The question before us concerns the constitutionality of § 230(3) of the New York Correction Law, McKinney's Consol.Laws, c. 43, which denied appellee state prisoners 'good time' credit for their presentence incarceration in county jails.1 Appellees claim that disallowing such credit to them while permitting credit up to the full period of ultimate incarceration for state prisoners who were released on bail prior to sentencing deprived them of equal protection of the laws. The three-judge District Court, one judge dissenting, upheld their claim, 332 F.Supp. 973 (1971). The Commissioner of Correction and other officials (hereafter Commissioner) have appealed and we noted probable jurisdiction, 405 U.S. 986, 92 S.Ct. 1247, 31 L.Ed.2d 452 (1972).2

The challenged New York sentencing system is a complex one, and some basic definitions are required at the outset. Jail time denotes that time an individual passes in a county jail prior to trial and sentencing. Good time is awarded for good behavior and efficient performance of duties during incarceration. Both good time and jail time figure variously in the calculations of a series of release dates that each prisoner receives upon his arrival at state prison. Each inmate has both a minimum parole date, which is the earliest date on which he may be paroled at the discretion of the Parole Board, and a statutory release date which is the earliest date he must be paroled by the Parole Board.3 The minimum parole date is calculated under §§ 230(2) and 230(3) by subtracting the greatest amount of good time that can be earned (10 days per month) from the minimum sentence of an indeterminate term.4 The statutory release date is calculated under § 230(4) by subtracting the greatest amount of good time that can be earned (5 days per month) from the maximum sentence of an indeterminate term.

Although appellees did receive jail-time credit for the period of their presentence incarceration in county jail, § 230(3) explicitly forbids, in calculating the minimum parole date, any good-time credit for the period of county jail detention served prior to transfer to state prison.5 Appellee Royster, being unable to post bail, served 404 days' jail time in the Nassau County Jail prior to his transfer to state prison to serve consecutive 5-to-10-year terms for burglary in the third degree and grand larceny in the first degree. Appellee Rutherford also failed to make bail and spent 242 days' jail time in Nassau County Jail prior to his trial, sentencing, and transfer to state prison for concurrent terms of 10 to 20 years for robbery in the first degree and two and one-half to five years for grand larceny in the second degree. It is undisputed that, were appellees Royster and Rutherford to receive good-time credit for their presentence confinement in county jail, they would be entitled to appear before the Parole Board approximately four and three months earlier, respectively, than under the computation required by § 230(3).

Two additional points merit mention. While New York does deny good-time credit for jail time in computing the minimum parole date under §§ 230(2) and (3), it allows such credit in calculating the statutory release date under § 230(4).6 Finally, § 230(3) itself provides that good-time credit for jail time shall be awarded to those prisoners confined after sentence in county penitentiaries, as opposed to those convicted of felonies, such as appellees, who are transferred after sentence to state prison.7

* Section 230(3) of the New York Correction Law does, as appellees note, draw a distinction 'between the treatment of state prisoners incarcerated prior to sentencing and those who were not similarly incarcerated.'8 Appellees contend that 'denying state prisoners good-time credit for the period of their pre-sentence incarceration in a County Jail whereas those fortunate enough to obtain bail prior to sentence (receive) a full allowance of good time credit for the entire period which they ultimately spend in custody'9 violates equal protection of the laws and discriminates against those state prisoners unable to afford or otherwise qualify for bail prior to trial.

We first note that any relative disadvantage the distinction works on appellees is lessened by the fact that New York on September 1, 1967, replaced § 230 of its Correction Law with §§ 803 and 805, which apply to all convictions for offenses after that date.10 Under the new scheme, 'good time earned on the minimum sentence is abolished. A prisoner meets with the Parole Board at the expiration of his minimum term, regardless of how much good time he has earned or of how much time he spent in jail prior to arriving at state prison.'11 New York has given appellees—and all those sentenced for offenses committed prior to September 1, 1967—a chance to elect the new procedure, but appellees declined to do so. Appellees thus enjoy at least as favorable a position as all state prisoners convicted for offenses committed subsequent to September 1, 1967, including those released on bail prior to sentence. Appellees thus are disadvantaged in the computation of time only in comparison with those who were convicted of offenses committed prior to September 1, 1967, and made bail prior to trial. Even the adverse impact of this difference is lessened, though not eliminated, by the fact that New York did not deprive appellees of credit for the full amount of actual time spent in jail prior to trial and sentencing but only of the potential additional 10 days per month of good time ordinarily available under § 230(2) to inmates for good conduct and efficient performance of duty.12

