dissenting:
The majority ignores what the trial court actually did in revoking appellant’s probation and, instead, reviews what the trial court could have done in the exercise of its discretion. By taking this erroneous analytic shortcut, which leads to easy affirmance, the majority avoids reaching the primary — and dispositive — issue appellant raises: whether the trial court violated appellant’s constitutional rights by admitting a police officer’s hearsay testimony without first making the required finding of “good cause” for not allowing appellant the opportunity to confront and cross-examine the declarants whose statements the officer reported (the complainant and a government eyewitness to appellant’s alleged armed assault). I believe that appellant is correct; the trial court violated his due process right, as a probationer, to confront and cross-examine adverse witnesses, Gagnon v. Scarpelli, 411 U.S. 778, 786, 93 S.Ct. 1756, 1761-62, 36 L.Ed.2d 656 (1973); *210Super.Ct.Crim.R. 32.1(a)(2)(D). I therefore would reverse and remand for a new probation revocation hearing. Respectfully, I dissent.
I.
As the majority recognizes, ante at 203, probation revocation consists of two distinct steps: (1) after a final hearing, the trial court first must find whether the probationer has violated a condition of probation; 1 (2) if the court finds a violation, it may then revoke probation or take any other appropriate action in the exercise of its discretion. See Resper v. United States, 527 A.2d 1257, 1260 (D.C.1987); Saunders v. United States, 508 A.2d 92, 95 (D.C.1986); see also Black v. Romano, 471 U.S. 606, 611, 105 S.Ct. 2254, 2257-58, 85 L.Ed.2d 636, reh’g denied, 473 U.S. 921, 105 S.Ct. 3548, 87 L.Ed.2d 671 (1985). The first step, therefore, is not discretionary; in conducting the required hearing, the trial court must accord a probationer the minimal due process protections mandated by Gagnon, 411 U.S. at 786, 93 S.Ct. at 1761-62, and Morrissey v. Brewer, 408 U.S. 471, 489, 92 S.Ct. 2593, 2604, 33 L.Ed.2d 484 (1972). The second step, however, is discretionary, and we will reverse for abuse of discretion only if (for example) the “trial court’s action was [not] within the range of permissible alternatives,” Johnson v. United States, 398 A.2d 354, 365 (D.C.1979), and, even then, only if “the error in the discretionary determination jeopardized the fairness of the proceeding as a whole,” or “the error had a possibly substantial impact upon the outcome,” id. at 366.
The trial judge first found, by more than a preponderance of the evidence,2 that appellant (1) had used illegal drugs, thereby violating one substantive condition of his probation,3 and (2) had committed a crime, thereby violating the other substantive condition of his probation. The trial court then exercised its discretion — based on those two findings — and revoked appellant’s probation. Contrary to the majority’s creative reading, the judge did not purport to exercise his discretion to revoke probation based solely on the (step one) factual finding of illegal drug use and, thus, to reserve the “reliable” hearsay information about appellant’s newly-committed crime exclusively for use in its (step two) revocation and resentencing decision.4 *211The fact is, the trial court considered both the fact of drug use and the fact of the new crime as part of its step one “violation” analysis; the new crime evidence was not used solely as part of the court’s step two “revocation resentencing” analysis. Put another way, in the trial court’s analysis, both the drug use and the new crime— taken together — were essential to a (step one) finding of probation violation sufficient to trigger a (step two) discretionary imposition of sanction. As a consequence, evidence of the new crime, as well as the drug use, were also available for the trial court to consider when making its sanction decision; but by using the new crime evidence as essential to the (step one) violation finding, the court necessarily had to assure that the finding based on that evidence resulted from the constitutional process required for step one findings.
More specifically, as elaborated below, the majority was required to consider whether the admission of evidence of appellant’s alleged new crime met due process hearing requirements both as to confrontation rights and as to the required burden of proof — two due process inquiries the majority ignores. Instead, by erroneously construing what the trial court did, the majority, in Part IV of its opinion, addresses an issue not really joined in this case: the trial court’s ability to consider hearsay evidence of appellant’s commission of another crime when considering (step two) resentencing alternatives. That issue, however, was not even briefed or argued.
In sum, the majority conveniently disregards one of the two probation violation findings the trial court found essential in deciding whether to exercise its discretion to impose a sanction by revoking probation. Indeed, the finding the majority ignores— that appellant had committed a violent offense — was clearly the primary reason the trial court decided to revoke appellant’s probation because, as the trial court stated, his “continued presence in the community ... would not be in the best interests of the community.” By assuming that the trial court decided to revoke probation (or would have revoked probation) solely on the basis of appellant’s drug use, the majority erroneously substitutes its own exercise of discretion for that of the trial court.
To be clear: when I say the majority improperly substituted its discretion for that of the trial judge, I am not saying that my colleagues have improperly “not[ed the] historical fact” that the trial judge made a finding of unlawful drug use. Ante at 208. Rather, they improperly say, in effect, that probation could have been revoked — and therefore we are going to deem it as having been revoked — based on that finding alone. In doing so the majority fails to note another “historical fact”: the trial court did not revoke probation — in its discretion — merely because of the finding of unlawful drug use. Rather, for all we can tell, the court decided to impose the ultimate revocation sanction, instead of a lesser one, because it found as part of its (step one) violation analysis both that appellant had committed an armed assault and that appellant had used illegal drugs.
