BOTSFORD, J.

In Diatchenko v. District Attorney for the Suffolk Dist., 466 Mass. 655 (2013) (Diatchenko I), this court considered the constitutionality of a life sentence without parole when applied to a juvenile homicide offender,3 and, following Miller v. Alabama, 132 S.Ct. 2455 (2012), determined that the mandatory imposition of such a sentence violates the prohibition against cruel and unusual punishments in the Eighth Amendment to the United States Constitution as well as art. 26 of the Massachusetts Declaration of Rights.4 Diatchenko I, supra at 668. The court held that a juvenile homicide offender who is convicted of murder in the first degree and receives a mandatory sentence of life in prison must be afforded a "meaningful opportunity to obtain release based on demonstrated maturity and rehabilitation," and this opportunity must come through consideration for release on parole. Id. at 674, quoting Graham v. Florida, 560 U.S. 48, 75 (2010).

The court's opinion in Diatchenko I has given rise to questions concerning how the opportunity for release on parole will be protected for juvenile homicide offenders. Specifically, Gregory Diatchenko and Jeffrey S. Roberio,5 each of whom was convicted of murder in the first degree many years ago for a crime committed when he was seventeen years old,6 argue that in order to ensure that their opportunity for release through parole is meaningful, they must have, in connection with a petition for release before the parole board (board), access to counsel, access to funds for counsel and for expert witnesses because they are indigent, and an opportunity for judicial review of the decision on their parole applications. For the reasons discussed below, we agree in substance with Diatchenko and Roberio.7

1. Procedural history. a. Diatchenko. In March of 2013, Diatchenko filed the present action in the county court, seeking a declaration that, because he was convicted of murder in the first degree and was seventeen at the time he committed the offense, his mandatory sentence of life without parole was unconstitutional following the United States Supreme Court's decision in Miller, 132 S. Ct. at 2469. The single justice reported the case to the full court.

The court issued its opinion in December, 2013. See Diatchenko I, 466 Mass. at 655. Having determined that juvenile homicide offenders could not validly be sentenced to life in prison without parole, the court turned to the task of finding an appropriate way to achieve a constitutionally permissible result, while still recognizing the Legislature's primary role in establishing sentences for criminal offenses. The approach we took was to declare invalid, as applied to juvenile homicide offenders, certain language in G. L. c. 265, § 2, creating an exception to parole eligibility for those convicted of murder in the first degree and leaving in full effect the remainder of the statute that imposed a mandatory sentence of life imprisonment. See Diatchenko I, supra at 673. The result was that any juvenile offender previously convicted of murder in the first degree, including Diatchenko, became eligible for parole after serving fifteen years of his or her sentence. See id. See also G. L. c. 265, § 2, as amended through St. 1982, c. 554, § 3; G. L. c. 127, § 133A, as amended through St. 1965, c. 766, § 1. Because Diatchenko had already served approximately thirty-one years of his life sentence, he became eligible for parole immediately. See Diatchenko I, supra.8

Pursuant to the opinion's rescript, the case was remanded to the single justice with the direction to enter a judgment consistent with the court's opinion in the case and to "take such further action as is necessary and appropriate." On February 27, 2014, Diatchenko filed a motion for entry of a judgment that would include a number of orders of specific relief, and also filed a motion for funds to retain an expert in connection with his hearing before the board. The district attorney for the Suffolk District (district attorney), the chair of the board, and the Commissioner of Correction (commissioner) filed oppositions. After a hearing, the single justice reserved and reported Diatchenko's case as well as Roberio's case, next discussed, to the full court.

In connection with the Diatchenko case, the single justice reported the following questions:

b. Roberio. Following the Supreme Court's decision in Miller, in June, 2013, Roberio sought relief from his mandatory sentence of life without parole by moving in the Superior Court for resentencing under Mass. R. Crim. P. 30, as appearing in 435 Mass. 1501 (2001). He also filed a motion for funds pursuant to rule 30 (c) (5) to pay an expert neuropsychologist for assistance in connection with his motion for resentencing. The motion for funds was allowed, but Roberio's motion for resentencing was stayed pending the release of our decision in Diatchenko I, at which point he was resentenced to life with parole eligibility after fifteen years in prison. Because Roberio had been in prison for more than fifteen years, he was immediately eligible for parole.

On February 27, 2014, Roberio filed another motion for funds pursuant to rule 30 (c) (5) to retain the services of a second neuropsychologist because the previous neuropsychologist had died; Roberio sought to retain the expert in order to continue to seek to have his sentence reduced to a term of years or, alternatively, to assist him in connection with seeking parole. A second Superior Court judge allowed the motion after hearing, but stayed the order to permit the Commonwealth to seek relief from the single justice. On March 10, 2014, the Commonwealth filed a petition for relief under G. L. c. 211, § 3, challenging the orders allowing Roberio's requests for funds to retain the experts. As indicated, on May 23, 2014, the single justice reserved and reported the Roberio case to the full court for decision, to be paired with the Diatchenko case. In September, 2014, Roberio filed a motion to intervene in the Diatchenko case. The single justice allowed the motion.

2. Suggestion of mootness. "Litigation ordinarily is considered moot when the party claiming to be aggrieved ceases to have a personal stake in its outcome." Acting Supt. of Bournewood Hosp. v. Baker, 431 Mass. 101, 103 (2000), quoting Attorney Gen. v. Commissioner of Ins., 403 Mass. 370, 380 (1988). The chair of the board, the commissioner, and the district attorney suggest that the case is moot with respect to Diatchenko because on October 31, 2014, the board approved his application for parole, and therefore, they contend, Diatchenko no longer has a personal stake in the resolution of the present case. See Massachusetts Parole Board, No. W38579, at 1 (Oct. 31, 2014). However, Diatchenko has not yet been released on parole; rather, the board required that Diatchenko first spend twelve months in a lower security prison before he may be released, so that he may "transition gradually to the community." Id. at 7. Since Diatchenko has not yet been released, he continues to have a personal stake in the outcome of the case, and therefore his petition is not moot. Moreover, Roberio has been permitted to intervene in the Diatchenko case, and he has not yet had a parole hearing. Even if the case were moot as to Diatchenko, therefore, it is not moot with respect to Roberio. We proceed to consider the reported questions and related claims raised on their merits.

3. Discussion. a. Right to assistance of counsel. The first reported question asks whether a juvenile homicide offender must be afforded the assistance of counsel in connection with his or her initial parole hearing.9 It is important to view the question in context. The court's conclusion in Diatchenko I, that juvenile homicide offenders could not permissibly be subjected to life in prison without any opportunity for parole, flowed from the "fundamental `"precept of justice that punishment for crime should be graduated and proportioned" to both the offender and the offense,'" a central tenet of the Eighth Amendment and of art. 26. Diatchenko I, 466 Mass. at 669, quoting Miller, 132 S. Ct. at 2463. Drawing from the United States Supreme Court's recent decisions that focused on the requirement of proportional sentencing of youth, and in particular the decisions in Miller and Graham,10 Diatchenko I observed that "children are constitutionally different from adults for purposes of sentencing" and that the "distinctive attributes of juvenile offenders" render suspect the traditional justifications for imposing sentences of life without parole on these individuals. Diatchenko I, supra at 670-671, quoting Miller, supra at 2465. Therefore, in Diatchenko I, we held that Diatchenko and all juvenile homicide offenders serving mandatory life sentences deserve at least a "meaningful opportunity to obtain release based on demonstrated maturity and rehabilitation," and that accordingly, at the appropriate time, they must be considered for parole suitability. Diatchenko I, supra at 671, 674, quoting Graham, 560 U.S. at 75. In other words, the conclusion we reached was that parole eligibility is an essential component of a constitutional sentence under art. 26 for a juvenile homicide offender subject to mandatory life in prison.11

In general, there is no constitutionally protected liberty interest in a grant of parole. See Greenholtz v. Inmates of the Neb. Penal & Correctional Complex, 442 U.S. 1, 7 (1979); Quegan v. Massachusetts Parole Bd., 423 Mass. 834, 836 (1996); Greenman v. Massachusetts Parole Bd., 405 Mass. 384, 388 n.3 (1989). However, the Supreme Court has acknowledged that in some cases, a liberty interest in parole requiring at least some minimal due process rights may derive from language in a State's parole statute that creates a "protectible expectation of parole." See Greenholtz, supra at 11-12 (statutory language and structure of Nebraska parole statute created expectancy of release constituting liberty interest entitled to protection of due process clause). See also Board of Pardons v. Allen, 482 U.S. 369, 371-372, 381 (1987).

