(dissenting, with whom Botsford and Duffly, JJ., join). The court today effects a sea change in the scope of discovery permitted in conjunction with a psychiatric examination pursuant to Mass. R. Grim. P. 14 (b) (2) (B), as amended, 463 Mass. 1501 (2012) (rale 14 [b] [2] [B]). I write separately because I believe this sweeping expansion of the discovery obligation, representing a significant departure from current practice, is premature and unwise.
Although the court purports to refer the “scope of requisite *650disclosure” required by rule 14 (b) (2) (B), ante at 648, to the standing advisory committee on the rules of criminal procedure (committee), the committee is in reality not being asked to advise whether a vastly expanded scope of discovery is necessary or appropriate. The court today has essentially already defined that scope to include the disclosure of all of an individual’s medical and psychiatric treatment providers from any time in his or her life. Ante at 648-649. The committee is instead being asked only to implement that expansion.
In concluding that such mandatory discovery is no more than “part and parcel” of a rule 14 (b) (2) (B) examination, ante at 645, the court decides for the first time that a defendant must identify, for the use of the Commonwealth’s expert, all of his or her physical and mental health treatment providers and that, upon the expert’s request, those providers must thereafter supply the expert with their treatment records. I disagree that rule 14 (b) (2) (B) as it presently stands can fairly be read to require such mandatory disclosure. I would accordingly affirm the motion judge’s decision as being, on the record before him, squarely within his discretion. That being said, I nonetheless recognize that the Commonwealth raises important questions concerning the proper scope of a rule 14 (b) (2) (B) examination and appropriate related discovery, and that these questions deserve serious consideration.
To avoid the unnecessary risk of untold consequences from a precipitous expansion of mandatory discovery obligations, however, I would refer such questions to the committee, or to an ad hoc committee created for this purpose, and seek its advice concerning whether and to what extent rule 14 (b) (2) (B) should explicitly require the pretrial disclosure of treatment providers and the production of treatment records in conjunction with the rule 14 (b) (2) (B) examination. In performing its work, the committee (or ad hoc committee) should be tasked, among other things, with investigating whether practitioners1 are experiencing any difficulties with the current version of the rule in this regard and, if so, the type and scope of changes to the rule that would best address those difficulties and shortcomings.
*651As to my first point of disagreement with the court, I do not agree that the current version of rule 14 (b) (2) (B) requires the types of discovery the Commonwealth seeks. The rule requires that when a defendant has given notice, or a judge has otherwise determined that a defendant intends to offer the testimony of an expert witness on the issue of his mental condition at a relevant time, and that this expert will rely upon the defendant’s statements as to his mental condition, the defendant may be ordered to “submit to an examination” by the Commonwealth’s expert. The rule expressly provides that “[t]he examination shall include such physical, psychiatric, and psychological tools as the examiner deems necessary to form an opinion as to the mental condition of the defendant at the relevant time.” Mass. R. Grim. R 14 (b) (2) (B) (i). The rule is silent, however, as to any requirement that the defendant provide to the Commonwealth’s expert his prior treatment records or other material from external sources. This silence is consistent with the view that, under the current rule, the examination permits the Commonwealth’s expert to obtain information directly from the defendant, who presents himself to the examiner and submits to the interview and the examiner’s inquiries of him, as well to any tests that the examiner requires.
The “examination” to which the rule refers is otherwise undefined. Dictionary definitions do not aid the court’s interpretation of its scope.2 In concluding that treatment records are nevertheless encompassed in the rule’s “examination” requirement, the court instead relies upon a publication by the American Psychiatric Association of what is there characterized as best practice guidelines for the purpose of clinical treatment of adult psychiatric patients. Ante at 643. Clinical treatment, involving as it does a physician-patient relationship geared toward maximizing the patient’s best interests, is hardly what characterizes the forensic examination plainly contemplated by the rule. A rule 14 (b) (2) (B) examination has generally been understood to *652include a “compelled interview” of the defendant, Commonwealth v. Callahan, 386 Mass. 784, 789 (1982), S.C., 401 Mass. 627 (1988), as well as tests the examiner deems necessary.3 See Commonwealth v. Poissant, 443 Mass. 558, 565 (2005) (“interview[] by a Commonwealth expert”). See also Commonwealth v. Connors, 447 Mass. 313, 317 n.7 (2006), quoting Commonwealth v. Poissant, supra at 559 n.l (no meaningful distinction between “interview” and G. L. c. 123A, §§ 13 and 14, “examination”).
