(dissenting in part). With due respect, I dissent from that part of the majority opinion which holds that the admission of the drug certificates was not harmless beyond a reasonable doubt. I also depart from the majority in the suggestion that it is not the whole trial record — Commonwealth case-in-chief and defense case — which is to be considered in determining the question whether an error, here the admission of the certificates, was harmless beyond a reasonable doubt.1
*485Consideration of the entire trial record of prosecution and defense evidence. Under Commonwealth v. Vasquez, 456 Mass. 350 (2010), the standard of review is whether the error in the introduction of the drug certificates was harmless beyond a reasonable doubt. In reviewing whether an error is so harmless, it is the trial record in its entirety, including both the Commonwealth’s and the defendants’ evidence, that is to be considered. “[A]n appellate court must ask ‘whether on the totality of the record before us, weighing the properly admitted and the improperly admitted evidence together, we are satisfied beyond a reasonable doubt that the tainted evidence did not have an effect on the jury and did not contribute to the jury’s verdicts.’ ” Id. at 369 (Cordy, J., concurring in part and dissenting in part), quoting from Commonwealth v. Tyree, 455 Mass. 676, 701 (2010) (emphasis supplied). Because it is the entire trial record that is to be considered, I disagree with the majority that, “we should not consider [the defendants’] testimony in analyzing the question of harmlessness.” Ante at 481.
Various factors are to be weighed, including, but not limited to, “the importance of the evidence in the prosecution’s case; the relationship between the evidence and the premise of the defense . . . [and] whether the erroneously admitted evidence was merely cumulative of properly admitted evidence.” Vasquez, 456 Mass. at 360 n.12, quoting from Tyree, 455 Mass. at 701.
The defendants’ testimony rendered the error in the admission of the drug certificates harmless beyond a reasonable doubt. Contrary to the majority, I would conclude that the admission of the drug certificates was harmless error, because in addition to other expert evidence concerning what the substances were, both defendants — in order to explain the existence of the cocaine and marijuana found in their rooms and in other parts of the apartment — took the stand at trial, acknowledged that the drugs were theirs, and explicitly admitted in their testimony that the substances were, in fact, cocaine and marijuana, the defendants contending only that these controlled substances *486were being held for personal use. The defendant Ronald Mendes testified that the marijuana and cocaine seized in his room belonged to him, and that he smoked marijuana every day and used cocaine three times a week, sometimes adding the cocaine to his “weed” and making a “blunt.” The defendant Raymond Mendes acknowledged that he kept cocaine and marijuana in the apartment, used these substances himself and with his codefendant twin brother Ronald,2 and also acknowledged that he gave the substances to guests, “do[ing] the blunt and the cocaine . . . that’s when I have a lady friend come over.” Raymond offered details about how to roll the marijuana into a “blunt” cigar by taking out the tobacco.
All of this was powerful substantive evidence, direct from the mouths of the defendants, that the substances were, in fact, cocaine and marijuana. In addition, the defense offered an expert on addictive drug use, who described the practice of using cocaine and marijuana — seeking to buttress and corroborate the defendants’ testimony to the effect that, even if the marijuana and cocaine taken from the apartment belonged to the defendants, the drugs so held by the defendants would be consistent with personal consumption, rather than distribution. There was also expert testimony in the Commonwealth’s case-in-chief by a qualified police expert who examined the exhibits containing the controlled substances, described what cocaine and marijuana look like, and stated that the substances packaged in the exhibits appeared to be cocaine and marijuana.
Thus, apart from, and cumulative to, the drug certificate evidence, the defendants’ testimonial admissions, the defense drug expert’s corroborating evidence, and the prosecution drug qualified drug expert, taken in totality, provided persuasive probative evidence that the substances were cocaine and marijuana. Therefore, applying the standards from the Vasquez and Tyree cases quoted above, in my opinion, this other independent evidence rendered the error in admission of the drug certificates harmless beyond a reasonable doubt.
To be noted is that all of this other drug identifying information was introduced at trial as substantive evidence. Hence, this *487is not case in which, in counter to the government’s evidence, a defense strategy is advanced not by introducing evidence in the defense case (including, perhaps, as here by the defendants’ testimony), but rather the defense strategy is pursued though the means of counsel’s opening statement and closing argument, and counsel’s interrogation of witnesses in an effort to persuade the fact finder at trial, that, even assuming illicit drugs were present, such drugs were for personal use.3 To the contrary, there was more than a defense theory advanced in this case; instead, substantive evidence was developed of and concerning the subject drugs being cocaine and marijuana. Given this substantive evidence, the principle applies to this case that, “[pjroof that a substance is a particular drug need not be made by chemical analysis and may be made circumstantial evidence.” Commonwealth v. Dawson, 399 Mass. 465, 467 (1987). “[Sjuch evidence may be ‘so powerful’ as to ‘nullify any effect’ that the drug certificates ‘might have had on the jury or the verdictfs].’ ” Commonwealth v. Charles, 456 Mass. 378, 381-382 (2010), quoting from Tyree, supra at 704 n.44.