The invalid consequence of the majority’s mistaken analysis is that it allows the majority to shift the troublesome hearsay evidence of the alleged new crime from the step one violation phase to the step two discretionary sanction phase of the analysis where the majority can dispense with constitutional concerns like due process. That will not do. In the sections that follow, I will outline the facts most relevant to this appeal, discuss the due process requirements applicable to probation revocation, *212and assess the trial court’s exercise of discretion.
II.
On October 23, 1989, the government charged appellant, who was on probation at the time, with assault with intent to kill while armed. Less than two months later, the government voluntarily dropped its charge, purportedly because it was unable to locate the complaining witness, Michael London. At the probation revocation hearing, a doctor testified that, on October 10, 1989, while on duty at D.C. General Hospital, she had treated London for a superficial scalp wound and two gunshot wounds to the abdomen. Detective George Taylor testified regarding his interviews with London and Charese Drake, the government’s other eyewitness, including their respective identifications of appellant as the shooter. Roscoe Jackson was the only eyewitness to the shooting who testified at the hearing. He stated that he had witnessed the entire shooting incident and that appellant was not the shooter. Furthermore, Jackson testified that at the time of the shooting, Drake was standing next to him on the stairway of the building in which they both lived. Appellant testified that at the relevant time he had been at the home of Rhonda McCord helping her take care of their sick son. McCord corroborated appellant’s story. Appellant also said that he and government witness Drake had once been romantically involved and that, after their breakup, Drake had made inappropriate comments to a girlfriend of his.
Neither the complaining witness, Michael London, nor the government’s eyewitness, Charese Drake, testified at the hearing. The government failed to produce London, and although Drake was present and was called as a government witness, she told the court that she did not want to testify, and the prosecutor stated that he did not think she could testify at that time.5 Over appellant’s objection, the trial court permitted the government to attempt to prove the probation violation (commission of a new offense) through the hearsay testimony of Detective Taylor. At the conclusion of the hearing, the trial court stated that it was “reasonably satisfied” that appellant had shot London.
III.
“The Due Process Clause of the Fourteenth Amendment imposes procedural and substantive limits on the revocation of the conditional liberty created by probation.” Black, 471 U.S. at 610, 105 S.Ct. at 2257 (citing Bearden v. Georgia, 461 U.S. 660, 666 & n. 7, 103 S.Ct. 2064, 2069 & n. 7, 76 L.Ed.2d 221 (1983)). In making its finding that appellant had committed a new crime while on probation, the trial court clearly violated appellant’s due process rights. In Gagnon, the Supreme Court stated that a probationer has the constitutional right to confront and cross-examine adverse witnesses “unless the hearing officer specifically finds good cause for not allowing confrontation.” 411 U.S. at 786, 93 S.Ct. at 1762; see Super.Ct.Crim.R. 32.1(a)(2)(D). The trial court failed to make any finding on the record that there was “good cause” excusing the government’s failure to produce eyewitness testimony. Without a government showing and a trial court finding of good cause, the court violated appellant’s constitutional right to confrontation when it relied on Detective Taylor’s hearsay testimony about the incriminating identifications and statements by two eyewitnesses in lieu of testimony from those witnesses.
The trial court should have required the government, on the record, to show “good cause” why London was not available to testify and why Drake did not want to testify even though she was present at the hearing. Only after such a showing could the trial court balance “the probationer’s right to confrontation against the Government’s good cause for denying it.” United States v. Simmons, 812 F.2d 561, 564 (9th Cir.1987). Although there are no “fixed rules on what [constitutes] good cause in every case[,] [a]s the Supreme Court noted in Gagnon, ‘in some cases there is simply *213no adequate alternative to live testimony.’ ” United States v. Penn, 721 F.2d 762, 765 (11th Cir.1983) (quoting Gagnon, 411 U.S. at 783 n. 5, 93 S.Ct. at 1760 n. 5)).
The Superior Court has outlined the procedures it should follow at a probation revocation hearing when the government wants to introduce hearsay testimony of police officers (or others) rather than testimony of declarant-witnesses. See United States v. Peters, Crim. No. 9956-75 (D.C.Super.Ct. Dec. 12, 1975) (opinion of then Chief Judge Harold H. Greene), incorporated by appendix in In re A.W., 353 A.2d 686, 688-96 (D.C.1976) (Nebeker, J., concurring in per curiam).
Since the probationer’s right to confront and cross-examine adverse witnesses is constitutionally mandated (408 U.S. at 489, 92 S.Ct. 2593 [at 2604]), the standard of “good cause” for denial of this right, referred to in both the Morrissey and Gagnon decisions, would only be met where the government presents specific facts, such as threats by the probationer to other witnesses, which show that a confrontation would present a clear danger to the witness. The fact that the witness will also testify at the probationer’s criminal trial could not, alone, justify a denial of the probationer’s constitutional rights to confront his accuser. As Mr. Justice Brennan, concurring in Morrissey, supra, (408 U.S. at 491, 92 S.Ct. 2593 at 2605) stated, “For each hearing the [probationer] is entitled to ... confront and cross-examine adverse witnesses, unless it is specifically found that a witness would thereby be exposed to a significant risk of harm.”