The rule 14 (b) (2) (B) examination does not implicate a doctor-patient relationship, is evaluative in nature and purpose, and is intended solely to form the basis for the opinion that the expert will render as to the defendant’s mental condition at the relevant time. It is a short step from the court’s flawed premise as to the nature of the “examination” at issue to its mistaken view that the language of rule 14 (b) (2) (B), allowing for an examination, allows also “for all that is inherent in a psychiatric examination,” ante at 643, and that this must include, if the examination is to be “comprehensive and meaningful,” id., the expert’s review of potentially all of a defendant’s medical and psychiatric records, throughout his or her life. Ante at 648-649. Of equal concern is the fact that, on this logic, because the wholesale disclosure of treatment providers and documents is but “part and parcel” of the rule 14 (b) (2) (B) examination itself, such disclosure “falls within the scope of the limited waiver effectuated when a defendant is required to submit to a rule 14 (b) (2) (B) examination.” Id. at 645, 646.
The court discerns further support for its position in the 2012 amendments to rule 14 (b) (2) (B), which addressed the written reports that the experts must file with the court as to the mental condition of the defendant at the relevant time. Ante at 643. The *653amendments4 make clear that the reports of both parties’ experts “must include a written summary of the expert’s expected testimony that fully describes: the defendant’s history and present symptoms; any physical, psychiatric, and psychological tests relevant to the expert’s opinion regarding the issue of mental condition and their results; any oral or written statements made by the defendant relevant to the issue of the mental condition for which the defendant was evaluated; the expert’s opinions as to the defendant’s mental condition, including the bases and *654reasons for these opinions; and the witness’s qualifications.” Mass. R. Crim. P. 14 (b) (2) (B) (iii).
The court reads into the requirement that the experts’ reports contain a summary that “fully describes” these various matters the obligation that the experts themselves gather a full history of the defendant. Ante at 643-644. The court then sees no way that this extrapolated “requirement” can be met absent the defendant’s compilation and disclosure to the experts of all of the defendant’s treatment providers, throughout that individual’s lifetime, and by the providers’ production of expert-designated treatment records. Ante at 643-645, 647-649.
The rule as written requires no such thing. It does not require that the expert for either party obtain a full history of the defendant any more than it requires either expert to perform physical, psychiatric, or psychological tests. What it does require from the experts for both parties is that they produce reports fully describing, inter alia, whatever tests were in fact performed and their results, whatever symptoms have been observed, and whatever history of the defendant has been taken. Mass. R. Crim. P. 14 (b) (2) (B) (iii).
Moreover, the Commonwealth has not articulated any reasons why it needs the discovery it seeks in this case. In appropriate circumstances, where necessity is established, Mass. R. Crim. P. 14 (b) (2) (C) (authorizing “[additional discovery” of “other material and relevant evidence relating to the defendant’s mental condition”) already provides a trial judge “the flexibility to require the parties to provide additional discovery beyond the information contained in the notice that the defendant must give and the reports that the experts must file.” See Reporters’ Notes to Rule 14 (b) (2) (C), Mass. Ann. Laws Court Rules, Rules of Criminal Procedure, at 1523 (LexisNexis 2012). As the Reporters’ Notes make clear, however, “[i]t is a very limited grant of discretion and should be reserved for cases presenting discovery issues that are out of the ordinary.” Id.
The court maintains that the mandated disclosure of treatment providers and records has always been “part and parcel” of a rule 14 (b) (2) (B) examination, ante at 645; I conclude otherwise. Based on the plain language of the rule, this court’s prior holdings, see Commonwealth v. Sliech-Brodeur, 457 Mass. 300, *655318-319, 325-326 (2010) (Sliech-Brodeur), and Blaisdell v. Commonwealth, 372 Mass. 753, 759-764 (1977), as well as the absence of any showing of necessity by the Commonwealth, I would hold that the motion judge acted within his discretion in denying the Commonwealth’s request for the defendant’s medical and psychiatric records prior to the exchange of expert reports set forth in the rule.