That the most probative testimony concerning the nature of the unlawful controlled substances was forthcoming in the defendants’ own words — and reflected a wealth of experience *488in using the drugs by these defendants — sharpens the proof line because it is each defendant who inculpated himself and provided direct substantive, probative evidence about the nature of the controlled substances. Thus, in this case, the defendants’ trial testimony and defense evidence went far to prove the nature of the drugs. In my judgment, a defendant cannot have it both ways, i.e., take the stand at trial and testify that the controlled substances were particular drugs, and then shift stance to contend on appeal that a conviction was fraught with error because certificates of drug analysis were introduced. Such switches are, in effect, a disavowal of the defendant’s testimonial acknowledgment under oath that the substances were certain unlawful substances, here cocaine and marijuana. Here, in considering whether the error in admitting the drug certificates was harmless beyond a reasonable doubt, the defendants should be held to their words under oath at trial. Cf. United States v. Havens, 446 U.S. 620,626-627 (1980) (this Court has “repeatedly insisted that when defendants testify, they must testify truthfully or suffer the consequences. . . . The defendant’s obligation to testify truthfully is fully binding on him”).
To the defendants’ testimony, I would add, in the harmless error calculus, the prosecution’s police expert who described what cocaine and marijuana look like, and the various forms of these controlled substances and methods of packaging for sale, and the theme of the defense drug expert that, even though cocaine and marijuana may were involved, such drugs may be for personal use. All this evidence, when bundled — and even when assessed apart from the chemical analysis in the erroneously admitted drug certificates — brings this case within the core of the class of substantive and circumstantial evidence which Commonwealth v. Dawson, supra, held may prove the nature of an unlawful drug.
The majority relies on Commonwealth v. Charros, 443 Mass. 752, cert, denied, 546 U.S. 870 (2005). But I do not see Charros as providing legal justification for the defendants being able to say one thing at trial under oath — acknowledging that the controlled substances were cocaine and marijuana and offering a defense drug expert to the same effect ■— but, then postconviction, on appeal, stepping away from the defense evidence presented.
*489First, I do not believe that Charros, which involved a defendant’s trial testimony following the erroneous denial of a suppression motion, is apposite. In Charros, the court focused on the prejudicial effect of the defendant’s testimony, which may not have been given had the evidence been suppressed. Specifically, the defendant’s trial testimony that she had taken money from a strong box provided a critical link to the twenty-eight grams of cocaine. The point is: there was an important and potentially outcome-determinative contested issue in Charros concerning whether the defendant had knowledge that cocaine was being held in the apartment for distribution, versus a defense position that she was not aware of her husband’s drug business. In this case, there is no such contested defense issue, given the defendants’ concessions that the drugs were cocaine and marijuana, albeit supposedly held for personal use.
A second reason Charros is inapposite is that the court noted in that case that, “[i]t is virtually impossible to say, on this record, whether [the defendant] would have testified had the evidence been suppressed.” Id. at 766. That is absolutely not so in this case. To the contrary, it is perfectly clear from the case record here — beginning with trial counsels’ openings that the defendants would testify, would acknowledge that the substances were cocaine and marijuana, and would offer expert evidence to that end.4
*490Third, looking to Charros, the majority concludes that the defendant’s testimony is not “countable” because the government has the burden of proof on all elements of a case. That is, of course, so. But, we are not here considering appellate review of a motion for a required finding of not guilty at the close of the government’s case, where only the evidence in the Commonwealth case-in-chief counts. Rather, we are reviewing the entire case record, including the defense case — all, I submit, to be counted in the harmless beyond a reasonable doubt analysis. For these reasons, Charros, in my view, cannot be read to warrant reversal in this case because of the Melendez-Diaz and Vasquez error.
In certain respects, this case is similar to Commonwealth v. Villatoro, 76 Mass. App. Ct. 645, 652 (2010), in which we held that admission of the drug certificates was harmless beyond a reasonable doubt. In that case, “[t]he defendant not only admitted that the substance in question was marijuana, he testified at length on the subject, asserting the distinction between different grades of ‘weed,’ explaining why he also had smoking implements and baggies on his person, and detailing his experience and long history of marijuana use. . .. Additionally, the arresting officer recounted that he had received Drug Enforcement Administration task force training and ATF drug recognition training; he testified further that he also recognized the odor of marijuana when he approached the defendant based on his own experience, including hundreds of marijuana arrests.” Id. at 652-654.5 In addition, the majority opinion in this case appears *491to be inconsistent with the holding in Commonwealth v. DeMatos, 77 Mass. App. Ct. 727 (2010). In DeMatos, this court held that the error in admission of drug certificates was harmless beyond a reasonable doubt where the evidence was that the defendant, by an out-of-court admission, stated that he was using cocaine at the time of his arrest. This out-of-court admission was, in turn, buttressed by police officer’s testimony that the defendant appeared “high” when apprehended. If, as in De-Matos, such an out-of-court admission, coupled with other evidence of drug distribution, rendered the admission of the drug certificates harmless error, I fail to see how an in-court admission by a defendant under oath, also buttressed by other evidence, is to be afforded less weight in the harmless beyond a reasonable doubt analysis. Yet, to accept the majority analysis is to do that, inconsistently with DeMatos. That is, while this court has in that latter case afforded weight to an out-of-court admission by a defendant, the majority opinion in this case would not afford equal or greater weight to a defendant’s in-court testimony under oath that a substance is a particular unlawful drug, here, cocaine.