Here, G. L. c. 127, § 130, does not create an expectation of release through parole, as Justice Spina's dissent points out. See post at 39-40. Rather, what is at issue is art. 26's requirement that a juvenile homicide offender serving a mandatory life sentence be provided a meaningful opportunity to obtain release, so that his or her sentence is not effectively one of straight life in prison — an outcome that art. 26 prohibits. In this context, where the meaningful opportunity for release through parole is necessary in order to conform the juvenile homicide offender's mandatory life sentence to the requirements of art. 26, the parole process takes on a constitutional dimension that does not exist for other offenders whose sentences include parole eligibility.12

Thus, for example, in the case of an adult defendant convicted of armed robbery and sentenced to a term of not less than sixteen nor more than twenty years in prison, the defendant would be eligible for parole in sixteen years,13 but if the defendant were denied a meaningful opportunity for release on parole, this would not render the sentence cruel or unusual and therefore unconstitutional under art. 26. This is so because a State has no obligation to provide a parole system, see Greenholtz, 442 U.S. at 7-8, and if the defendant were to serve his or her entire sentence of twenty years with no opportunity at all for release on parole, that would have been a permissible sentence for the judge to have imposed at the outset. The same is not true for juvenile homicide offenders; under G. L. c. 265, § 2, they must be sentenced to life in prison, but art. 26 does not allow either the Legislature or a judge to sentence such an offender to life in prison without the possibility of parole.14

We turn, then, to the question of what is procedurally required in order to protect a juvenile homicide offender's expectation of "a meaningful opportunity to obtain release based on demonstrated maturity and rehabilitation." Graham, 560 U.S. at 75.15 "The extent of procedural due process which must be afforded in any situation varies with the nature of the private and governmental interests at stake ..., but basic to due process is the right to be heard `at a meaningful time and in a meaningful manner.'" Department of Pub. Welfare v. J.K.B., 379 Mass. 1, 3-4 (1979) (J.K.B.), quoting Armstrong v. Manzo, 380 U.S. 545, 552 (1965). This court has concluded, for example, that an "indigent parent facing the possible loss of a child cannot be said to have a meaningful right to be heard in a contested proceeding without the assistance of counsel." J.K.B., supra at 4. See Adoption of Meaghan, 461 Mass. 1006, 1007-1008 (2012) (where child's guardians filed petition for adoption that, if granted, would terminate parental rights, both nonconsenting indigent father and consenting child entitled to appointed counsel to provide meaningful opportunity to be heard). See also Guardianship of V.V., 470 Mass. 590, 592-593 (2015). For reasons we discuss next, the court's reasons for deeming appointment of counsel necessary in this context are instructive here: "[t]he petition may well involve complex questions of fact and law, and require the marshalling and rebutting of sophisticated expert testimony"; and "[p]rovision of appointed counsel not only safeguards the rights of the parents, but it assists the court in reaching its decision with the `utmost care' and `an extra measure of evidentiary protection,' required by law." J.K.B., supra, quoting Custody of a Minor (No. 1), 377 Mass. 876, 877, 884 (1979).

By statute, the board is required to determine an individual's suitability for parole based on whether there is, in the opinion of the board, a "reasonable probability that, if [a] prisoner is released with appropriate conditions and community supervision, the prisoner will live and remain at liberty without violating the law and that release is not incompatible with the welfare of society." G. L. c. 127, § 130. The decision is a discretionary one for the board "with which, if otherwise constitutionally exercised, the judiciary may not interfere."16 See Commonwealth v. Cole, 468 Mass. 294, 302 (2014). In rendering a parole decision, the board is entitled to obtain significant amounts of information, including the following: recommendations from parole staff; the inmate's prior criminal record; reports concerning the nature and circumstances of the offense, such as police reports, grand jury minutes, and trial transcripts; victim statements; information about the inmate's physical, medical, mental, and psychiatric status; disciplinary reports; classification reports; work evaluations; and records of educational achievements. See 120 Code Mass Regs. § 300.05 (1997). See also G. L. c. 127, § 135. The Department of Correction (department) maintains much of this information in a so-called "six-part folder" for the individual inmate that dates back to when the inmate was first detained in a Massachusetts correctional institution. See 103 Code Mass. Regs. §§ 155.07, 155.08 (2004). However, an inmate's access to certain evaluative information contained in this folder as well as other types of information available to the board may be restricted. See 103 Code Mass. Regs. §§ 155.10, 157.08 (2005); 120 Code Mass. Regs. §§ 301.04, 500.06 (2001).

The full board conducts initial parole hearings for individuals serving life sentences. 120 Code Mass. Regs. § 301.06(1) (2001). Notice of the hearing is provided to government officials, including the Attorney General, the office of the district attorney in whose district the inmate's sentence was imposed, the chief of police of the municipality where the crime was committed, and the Executive Office of Public Safety, as well as to the victim or the victim's immediate family members. See G. L. c. 127, § 133A; 120 Code Mass. Regs. § 301.06(3) (2001). During the parole hearing, the inmate or his or her representative has an opportunity to make an opening statement, and then the inmate responds to questions from the board. 120 Code Mass. Regs. § 301.06(4) (2001). The board also may pose questions to any individual who appears in support of the inmate. Id. After the inmate has completed his or her presentation, the victim or victim's family has an opportunity to speak, as do public officials, and the board is tasked with eliciting "available evidence and testimony unfavorable to the inmate upon any relevant subject." Id. The board may permit the inmate to make a closing statement and may allow parties to submit memoranda or other documentation after the hearing. 120 Code Mass. Regs. §§ 301.06(4), (5) (2001). The board permits attorneys to represent inmates serving life sentences at their parole hearings, although currently there is no provision for providing counsel to those who are indigent.17 120 Code Mass. Regs. § 300.08 (1997).

The question the board must answer for each inmate seeking parole, namely, whether he or she is likely to reoffend, requires the board to weigh multiple factors and consider a wide variety of evidence. In the case of a juvenile homicide offender — at least at the initial parole hearing — the task is probably far more complex than in the case of an adult offender because of "the unique characteristics" of juvenile offenders. Diatchenko I, 466 Mass. at 674. See Miller, 132 S. Ct. at 2464. A potentially massive amount of information bears on these issues, including legal, medical, disciplinary, educational, and work-related evidence. In addition, although a parole hearing is unlike a traditional trial in that it does not involve direct and cross-examination of witnesses by attorneys, because the inmate's parole application may well be opposed by both the victim's family and public officials, it would be difficult to characterize this as an uncontested proceeding.

