In discussing the admission of a particular form of hearsay, the Supreme Court has observed:
[Individual pieces of evidence, insufficient in themselves to prove a point, may in cumulation prove it. The sum of an evi-dentiary presentation may well be greater than its constituent parts.... [A] piece of evidence, unreliable in isolation, may become quite probative when corroborated by other evidence.
Bourjaily v. United States, 483 U.S. 171, 179-80, 107 S.Ct. 2775, 2781, 97 L.Ed.2d 144 (1987). This observation is relevant to the case before us in which we decide whether evidence chiefly — though not exclusively— hearsay in nature constituted “substantial evidence” of misconduct sufficient for us to sustain a hearing examiner’s denial of petitioner’s application for unemployment compensation. We hold that the evidence satisfied that standard, and therefore affirm.
I.
A.
Petitioner was employed as a security guard by Diamond Security, Inc., from April 21, 1988 through November 27, 1989, when he was fired as a result of a series of job-related acts of misconduct. After a Department of Employment Services (DOES) claims examiner denied petitioner’s request for unemployment compensation, petitioner appealed, and an appeals examiner convened a hearing on February 22, 1990, at which petitioner and his former job supervisor testified. The examiner concluded that petitioner did not qualify for unemployment benefits because he had been discharged for misconduct. D.C.Code § 46-111(b) (1990). The examiner based this finding chiefly on disciplinary action reports (DARs) contained in petitioner’s employment record, as well as the supervisor’s testimony and the examiner’s negative assessment of petitioner’s credibility. The Office of Appeals and Review affirmed the examiner’s decision.
B.
The supervisor, John Steele, testified at the hearing that petitioner was fired because “over a period of time, [he] consistently and constantly continued to break the rules and regulations after being counselled by my supervisors as well as by myself-” The most recent incident, which was the “last straw” for the employer and resulted in the termination, took place on November 23, 1989,1 when petitioner failed to report to *397work. Steele testified that after being informed of this fact, he called petitioner’s home.2 Petitioner’s wife said that he was sick in bed and could not come to the phone. The following day petitioner called Steele to explain that he had been absent from work because he was sick. According to Steele, this violated the employer’s established procedure “in respect to calling off duty that he was not coming to work” (emphasis added).
The record contains twenty-two disciplinary reports concerning petitioner prepared by various Diamond Security sergeants and generally signed by Steele, who also personally prepared and signed three of them. Among the offenses listed are: failing to report for duty, tardiness, falsely claiming he was at work, drinking or sleeping on duty, being out of uniform, taking home the company radio, having a television on the work site, and failing to obey orders. Petitioner signed seven of the nineteen reports without comment, indicating he had received and read them, and signed one other report under protest. Most of the reports were prepared the same day the misconduct occurred; others were prepared within three days (in one instance six days) of the incident. The appeals examiner relied specifically on seven of the reports,3 but took account of the others (“The misconduct in this case included the following ...” (emphasis added)).
Although Steele did not prepare most of the DARs, he testified that he wrote the November 6, 17, and 23, 1989 reports since he was “the manager of the building that [petitioner] was working at,” and he therefore had personal knowledge of these incidents. Otherwise, Steele would review such reports and discuss them with the employee involved and “counsel” him. Steele listed a number of reports for which he had personally counseled petitioner contemporaneously with the infractions, testifying that petitioner was “personally present to review and to voice any objections” to the reports.
Petitioner did not deny speaking with Steele “about the problems that we had with the schedule and working at Diamond Security,” but denied the basis for the reports. He contended that there were inconsistencies in the DARs, that he did not have knowledge of some of them, that they were false, and that they were written up in order to avoid paying him unemployment and as retribution for his having won a wage and hour award. He also objected to the fact that the persons who had written the individual reports were not present for him to cross-examine.
II.
A decision by DOES must be supported by substantial evidence, Jadallah v. District of Columbia Dep’t of Employment Servs., 476 A.2d 671, 675 (D.C.1984), defined as “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” Nova Univ. v. Educational Inst. Licensure Comm’n, 483 A.2d 1172, 1190 (D.C.1984), cert. denied, 470 U.S. 1054, 105 S.Ct. 1759, 84 L.Ed.2d 822 (1985) (citations omitted). Since the appeals examiner based her decision primarily on the evidence in the disciplinary reports, whose authors — except in the case of Steele — were not present to testify, we must decide whether the hearsay evidence presented was substantial as thus defined.