That the rule as written does not require the discovery now mandated deepens my concern as to the risk of adverse consequences attendant upon the court’s decision and its departure from current practice. A defendant who has suffered a severe head injury such as the defendant in Commonwealth v. Alvarez, 433 Mass. 93, 100-104 (2000), and who intends to claim that the brain injury affected her ability to control her behavior at the time of the crime, would also have to disclose treatment for alcohol dependency that she had undergone twenty years prior to the head injury, and that forms no part of her intended defense, if the Commonwealth’s expert deems such treatment “necessary to conduct a psychiatric evaluation.” Ante at 648. Similarly, a married defendant who is being treated for Parkinson’s disease, and who claims that one of the side effects of one of the medications that he is taking impacted his mental state at the time of the offense, would have to disclose treatment records for a sexually transmitted disease that he contracted, and for which he was treated successfully, years before the crime. A defendant would likewise be required to mm over to the Commonwealth’s expert statements he may have made years earlier to a treating psychiatrist concerning other, unrelated crimes. Where a defendant intends to introduce evidence of a pattern of prior abuse (the so-called “battered woman’s syndrome” defense) as relevant to her mental condition at the time of the offense, a lifetime of medical treatment for physical conditions would have to be provided to the Commonwealth’s expert.
Defendants ordinarily have not been required to produce prior treatment records either before or after delivery of the experts’ reports, and certainly not all such treatment records upon designation by the Commonwealth’s expert, irrespective of whether defense counsel intends to use them at trial or to provide *656them to his or her own expert. In stark contrast to present practice, the court’s decision will leave a defense attorney who omits the sources of such treatment records, inadvertently or not, subject to possible claims of ineffective assistance or to bar disciplinary proceedings.* ***5 See ante at note 4. The court brushes aside concern that defense counsel will be forced to disclose records that, for strategic reasons, counsel does not otherwise intend to use at trial or to provide for his or her own expert’s use, and that this may implicate, among other things, conflict of interest considerations.6 Indeed, the court’s directives that a defendant must “cooperate” with the Commonwealth’s expert “to the same extent” as with the defendant’s own expert, ante at note 3, and that the defendant’s expert must also be able to designate records not provided by defense counsel, ante at 648, appear designed to ensure that conflicts of interest will arise.
Moreover, rule 14 (b) (2) (B) (ii) provides that “[n]o statement, confession, or admission, or other evidence of or obtained from the defendant during the course of the examination, except evidence derived solely from physical examinations or tests, may be revealed to the prosecution or anyone acting on its behalf unless so ordered by the judge.” Apart from underscoring that rule 14 (b) (2) (B) does not anticipate that the Commonwealth’s psychiatric expert will have the subject treatment *657records during the court-ordered examination of the defendant, it is far from clear whether statements contained in those records concerning other crimes, revealed to psychiatrists or psychologists potentially years prior to the offense, would be deemed to have been made “during the course of the examination.” If that were so, nothing in the court’s holding would appear to preclude the examiner from disclosing these statements to the Commonwealth, a prospect that is fraught with difficulty. See Sliech-Brodeur, supra at 318 n.23 (“We have recognized the court-appointed examiner as an agent of the prosecution”).
While awaiting the committee’s implementation of today’s discovery mandate, the court devises an interim procedure whereby “a defendant is to provide the rule 14 (b) (2) (B) examiner with the same records provided to or considered by the defense expert,”7 and the examiner may also request from the defendant “the names, addresses, dates of treatment, and areas of specialized practice of all treatment providers,” so that the Commonwealth’s expert can augment the records to be received. Ante at 648-649. As with all mandated discovery of treatment providers and records in conjunction with the rule 14 (b) (2) (B) examination, pursuant to the interim procedure, this mandated discovery is to be produced without any showing of relevance by the Commonwealth,8 without any judicial deter*658mination of possible privilege issues9 and, indeed, without any review whatsoever by the trial judge.