Thus, like a proceeding to terminate parental rights, a parole hearing for a juvenile homicide offender serving a mandatory life sentence involves complex and multifaceted issues that require the potential marshalling, presentation, and rebuttal of information derived from many sources. See J.K.B., 379 Mass. at 4. An unrepresented, indigent juvenile homicide offender will likely lack the skills and resources to gather, analyze, and present this evidence adequately.18 Furthermore, although parole hearings are not contested in the strictest sense, the juvenile homicide offender seeking parole is likely to be required to overcome arguments by both victims' family members and government officials opposed to the offender's release; the former of these parties may present as particularly sympathetic, while the latter will likely have greater advocacy skills than the offender seeking parole.19

In sum, given the challenges involved for a juvenile homicide offender serving a mandatory life sentence to advocate effectively for parole release on his or her own, and in light of the fact that the offender's opportunity for release is critical to the constitutionality of the sentence, we conclude that this opportunity is not likely to be "meaningful" as required by art. 26 without access to counsel.

Turning to the question of appointment of counsel for indigent juvenile homicide offenders like Diatchenko and Roberio, G. L. c. 211D, § 5, authorizes the Committee for Public Counsel Services (committee) to maintain a system for appointment of counsel at any stage of a criminal or noncriminal proceeding in which "the laws of the commonwealth or the rules of the supreme judicial court require that a person in such proceeding be represented by counsel ... provided ... that such person is unable to obtain counsel by reason of his indigency." In light of our conclusion here that a juvenile homicide offender serving a mandatory life sentence must have access to counsel in connection with an initial application for parole, § 5D offers legislative authorization and an appropriate mechanism, through the work of the committee, for the appointment of counsel for indigent juvenile homicide offenders.20

b. Access to funds for expert witnesses. The second reported question concerns access to expert witnesses.21 Diatchenko and Roberio contend that, like access to counsel, it is necessary, in order to secure a meaningful opportunity for release, to have access to the assistance of expert witnesses. Specifically, they argue that, as juvenile offenders convicted of murder, they need experts to be able to explain and offer opinions on issues concerning the relationship between neurobiological immaturity and culpability in general as well as factors relating to each of their individual and family circumstances that may help both to explain past conduct and assess future risk of reoffending. As this court acknowledged in Diatchenko I, scientific research on adolescent brain development has revealed "myriad significant ways that this development impacts a juvenile's personality and behavior," some of which suggest decreased moral culpability for certain juvenile homicide offenders or indicate a greater potential for them to mature to a point where they no longer engage in the behaviors that led to their crimes. See Diatchenko I, 466 Mass. at 669-670.22 While the assistance of a psychologist or other expert witness may not be necessary for every juvenile homicide offender serving a life sentence who seeks parole, in some cases such assistance may be crucial to the juvenile's ability to obtain a meaningful chance of release.23

Neither G. L. c. 211D, § 5, nor any other statute expressly authorizes the expenditure of funds for expert witnesses to assist such a juvenile in the context of a parole hearing. Roberio argues that the allowance of the fee request is authorized under Mass. R. Crim. P. 30 (c) (5), which in relevant part provides: "The court, after notice to the Commonwealth and an opportunity to be heard, may also exercise discretion to allow the defendant costs associated with the preparation and presentation of a motion under this rule." However, we agree with the Commonwealth that in its current form, rule 30 (c) (5) does not authorize the allowance of funds to a defendant to retain an expert witness in connection with a parole hearing, because a parole hearing is not a "motion under this rule [i.e., rule 30]."24

It is also the case that G. L. c. 261, §§ 27A-27G, the statutory provisions generally authorizing the payment of public funds to cover costs and fees of indigent litigants, apply most directly to costs and fees relating to court proceedings, not proceedings before administrative or executive agencies like the board. See, e.g., Doe, Sex Offender Registry Bd. No. 89230 v. Sex Offender Registry Bd., 452 Mass. 764, 778-780 (2008). In addition, this court has held that G. L. c. 261, § 27C (4), provides "extra fees and costs," including funds for expert witnesses,25 only in the context of a "prosecution, defense or appeal." See, e.g., Commonwealth v. Davis, 410 Mass. 680, 684 (1991). See also Commonwealth v. Arriaga, 438 Mass. 556, 569 (2003). However, these cases have generally addressed the availability of costs for indigent defendants pursuing nonconstitutionally mandated procedures.26 Moreover, even where a defendant's right to a particular postconviction procedure is not constitutionally guaranteed, as is the case, for example, with motions for a new trial, this court has still required that indigent defendants nevertheless have meaningful access to whatever postconviction proceedings the State makes available. See Commonwealth v. Conceicao, 388 Mass. 255, 261-262 (1983).27 See also Reporter's Notes to Rule 30 (c) (5), Mass. Rules of Court, Rules of Criminal Procedure, at 223 (Thomson Reuters 2014) (discussing 2001 amendments to rule 30 allowing judges discretion to authorize costs for indigent defendants pursuing postconviction procedures).

Because the postconviction proceeding at issue here, a parole hearing for a juvenile homicide offender, is required in order to ensure that an offender's life sentence conforms to the proportionality requirements of art. 26, the proceeding is not available solely at the discretion of the State. Rather, it is constitutionally mandated, and as such, it requires certain protections not guaranteed in all postconviction procedures. It is appropriate, therefore, to construe G. L. c. 261, §§ 27A-27G, to authorize a Superior Court judge, upon motion of a parole-eligible, indigent juvenile homicide offender, to allow for the payment of fees to an expert witness to assist the offender in connection with his or her initial parole proceeding in certain limited contexts — specifically, where it is shown that the juvenile offender requires an expert's assistance in order effectively to explain the effects of the individual's neurobiological immaturity and other personal circumstances at the time of the crime, and how this information relates to the individual's present capacity and future risk of reoffending. The judge may exercise discretion to do so when the judge concludes that the assistance of the expert is reasonably necessary to protect the juvenile homicide offender's meaningful opportunity for release.28

c. Availability of judicial review. The third reported question asks whether there must be an opportunity for judicial review of a decision denying parole to a juvenile homicide offender and, if so, what form judicial review will take. The board, the commissioner, and the district attorney argue that art. 30 of the Massachusetts Declaration of Rights prohibits judicial review in this context. Article 30 requires strict separation of judicial and executive powers, and the power to grant parole, being fundamentally related to the execution of a prisoner's sentence, lies exclusively within the province of the executive branch. See Cole, 468 Mass. at 302-303; Commonwealth v. Amirault, 415 Mass. 112, 116-117 (1993). However, as we have noted, the right of the executive branch to exercise this power without intervention from the judiciary is subject to the provision that the power must be "constitutionally exercised." See Cole, supra at 302. This is not to suggest that the board is unconstitutionally exercising this power currently,29 or is likely to do so in the future, but only that this court retains the responsibility with respect to parole hearings to ensure that any constitutional requirements are met. Thus, this court has never held that art. 30 precludes any type of judicial review of parole board decisions. In fact, Massachusetts courts have engaged in limited review of parole proceedings, consistently if not frequently. See, e.g., Quegan, 423 Mass. at 835 (prisoner sought declaration that board may not consider refusal to admit guilt in parole determination); Greenman, 405 Mass. at 386 (prisoner challenged basis of parole denial as beyond board's statutory authority); Blake v. Massachusetts Parole Bd., 369 Mass. 701, 702 (1976) (prisoner sought declaration of right to appear personally before board in order to argue for early parole eligibility); Doucette v. Massachusetts Parole Bd., 86 Mass.App.Ct. 531, 532 (2014) (prisoner pursued civil rights claim alleging violation of due process in parole revocation proceeding as well as certiorari action challenging merits of board's decision to revoke parole).30,31

