KANTROWITZ, J.

In response to the allowance of the Commonwealth's motion for sequestration, inexperienced defense counsel told his client to wait outside the courtroom. Fifteen minutes after the start of the bench trial in a busy District Court, the judge noticed the absence of the defendant and inquired as to his whereabouts. Told that he was outside due to the sequestration order, the judge indicated the obvious — that the order did not pertain to the defendant. The defendant was beckoned and the trial resumed, nothing being said about his absence. The defendant was found guilty on the two charges of indecent assault and battery on a person over fourteen. Ruling on the defendant's motion for a new trial, filed almost two years later, the trial judge, reasoning that the defendant had missed little of consequence during his absence from the courtroom, denied the motion. Based on our determination that counsel was ineffective, as well as our concerns about the constitutional violation, we reverse.

The defendant raises several issues in his appeal, only two of which need be addressed: whether counsel was ineffective, and the interrelated issue whether the absence of the defendant during a segment of the testimony of the complainant violated his right to be present at his trial and his right of confrontation as guaranteed by the Sixth and Fourteenth Amendments to the United States Constitution and by art. 12 of the Declaration of Rights of the Massachusetts Constitution. Facts. The defendant was a nursing supervisor at the Wingate Nursing Home (Wingate) in the Brighton section of Boston. The complainant was an eighteen year old high school student who worked there as a part-time kitchen aide. She alleged that on August 25, 2000, the defendant called her into his office whereupon he touched her breast and her vaginal area.

On the day of trial, prior to the complainant testifying, the prosecutor moved to sequester the witnesses. The judge granted the motion and all the witnesses, including the defendant, at the direction of his counsel, left the courtroom.

During the defendant's absence, the complainant stated her name, age, and where she attended school. She also testified that she had worked at Wingate "[f]or about two to four months." In addition, she said that her mother and sister also worked there and that on the day in question, she started work at 4:00 P.M.

At this point, the judge noticed that the defendant was absent. The record is silent as to when the defendant actually returned to the courtroom. Appellate counsel presses that it is unclear exactly when the defendant reappeared and that additional damning testimony was offered in his absence. While the record could have been made clearer, the more reasonable inference is that the defendant appeared after the judge noticed his absence and the court officer indicated that he would retrieve him.

The complainant then testified to the inappropriate touching, her reaction thereto — she pushed the defendant and ran to the bus stop to catch her bus — and the people she told about the incident. She further said that she did not go into work the following days, not returning until over a week later, on September 5, 2000, when the defendant again asked her to come to his office. She went, but this time brought Adler Bernadin, the Wingate receptionist, with her. In general, the complainant's testimony was contradictory with regard to several dates.

Needless to say, the defendant's testimony differed significantly from that of the complainant. As a nursing supervisor at Wingate, he testified that he had to reprimand the complainant on three separate occasions between August 30 and September 6, 2000, for work-related reasons. The defendant said that when he learned that she was the daughter of another Wingate employee, he contacted the complainant in order to obtain her mother's new telephone number for an updated Wingate employee directory because he was unable to reach the mother directly. The defendant said he did not like the complainant's work attitude and denied touching her.

The judge found the defendant guilty, but remarked that he was "troubled by the . . . dates and the discrepancies regarding the dates." Ineffective assistance of counsel. When evaluating claims of ineffective assistance of counsel we conduct a "discerning examination and appraisal of the specific circumstances of the given case to see whether there has been serious incompetency, inefficiency, or inattention of counsel — behavior of counsel falling measurably below that which might be expected from an ordinary fallible lawyer — and, if that is found, then, typically, whether it has likely deprived the defendant of an otherwise available, substantial ground of defence." Commonwealth v. Saferian, 366 Mass. 89, 96 (1974). "We look at the question of assistance of counsel as a practical not an abstract matter." Id. at 98. See Commonwealth v. Urena, 417 Mass. 692, 699 (1994) (the defendant must show "actual prejudice"). To satisfy the second prong of the ineffective assistance claim, the defendant must show that "better work might have accomplished something material for the defense." Commonwealth v. Satterfield, 373 Mass. 109, 115 (1977).

We are concerned primarily with two aspects of counsel's representation. First, he sent the defendant out of the courtroom in response to an allowed motion to sequester. Suffice it to say, this was a major blunder, which we discuss below. Second, counsel failed to introduce the work records of the complainant that directly contradicted her testimony.

The complainant testified at trial that after the alleged touching on August 25, she did not return to work until September 5, because she did not "feel like going to work." Her work records demonstrated the opposite, that she worked eight of the ten days between August 25 and September 5. The case was a close one, with the main inculpatory evidence supplied by the complainant. Clearly, in affirming past cases, such evidence has been held sufficient to carry the Commonwealth's burden. Here, however, counsel had an opportunity to counter testimony with documentary evidence to the contrary, and failed to pursue it. To his credit, counsel did secure the work records of the defendant. Those records indicated that he was not working on September 2, the day the complainant told Wingate administrator Rosemary McLaughlin the incident occurred. Since counsel's strategy, as testified to at the hearing on the motion for a new trial, was to highlight the discrepancies among dates, there was no reason to ignore the highly compelling evidence contained in the complainant's work records. See Commonwealth v. Alvarez, 433 Mass. 93, 102 (2000). As counsel was able to obtain his client's work records, he should also have obtained those of the complainant from the same source.