In addition to its failure to articulate why it needs the discovery it seeks in this case, the Commonwealth has not established why the sweeping expansion of the scope of permissible discovery under rule 14 (b) (2) (B) it advocates is warranted and appropriate. Given the absence of exigency, the limits of the information before us, and the importance of the interests involved, the court today plunges unnecessarily into uncharted waters. To be sure, we are the ultimate interpreters of rule 14 (b) (2) (B). In performing that task, however, we should tread carefully before embarking on a significant change in practice, first seeking the advice and counsel of those familiar with the rule and with any perceived shortcomings in its application. If, in the interests of more open discovery and fair*659ness to the Commonwealth, see Sliech-Brodeur, supra at 324-325, earlier and more expansive discovery of a defendant’s treatment providers and records is shown to be warranted, appropriate changes would be in order. This should occur only after a period of due consideration by the committee and by the court’s rules committee, after a period of public comment by practitioners in the field, and after further reflection by the court.
Because I believe that changes of such moment should not be made without public consideration and comment, and after duly weighing the possible consequences, I respectfully dissent.
use the word “practitioners” to include both practicing defense attorneys and prosecutors, as well as practicing psychiatrists and psychologists who are called upon to perform rule 14 (b) (2) (B) examinations.
A dictionary definition of an “examination” is “the act or process of examining or state of being examined.” Webster’s Third New International Dictionary 790 (1993). To “examine,” in turn, means “to test by an appropriate method ... to look over: inspect visually or by use of other senses . . . to inspect or test for evidence of disease or abnormality... to inquire into the state of especially] by introspective processes.” Id.
In Blaisdell v. Commonwealth, 372 Mass. 753, 759 (1977) (Blaisdell), we discussed the “nature of the psychiatric examination,” and observed that “[t]he primary diagnostic source in such a situation often is that which the examiner may glean from the nature and content of the defendant’s statements.” Among other things, “a defendant in such an examination [may] be called on to recite his life history, emotions, feelings, thoughts and views as to relations with others . . . ; [and] he may well have to talk about the crime charged itself as well as acts, events and emotions relative to its commission.” Id. at 759-760.
The Reporters’ Notes indicate that the 2012 amendments to rule 14 (b) (2) (B) were made in order to incorporate in the rule this court’s holding in Commonwealth v. Sliech-Brodeur, 457 Mass. 300, 321 (2010) (Sliech-Brodeur), a holding that does not require today’s result. Reporters’ Notes to Rule 14 (b) (2) (B), Mass. Ann. Laws Court Rules, Rules of Criminal Procedure, at 1523 (LexisNexis 2012). In that case, we held that rule 14 (b) (2), “from its inception, was intended to serve as the single, self-contained, and comprehensive rule governing pretrial notice and discovery from expert witnesses concerning a lack of criminal responsibility defense.” Sliech-Brodeur, supra. Discussing Blaisdell, supra, we noted that, where a defendant intends to rely at trial on an expert’s opinion as to his or her mental state “at or about the time of the commission of the crime, the expected proffer of such expert’s testimony acts as a waiver of the defendant’s privilege to the extent that the defendant may be ordered to submit to an independent psychiatric examination by a psychiatrist of the Commonwealth’s or the court’s choosing.” Sliech-Brodeur, supra at 316, citing Blaisdell, supra at 766. We emphasized that “the scope of reciprocal discovery that rule 14 prescribes is carefully limited. When a defendant serves notice that she will call an expert witness to testify about her mental condition at the time of the crime based on her testimonial statements, the rule only authorizes a court-ordered psychiatric examination of the defendant by the Commonwealth’s expert, and nothing more.” Sliech-Brodeur, supra at 318 (footnotes omitted). We pointed out also that, in Blaisdell, supra at 759, we had “carefully distinguished between a psychiatric inquiry and ‘[mjatters which may be relevant to a defendant’s physiological condition, where objective tests such as X-rays, blood tests and electroencephalographs may be relevant.’ ” Sliech-Brodeur, supra at 319 n.27.
Thus, we concluded that disclosure to the Commonwealth’s expert of the defendant’s statements to her psychiatric expert, that expert’s notes, the results of tests he performed, and other materials upon which the defendant’s expert relied, prior to trial, was error. Id. at 321. We determined, however, that rule 14 (b) (2) should be amended to require a defendant’s expert to produce, at a point to be recommended by the court’s standing advisory committee on the rules of criminal procedure, “a report that includes the defense expert’s opinion and the bases and reasons for this opinion,” and asked the committee to propose such an amendment. Sliech-Brodeur, supra at 325. The 2012 amendments were made accordingly, requiring the defense expert’s report to be produced after the Commonwealth has delivered its expert’s report to the defendant. See Mass. R. Crim. P. 14 (b) (2) (B) (iii).