As previously stated, the parole hearing acquires a constitutional dimension for a juvenile homicide offender because the availability of a meaningful opportunity for release on parole is what makes the juvenile's mandatory life sentence constitutionally proportionate. In this particular context, judicial review of a parole decision is available solely to ensure that the board exercises its discretionary authority to make a parole decision for a juvenile homicide offender in a constitutional manner, meaning that the art. 26 right of a juvenile homicide offender to a constitutionally proportionate sentence is not violated.32

That being said, the art. 26 right of a juvenile homicide offender in relation to parole is limited. To repeat: it is not a guarantee of eventual release, but an entitlement to a meaningful opportunity for such release based on demonstrated maturity and rehabilitation. See Diatchenko I, 466 Mass. at 674. That entitlement arises directly from the recognition that children are constitutionally different from adults, with "diminished culpability and greater prospects for reform," Miller, 132 S. Ct. at 2464, based on their "distinctive attributes" of youth. See Diatchenko I, supra at 660, 671. These include children's "lack of maturity and an underdeveloped sense of responsibility, leading to recklessness, impulsivity, and heedless risk-taking"; vulnerability "to negative influences and outside pressures, including from their family and peers; ... limited contro[l] over their own environment[;]... [lack of] the ability to extricate themselves from horrific, crime-producing settings"; and unique capacity to change as they grow older (citations and quotations omitted). Id. at 660. Absent consideration of these attributes, a juvenile homicide offender may not be permitted a real chance to demonstrate maturity and rehabilitation. See id. at 675 (Lenk, J., concurring), citing Miller, 132 S. Ct. at 2468. The purpose of judicial review here is not to substitute a judge's or an appellate court's opinion for the board's judgment on whether a particular juvenile homicide offender merits parole, because this would usurp impermissibly the role of the board. Rather, judicial review is limited to the question whether the board has carried out its responsibility to take into account the attributes or factors just described in making its decision.

With this in mind, we consider the form of judicial review of a board decision denying initial parole to a juvenile homicide offender. Diatchenko and Roberio suggest that judicial review in this context should be in the nature of certiorari, as described in G. L. c. 249, § 4, rather than through an action for declaratory relief under G. L. c. 231A. We agree that certiorari is appropriate here, although we do not agree with their view of the scope or standard of that review.

"[A] complaint for declaratory relief is an appropriate way of testing the validity of regulations or the propriety of practices involving violations of rights, which are consistent and repeated in nature.... It is not, however, an appropriate remedy where the validity of an adjudication ... in an individual case is being challenged. There relief in the nature of certiorari is to be sought." (Citation omitted.) Averett v. Commissioner of Correction, 25 Mass.App.Ct. 280, 287 (1988), S.C., Averett, petitioner, 404 Mass. 28 (1989). See Grady v. Commissioner of Correction, 83 Mass.App.Ct. 126, 135-136 (2013). As discussed, the type of limited judicial review contemplated would focus on the parole determinations relating to a particular juvenile homicide offender. It thus falls into the category of cases appropriate for certiorari review.

The standard of review to be applied is a separate question, because the "standard of review for an action in the nature of certiorari depends on `the nature of the action sought to be reviewed.'" Rivas v. Chelsea Hous. Auth., 464 Mass. 329, 334 (2013), quoting Black Rose, Inc. v. Boston, 433 Mass. 501, 503 (2001). See G. L. c. 249, § 4. Because the decision whether to grant parole to a particular juvenile homicide offender is a discretionary determination by the board, see Cole, 468 Mass. at 302; G. L. c. 127, § 130, an abuse of discretion standard is appropriate. See Forsyth Sch. for Dental Hygienists v. Board of Registration in Dentistry, 404 Mass. 211, 217 (1989) (review of discretionary administration or decision in certiorari action limited to whether act or decision was "arbitrary and capricious"); Doucette, 86 Mass. App. Ct. at 541. See generally L.L. v. Commonwealth, 470 Mass. 169, 185 n.27 (2014). The question for the reviewing judge will be whether the board abused its discretion in the manner in which it considered and dealt with "the distinctive attributes of youth [that] diminish the penological justifications for imposing the harshest sentences on juvenile offenders," as they relate to the particular circumstances of the juvenile homicide offender seeking parole. Miller, 132 S. Ct. at 2465. Accord Diatchenko I, 466 Mass. at 671. In this context, a denial of a parole application by the board will constitute an abuse of discretion only if the board essentially failed to take these factors into account, or did so in a cursory way. A judge may not reverse a decision by the board denying a juvenile homicide offender parole and require that parole be granted. Rather, if the judge concludes that the board's consideration of the juvenile offender's status as a juvenile and the distinctive attributes of his or her youth did constitute an abuse of discretion — was arbitrary and capricious — a remand to the board for rehearing would be appropriate.33

It remains for us to address Diatchenko's argument that juvenile homicide offenders seeking review of a parole denial should be able to bring an action for certiorari to a single justice of this court as a matter of course. Although this court and the Superior Court have concurrent jurisdiction to entertain actions in the nature of certiorari under G. L. c. 249, § 4, as with most original actions for certiorari, these actions are most appropriately brought in the Superior Court.

Finally, we summarize the scope of our opinion in this case, and clarify what the opinion does not say. First, we consider here only the initial parole hearing available to juvenile homicide offenders. For the reasons discussed supra, the procedural protections of representation by counsel and the opportunity to obtain expert assistance in connection with that initial parole hearing are necessary for such offenders in light of their mandatory life sentences and the constitutional requirement of proportionality in sentencing. See Diatchenko I, 466 Mass. at 669-671; id. at 675 (Lenk, J., concurring). In Commonwealth v. Okoro, post 51 (2015), also decided today, and for the same reasons, we afford the same procedural protections to juvenile offenders convicted of murder in the second degree, who also are subject to mandatory life sentences with eligibility for parole. Nothing in this opinion, however, is intended to suggest that any other class of offenders is also entitled to these protections in connection with the parole hearing process.

Second, in affording juvenile homicide offenders the procedural protections at issue here, we emphasize that the determination whether to grant a parole application of an individual juvenile homicide offender is, and remains, a discretionary decision for the board to make. As previously noted, that standard is governed by G. L. c. 127, § 130, which prohibits a prisoner from receiving parole unless the board concludes that if the prisoner is released, "the prisoner will live and remain at liberty without violating the law and that release is not incompatible with the welfare of society."

Third, and relatedly, the board remains fully authorized to determine, consistent with legislative mandates,34 the rules and procedures it deems appropriate for the conduct of its parole hearings, and free to reach whatever decision in each case it deems appropriate. The dissents suggest that in establishing minimal requirements of due process for juvenile homicide offenders in their parole hearings, the court interferes unnecessarily and improperly with the operations of the parole board, an executive agency, trenching on principles of separation of powers. Post at 35-36, 48-50. Our decision does not commit this offense. Insofar as we conclude that the provision of counsel and of funds for expert witnesses is required for juvenile homicide offenders, these are procedures whose sole purpose is to protect the constitutional entitlement that these juvenile offenders have to a meaningful opportunity for parole release.35 Finally, the limited judicial review provided here does not authorize judges to substitute their judgment with respect to the parole release decision for the board's. As discussed, the judiciary's only role in these cases will be to ensure that the board's determination whether to grant or deny parole to a juvenile homicide offender is "constitutionally exercised," Cole, 468 Mass. at 302, in the sense that the board properly has taken into account the offender's status as a child when the crime was committed.