We note, further, that the distinction of which appellees complain arose in the course of the State's sensitive and difficult effort to encourage for its prisoners constructive future citizenship while avoiding the danger of releasing them prematurely upon society. The determination of an optimal time for parole eligibility elicited multiple legislative classifications and groupings, which the court below rightly concluded require only some rational basis to sustain them. James v. Strange, 407 U.S. 128, 140, 92 S.Ct. 2027, 2034, 32 L.Ed.2d 600 (1972); Lindsey v. Normet, 405 U.S. 56, 73—74, 92 S.Ct. 862, 874—875, 31 L.Ed.2d 36 (1972); Schilb v. Kuebel, 404 U.S. 357, 92 S.Ct. 479, 30 L.Ed.2d 502 (1971); Dandridge v. Williams, 397 U.S. 471, 487, 90 S.Ct. 1153, 1162, 25 L.Ed.2d 491 (1970). Appellees themselves recognize this to be the appropriate standard.13 For this Court has observed that '(t)he problems of government are practical ones and may justify, if they do not require, rough accommodations, illogical, it may be, and unscientific.' Metropolis Theatre Co. v. City of Chicago, 228 U.S. 61, 69—70, 33 S.Ct. 441, 443, 57 L.Ed. 730 (1913). We do not wish to inhibit state experimental classifications in a practical and troublesome area, but inquire only whether the challenged distinction rationally furthers some legitimate, articulated state purpose. We conclude that it does.

The Commissioner defends the distinction by noting that 'state prisons differ from county jails with respect to purpose, usage and availability of facilities.' State prisons are 'intended to have rehabilitation as a prime purpose and the facilities at these institutions are built and equipped to serve this purpose.' The Commissioner cites the presence at state prisons of 'educational and vocational services such as schools, factories, jobtraining programs and related activities.'14 At argument, the Commissioner noted: 'We have barber shops. We teach trades. We manufacture a lot of goods. . . . Greenhaven State Prison has a textile factory.'15

We pass no judgment on the success or merits of the State's efforts, but note only that at state prisons a serious rehabilitative program exists. County jails, on the other hand, serve primarily as detention centers. The State asserts they are 'neither equipped nor intended to do anything more than detain people awaiting trial and maintain no schools, run no factories and require no work from these inmates.'16 While appellees do point to the existence of some rehabilitative or recreational facilities within some county jails,17 it is clear that nothing comparable to the State's rehabilitative effort exists.

These significant differences afford the basis for a different treatment within a constitutional framework. We note that the granting of good-time credit toward parole eligibility takes into account a prisoner's rehabilitative performance. Section 230(2) of the New York Correction Law authorizes such credit toward the minimum parole date 'for good conduct and efficient and willing performance of duties assigned (emphasis added).'18 The regulations of the New York Department of Correction, 7 N.Y.C.R.R. § 260.1(a), state that: '(T)he opportunity to earn good behavior allowances offers inmates a tangible reward for positive efforts made during incarcertation (emphasis added).'19 As the statute and regulations contemplate state evaluation of an inmate's progress toward rehabilitation, in awarding good time,20 it is reasonable not to award such time for pretrial detention in a county jail where no systematic rehabilitative programs exist and where the prisoner's conduct and performance are not even observed and evaluated by the responsible state prison officials. Further, it would hardly be appropriate for the State to undertake in the pretrial detention period programs to rehabilitate a man still clothed with a presumption of innocence. In short, an inmate in county jail is neither under the supervision of the State Correction Department nor participating in the State's rehabilitative programs. Where there is no evaluation by state officials and little or no rehabilitative participation for anyone to evaluate, there is a rational justification for declining to give good-time credit.21

We do not agree with the court below that the integrity of appellants' assertions as to rehabilitation is undermined by the fact that the State does grant under § 230(3) good-time credit for presentence jail time to county penitentiary inmates and under § 230(4) to state prisoners for the purpose of calculating their statutory release dates.22 The legislature could have concluded rationally that county penitentiary inmates, who are nonfelons with less than one-year sentences, required quantitatively and qualitatively less rehabilitation—with fewer risks of misevaluation—than inmates confined to state prison for more serious crimes. And the legislature could rationally have distinguished between the minimum parole date and the statutory release date on the ground that an acceleration of the minimum parole date posed a greater danger that an inmate would be released without adequate exposure to rehabilitative programs and without adequate evaluation by prison officials. Thus, New York's decision to deny good-time credit for presentence jail time solely with respect to a state prisoner's minimum parole date is rationally justified on the ground that the risk of prematurely releasing unrehabilitated or dangerous criminals may well be greatest when the parole decision is made prior to expiration of the minimum sentence.