We cannot say with confidence that this evidence would not "have accomplished something material for the defense." Commonwealth v. Satterfield, 373 Mass. at 115. See Commonwealth v. Martin, 427 Mass. 816, 822 (1998) (counsel's failure to challenge evidence that the victim's body had the hallucinagen LSD in it deprived the defendant of an otherwise available substantial ground of defense); Commonwealth v. Alvarez, 433 Mass. at 101-102 (proper review of the defendant's medical records before trial would have shown the extent of the defendant's mental illness, which could have had a significant impact on the jury's assessment of the evidence).

The complainant's work records, if entered in evidence, could have accomplished two results. They could have been used to impeach the complainant's testimony that she did not return to work for a significant period of time after the alleged incident. In addition, they could have been used to challenge the complainant's emotional reaction to the alleged touching by showing that her testimony that she did not "feel like going to work" was wholly unsupported by her actions. By failing to introduce this significant piece of evidence at trial, defendant's counsel was ineffective.

Absence from the courtroom. Bedrock Federal and State constitutional principles ensure a defendant's right to both presence and confrontation at trial. These rights, however, are not absolute and may be waived. See Commonwealth v. Flemmi, 360 Mass. 693, 694 n. 1 (1971) (defendant's voluntary failure to return to court constituted a waiver of his right of confrontation); Commonwealth v. L'Abbe, 421 Mass. 262, 268-269 (1995) (defendant who is competent to stand trial may voluntarily and knowingly waive his right to be present); Commonwealth v. Senati, 3 Mass. App. Ct. 304, 307 (1975) (defendant's right to be present at trial may be forfeited by misconduct).

Here, the defendant did not absent himself; he left only due to counsel's instructions. What is troubling is that upon his return, no one appeared particularly concerned about a violation of a fundamental constitutional right. Indeed, the testimony continued with nothing said of what had transpired. Given defense counsel's lack of experience in handling criminal cases, this is not surprising. The prosecutor and the judge, however, also stood silent.

A similar situation occurred in an early Texas case, Sullivan v. State, 90 Tex. Crim. 170 (1921), where a criminal trial resumed after lunch without the presence of the defendant, who had not returned on time. The judge stopped the trial upon realizing the defendant was not present. Upon the defendant's return a few moments later, "the identical evidence given during his absence was reintroduced from [the same] witness." Id. at 173. The Texas Court of Criminal Appeals held "that the accused was confronted with the witnesses against him and given every opportunity to cross-examine and preserve any rights due him, and that he was present at his trial within the contemplation of [the Texas] statute," id. at 175, mandating the "personal presence of the accused in a felony case at the trial." Id. at 173.

Generally, "any violation of a constitutional right gives rise to presumptive prejudice," requiring reversal of the conviction, unless the Commonwealth can make an affirmative showing that the error was harmless beyond a reasonable doubt. See Commonwealth v. MacDonald (No. 1), 368 Mass. 395, 399 (1975), citing Commonwealth v. Robichaud, 358 Mass. 300, 302 (1970).

In Commonwealth v. Rios, 412 Mass. 208, 214 (1992), involving the defendant's absence at trial from portions of the testimony against him, the court left open the question whether such a violation, even if preserved, could, indeed, be treated under a harmless error standard. Instead, the court noted that "[s]ome constitutional rights are so basic that their violation can never be treated as harmless error." Id. at 214 n. 8. The court further noted that the Commonwealth must under any circumstances "make an affirmative showing that the error was harmless in order to overcome the presumptive prejudice of the constitutional violation." Id. at 214.

The Commonwealth urges us to distinguish Commonwealth v. Rios, supra, on the ground that the testimony there bore directly on the question of the defendant's guilt, while here only preliminary facts, already known to the defendant, were established. While the position has some appeal, we decline to distinguish Rios in this manner.

First, the testimony of the complainant was not merely introductory. She testified to working for a period of time longer than that which she worked. As the trial strategy was to highlight the discrepancies in her story, this stood as one additional potential falsehood.

Second, and in a more general sense, one practicality of the defendant's presence is to "communicate orally with his counsel in the course of a witness's testimony since he may have information which may aid his counsel in examining the witness." Commonwealth v. Robichaud, 358 Mass. at 303. In addition, "[m]ost believe that in some undefined but real way recollection, veracity, and communication are influenced by face-to-face challenge." Commonwealth v. Bergstrom, 402 Mass. 534, 542 (1988), quoting from United States v. Benfield, 593 F.2d 815, 821 (8th Cir. 1979).

Conclusion. A case may be made that, standing alone, each of the trial errors was not so prejudicial as to warrant a new trial; that counsel was able to establish the discrepancies of the complainant without offering yet another, albeit more compelling, instance; and that the defendant missed little of the testimony against him. Given the combination of circumstances, though, we believe a new trial is necessary. See Commonwealth v. Cancel, 394 Mass. 567, 576 (1985). As we have noted, we are also troubled by the lack of awareness and appreciation that in the face of a violation of a basic constitutional right, neither the judge nor the parties took any ameliorative actions. If, in fact, the matter were given the attention it deserved, in all likelihood either the defendant on the record would have waived any rights he held or, as was done in Sullivan v. State, supra, the complainant would simply have repeated her testimony. In view of the shortcomings of counsel, the gravity of the constitutional violation, and the passivity of all concerned, as well as the lack of strength of the Commonwealth's case, a new trial is mandated. Order denying motion for new trial reversed. Judgments reversed. Findings set aside.