4. Applicability of this decision. Diatchenko and Roberio appear to confine their requests to the limited group of individuals who were convicted of murder in the first degree and sentenced to mandatory life without parole prior to the Supreme Court's decision in Miller, and who became eligible for parole pursuant to this court's decision in Diatchenko I. We do not share the view that the decision in this case applies only to that limited group. Rather, it applies more generally to all juvenile offenders convicted of murder.

5. Conclusion. The matter is remanded to the county court, where the single justice will enter a judgment consistent with this opinion.

So ordered.

SPINA, J. (dissenting, with whom Cordy, J., joins).

I respectfully dissent from the decision of the court today. The court has misconstrued Diatchenko v. District Attorney for the Suffolk Dist., 466 Mass. 655, 674 (2013) (Diatchenko I), which required only a "meaningful opportunity to obtain release" in the form of a parole hearing for juveniles convicted of murder in the first degree. The court instead has created a path by which such an offender may obtain, as of right, access to counsel, funds for expert witnesses, and, if denied parole, judicial review of the decision of the parole board (board). The solution at which the court arrives today ignores previous statements of the law on this matter. Our decision in Diatchenko I did not create a significant liberty interest in the outcome of the parole hearing. Diatchenko I stood solely for the proposition that the exception to parole eligibility in G. L. c. 127, § 133A, no longer applies to Gregory Diatchenko and Jeffrey S. Roberio and left the remainder of the statutory scheme unchanged. That statutory scheme continues to apply unaltered to them and similarly situated inmates.

1. Meaningful opportunity. In Diatchenko I, we addressed the United States Supreme Court's holding in Miller v. Alabama, 132 S.Ct. 2455 (2012), that juveniles convicted of murder in the first degree could no longer receive life sentences without the possibility of parole unless a court determined they were incorrigible. We adopted the language in Miller, first expressed in Graham v. Florida, 560 U.S. 48, 75 (2010), that a juvenile offender receiving a life sentence must receive "some meaningful opportunity to obtain release based on demonstrated maturity and rehabilitation." Inherent in this line of cases is the judicial recognition that "children are constitutionally different from adults for purposes of sentencing." Diatchenko I, 466 Mass. at 670, quoting Miller, supra at 2464. The Supreme Court reasoned that a sentence of life in prison without the possibility of parole removes any penological justification for the sentence because it "forswears altogether the rehabilitative ideal." Graham, supra at 74.

The court says "the meaningful opportunity for release through parole is necessary in order to conform the juvenile homicide offender's mandatory life sentence to the requirements of art. 26 [of the Massachusetts Declaration of Rights]." Ante at 19. I agree. After Diatchenko I, a juvenile convicted of murder in the first degree, like every juvenile who is sentenced to incarceration, is eligible for parole, whereas before such a juvenile was not. The thrust of Diatchenko I was an expectation of parole eligibility, and no more.

The court improperly synthesizes two premises to arrive at a more significant but now constitutionally untenable conclusion. The court correctly recognizes that (1) children are "constitutionally different from adults for purposes of sentencing" and (2) that a life sentence for a juvenile convicted of murder in the first degree is cruel and unusual under art. 26 without a meaningful opportunity for release through a demonstration of rehabilitation. Fusing these propositions together, the court concludes that the "meaningful opportunity" for release for juveniles convicted of murder in the first degree has a "constitutional dimension" that exists for no others and requires "additional procedural protections." Ante at 19 & note 14. This conclusion is erroneous because the court applies the first premise to the second when, in fact, the second premise flows from the first.

The court states that other sentences, except life sentences for juveniles convicted of murder in the first degree, "include parole eligibility." Ante at 19. The opposite is true. Parole is an executive action separate and distinct from a judicial sentence. See Commonwealth v. Cole, 468 Mass. 294, 302 (2014) ("[The granting of parole] is a function of the executive branch of government with which, if otherwise constitutionally exercised, the judiciary may not interfere"). Cf. Simms v. State, 65 Md.App. 685, 689 (1986) ("A parole is an act of executive clemency. It does not involve the sentencing function or any other judicial function"). Cf. also Knight v. United States, 73 F.3d 117, 119 (7th Cir. 1995), cert. denied, 519 U.S. 827 (1996) ("Parole is an extension of the [c]onstitutional grant of clemency power given to the President"); State v. Hewett, 270 N.C. 348, 352 (1967) ("Probation relates to judicial action taken before the prison door is closed, whereas parole relates to executive action taken after the door has closed on a convict"). Were Massachusetts to abandon its system of parole, art. 26 would only require that juveniles convicted of murder in the first degree — and thus sentenced to life — be afforded some opportunity for release from imprisonment through a demonstration of rehabilitation, the only constitutionally available penological justification for the State's harshest penalty. Miller, 132 S. Ct. at 2468 ("this mandatory punishment [of life without parole] disregards the possibility of rehabilitation even when the circumstances most suggest it"). In such a hypothetical scenario, art. 26 would not require parole for any juvenile sentenced to a term of years because that sentence — or any other lesser sentence — has a penological justification other than rehabilitation. See id. at 2465-2466 (outlining penological justifications of sentences as applied to juveniles).

In constitutionally guaranteeing that juveniles convicted of murder in the first degree are eligible for parole, we have already previously respected juveniles' constitutional distinctiveness from adults convicted of murder in the first degree by the imposition of a sentence that is not cruel and unusual. By imposing today these additional procedural protections, the court reaches beyond the judicial function of sentencing to regulate the conduct of the initial parole hearing itself, the manifestation of the executive prerogative to execute the sentence. In so doing, the court transforms the conduct of the parole hearing into part of the sentencing process, at least for juveniles convicted of murder in the first degree, and implicates the action of the board in the sentence itself.

The Legislature never intended such a relationship between sentence and parole. Moreover, it is something that we expressly said in Cole, 468 Mass. at 302, is forbidden, because sentencing is "a quintessential judicial power." Id., quoting Commonwealth v. Rodriguez, 461 Mass. 256, 264 (2012). In Cole, we held that the executive branch's imposition of punishments under G. L. c. 127, § 133D (c), against those who violated community parole supervision for life improperly interfered with the judicial power to impose a sentence. Cole, supra. Today we are dealing with the opposite scenario, in which the court subsumes the executive power to regulate the conduct of a parole hearing into part of the sentencing process.

If the court's decision should be considered not to have rendered the conduct of the initial parole hearing of a juvenile convicted of murder in the first degree part of the sentencing process, then the court's justification for "additional procedural protections" in such a hearing fails because "children are constitutionally different from adults for purposes of sentencing" (emphasis added). Diatchenko I, 466 Mass. at 670, quoting Miller, 132 S. Ct. at 2465. Parole is not part of the sentencing process and thus the parole hearing need not recognize the difference between children and adults for purposes of art. 26.

The Supreme Court specifically identified traditional parole hearings as capable of providing that "meaningful opportunity to obtain release." Graham, 560 U.S. at 75. In both Graham and Miller, the Court even went so far as to explicitly state that "a State is not required to guarantee eventual freedom." Miller 132 S. Ct. at 2469; Graham, supra. The term "meaningful opportunity" was a warning that the Eighth Amendment to the United States Constitution "forbid[s] States from making the judgment at the outset that those offenders never will be fit to reenter society" (emphasis added). Graham, supra. "The Eighth Amendment does not foreclose the possibility that [a juvenile convicted of murder in the first degree] will remain behind bars for life." Id. Read together these cases stand for the proposition that Diatchenko and Roberio, and similarly situated inmates, must be afforded a standard parole hearing, and by implication, this hearing will provide these individuals with the "meaningful opportunity" of release.

