(concurring in part and dissenting in part, with whom Ireland and Cowin, JJ., join). I agree that the standard of review to be applied in this case is whether the Federal constitutional error, admission of the certificates of drug analysis (drug certificates), was harmless beyond a reasonable doubt. I also agree that an 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 [fact finder] and did not contribute to the [fact finder’s findings].” Commonwealth v. Tyree, 455 Mass. 676, 701 (2010).
I further agree that in determining whether the tainted evidence may have had an effect on the fact finder or contributed to his findings of guilt, “we examine various factors, including the importance of the evidence in the prosecution’s case; the relationship between the [tainted] evidence and the premise of the defense; who introduced the issue at trial; the frequency of the reference; whether the erroneously admitted evidence was merely cumulative of properly admitted evidence;. . . and the weight or quantum of evidence of guilt.” Commonwealth v. Dagraca, 447 Mass. 546, 553 (2006), citing Commonwealth v. Mahdi, 388 Mass. 679, 696-697 (1983) (Dagraca factors). See ante at 360 n.12. Although these factors guide our review for harmless error beyond a reasonable doubt, “there is no uniform standard for all cases; the results of our review are determined by the circumstances of each case.” Id., citing Commonwealth v. Mahdi, supra at 697.
Where I disagree with the court is in the application of this standard to the case before us. Considering all the evidence in the context of the case as it was actually tried, through the lens of the Dagraca factors, I conclude that the admission in evidence of the drug certificates in the two distribution indictments was harmless beyond a reasonable doubt.1
In brief,2 the Commonwealth’s evidence at trial was that the *370Hampden County narcotics task force was investigating the sale of cocaine by a man named, “Flaco,” out of apartment 4L at 284 Dwight Street Extension in Springfield. An experienced undercover narcotics officer was sent to that address on July 7, 2005, in an effort to meet Flaco and buy cocaine from him. The officer walked up the stairs in the back to the fourth-floor porch where he encountered an individual standing outside the back door of apartment 4L. After knocking, he was permitted to enter the apartment, after which the door was barricaded behind him.
In the apartment, he spoke to Flaco, whom he later identified as the defendant. He told the defendant that he wanted to buy an “eight ball” of cocaine.3 The defendant then sent another individual who was present in the apartment to retrieve a clear plastic bag containing a substance that the officer observed was “consistent with crack cocaine.” The defendant then handed the bag to the officer who, in turn, gave the defendant $120. The officer asked to leave the apartment through the front door. That door was also observed to be barricaded, and another man stood in the hallway just outside.
The undercover officer returned to the same location to make another purchase of crack cocaine from the defendant on October 18, 2005. As he made his way up the rear stairs to the back porch of apartment 4L, he was confronted by several persons who wanted to know the purpose of his visit. When he reached the porch, he met the defendant and asked to buy another “eight ball” of crack cocaine. The defendant had a clear plastic bag in his hand, which, he claimed, contained only “sixteenths” (amounts of cocaine smaller than an eight ball). He then called to another person (Juan Rebollo) to bring up an “eight ball.” Eventually, the officer, the defendant, and Rebollo went inside apartment 4L, the doors of which were still barricaded, and the defendant directed Rebollo to sell the officer the eight ball of crack cocaine, which he did in exchange for $120.
