CORDY, J.

In 2007, the defendant, Kempess Sylvain, a noncitizen lawfully residing in the United States, pleaded guilty to possession of a controlled substance, subjecting him to automatic deportation from the United States. After the defendant's conviction was final, we decided Commonwealth v. Clarke, 460 Mass. 30, 34, 37, 45 (2011) (Clarke), which held that the rule announced in Padilla v. Kentucky, 130 S.Ct. 1473, 1483, 1486 (2010) (Padilla), regarding a criminal defendant's right under the Sixth Amendment to the United States Constitution to accurate advice as to the deportation consequences of a guilty plea, was not a "new" rule under Teague v. Lane, 489 U.S. 288, 301, 310 (1989) (Teague), and therefore applied retroactively to cases on collateral review. Thereafter, the defendant filed a motion for a new trial seeking to vacate his guilty plea on the ground that his attorney was constitutionally deficient in erroneously advising him that there would be no deportation consequences stemming from his guilty plea. The defendant's motion was denied, and he timely appealed. While the defendant's appeal was pending, the United States Supreme Court decided Chaidez v. United States, 133 S.Ct. 1103, 1105, 1111 (2013) (Chaidez), which held that Padilla did announce a "new" rule under Teague and, thus, does not apply retroactively to collateral challenges under Federal law. We granted the defendant's application for direct appellate review to consider whether we should continue to give Padilla retroactive effect in light of Chaidez.

We conclude, as a matter of Massachusetts law and consistent with our authority as provided in Danforth v. Minnesota, 552 U.S. 264, 282 (2008) (Danforth), that the Sixth Amendment right enunciated in Padilla was not a "new" rule and, consequently, defendants whose State law convictions were final after April 1, 1997, may attack their convictions collaterally on Padilla grounds. We thus affirm our decision in Clarke. We further conclude that under art. 12 of the Massachusetts Declaration of Rights, defense counsel has a duty to provide noncitizen defendants with accurate advice regarding the deportation consequences of pleading guilty or being convicted at trial and that this right also applies retroactively to cases on collateral review.

Having decided that the defendant may seek relief under the Sixth Amendment and art. 12, we conclude that although the defendant's counsel's erroneous advice may have been constitutionally inadequate, without additional findings we are unable to determine whether the defendant was sufficiently prejudiced to warrant vacating his guilty plea and ordering a new trial. Consequently, we remand the case to the Boston Municipal Court judge for further findings and proceedings consistent with this opinion.1

Background. The material facts are not in dispute. On the morning of April 15, 2007, a Boston police officer patrolling along Blue Hill Avenue in the Dorchester section of Boston witnessed the defendant engaging in a sexual act with a prostitute. As the officer approached, the defendant removed several small plastic baggies from his coat pocket and placed them in his mouth. Believing that the baggies contained "crack" cocaine and fearing that the defendant might overdose, the officer attempted to intercede. Although the defendant ingested the drugs, a subsequent search of his jacket revealed an additional baggie of "crack" cocaine. The incident took place within 1,000 feet of a child care center.

Following his arrest, the defendant was charged with one count of possession of cocaine with the intent to distribute, G. L. c. 94C, § 32A (a); and one count of a drug violation in a school zone, G. L. c. 94C, § 32J. The latter charge carried a minimum mandatory sentence of two years' imprisonment. In exchange for the dismissal of the school zone and distribution related charges, the defendant pleaded guilty to simple possession of cocaine, G. L. c. 94C, § 34, and was sentenced to eleven months in the house of correction suspended for two years. The defendant's conviction became final on October 2, 2007.2

In January, 2012, the defendant filed a motion to vacate his guilty plea pursuant to Mass. R. Crim. P. 30(b), as appearing in 435 Mass. 1501 (2001). Citing Padilla, supra, and Clarke, supra, the defendant contended that, as a noncitizen, "he was denied effective assistance of counsel when his trial counsel failed to advise him of the immigration consequences that could result from his guilty plea" and, therefore, the "plea was obtained in violation of his rights under the Sixth and Fourteenth Amendments to the United States Constitution and Article 12 of the Massachusetts Declaration of Rights."3

In support of his motion, the defendant submitted an affidavit of his counsel averring that, "At the time I represented [the defendant], I was aware that he was not a citizen of the United States [and] I advised [the defendant] ... that this disposition was not likely to result in his deportation because it was a conviction for straight [p]ossession with a sentence of under a year." The defendant also filed his own affidavit stating that, but for his counsel's erroneous advice, "I would not have agreed to plead guilty to something that would surely result in my deportation." The motion judge denied, without written findings, both the defendant's motion to vacate and his subsequent motion for reconsideration. The defendant appealed, and during the pendency of the appeal, the Supreme Court decided Chaidez. The defendant then filed an application for direct appellate review, which we granted.