This warning is in congruence with the Court's previous statements that "no constitutional or inherent right of a convicted person to be conditionally released before the expiration of a valid sentence" exists. Greenholtz v. Inmates of the Neb. Penal & Correctional Complex, 442 U.S. 1, 7 (1979). Accord Quegan v. Massachusetts Parole Bd., 423 Mass. 834, 836 (1996). Indeed, in Diatchenko I we recognized that "[o]ur decision should not be construed to suggest that individuals who are under the age of eighteen when they commit murder in the first degree necessarily should be paroled once they have served a statutorily designated portion of their sentences." Diatchenko I, 466 Mass. at 674. These statements cannot be reconciled with the court's reasoning today that the "process" of the initial parole hearing of a juvenile convicted of murder in the first degree "takes on a different constitutional dimension that does not exist for other offenders whose sentences include parole eligibility." Ante at 19.

Absent the recognition of a new liberty interest in the outcome of parole, the court does not explain the constitutional necessity of these additional protections but simply inserts a new "constitutional dimension." This "constitutional dimension" identified by the court is the foundation for the new constitutional rule that juveniles convicted of murder in the first degree require different procedural protections from those given to other offenders. The court provides juveniles under a mandatory life sentences with enhanced procedures that no others receive, yet there has been no suggestion that the parole hearing others receive falls short of a meaningful opportunity. We have never previously stated or hinted at such a difference in procedural safeguards. In Diatchenko I, we determined that the appropriate remedy to the defendant's challenge under Miller was to leave intact as much of the statutory scheme designed by the Legislature as possible, so far as it remained constitutional. Diatchenko I, 466 Mass. at 673. Accordingly, we struck down only the provision making juveniles ineligible for parole and let the remaining provisions of the statute stand. Id. In Commonwealth v. Brown, 466 Mass. 676 (2013), and Commonwealth v. Ray, 467 Mass. 115 (2014), we affirmed our intent to interfere with the enacted legislation as little as possible and do nothing more than invalidate the exception for parole eligibility.

In Brown, this court held that the rules of severability require trial judges to apply the parole statute as written with the exclusion of the one unconstitutional provision. Brown, 466 Mass. at 680. In so doing, this court upheld the trial judge's decision to impose "as much of the sentencing scheme set forth in [the statute] as would be permissible in light of Miller's prohibition against mandatory sentences of life without parole for juveniles." Id. We would not have instructed trial judges to apply the statute in a manner that preserved as much of the expressed intent of the Legislature as possible if we intended to create a process different from that provided for in the then-existing statutory scheme.

More recently, in Ray, we expressed a view that the normal procedures governing consideration of parole release would apply to juveniles convicted of murder in the first degree. Ray, 467 Mass. at 139-140. "Pursuant to our holding in Diatchenko, ... the defendant's life sentence remains in force, but the exception in G. L. c. 265, § 2, rendering him ineligible for parole, no longer applies. The defendant is eligible for parole in accordance with the terms of G. L. c. 127, § 133A." Id. See Commonwealth v. Keo, 467 Mass. 25, 47 (2014) ("the lesser punishment under G. L. c. 265, § 2, of mandatory life in prison with the possibility of parole, set pursuant to the parole eligibility statute in effect at the time of the juvenile offender's crime, would apply"). This language strongly suggests that the court intended for the remainder of the statutory scheme to apply to Diatchenko and Roberio and that they are entitled only to the same parole hearing process as other inmates.

Undoubtedly, Diatchenko and Roberio have a right to a "hearing that shall afford [them] a meaningful opportunity to obtain release," Diatchenko I, 466 Mass. at 674, but only via the same processes and established procedures that all other inmates serving life sentences have, and not through a new liberty interest in parole with accompanying greater constitutional protections. The court today seemingly "ignores the distinction, adopted by the Supreme Court, between [potentially] being deprived of a liberty that one already has and being denied a conditional liberty that one desires." Greenman v. Massachusetts Parole Bd., 405 Mass. 384, 388 n.3 (1989).

Moreover, in Diatchenko I, we outlined the process necessary to afford a juvenile convicted of murder in the first degree such a "meaningful opportunity," saying only that

466 Mass. at 674.1 We did not hold that the Massachusetts Constitution requires a new kind of parole hearing; and we said nothing about changing the standard process in any respect (much less requiring appointed counsel or granting funds for expert testimony) in order for the juvenile offender to obtain his "meaningful opportunity." Instead, we said that a process that considers the above mentioned factors provides juvenile offenders with a "meaningful opportunity to obtain release."

This understanding is in line with decisions of Massachusetts and Federal courts that have long held that the possible release arising under the parole statute does not create a liberty interest in parole. See Greenman, 405 Mass. at 388 n.3 ("The individual characteristics of the Massachusetts statutory parole scheme do not give rise to a liberty interest under Federal law"). See also Doe v. Massachusetts Parole Bd., 82 Mass.App.Ct. 851, 858 (2012) ("A prisoner in the Commonwealth does not have a liberty interest in the future grant of parole"); Lynch v. Hubbard, 47 F.Supp.2d 125, 127-128 (D. Mass. 1999) (Massachusetts parole statute's negative phrasing prevents an expectation or presumption of release). Essentially, under G. L. c. 127, § 133A, Diatchenko and Roberio do not have an expectation or presumption of release and Diatchenko I did nothing to overtly change the statutory scheme. If we had intended to create an entirely new liberty interest in parole where there had been none previously, we would have explicitly said so. We did not, and Diatchenko I did not create a liberty interest in parole for juveniles convicted of murder in the first degree.

2. Right to counsel. The court concludes that juveniles convicted of murder in the first degree who seek parole constitutionally are entitled to representation by counsel because a parole hearing is a contested, complex proceeding similar to that involving the termination of parental rights. Therefore, because juveniles convicted of murder in the first degree — imprisoned at a young age — are unlikely to advocate as fully as possible for themselves and a parole hearing is similar to a proceeding terminating parental rights, the court concludes that constitutionally guaranteed access to counsel best ensures that the parole hearing is a "meaningful opportunity." I disagree.

The court's analogy between parental right termination proceedings and parole hearings does not withstand closer scrutiny. The proceedings we examined in Department of Pub. Welfare v. J.K.B., 379 Mass. 1 (1979), can result in the loss of rights to conceive and raise one's children — rights that are "essential ... basic civil rights of man ... far more precious ... than property rights." Id. at 3, quoting Stanley v. Illinois, 405 U.S. 645, 651 (1972). In J.K.B., supra at 4, we affirmed that one cannot lose a right without due process, and we ensured that due process be observed by access to counsel for indigent parents. Parole hearings, however, do not result in the loss of any rights. As explained above, an expectation of parole simply does not exist in these proceedings and our decision in Diatchenko I has not changed that fact.2 Without an expectation of parole, a juvenile convicted of murder in the first degree has no protected liberty interest, or right, to lose.3

Our decision in Diatchenko I did not suggest that the current parole process did not adequately provide a "meaningful opportunity to obtain release." We most certainly did not suggest that publicly funded counsel is necessary to protect one's interest in a fair hearing. The right to counsel based in the Sixth Amendment to the United States Constitution and art. 12 of the Massachusetts Declaration of Rights does not traditionally have an application to parole hearings. The United States Supreme Court explicitly noted that the right to counsel does not extend to postconviction collateral proceedings, see Douglas v. California, 372 U.S. 353, 356 (1963), and that "[i]n the context of parole ... the procedures required are minimal." Swarthout v. Cooke, 131 S.Ct. 859, 862 (2011).