*398“Hearsay evidence is admissible in administrative proceedings unless it is irrelevant, immaterial, or unduly repetitious.” Lim v. District of Columbia Taxicab Comm’n, 564 A.2d 720, 724 (D.C.1989) (citation and quotation marks omitted); D.C.Code § l-1509(b). “If hearsay evidence is found to be reliable and credible, it may constitute substantial evidence.” Simmons v. Police & Firefighters’ Retirement & Relief Bd., 478 A.2d 1093, 1095 (D.C.1984) (citing Johnson v. United States, 202 U.S.App.D.C. 187, 190-91, 628 F.2d 187, 190-91 (1980)). At the same time, “administrative findings and conclusions based exclusively on hearsay [are subject] to exacting scrutiny.” Lim, supra. More than once we have declined to uphold a DOES finding of misconduct where an employer’s hearsay evidence was refuted by the claimant’s sworn testimony. E.g., Jadallah, supra; McLean v. District of Columbia Dep’t of Employment Servs., 506 A.2d 1135, 1137-38 (D.C.1986).
We have not, however, mechanically rejected agency findings for lack of substantial evidence whenever the finding was based mainly, or even entirely, on hearsay evidence contradicted by sworn testimony. Rather, the test remains as we described it in Simmons and Lim: hearsay found to be reliable and credible may constitute substantial evidence, “especially ... where the evidence is uncontradicted,” Simmons, 478 A.2d at 1095; but without extrinsic corroboration (proof al-iunde ) such evidence will be “scrutinized]” carefully. Lim, 564 A.2d at 724. See also Jadallah, 476 A.2d at 677 (Ferren, J., concurring) (“Absent some indicia of reliability, hearsay evidence alone should not be permitted to offset the sworn testimony of a witness and to constitute substantial evidence in support of an agency position”); Martin v. District of Columbia Police & Firefighters’ Retirement & Relief Bd., 532 A.2d 102, 109-10 n. 2 & accompanying text (D.C.1987); Johnson, supra, 202 U.S.App.D.C. at 190-91, 628 F.2d at 190-91 (cited in Martin and Simmons) (“rejecting] a per se approach that brands evidence as insubstantial solely because it bears the hearsay label”; “[i]nstead ... evaluating] the weight each item of hearsay should receive according to the item’s truthfulness, reasonableness, and credibility”).4
In this case, a variety of factors confer reliability on the DAR reports, and these in turn, viewed together with Steele’s testimony, provide substantial support for the examiner’s finding that petitioner was terminated for conduct manifesting “a disregard of standards of behavior which the employer [had] a right to expect of his employees.” D.C.Code § 46-lll(b)(2). See, e.g., Shepherd v. District of Columbia Dep’t of Employment Servs., 514 A.2d 1184 (D.C.1986) (pattern of absenteeism and tardiness). Whether or not they fit within the hearsay exception for business records (a question we need not decide), the DARs were completed as part of Diamond Security’s regular procedure for disciplining employees. They were prepared by a succession of sergeants contemporaneously with the events, and were routinely followed up by personal counseling, in some cases by Steele himself — who had personal knowledge of three of the incidents. This aggregation of prompt reports by different supervisors tends to disprove either that the DARs stemmed from faulty perception or memory or that the writers lacked objectivity or “disinterested[ness].” Simmons, 478 A.2d at 1095. Moreover, in large part they were “consistent with each other in that they described the same pattern of behavior” by appellant, id. — absence from or tardiness in reporting to work, falsely representing that he was at work, and sleeping or drinking on the job. The fact that Steele (who testified and could be cross-examined) had personally counseled petitioner following many of the incidents is important. Were the reports all or mostly baseless, as petitioner asserted at the hearing, one would expect him to have voiced some objection to them to Steele at the time; yet Steele testified to no such *399denials or to any reason he had acquired to doubt the reliability of the reports based on petitioner’s reaction during the counseling.