In sum, taking the defendants’ testimonial admissions that the substances were cocaine, the defense expert evidence centering on these two controlled substances and the police expert testimony, I would conclude that the error in admitting the drug certificates was harmless beyond a reasonable doubt. “[S]o powerful [was all of this other evidence] as to nullify any effect that the improperly admitted evidence might have had on the fact finder or the findings.” Vasquez, supra at 362 (internal quotations omitted).
For these reasons, I dissent.
I concur with the majority analysis that there was no error arising out of the informant information in the search warrant or in the questioning and *485testimony of the Commonwealth’s drug expert. Indeed, I believe that the evidence provided by the prosecution drug-qualified expert and defense drug-qualified expert is to be added to the defendants’ testimony in support of the determination that the error in the admission of the drug certificates was harmless beyond a reasonable doubt. See further discussion herein.
Because the defendants share the same surname, I refer to them by their first names.
Formulating a strategy and theory of defense is quite different from introducing substantive evidence defining and identifying the subject controlled substances. Indeed, the presence of the substantive evidence stemming from the defendants’ testimonial admissions and the defense expert evidence (as well as the qualified police expert evidence) distinguishes this case from Commonwealth v. Fluellen, 456 Mass. 517 (2010), and Commonwealth v. Charles, 456 Mass. 378 (2010). In Fluellen, the defense theory was not to contest that the substances were crack cocaine, but to assert that the cocaine was for personal use. This defense strategy was developed only via attorney argument and cross-examination. Similarly, in Charles, defense counsel referred to the substances as marijuana and crack cocaine in opening statement, examination, and closing argument. But there was not substantive evidence or any stipulation in Charles concerning what the substances were. Thus, in holding in the Charles case, that the error in admitting the certificates was not harmless beyond a reasonable doubt, the court noted that, “the arresting police officers, neither of whom was qualified as an expert in or had specialized training or experience in narcotics identification, offered only conclusory, and largely equivocal, testimony regarding the composition of the substances. The officers certainly, ‘did not articulate how their expertise permitted them to identify the substances’ as cocaine and marijuana.” Id. at 382, quoting from Commonwealth v. Melendez-Diaz, 76 Mass. App. Ct. 229, 233 (2010). That is quite different from the evidence in this case.
In concession about the controlled substances at issue, defense counsel for the defendant Ronald Mendes previewed the defense evidence to be introduced:
“My client is here for one reason and one reason only, to say he’s not guilty of possession with intent, possession of intent of cocaine, possession with intent of marijuana. My client is going to concede that he had marijuana in his house and had cocaine in his house, but those were for his own personal use, they were not for the purpose of distributing to anybody else” (emphasis added).
Trial counsel for defendant Raymond Mendes, although not using the word “concede,” provided a similar preview of the defense evidence which, in effect made a similar concession.
“In this case that it’s the important for you to listen to everything that the officers tell you, but also what Ray Mendes will tell you.
“A couple of the officers searched his bedroom, and he will tell you, in fact, he will tell you like he told the police exactly where the marijuana was.
*490“He will also tell you why the marijuana that they found in his house was located where it was, where the money was, what it’s used for. So this case again will be as much about what the government witnesses tell you as it is about what Ray Mendes will tell you.
“And then finally there will be an additional witness on behalf of Ray Mendes, his name is Dr. Alan Wartenberg. For the past twenty plus years Dr. Wartenberg has worked closely with individuals who are addicted to all varieties of drugs. He will inform us all about how drugs are used, the quantities, sometimes surprisingly what will be used by an individual. And much like Sergeant Montana for the government, will explain what the tools of the trade are for, Dr. Wartenberg will explain how somebody that uses drugs, maybe even addicted to drugs consumes them.”
The majority in note 7 ante, emphasizes that in this case there were seven *491certificates of analysis. I fail to see the significance of that enumeration vis-a-vis the harmless beyond a reasonable doubt question. Each of the defendants Ronald and Raymond were convicted of one count of possession of cocaine and one count of possession of marijuana. While separate certificates of analysis for the cocaine and marijuana would be required depending on the place of seizure within the apartment, the defendants were not charged with separate offenses dependent on where the cocaine was located. Thus, the essential issue remains whether the defendants’ testimony that the substances were cocaine and marijuana rendered admission of the certificates harmless error.
Finally, as to the ecstasy count (which was on file and not detailed in the briefs), in my view, the same result obtains, as with the cocaine and marijuana, i.e., Raymond, in his testimony, acknowledged the substance seized was ecstasy.