Neither appellees nor the court below contended that increased opportunity for state evaluation of an inmate's behavior and rehabilitative progress was not a purpose of the challenged provision of § 230(3). Appellees state only that the rehabilitative purpose was not the 'overriding' one,23 and the District Court noted that 'the legislature's primary aim in enacting the good the statute was to foster and insure the maintenance of prison discipline.' 332 F.Supp. at 978 (emphasis added).24 We do not dispute these statements: the disciplinary purpose is certainly an important and possibly the 'primary' aim of the legislation.25 Yet, out decisions do not authorize courts to pick and choose among legitimate legislative aims to determine which is primary and which subordinate. Rather, legislative solutions must be respected if the 'distinctions drawn have some basis in practical experience,' South Carolina v. Katzenbach, 383 U.S. 301, 331, 86 S.Ct. 803, 820, 15 L.Ed.2d 769 (1966), or if some legitimate state interest is advanced, Dandridge v. Williams, 397 U.S., at 486, 90 S.Ct., at 1162. So long as the state purpose upholding a statutory class is legitimate and nonillusory, its lack of primacy is not disqualifying.

When classifications do not call for strict judicial scrutiny, this is the only approach consistent with proper judicial regard for the judgments of the Legislative Branch. The search for legislative purpose is often elusive enough, Palmer v. Thompson, 403 U.S. 217, 91 S.Ct. 1940, 29 L.Ed.2d 438 (1971), without a requirement that primacy be ascertained. Legislation is frequently multipurposed: the removal of even a 'subordinate' purpose may shift altogether the consensus of legislative judgment supporting the statute. Permitting nullification of statutory classifications based rationally on a nonprimary legislative purpose would allow courts to peruse legislative proceedings for subtle emphases supporting subjective impressions and preferences. The Equal Protection Clause does not countenance such speculative probing into the purposes of a coordinate branch. We have supplied no imaginary basis or purpose for this statutory scheme, but we likewise refuse to discard a clear and legitimate purpose because the court below perceived another to be primary.

As the challenged classification here rationally promotes the legitimate desire of the state legislature to afford state prison officials an adequate opportunity to evaluate both an inmate's conduct and his rehabilitative progress before he is eligible for parole, the decision of the District Court is reversed.

Reversed.

Mr. Justice DOUGLAS, with whom Mr. Justice MARSHALL concurs, dissenting.

Under § 230(3) of the New York Correction Law, a prisoner loses 'good time' as punishment for offenses against the discipline of the prison. The statutory appearance of inmates before a parole board is computed by allowance of up to 10 days for 'good conduct' each month under the law governing appellees.1 No 'good time' credit is allowed, however, for the period of their presentence incarceration in a county jail. Thus, two prisoners—one out on bail or personal recognizance pending trial and the other confined in jail while awaiting trial—are treated differently when it comes to parole, through each is convicted of the same crime and receives the identical sentence. The result, as the opinion of the Court makes plain, is that appellees are required to wait some months longer before they may appear before the Parole Board than do those who were out on bail or on personal recognizance pending trial but sentenced to the same term for the same crime.

The 'good time' deduction is not based on progress toward rehabilitation but is an inducement to inhibit bad conduct. That is what the three-judge court held in 332 F.Supp. 973. That construction accurately reflects New York's interpretation of § 230(3). The court in Parez v. Follette, 58 Misc.2d 319, 295 N.Y.S.2d 231, said:

'The policy underlying the discretionary grant of good time reductions is clear. The attitude and conduct of prisoners should improve if they are offered an incentive for good and productive behavior while at the same time the fact that reductions can be withheld will inhibit bad conduct.' Id., at 321, 295 N.Y.S.2d, at 233.

That discipline—not rehabilitative progress—is the key to 'good time' credit is evidenced in another way. Once a prisoner arrives at prison, his future 'good time' is immediately computed and credited to his sentence. 'In effect, then, a prisoner does not 'earn' good time credit as time goes on for exemplary performance in assorted prison programs but rather simply avoids being penalized for bad behavior.' 332 F.Supp., at 978. That is confirmed by § 235 of the New York Correction Law:

'(a) punishment for offenses against the discipline of the prison or penitentiary (is) in accordance with the rules hereinbefore mentioned. Reduction credited to a prisoner in the first instance, in his account, by the warden, as provided in section two hundred and thirty, shall stand as the reduction allowed, unless withheld wholly or partly by the board as punishment, as above provided.'