Discussion. The defendant urges us to continue to apply Padilla retroactively, despite the Supreme Court's decision in Chaidez. In particular, he contends that Danforth, supra at 282, allows us to continue to apply the retroactivity framework from Teague, supra, but nevertheless reach a divergent conclusion from Chaidez. Specifically, he asserts that despite the Supreme Court's conclusion in Chaidez that Padilla announced a "new" rule, we are free to arrive at the opposite conclusion as a matter of State law and, by doing so, provide greater protection for defendants challenging their convictions on collateral review. Alternatively, the defendant urges us to recognize a remedy under art. 12 that parallels the Sixth Amendment right enunciated in Padilla.4

The Commonwealth responds by construing the defendant's argument about the retroactivity of the Sixth Amendment right in Padilla as attempting to discard our State law version of the Teague framework and replace it with an undefined alternative. Although the Commonwealth acknowledges our authority to depart from the Supreme Court on this issue based on its decision in Danforth, the Commonwealth maintains that doing so ignores that prior to Padilla, criminal defense attorneys had no obligation to advise their clients of the immigration consequences of a guilty plea. The Commonwealth further contends that there is no basis for interpreting art. 12 as providing a right to accurate advice from counsel regarding the deportation consequences of a guilty plea that would apply retroactively to cases on collateral review.

1. Retroactivity. a. Sixth Amendment right to effective assistance of counsel following Padilla. In Padilla, supra at 1486, the United States Supreme Court held that the Sixth Amendment requires a criminal defense attorney to provide accurate advice regarding the deportation consequences arising from a guilty plea. According to the Court, failure to provide such advice is a "constitutional deficiency" that satisfies the first prong of the test for ineffective assistance of counsel under Strickland v. Washington, 466 U.S. 668 (1984) (Strickland).5 Padilla, supra at 1483. The Court did not explicitly state whether Padilla would apply retroactively to cases on collateral review.

Thereafter, in Clarke, supra at 45, we were required to confront whether the Federal constitutional right recognized in Padilla applied retroactively to criminal convictions that were final at the time Padilla was decided. In our decision, we relied on the analytical framework set forth in Teague, supra at 310, which we adopted in Commonwealth v. Bray, 407 Mass. 296, 300-301 (1990) (Bray). Under Teague and its progeny, although "new constitutional rules of criminal procedure will not be applicable to those cases which have become final before the new rules are announced," id., "old rule[s] appl[y] both on direct and collateral review." Whorton v. Bockting, 549 U.S. 406, 416 (2007).6 As this framework suggests, the determination whether a case announces a "new" rule is at the heart of the retroactivity analysis. According to the Supreme Court in Teague, supra at 301, "a case announces a new rule when it breaks new ground or imposes a new obligation on the States or the Federal Government [or] if the result was not dictated by precedent existing at the time the defendant's conviction became final" (emphasis in original). Subsequent decisions of the Supreme Court have opined that a rule is "dictated by precedent" if the result was "apparent to all reasonable jurists" at the time the defendant's conviction became final (emphasis added). Chaidez, supra at 1107, quoting Lambrix v. Singletary, 520 U.S. 518, 527-528 (1997). Thus, a case announces a "new" rule if the result was not apparent to all reasonable jurists at the time the defendant's conviction became final. See, e.g., Graham v. Collins, 506 U.S. 461, 477 (1993) ("determinative question is whether reasonable jurists reading the case law that existed in 1984 could have concluded that [defendant's] sentencing was not constitutionally infirm" [emphasis in original]); Wright v. West, 505 U.S. 277, 304 (1992) (O'Connor, J., concurring) ("new rule inquiry [asks] whether `reasonable jurists' could disagree as to whether a result is dictated by precedent"); Sawyer v. Smith, 497 U.S. 227, 234 (1990) ("Teague serves to ensure that gradual developments in law over which reasonable jurists may disagree are not later used to upset finality of [S]tate convictions valid when entered"); Butler v. McKellar, 494 U.S. 407, 415 (1990) (constitutional rule that is "susceptible to debate among reasonable minds" qualifies as new rule).