The court seems to have imposed an obligation upon defense counsel to compile information identifying all of the defendant’s treatment providers. How this is to be accomplished is unclear when it is questionable whether even an eighteen year old defendant or his family members would have readily at their disposal specifics as to “names, addresses, dates of treatment, and areas of specialized practice of all treatment providers.” Ante at 649. See ante at note 3, 648-649. For an older defendant, particularly one with a history of mental illness, and who is dependent upon the record-retention policies of individual health care providers, such information may be impossible to obtain.
Relying on Commonwealth v. Alvarez, 433 Mass. 93, 101-104 (2000), for the proposition that defense counsel renders ineffective assistance when failing to provide relevant medical records to the defense expert, the court mandates that, going forward, a defendant must produce all treatment records, of whatever relevance, that the Commonwealth’s expert designates. Ante at 644-645 & note 4. Of course, in Commonwealth v. Alvarez, supra at 100-102 & n.9, counsel was not ineffective for having made a strategic choice not to give certain clearly relevant medical records to his expert. Counsel was ineffective because he failed in the first instance to investigate, obtain, or review those records; he later failed to prepare his own witness adequately by not providing the witness with those records.
Apparently the defendant will bear the expense of producing these potentially voluminous records.
While the court states that it “expect[s]” that neither the Commonwealth’s nor the defendant’s expert “will need to review records that are irrelevant to the issue of the defendant’s condition at the time of the commission of the alleged offense,” ante at note 9, it does not suggest that relevancy is a condition of the obligation to produce treatment records. I am unaware of any other instance in our discovery jurisprudence where matters of relevancy are presumptively immaterial. Contrast Commonwealth v. Lampron, 441 Mass. 265, 269 (2004), quoting United States v. Nixon, 416 U.S. 683, 699-700 (1974); Fed. R. Grim. P. 17(c); Mass. R. Crim. P. 17, 378 Mass. 885 (1979).
In any event, given the limited information that the Commonwealth’s examiner may have available by which to determine relevancy, it is uncertain how such determinations will be made. Moreover, since any undisclosed record the Commonwealth’s examiner deems “necessary” is to be subpoenaed by the clerk and delivered to the Commonwealth’s expert, without the involvement of a judge, it is less than clear how a defendant will “have the opportunity to move to exclude” any “objectionable” material. Ante at 649.
belying in part on Commonwealth v. Callahan, 386 Mass. 784, 789 (1982), S.C., 401 Mass. 627 (1988), the court states that both constitutional and statutory privilege have been waived when a defendant gives notice of intent to offer expert testimony regarding his mental condition, ante at 645-648, because the defendant could then be ordered to submit to a rule 14 (b) (2) (B) examination, “including all that a comprehensive examination entails.” Ante at 646. In that case, however, we explained that:
“The Commonwealth relies on our decision in Blaisdell to claim that by offering expert testimony the defendant waived his privilege against self-incrimination, as well as the protections of [G. L. c. 233,] § 23B. The Commonwealth misreads our decision in Blaisdell. In Blaisdell, we ruled that when a defendant notifies the Commonwealth that he intends to raise the issue of his criminal responsibility and to present the evidence of experts who have examined him, then he may be required to submit to a court ordered psychiatric examination. This is so because the defendant, by voluntarily proffering such evidence to the jury, has waived his privilege against self-incrimination to a limited extent. However, we did not hold that the defendant thereby waived his privilege against self-incrimination entirely. Indeed, we imposed stringent guidelines on the use of the fruits of the compelled interview. ... In Commonwealth v. Goulet, 374 Mass. 404, 411 n.4 (1978), we again made it clear that the waiver we found in Blaisdell was a limited waiver that could require a defendant to submit to a court ordered examination. We stated that ‘[t]his waiver is implied in the interest of giving the Commonwealth a fair chance to present countervailing psychiatric testimony; it is not to be understood as a complete relinquishment of the Fifth Amendment and art. 12 privilege which could allow pressure on the defendant to take the witness stand.’ Id.”
Commonwealth v. Callahan, supra at 788-789.