Two days later, on October 20, 2005, the officers executed a search warrant on apartment 4L. In executing the warrant, the *371front door had to be broken down because it remained barricaded. On entering the apartment, the officers found the defendant with Rebollo and two other persons. An additional person had jumped out the window and money was being flushed down the toilet. The defendant was searched, and the officers found $493 in cash on his person. The search also recovered clear plastic sandwich bags, and a plastic bag containing a white powder substance (described in the testimony as “narcotics”).4
I would apply the Dagraca factors as follows. With respect to the first factor, the importance of the evidence, although the certificates were obviously part of the Commonwealth’s case and were admitted in evidence along with the drugs, the most important and significant evidence that the defendant illicitly distributed a controlled class B substance (cocaine) on July 7 and October 18, 2005, were his actions and words on those dates. Leaving aside the certificates, the evidence was powerful and established that a person (identified as the defendant) was in the business of selling cocaine out of apartment 4L. The undercover officer came to that location, which was both barricaded and, inferentially, guarded both in front and in back, ordered a quantity of crack cocaine, and was given a clear plastic bag containing rocks of white substances which appeared to be and were plainly represented to be crack cocaine, in exchange for a substantial and definite amount of cash, $120. Virtually this same transaction, involving the same undercover officer, was repeated several months later. When a search warrant was executed at the apartment two days after the last sale, the defendant was present, money was being flushed down the toilet, a confederate jumped out a window, and a large quantity of cash as well as drug weighing and packaging paraphernalia were found in the apartment, along with more white powder. The certificates were at most pro forma; their existence was not even mentioned in the prosecutor’s closing argument.5
Second, the certificates bore no relationship to the premise of *372the defense, which was essentially that the defendant was mistaken for someone else who may have been selling cocaine out of his apartment on those dates. While not stipulating that the substances involved in the transactions on July 7 and October 18 were cocaine, the defendant in no way suggested that they might not be. His defense at trial was that he was not present at his apartment on July 7, and in addition to testifying on his own behalf, he called alibi witnesses to corroborate that he was elsewhere. As for October 18, he testified that the undercover officer arrived with another man who asked to speak to Rebollo, to whom he referred them without further interaction. Indeed, the defendant called Rebollo (an admitted crack cocaine seller and user) to testify that he in fact sold the “eight ball of cocaine” on that date, and had already pleaded guilty to having done so. Consistent with the defense, however, Rebollo testified that the defendant was not in the room where and when he sold the cocaine, and that he did not give any of the $120 he received for the “eight ball” to the defendant. This testimony both underscores the complete lack of relationship between the defense in the case and the improperly admitted certificates confirming that the substance sold was cocaine, and firmly corroborates the representations made by the defendant to the undercover officer during the transactions that the drag being sold was cocaine.6
Finally, and most important, the evidence that cocaine was *373distributed on July 7, and October 18, 2005, as admitted by the defendant during those transactions and corroborated by their circumstances as well as the testimony of Rebollo, was overwhelming. The impact of the certificates on the fact finder, if any at all, was cumulative of that overwhelming evidence.
The court concludes, however, ante at 362, quoting Commonwealth v. Tyree, 455 Mass. 676, 704 n.44 (2010), that this very powerful circumstantial evidence did not “nullify any effect” that the certificates might have had on the fact finder, because, essentially, the certificates had the effect of proving that the dmgs were cocaine rather than some other substance. Of course, the Commonwealth has the burden of proving the substance was cocaine, as it has done in this case with ample circumstantial evidence, but the Commonwealth does not have the burden to disprove every hypothesis that might be advanced in favor of the defendant’s innocence. See, e.g., Commonwealth v. Farley, 443 Mass. 740, 745-746 (2005) (“The Commonwealth carries the burden to prove each and every element of the crime beyond a reasonable doubt. That burden does not include proof beyond a reasonable doubt that every theory of the case argued by the defendant could not be true”). At trial, there was neither a suggestion nor a theory that the substance might be counterfeit, that is, something other than the cocaine it was represented and appeared to be. Consequently, it is complete speculation that the certificates might have had any effect on the fact finder’s consideration of what was plainly a nonissue in the case.7
As concerns the certificate admitted with respect to the cocaine found in the defendant’s apartment on October 20,1 am of a different view. While the circumstantial evidence, apart from the certificate, may have been sufficient to support a conviction, that is not the test we apply. The defendant never admitted or otherwise represented to the officers that the substance found on that date was cocaine, and there was no testimony from Rebollo regarding *374that substance at all. In the absence of such evidence, I cannot conclude that the certificate had no effect on the verdict, and would reverse.