In Clarke, we concluded that "[t]here is no question that the holding in Padilla is an extension of the rule in Strickland," Clarke, supra at 37, and that Padilla is the "definitive application of an established constitutional standard on a case-by-case basis, incorporating evolving professional norms[7] (on which the standard relies) to new facts." Clarke, supra at 43. This determination reflected our recognition that the standard for measuring ineffective assistance of counsel under Strickland is one of general applicability, designed to evaluate the reasonableness of an attorney's acts or omissions in a multitude of factual contexts. Clarke, supra at 36, 38-39, 43. See Williams v. Taylor, 529 U.S. 362, 390-391 (2000). Because application of such a general standard to a particular factual scenario rarely produces a new rule, Clarke, supra at 36, quoting Wright v. West, 505 U.S. 277, 308-309 (1992) (Kennedy, J., concurring), we concluded that Padilla did not announce a new rule and, thus, that the Sixth Amendment right enunciated in Padilla applied retroactively to cases on collateral review under the Teague framework.8,9 Clarke, supra at 45.

Our decision in Clarke was soon cast into doubt by the United States Supreme Court's decision in Chaidez.10,11 The Supreme Court's decision began by acknowledging, as we did in Clarke, supra at 36, 38-39, 43, that "`where the beginning point' of our analysis is a rule of `general application, a rule designed for the specific purpose of evaluating a myriad of factual contexts, it will be the infrequent case that yields a result so novel that it forges a new rule, one not dictated by precedent.'" Chaidez, supra at 1107, quoting Wright v. West, supra at 309 (Kennedy, J., concurring). For this reason, the Court conceded that "garden-variety applications of the test in [Strickland] for assessing claims of ineffective assistance of counsel do not produce new rules." Chaidez, supra.

However, according to the Court, Padilla "did something more" than "merely [make] clear that a lawyer who neglects to inform a client about the risk of deportation is professionally incompetent." Chaidez, supra at 1108. Specifically, Padilla considered the unsettled preliminary question whether "advice about deportation [was] `categorically removed' from the scope of the Sixth Amendment right to counsel because it involved only a `collateral consequence' of a conviction, rather than a component of the criminal sentence."12 Chaidez, supra, quoting Padilla, supra at 1482. According to the Court, prior to Padilla, the State and lower Federal courts had "almost unanimously concluded that the Sixth Amendment does not require attorneys to inform their clients of a conviction's collateral consequences, including deportation." Chaidez, supra at 1109. See id. at 1109 nn.7-8 (collecting cases).13 Consequently, the Court reasoned that insofar as Padilla, supra at 1482, concluded that "advice regarding deportation is not categorically removed from the ambit of the Sixth Amendment right to counsel," the decision altered the law of most jurisdictions and, therefore, represented a "new" rule under Teague. Chaidez, supra at 1110-1111. Accordingly, Padilla did not apply retroactively, a conclusion that is plainly at odds with our decision in Clarke.

The decision in Chaidez was not unanimous. Justice Sotomayor, with whom Justice Ginsburg joined, penned a dissenting opinion that took an entirely different view of the interrelationship between the Strickland standard and the Court's decision in Padilla, one more akin to our reasoning in Clarke. The dissent began by pointing out that "the proper measure of attorney performance remains simply reasonableness under prevailing professional norms." Chaidez, supra at 1114 (Sotomayor, J., dissenting), quoting Strickland, supra at 688. Moreover, the reasonableness prong "takes its content from the standards by which lawyers judge their professional obligations ... and those standards are subject to change." Chaidez, supra at 1114 (Sotomayor, J., dissenting), citing Strickland, supra. For this reason, in Padilla, the Court's application of Strickland "followed naturally" from the "changes in immigration law and the accompanying evolution of professional norms" over the previous fifteen years. Chaidez, supra at 1116 (Sotomayor, J., dissenting).