We consistently have rejected claims that an inmate is entitled to counsel at parole hearings. See Cole, 468 Mass. at 306; Quegan v. Massachusetts Parole Bd., 423 Mass. 834, 840 (1996) (no right to representation before board unless there is independent and pending criminal proceeding that could be affected by parole proceedings).4 Parole is not a part of the criminal prosecution or the adversarial process, but rather arises subsequently and is supervised by an executive administrative agency rather than the court. Because parole is separate and apart from criminal proceedings for those convicted of murder in the first degree as juveniles, the full breadth of due process rights, including the right to counsel, does not apply during such hearings.

Further, at this juncture, Diatchenko and Roberio have not made a sufficient showing that the parole hearing process available to them is inadequate or that the unique skills of a lawyer are necessary in order to have a "meaningful opportunity to obtain release." This is particularly so given that the current parole process requires the board to consider the circumstances of the crime, including whether Diatchenko and Roberio were juveniles at its commission, and whether they have been rehabilitated. Additionally, numerous inmates convicted of murder in the second degree as juveniles have been paroled after release hearings conducted without the aid of appointed counsel. While "lifer hearings" certainly require considerable preparation, the board is not called upon to resolve disputed issues of fact, strict rules of evidence do not apply, and witnesses need not be subjected to cross-examination.

The court maintains that an attorney is needed to collect materials pertaining to a juvenile homicide offender's criminal history and personal development after conviction. However, at the time of a parole hearing, the factual record in these cases already has been well established either in a trial transcript or in a decision of this court. Additionally, the Department of Correction (department) keeps a historical record containing detailed medical, psychiatric, and disciplinary records in each inmate's six-part folder. 103 Code Mass. Regs. § 155.07 (2014). These records are available to Diatchenko and Roberio before their hearings and to the board for review.5 See G. L. c. 127, § 135; 103 Code Mass. Regs. § 157.08 (2005); 120 Code Mass. Regs. § 300.05(1)(i) (1997). Finally, and notably, the court does not suggest that the statutory standard for granting parole or the requirements for membership to the board are unconstitutional.

3. Expert witness funds. The court also concludes that a parole-eligible juvenile convicted of murder in the first degree may petition a Superior Court judge to authorize the payment of fees to retain an expert witness to explain effectively "the effects of the individual's neurobiological immaturity and other personal circumstances at the time of the crime, and how this information relates to the individual's present capacity and future risk of reoffending." Ante at 27. The majority derives this right from the same mistaken interpretation that a "meaningful opportunity" of parole grants juveniles convicted of murder in the first degree more rights in a parole hearing than any other class of inmate. For substantially the same reasons that a juvenile convicted of murder in the first degree is not guaranteed access to counsel, neither is he or she guaranteed access to funds for expert witness testimony.

The power to allocate and direct public funding among competing public purposes is traditionally within the purview of the Legislature. See Opinion of the Justices, 430 Mass. 1201, 1202 (1999); County of Barnstable v. Commonwealth, 422 Mass. 33, 45 (1996). The court construes G. L. c. 261, §§ 27A-27G, as authorizing the expenditure of public funds because the parole hearing at issue is constitutionally mandated. Ante at 27. For support, the court cites our cases that guaranteed "meaningful access to whatever postconviction proceedings the State makes available" for indigent defendants who sought postconviction relief. Ante at 26-27, citing Commonwealth v. Conceicao, 388 Mass. 255, 261-262 (1983). At issue in Conceicao was the question whether "meaningful access" included access to counsel as of right. Id. at 258. We concluded that the decision to grant access to counsel for the preparation of a motion for a new trial was within the discretion of the motion judge. Id. at 262. We recommended counsel only in the event the defendant demonstrated a colorable or meritorious issue. Id. Importantly, we recognized that not every inmate need be placed on exactly the same footing as any other by providing counsel in order to guarantee meaningful access. Id. at 261.

General Laws c. 261, § 27C (4), echoes the legislative acknowledgment that "meaningful access" does not necessarily require the blanket authorization of public funds in support of a defendant's efforts following his direct appeal. This section authorizes provision of public funds needed by an indigent applicant for an "effective ... prosecution, defense or appeal." Yet funds under the statute are generally not available to support a defendant's effort to obtain postconviction relief, because those proceedings are not a part of the prosecution, defense, or appeal. See Commonwealth v. Arriaga, 438 Mass. 556, 569 (2003).

Finally, according to its enabling statute, members of the board must come from a diverse background, including the fields of psychology or psychiatry. G. L. c. 27, § 4. Additionally, at least one member of the board must now have experience in forensic psychology, St. 2014, c. 189 (1), and the board must consider scientific and technical factors at its hearings. The board now is obligated to consider youth-related factors in order to fulfil the mandates of both Miller and Diatchenko.6 These requirements assist in ensuring that Diatchenko's and Roberio's hearings provide a truly "meaningful opportunity" for release, without a need for their own experts.

4. Certiorari. The court today establishes judicial review of the denial of parole to a juvenile convicted of murder in the first degree through an action for certiorari. Certiorari is available when there is "(1) a judicial or quasi-judicial proceeding, (2) from which there is no other reasonably adequate remedy, and (3) a substantial injury or injustice arising from the proceeding under review." Indeck v. Clients' Sec. Bd., 450 Mass. 379, 385 (2008). Such review conflicts with our previous understanding of the separation of powers enshrined in art. 30 of the Massachusetts Declaration of Rights. "The granting of parole, or conditional release from confinement, is a discretionary act of the parole board" and "is a function of the executive branch of government with which, if otherwise constitutionally exercised, the judiciary may not interfere." Cole, 468 Mass. at 302. See Stewart v. Commonwealth, 413 Mass. 664, 669 (1992). We previously have stated that a statute that "impermissibly allocates a power held by only one branch to another" violates art. 30. Cole, supra. Today's holding violates art. 30 because it permits a judge to "nullify the discretionary actions of the parole board." Commonwealth v. Amirault, 415 Mass. 112, 116-117 (1993). Accord Woods v. State Bd. of Parole, 351 Mass. 556, 559 (1967) ("Even by a writ of mandamus, the board may be required merely to consider a prisoner's petition for parole. The board may not be required to exercise any discretion for the benefit of a prisoner").

As detailed above, Diatchenko I did not create any additional rights for a juvenile convicted of murder in the first degree more expansive than those possessed by any other class of inmate. The use of certiorari to ensure that a parole hearing provides a "meaningful opportunity" for release ignores the existence of a "reasonably adequate remedy." Indeck, 450 Mass. at 385. An inmate may seek relief from decisions of the board by means of an action for declaratory relief under G. L. c. 231A. See Gangi v. Massachusetts Parole Bd., 468 Mass. 323, 324 (2014); Massachusetts Parole Bd. v. Brusgulis, 403 Mass. 1010, 1011 (1989). Chapter 231A provides inmates with the opportunity to challenge the "practices or procedures [of the board] ... alleged to be in violation of the Constitution of the United States or of the constitution or laws of the commonwealth." G. L. c. 231A, § 2. Accordingly, Diatchenko, Roberio, and similarly situated inmates may contest the board's practices that fail to consider the unique characteristics of juvenile offenders as well as displayed growth and change from adolescence, as required by Diatchenko I.

