 5,000 square foot exercise yard. Post at 768. Such differences are insignificant and immaterial where the explicit *757nature of East Wing confinement is nondisciplinary segregation from the general prison population, and where the time during which prisoners can participate in collective activities is minimal.
It is undisputed that prisoners housed in the East Wing are neither given a release date from segregated confinement, nor are they told what behavior will qualify them for placement in the West Wing, or what behavioral modifications will result in their transfer out of the East Wing. There is no meaningful review of a prisoner’s conduct while in the East Wing. Indeed, as described by Dallman, and not contested by the defendants, many prisoners housed in the East Wing do not receive even the six-month review mandated by 103 Code Mass. Regs. §§ 420.00.
The dissent recognizes, post at 768, that the “the merits of that ruling are not now before us”: that final order, never appealed, has the full force of law. Neither this court, nor any other, has suggested that the decision reached by the single justice is incorrect in any respect.
The defendants make a fleeting suggestion that the DSU regulations are “no longer of any force and [e]ffect” because the commissioner exercised his authority to “repeal” them following the closure of the DSU. The claim is without merit for, as noted, a single justice of this court enjoined the repeal of the DSU regulations.
There is no requirement that the moving party dispute facts that are not material to the claim for which summary judgment is sought. While the commissioner is “not required to set forth his entire defense to the plaintiffs’ claims to defeat a motion for summary judgment,” as the dissent notes, post at 774 n.15, the defendants are, of course, required to produce evidence sufficient to create a genuine dispute of material fact. They have not done so.
The dissent concedes that, “[i]n 1985, prisoners who posed a danger to other prisoners, prison property, or the safe operation of the prison while living within the general population could be removed from that population and placed in a DSU where conditions were significantly more restrictive.” Post at 768. There is nothing to suggest that these dangerous prisoners were any less so in 1985, and the single justice concluded that segregation of even dangerous prisoners could only occur if certain due process protections were in place, such that the subjective views of prison authorities was conditioned on appropriate standards subject to review. The dissent further concedes that prisoners housed in the East Wing are kept there at “the discretion of the superintendent.” Post at 767. It is just this “discretion” that the due process protections in the regulations are designed to ensure is properly exercised.
Contrary to the dissent’s claim, the motivations of the defendants in segregating some prisoners in the East Wing is irrelevant to the plaintiffs’ due process claim. Nothing in Longval v. Commissioner of Correction, 404 Mass. 325 (1989), suggests, let alone requires, that the motivation of the defendants in creating a system of housing is an element of a plaintiff-prisoner’s due *761process claim. The review is an objective one, as the motion judge correctly understood. Still less is pretext, as used in discrimination cases, of any relevance. Post at 772 n.ll. Rather, as Justice Kaplan has noted, Longval v. Commissioner of Correction, supra, “suggested that where the conditions in a segregation unit, however named by the correction officials, were as severe as those at the D.S.U., the unit should be dealt with, at least for such purposes as requirements of hearings and so forth, as a D.S.U.” Martino v. Hogan, 37 Mass. App. Ct. 710, 721 (1994).
We note that the superintendent describes the organization of Cedar Junction as containing “a number of different general population housing units with attendant, but not significantly different, levels of privileges.” Assistant Deputy Commissioner Ronald Duval describes both the East Wing and the West Wing as the. “general population” at Cedar Junction. Duval’s affidavit of July 10, 1995, further describes Cedar Junction as housing “an inmate population of 858 of which 734 inmates are housed in general population.” The dissent ignores the regulatory definition of “general population,” stating that the “general population” is where the “majority of prisoners normally live.” Post at 770. What constitutes the “general population” is not determined by the number of prisoners confined to a particular area, nor is it dependent on a particular physical location of prisoners, as the dissent assumes. Post at 770. The applicable regulations, 103 Code Mass. Regs. §§ 421.00, prohibit the segregated confinement of some prisoners for nondisciplinary reasons without due process. Whether such prisoners are housed in a unit labeled a disciplinary segregation unit or in only one wing at Cedar Junction is not relevant to the applicability of the regulations.
The Spectrum program, described by the dissent, is a compelling example that the defendants can, and do, address issues of prison violence and gang membership without violating regulations governing the treatment of prisoners. See post at 767 n.4.
That “two-thirds” or a “majority,” post at 764, of prisoners at Cedar Junction are housed in the East Wing, as the dissent notes, is not material: the number of prisoners subjected to near-solitary conditions for nondisciplinary reasons does not vitiate the legal obligation of the defendants to comply with extant regulations that govern the placement of prisoners in such conditions.
The dissent takes issue with the analysis of the plaintiffs’ expert, William H. Dallman, as not relevant. See post at 774 n.16. To the contrary, it lends further support to the plaintiffs’ argument that their segregated confinement occurs in violation of the very harm the DSU regulations were promulgated to prevent.
A deputy superintendent of Cedar Junction testified that the “majority of inmates in the Commonwealth who are committed remain at [Cedar Junction] generally overnight. They are booked in and pictures [are] taken and then they are moved out to Concord the following day.”
The record does not reveal the average number of days that prisoners who are being “processed through” the East Wing remain there before they are transferred to other institutions or the West Wing. When we say “brief,” we have in mind days, not weeks. The defendants may “not postpone indefinitely the happening of the events that will terminate” the undefined status of such prisoners. Royce v. Commissioner of Correction, 390 Mass. 425, 430 (1983).