According to the dissent, Padilla reached the result that it did "because those norms reflected changes in immigration law..., not because the Sixth Amendment right had changed at all." Chaidez, supra at 1117 (Sotomayor, J., dissenting). Thus, in the same way that we concluded in Clarke, supra, that application of a general standard designed to apply to varying factual scenarios does not engender a new legal rule, the dissent in Chaidez, supra at 1115, agreed that "where we merely apply Strickland in a way that corresponds to an evolution in professional norms, we make no new law."

b. Application of Padilla in Massachusetts following Chaidez. In Clarke, supra at 45, our analysis was concerned solely with the question whether, in the absence of Supreme Court guidance, the Sixth Amendment right to effective assistance of counsel, as explicated in Padilla, applied retroactively to cases on collateral review. We did not consider whether the right to the effective assistance of counsel under art. 12 also included the right to accurate advice from counsel concerning the deportation consequences of pleading guilty, or whether such a right might apply retroactively. Because the defendant raises claims under both the Sixth Amendment and art. 12, we address both avenues of potential relief.

i. Retroactivity of the Sixth Amendment right to effective assistance of counsel under Massachusetts law. Given that the Supreme Court's holding in Chaidez is plainly at odds with our decision in Clarke, the question is whether we may give broader retroactive effect to Padilla as a matter of State law than it would otherwise enjoy under Federal law.14 We conclude that we may.

As discussed above, the Supreme Court's test for retroactivity is set forth in Teague, supra at 307, and its progeny.15 The Teague analysis is based on two primary policy considerations: comity and finality.16 Danforth, supra at 279-280; Teague, supra at 306. The benefit of Teague is that it provides a "bright line rule on the issue of when relief is to be retroactive." Danforth v. State, 761 N.W.2d 493, 499 (Minn.2009). In view of our concern that the finality of convictions not be unduly disturbed and our desire to have a clearly defined retroactivity standard, we adopted the Teague framework in Bray, supra at 300-301. Under the Teague-Bray framework, we first determine whether a rule is "new" or "old." See Teague, supra at 301; Bray, supra. If a rule is "new," it applies only to defendants whose cases are not final unless two narrow exceptions apply;17 if a rule is "old," it also applies retroactively to defendants whose cases were final at the time the rule was announced. Whorton v. Bockting, 549 U.S. 406, 416 (2007).

Although we consider the retroactivity framework established in Teague to be sound in principle, the Supreme Court's post-Teague expansion of what qualifies as a "new" rule has become so broad that "decisions defining a constitutional safeguard rarely merit application on collateral review." Colwell v. State, 118 Nev. 807, 818, cert. denied, 540 U.S. 981 (2003). As discussed above, according to the original formulation discussed in Teague, supra at 301, "a case announce[d] a new rule if the result was not dictated by precedent" at the time the defendant's conviction became final. In its subsequent jurisprudence, however, the Supreme Court has greatly expanded the meaning of what is "new" to include results not "apparent to all reasonable jurists" at the time. Lambrix v. Singletary, 520 U.S. 518, 527-528 (1997).

Although we adopted the Teague retroactivity framework in Bray, supra, including the Court's original construction of what constitutes a "new" rule, we have not specifically considered whether we ought to incorporate the Supreme Court's broadened formulation of that test into our own definition of what constitutes a "new" rule under Bray. See Commonwealth v. Melendez-Diaz, 460 Mass. 238, 247-248 (2011) (declining to consider whether, as matter of State law, broader retroactive effect may be given to Federal constitutional rule and instead deciding that Melendez-Diaz v. Massachusetts, 557 U.S. 305, 311 [2009], announced new rule based on Federal retroactivity standard set forth in Teague and its progeny). We conclude that we should not adopt this expansion. Rather, we continue to adhere to the Supreme Court's original construction that a case announces a "new" rule only when the result is "not dictated by precedent." Our ability to adopt this narrower interpretation, and thereby expand the availability of remedies for violations of Federal constitutional rights, is specifically permitted by the Supreme Court's decision in Danforth.

In Danforth, supra at 266, the Supreme Court considered whether the retroactivity analysis of Teague "constrains the authority of [S]tate courts to give broader effect to new rules of criminal procedure than is required by that opinion."18 Drawing on the "general principle that States are independent sovereigns with plenary authority to make and enforce their own laws as long as they do not infringe on the [F]ederal constitutional guarantees," Danforth, supra at 280, the Court concluded that "considerations of comity militate in favor of allowing [S]tate courts to grant [collateral] relief to a broader class of individuals than is required by Teague." Id. at 279-280. According to the Court, the "finality of [S]tate convictions ... is a matter that States should be free to evaluate, and weigh the importance of, when prisoners held in [S]tate custody are seeking a remedy for a violation of [F]ederal rights by their lower courts." Danforth, supra at 280.