Certiorari is limited to correcting substantial errors of law that affect material rights and are apparent on the record. Gloucester v. Civil Serv. Comm'n, 408 Mass. 292, 297 (1990). The only material right at stake to juveniles convicted of murder in the first degree is the expectation of parole eligibility, not the substance of the board's decision. Moreover, the use of certiorari permits the reviewing court only to affirm or set aside a decision of the tribunal whose actions are under review. Commonwealth v. Ellis, 11 Mass. 465, 466 (1814) ("this Court ... can only affirm the proceedings ... or quash them"); Commonwealth v. Blue-Hill Turnpike Corp., 5 Mass. 420, 423 (1809) ("on certiorari we can enter no new judgment"); Melvin v. Bridge, 3 Mass. 305, 306 (1807) ("If the Court were to consider these proceedings as certified on a certiorari, the plaintiff in error could not be relieved, as a judgment for costs could not be rendered, but only the proceedings affirmed or quashed"). Consequently, lacking any affirmative power, a court could only set aside a decision of the board and then remand the matter to the board, a process that could be repeated ad infinitum until the board grants parole. See Woods, 351 Mass. at 559. Not only are courts ill-equipped to decide whether parole should be granted, but such a decision — both historically and legally — has been reserved for the executive branch.

The court notes that judicial review by an action for certiorari would not encompass whether a particular juvenile convicted of murder in the first degree is entitled to release on parole but rather would be limited to the question whether the board has "constitutionally exercised" its discretion. Ante at note 16, citing Cole, 468 Mass. at 302. If the reviewing judge is not concerned with the individual outcome of the matter before him or her, then the judge is by default only reviewing the procedure of that matter. "[A] complaint for declaratory relief is an appropriate way of testing the validity of regulations or the propriety of practices involving violations of rights, which are consistent and repeated in nature." Nelson v. Commissioner of Correction, 390 Mass. 379, 388 n.12 (1983). This mechanism has been utilized in previous challenges to the procedures by which the board exercises its discretion. See Quegan, 423 Mass. at 835; Blake v. Massachusetts Parole Bd., 369 Mass. 701, 702-703 (1976).

The court — and Diatchenko and Roberio — do not contend that the board has failed in this respect such that a request for declaratory relief is warranted at this time. Importantly, the review process for granting parole is currently based on comprehensive, individualized assessments. In determining whether a particular inmate is suitable for parole, the board is charged by statute with ascertaining the extent to which the inmate has been rehabilitated, and the extent to which, if released, he or she would pose a risk to the community.7 See G. L. c. 127, § 130. The board performs a "risk and needs assessment" as well. Id. In so doing, it has the authority to review and evaluate an inmate's entire record. See Greenman, 405 Mass. at 387. As required by statute, the board must be provided with the complete criminal record of the inmate as well as reports on the inmate's social, physical, mental, and psychiatric condition and history. G. L. c. 127, § 135. Moreover, in making its determination, the board "shall consider whether, during the period of incarceration, the prisoner has participated in available work opportunities and education or treatment programs and demonstrated good behavior." G. L. c. 127, § 130. Finally, the board "shall also consider whether risk reduction programs, made available through collaboration with criminal justice agencies would minimize the probability of the prisoner re-offending once released." Id. All inmates are provided subsequent parole hearings if parole is initially denied. 120 Code Mass. Regs. § 300.01 (1997). These hearings are open to the public and parole-eligible offenders serving life sentences are permitted representation by counsel. 120 Code Mass. Regs. §§ 300.02(2), 300.08 (1997). Eventually, the board's decision becomes a public record. G. L. c. 127, § 130.

Further, in January, 2014, in response to Miller, the Legislature passed "An Act relative to juvenile life sentences for first degree murder" (act). St. 2014, c. 189. The act imposed a series of statutory changes affecting juveniles convicted of murder in the first degree including new sentencing and parole eligibility standards; mandating that at least one member of the board have experience in forensic psychology; authorizing the department to provide treatment and programming for youthful offenders irrespective of their crimes or duration of incarceration; and allowing the placement of qualified youthful offenders in a minimum security correctional facility, irrespective of their life sentence. The act further established a commission to

In addition, the board, on its own initiative, amended its "Guidelines for Life Sentence Decisions" (guidelines) in light of Diatchenko I, requiring consideration of age-related factors in all parole cases involving juveniles convicted of murder in the first degree and incorporating the specific factors that the concurring justices considered when evaluating parole suitability for such individuals. See note 1, supra. Accordingly, inmates like the defendant now must be "evaluated with recognition of the distinctive attributes of youth, including immaturity, impetuosity, and a failure to appreciate risks and consequences." See Diatchenko I, 466 Mass. at 675 (Lenk, J., concurring). The guidelines now provide that the board can and should consider, among other things, the specific facts of the crime and rehabilitation. Finally, in determining whether the inmate has been rehabilitated, the guidelines provide that the board shall consider his or her conduct while incarcerated.

Had this court intended to directly oversee the board's consideration of parole, we would have specifically provided guidance concerning the proper balance of the necessary factors or when to find that parole is warranted. Yet, we declined to do so, specifically holding that it was in the board's "purview" to evaluate the unique circumstances and conditions of the defendant. Diatchenko I, 466 Mass. at 674. See Doe v. Massachusetts Parole Bd., 82 Mass.App.Ct. 851, 861 (2012). This the board has done by revising its guidelines. Accordingly, a complaint for declaratory relief remains the best manner to ensure the meaningfulness of parole hearings by allowing challenges to procedural elements of these hearings such as the guidelines. See Nelson, 390 Mass. at 388 n.12. There has been no showing that declaratory relief would be appropriate at this time.

For the foregoing reasons, I respectfully dissent.

CORDY, J. (dissenting, with whom Spina, J., joins).

I join and agree completely with Justice Spina's dissent. I write separately only to underscore my strongly held view that the judicial branch should not intrude on what is plainly an executive branch function in the absence of a showing that that branch has failed to fulfil its legal or constitutional obligations. There is not a hint of such a showing in this case. To the contrary, all indicators of executive branch intentions support the conclusion that "meaningful opportunit[ies] to obtain release" on parole have been and will continue to be provided to individuals serving life sentences for murders they committed when they were juveniles. There is no demonstrated need for the court to construct and order funded a special parole and appellate process for such prisoners.1

While the directives in the court's ruling regarding counsel, appeals, and the funding of experts may seem relatively benign to some, in unnecessarily intruding on the functions of another branch the court steps over the line that separates the powers accorded to each in our constitutional structure — a separation we have proudly proclaimed as a necessary element of a constitutional democracy that ensures our government shall be one of laws and not of men.2 In doing so, the court also fails to accord the other branches the respect necessary to the proper functioning of a government where each has its own constitutional responsibilities. While the role of the judiciary may often include being a check on the other branches when they exceed or fail in the execution of those responsibilities, it is distinctly not to exercise them.3 Although we occasionally declare that the Massachusetts Declaration of Rights creates certain duties in other branches, such as ensuring a meaningful opportunity for release on parole, we leave it to those branches "to define the precise nature of the task[s] which they face in fulfilling" those duties. McDuffy v. Secretary of the Exec. Office of Educ., 415 Mass. 545, 620 (1993). To hold that such a meaningful opportunity can only occur in the context of a parole hearing with counsel appointed, experts on retainer, and a special appellate process, is to declare that we know best how to perform the tasks constitutionally assigned to others, in the absence of any evidence of failure or excess.4 This substitution at this juncture of our judgment for that of the parole board as to the expertise and advocacy necessary for it to properly exercise its executive discretion is a slippery slope, and one down which we should not embark.