Moreover, under § 230(4) of the Act, jail time is not excluded from the computation of a prisoner's maximum good-time allowance from the maximum term of an indeterminate sentence. This is the earliest date on which an inmate must be paroled, unlike the one we have here which involves the earliest date on which a prisoner may be paroled. But no rational grounds have been advanced for allowing 'good time' credit for jail time in one case but not in the other.

The claim that 'good time' is correlated to rehabilitative programs that only prisons have is the red herring in this litigation. The District Court exposed the fallacy in that rationale. Since the 'good time' credit is to induce good behavior by prisoners while they are confined, the place of their confinement becomes irrelevant. Jail-time allowance is allowed those confined in county penitentiaries. § 203(3). And, as I have said, jail time is credited in computing a prisoner's statutory release date.

It would seem that the 'good time' provision in § 230(3) is used capriciously, since it is allowed in cases not dissimilar to the present one.

After all is said and done, the discrimination in the present case is a statutory one leveled against those too poor to raise bail and unable to obtain release on personal recognizance.2 See People v. Deegan, 56 Misc.2d 567, 289 N.Y.S.2d 285. That is the real rub in the present case.

In Paul v. Warden, N.Y.L.J., May 21, 1969, p. 18, col. 6, the Court said:

'In computing the allowance of 'time off' for good behavior respondent considered only that time served subsequent to sentence as eligible for the allowance. Time served prior to sentence was excluded from the computation. The respondent's computation follows the method suggested by the Department of Correction.

'This court is not in agreement with (the) method employed. It is inequitable in that it discriminates against those persons charged with crime that are able to furnish bail upon arraignment and those remanded as a result of inability to furnish bail.3

'The inequity is blatantly apparent in the following cases. Two persons are charged with crimes identical in nature. On arraignment defendant A furnishes bail. A is subsequently sentenced, after a trial resulting in a verdict finding him guilty as charged, to one year in the county jail. Predicated upon his good behavior during the period of his incarceration A would be allowed a reduction of sixty days from the sentence of one year and would serve a total of 305 days. The defendant B, if confined for a period of 350 days prior to trial and sentence, and upon sentence was sentenced to confinement for one year would only be entitled to 'time off' for the period served following sentence or one-sixth of fifteen days for a total allowance of two days reduction in sentence despite good behavior during his entire period of imprisonment. B because of inability to furnish bail would thus serve 363 days as compared to the 305 days served by A.

'This court refuses to countenance such disparity and discrimination.'

If 'good time' were related to rehabilitative progress, I would agree that the law passes muster under the Equal Protection Clause of the Fourteenth Amendment. But since 'good time' is disallowed only to those who cannot raise bail or obtain release on personal recognizance, the discrimination is plainly invidious.

We deal here with a deepseated inequity. In New York City as of 1964, 49% of those accused were imprisoned before trial, while only 40% were imprisoned after conviction.4 See Wald, Pretrial Detention and Ultimate Freedom: A Statistical Study, 39 N.Y.U.L.Rev. 631, 634 (1964). It is poverty that is 'generally accepted as the main reason for pretrial detention.' Id., at 636. The inequality apparently appears in the end product since 'the longer the period of detention before disposition of the case, the greater the likelihood of a prison sentence. . . . The key seems to be the defendant's at-large status at the time of sentencing. The glow of freedom apparently shines through.' Id., at 635.

Another sample of 385 defendants showed that 64% of those continuously in jail from arraignment to adjudication were sentenced to prison, while only 17% of the 374 who made bail received prison sentences. Rankin, The Effect of Pretrial Detention, 39 N.Y.U.L.Rev. 641, 643 (1964). Detained persons are more likely to be sentenced to prison than bailed persons regardless of whether high or low bail amounts have been set. Id., at 641.

These studies were made by the Vera Foundation founded by Louis Schweitzer. See Programs in Criminal Justice Reform, Vera Institute of Justice, Ten-Year Report 1961—1971 (1972). That Report states that 'people who were too poor to afford bail or private counsel ended up in prison more often than those who could pay.' Id., at 96. And see Ares, Rankin, and Sturz, The Manhattan Bail Project: An Interim Report on the Use of Pre-Trial Parole, 38 N.Y.U.L.Rev. 67 (1963).

The present case is on the periphery of one of the most critical problems in criminal law enforcement.

The important issue involved in this case is not when and whether a prisoner is released. It concerns only the time when the Parole Board may give a hearing. To speed up the time of that hearing for those rich or influential enough to get bail or release on personal recognizance and to delay the time of the hearing for those without the means to buy a bail bond or the influence or prestige that will give release on personal recognizance emphasizes the invidious discrimination at work in § 230(3).