In sum, to the extent that the court’s opinion can be read to suggest that, absent a stipulation or, perhaps, evidence of field testing, see Commonwealth v. Connolly, 454 Mass. 808, 830-832 (2009), the admission of drug analysis certificates can never be harmless beyond a reasonable doubt, I strongly disagree. The case before us presents a concrete example of when, in the context of a drug case as tried, the erroneous admission of certificates was harmless beyond a reasonable doubt.8
For the reasons explained below, I agree that the defendant’s conviction of possession with intent to distribute the cocaine found in apartment 4L when it was searched on October 20, 2005, should be reversed, because the erroneous admission of the drug certificate as to that substance was not harmless beyond a reasonable doubt.
The opinion of the court sets out in greater detail the evidence at trial. I do not disagree with the court’s more extensive summary of that evidence.
The undercover officer testified that he had made hundreds of purchases of “crack” cocaine on the streets of Springfield, and was very familiar with the terminology used by drug dealers to describe quantities of crack cocaine, including the term “eight ball.”
The search of a second apartment, also rented to the defendant, led to the discovery of a large amount of cash in a strong box.
As the United States Supreme Court confirmed, its decision in Melendez-Diaz v. Massachusetts, 129 S. Ct. 2527 (2009), in no way altered the States’ ability to sustain a conviction of drug related offenses through circumstantial evidence. Id. at 2542 n.14. The court concedes as much. This court and other courts have repeatedly held that proof of the distribution of the particular *372substance can be accomplished without evidence of chemical analysis and expert testimony. See, e.g., Commonwealth v. Dawson, 399 Mass. 465, 467 (1987), and cases cited. See also United States v. Abuelhawa, 523 F.3d 415, 422-423 (4th Cir. 2008), rev’d on other grounds, 129 S. Ct. 2102 (2009) (even in absence of drugs, government can establish distribution of cocaine, relying on defendant’s statements to others and conversations, in code, regarding drug transactions), citing United States v. Dolan, 544 F.2d 1219, 1221 (4th Cir. 1976) (circumstantial proof to establish nature of substance may include “testimony that a high price was paid in cash for the substance, evidence that transactions involving the substance were carried on with secrecy or deviousness, and evidence that the substance was called by the name of the illegal narcotic by the defendant or others in his presence”).
Not surprisingly, the third factor weighs against the Commonwealth. It was the Commonwealth that offered the certificates in evidence and plainly worked at getting them admitted in the face of some confusion over which certificate related to which of the several quantities of drugs sent to the laboratory for analysis. As for the fourth factor, as noted above, the certificates were not mentioned in closing argument, undoubtedly because they had nothing to do with any actively contested issue in the case.
In our harmless error analysis, this court considers whether the error related to a live or contested issue at trial. See, e.g., Commonwealth v. Pena, 455 Mass. 1, 15 (2009) (admission of testimony related to decedent’s cause of death harmless beyond reasonable doubt because it was not contested issue at trial); Commonwealth v. Medina, 430 Mass. 800, 811 (2000) (erroneous malice instruction harmless where defense “focused instead on issues of identity and causation”); Commonwealth v. Doherty, 411 Mass. 95, 102 (1991) (at defendant’s trial, intent of principals not in dispute but only whether defendant had acted as coventurer with one or both principals).
Since Melendez-Diaz v. Massachusetts, 129 S. Ct. 2527 (2009), other intermediate appellate courts have reached similar conclusions. See Koenig v. State, 916 N.E.2d 200 (Ind. Ct. App. 2009) (in drug dealing prosecution, admission of laboratory report disclosing illegal drug in victim’s blood harmless, where defendant admitted having given drug to victim, and that he took drug himself); State v. Willis, 230 Or. App. 215 (2009) (admission of drug certificates harmless beyond reasonable doubt where State’s evidence included experienced arresting officer’s testimony that, although not absolutely certain, he recognized seized substance as methamphetamine; substance was hidden in defendant’s bra; and defendant admitted substance was contraband).