In this manner, the Court drew an important distinction between the existence of a Federal substantive right or remedy, the contours of which are fixed by Federal law, and the procedural availability of such a right, the scope of which may be set by State law. See Danforth, supra ("Any State could surely have adopted the rule of evidence defined in Crawford [v. Washington, 541 U.S. 36 (2004),] under [S]tate law even if that case had never been decided. It should be equally free to give its citizens the benefit of our rule in any fashion that does not offend [F]ederal law"); id at 289 ("States that give broader retroactive effect to this Court's new rules of criminal procedure do not do so by misconstruing the [F]ederal Teague standard. Rather they have developed [S]tate law to govern retroactivity in [S]tate postconviction proceedings"). The Supreme Court concluded that Teague does not "limit the authority of a [S]tate court, when reviewing its own [S]tate criminal convictions, to provide a remedy for a violation that is deemed `nonretroactive' under Teague." Danforth, supra at 282.

As it pertains here, Chaidez concluded that Padilla announced a "new" rule under Teague. However, based on our authority to conduct an independent review, "[we] are not required to blindly follow that court's view of what constitutes a new rule." Rhoades v. State, 149 Idaho 130, 139 (2010), cert. denied, 131 S.Ct. 1571 (2011). Instead, we reserve our prerogative to define and determine within the Bray framework whether a rule is "new." The Supreme Courts of other States have come to the same conclusion. See State v. Smart, 202 P.3d 1130, 1138-1140 (Alaska 2009); Rhoades v. State, supra; Danforth v. State, supra at 500; Colwell v. State, supra.

We conclude that Padilla did not announce a "new" rule for the purposes of our retroactivity test under Bray. Our opinion is informed in part by our continued adherence to our analysis in Clarke and Justice Sotomayor's dissent in Chaidez. In brief, Padilla did not announce a "new" rule for the simple reason that it applied a general standard — designed to change according to the evolution of existing professional norms — to a specific factual situation. See Clarke, supra at 36, 38-39, 43; Chaidez, supra at 1114-1116 (Sotomayor, J., dissenting). We also are not persuaded that Massachusetts precedent at the time Padilla was decided would have dictated an outcome contrary to that in Padilla. Indeed, long before Padilla was decided, it was customary for practitioners in Massachusetts to warn their clients of the possible deportation consequences of pleading guilty. See Clarke, supra at 43 n.15. See also Padilla, supra at 1485.

Because we conclude that under our State retroactivity analysis Padilla did not announce a "new" rule, the defendant, whose conviction was final at the time Padilla was decided, is entitled to seek relief under the Sixth Amendment right recognized in Padilla.

ii. Article 12. The defendant also contends that his attorney's erroneous advice constituted ineffective assistance of counsel under art. 12. We have not expressly stated that art. 12 demands that defense counsel provide defendants with accurate advice concerning the deportation consequences of a guilty plea or conviction at trial. That such a right exists, however, is implicit in our recent decision in Commonwealth v. Marinho, 464 Mass. 115 (2013) (Marinho).

In Marinho, supra at 122, we considered whether defense counsel's failure to accurately advise the defendant of the potential immigration consequences of a conviction at trial constituted ineffective assistance of counsel under the Sixth Amendment and art. 12. In light of Padilla's broad language and the prevailing "expectation[s] in the Massachusetts legal community," we concluded that "defense counsel [has] a duty to inform a noncitizen client that conviction, whether by plea or by trial, may carry adverse immigration consequences." Marinho, supra at 125. We further determined that failure to provide such advice constitutes behavior that falls "measurably below that which might be expected from an ordinary fallible lawyer." Marinho, supra at 126, quoting Commonwealth v. Saferian, 366 Mass. 89, 96 (1974) (Saferian).

Although the defendant in Marinho framed his argument in terms of the guarantees of the Sixth Amendment and art. 12, our decision did not make clear whether the holding was based solely on a defendant's rights under the Sixth Amendment, or also based on our interpretation of the defendant's rights under art. 12. We take the opportunity today to clarify that under art. 12 defense counsel must accurately advise a noncitizen client of the deportation consequences of a guilty plea or a conviction at trial.