Petitioner had access to the reports before the agency hearing, Simmons, 478 A.2d at 1095; Johnson, 202 U.S.App.D.C. at 191, 628 F.2d at 191,5 but his denial of misconduct was blanket and largely non-specific.6 Other than to say that the DARs were “just written up to evade paying me unemployment,” petitioner did not explain why or how the employer would have fabricated an extensive file of disciplinary reports prepared by several different sergeants. Moreover, the examiner discounted petitioner’s credibility because of shifting answers he gave her about when, in relation to a new job he had begun, he had also applied for unemployment benefits.
All of these circumstances persuade us that the disciplinary reports were reliable proof which “a reasonable mind might accept as adequate to support [the] conclusion” that petitioner had engaged in misconduct justifying termination. Nova Univ., 483 A.2d at 1190. Even if a small number of the DARs together might not have persuaded us of the reliability of the examiner’s conclusion, the sheer cumulation of reports made the body of proof self-corroborating and the “sum of [the] evidentiary presentation” more trustworthy than “its constituent parts” would have been if viewed in isolation. Bourjaily, 483 U.S. at 179-80, 107 S.Ct. at 2781. This was no “attenuated evidentiary chain” as in Jadallah, 476 A.2d at 677 (criticizing reliance on “hearsay within hearsay”), nor a case where an appreciable gain in reliability would have been achieved by requiring the authors of the individual reports to testify. Steele described both the process by which the disciplinary reports were prepared and the important follow-up in the form of counseling which regularly attended them and which he specifically performed in petitioner’s case.7 When added to this is the personal knowledge Steele had of three of the infractions on which the examiner expressly relied, there was no infirmity in the proof sufficient to permit us to reject the judgment of the hearing examiner.
Affirmed.
. Petitioner had previously been terminated on March 7, 1988, but was offered permanent reem*397ployment on April 15, 1988, which he accepted.
. It was disputed whether Steele or Sgt. Howe called petitioner’s home. While Steele testified that he made the call, petitioner and his wife claimed that it was Howe who called. The DAR, signed by both Steele and Howe, states, "I called [petitioner's home],” and also states that "action [was] taken by” Howe. The DAR does appear to be in Howe’s handwriting rather than Steele's, and, unlike the reports that were prepared solely by Steele, it contains both Steele’s and Howe’s signatures.
. These were (1) the November 6, 1989 DAR, which stated that petitioner had been sleeping on the job; (2) the November 2, 1989 DAR stating that petitioner was out of uniform; (3) the April 21, 1989 DAR stating that petitioner had falsely represented that he was on the job site; (4) the November 17, 1989 DAR stating that petitioner was late reporting for work; (5) and (6) the DARs of April 13 and 14, 1989, which cited petitioner for having a television on the job site; and (7) the November 23, 1989 DAR, which stated that petitioner had not reported for work, and that when he was called at home he refused to come to the telephone to report that he was sick. Petitioner denied all these incidents at the hearing, or stated that there was no basis for the reports.
. These principles are consistent with DOES’s evidentiary regulations. 7 DCMR § 312.7 provides:
Prior statements or written documents, in the absence of other reliable corroborating evidence, shall not constitute evidence sufficient to support a finding of misconduct by the Director.
. As to the DARs that he had not signed, petitioner denied "even know[ing] they [were] in my file,” but when the examiner pointed out that petitioner had "reviewed [the employer’s] documents” before the hearing, petitioner did not claim otherwise.
. It is argued that petitioner was not given the opportunity to explain each report. But, while the hearing examiner initially denied petitioner's request to respond to each report individually, she went on to state that petitioner "could go through one starting with — from September [1989] through the dates that [Steele] stated.” Petitioner was also allowed to present “any other evidence” and to make whatever statements he wished.
Petitioner did assert that the employer’s rules did not explicitly prohibit watching television on the job (one of the reported violations), but did not explain why after being warned not to do so on numerous occasions, he continued to bring a television to work. As for his explanation that he was sick on November 23, 1989 — the "last straw” — this did not counter the employer’s contention that he violated the procedure for reporting such absences, nor does it refute the numerous other documented instances of misconduct.
.As Steele explained in conclusion: "In Mr. James['s] case, I allowed him to continue to work, because he was a good worker until he started to mess up, and then he just continued, refused to conform to things that we talked about on each DAR until the bottom [line], until finally I didn’t have any choice but to terminate him” (emphasis added).