For the same reasons that we determined that the Sixth Amendment right enunciated in Padilla was not a "new" rule, we conclude that the defendant's coextensive right under art. 12 does not constitute a "new" rule. Like Strickland, supra at 688, our standard for ineffective assistance of counsel under Saferian, supra at 96, is a dynamic standard that evolves according to the advancement of professional norms. As we stated in Marinho, supra at 125, according to these norms, "the expectation in the Massachusetts legal community is that defense counsel should inform a client about immigration consequences associated with criminal conviction, however imposed." See Committee for Public Counsel Services, Assigned Counsel Manual Part IV, at 15 (rev. June 2011) ("Counsel must also advise the client ... of the consequences of a conviction, including ... deportation"); Clarke, supra at 43 n.15 ("since 1988, ... all staff attorneys and bar advocates in Massachusetts [have been required] to advise a defendant client of the immigration consequences of his or her criminal case"). See also Padilla, supra at 1485 (for "at least the past 15 years, professional norms have generally imposed an obligation on counsel to provide advice on the deportation consequences of a client's plea"). Finally, given the magnitude of the consequence to noncitizen defendants who plead guilty or are convicted at trial, tenets of fundamental fairness require that this right apply retroactively. Commonwealth v. Amirault, 424 Mass. 618, 639 (1997). Significantly, had we been presented with this issue at the time Padilla was decided, our conclusion that art. 12 provides such protection would have been the same.

For these reasons, the defendant is entitled to assert his claim for ineffective assistance of counsel under art. 12 on collateral review.

2. Ineffective assistance of counsel. We now proceed to the merits of the defendant's appeal. In order prevail on his claim for ineffective assistance of counsel, the defendant bears the burden of showing that (1) there has been "behavior of counsel falling measurably below that which might be expected from an ordinary fallible lawyer" and (2) that "it has likely deprived the defendant of an otherwise available substantial ground of defence." Saferian, supra.

According to the defendant's counsel's affidavit, "I advised [the defendant] ... that this disposition was not likely to result in his deportation because it was a conviction for straight [p]ossession with a sentence of under a year." This advice was plainly incorrect. Pursuant to 8 U.S.C. § 1227(a)(2)(B)(i) (2006), "[a]ny alien who at any time after admission has been convicted of a violation of ... any law or regulation of a State, ... relating to a controlled substance ... other than a single offense involving possession for one's own use of [thirty] grams or less of marijuana, is deportable." The defendant pleaded guilty to possession of cocaine (a class B substance) and, thus, was subject to deportation under 8 U.S.C. § 1227(a)(2)(B)(i). On its face, then, the defense counsel's affidavit is sufficient to establish that he failed to provide the defendant with accurate advice concerning the deportation consequences of pleading guilty in violation of Padilla, supra at 1483, thus satisfying the first prong of Saferian.

We are left to consider whether this deficient representation sufficiently prejudiced the defendant so as to justify vacating the defendant's guilty plea and ordering a new trial. "In the context of a guilty plea, in order to satisfy the `prejudice' requirement, the defendant has the burden of establishing that (1) `there is a reasonable probability that, but for counsel's errors, he would not have pleaded guilty and would have insisted on going to trial,'" Clarke, supra at 47, quoting Hill v. Lockhart, 474 U.S. 52, 59 (1985); and (2) that "a decision to reject the plea bargain would have been rational under the circumstances." Clarke, supra, quoting Padilla, supra at 1485. In this regard,

Clarke, supra at 47-48. With this requirement in mind, we turn to the record before us.

According to the defendant's affidavit submitted in support of his motion for new trial:

Although the defendant's affidavit is highly suggestive that he would have elected to go to trial but for his attorney's erroneous advice, we do not have the benefit of any findings or credibility assessments made by the motion judge. Without the benefit of such findings, it is not possible for us to say with any certainty whether the defendant's affidavit is merely self-serving or whether he was sufficiently prejudiced to justify vacating his guilty plea and ordering a new trial. See Saferian, supra at 96 ("whatever the attempted formulation of a standard in general terms, what is required in the actual process of decision of claims of ineffective assistance of counsel ... is a discerning examination and appraisal of the specific circumstances of the given case"). For this reason, we remand the case to the Boston Municipal Court with instructions to provide findings relating to the issue of prejudice and, if necessary, hold an additional evidentiary hearing on the defendant's motion for new trial for that purpose.

So ordered.