Whenever the Court determines that a witness would be subjected to such undue and unusual danger that the probationer may not confront and cross-examine him [or her], it should hear that witness’ testimony in camera, and make an independent determination on the record as to the relative reliability of the informant’s statement and those of the probationer and his [or her] witnesses (Birzon v. King, 469 F.2d 1241, 1244-45 (2d Cir.1972), as well as of the weight to be given to the statements of the informant.
Id. at 695 (appendix; text of United States v. Peters); see also Smith, supra note 1, 454 A.2d at 1355 n. 1 (noting this court’s approval of Peters’ procedural requirements).
According to the Peters procedures, if the trial court had found good cause to excuse Drake’s in-court testimony, it then should have heard Drake’s testimony in camera before making credibility and reliability findings on the record. Likewise, the court should have dealt with London’s absence under the Peters guidelines. Before admitting Detective Taylor’s hearsay testimony, the court should have required the government to show good cause for denying appellant the opportunity to confront and cross-examine London. Specifically, the trial court should have found on the record whether London was “unavailable” and then should have explained whether Detective Taylor’s hearsay testimony was “reliable” before admitting and considering it.6 Instead, by relying without good cause *214on Detective Taylor’s account of what Drake and London had said, the trial court denied appellant his constitutional right to challenge the credibility and recollection of those who had identified him as the shooter, contrary to the testimony of a third eyewitness, the only one who testified at the hearing.
The trial court’s failure to follow the Peters procedures thus violated appellant’s due process rights and blurred the important distinction between the preliminary hearing after arrest and detention, see supra note 1, and the final revocation hearing. At the more informal preliminary hearing, a police officer’s hearsay testimony may be enough to find probable cause to believe the probationer has violated a condition of probation. See Morrissey, 408 U.S. at 485-87, 92 S.Ct. at 2602-03; In re A. W., 353 A.2d at 690-91 (appendix; text of United States v. Peters). The final revocation hearing, however, with its additional due process protections, “must lead to a final evaluation of any contested relevant facts and consideration of whether the facts as determined warrant revocation.” Morrissey, 408 U.S. at 488, 92 S.Ct. at 2603. By dispensing with the “good cause [requirement] for not allowing confrontation,” Gagnon, 411 U.S. at 786, 93 S.Ct. at 1762, the trial court required the government to do little more than it did at the probable cause hearing: the same police officer provided the same hearsay testimony. The final revocation hearing was therefore transformed into a mere formality, the repetition of hearsay testimony from the preliminary hearing, contrary to Gagnon and Morrissey. See In re A.W., 353 A.2d at 692 (appendix; text of United States v. Peters).
Unfortunately, the majority does “not reach” these fundamental issues, preferring instead to focus exclusively on the theoretical sufficiency of the trial court’s finding of another violation of appellant’s probation, his illegal drug use. The majority then recreates the proceedings below by claiming that the trial court received evidence of the armed assault incident only as part of its discretionary ruling on revocation and sentencing. See ante at 207-209. As indicated above, however, that simply is not what happened. By ignoring the distinction between the final revocation hearing — circumscribed by due process procedures and protections — and the subsequent discretionary act of revocation and resen-tencing, the majority undermines the Supreme Court’s holdings in Gagnon and Morrissey.
IV.
When appellate judges review decisions committed to the trial judge’s sound discretion, it is elementary that they must not infer either what the trial judge could have done or what he or she might do on remand. It is thus improper for my colleagues in the majority to substitute their own exercise of discretion for the trial judge’s, even if they perceive an alternative, sufficient ground for revoking appellant’s probation. See Ibn-Tamas v. United States, 407 A.2d 626, 636 n. 17 (D.C.1979). When reviewing the trial court’s exercise of discretion, “[w]ere an appellate court to substitute its own judgment, the court would rationalize a result which the trial court itself, properly informed of the law, might not have reached, given factors at [the hearing] which the appellate court could not possibly perceive.” Wright v. United States, 508 A.2d 915, 920 (D.C.1986).
Here, the trial court premised its discretionary revocation of appellant’s probation on two findings it deemed essential to its conclusion that appellant violated his probation. One of these findings violated appellant’s constitutional rights under Gagnon and Morrissey. Accordingly, the trial court’s discretionary decision to revoke and resentence was erroneous: its “action was *215[not] within the range of permissible alternatives,” and it “relied upon an improper factor.” Johnson, 398 A.2d at 365. This error, moreover, “had a possible substantial impact upon the outcome,” id. at 366, for we cannot be certain the judge would have revoked appellant’s probation solely on a constitutional finding of illegal drug use, even if the government had presented hearsay evidence of a new criminal offense at the resentencing phase. The first time appellant was before the court on a probation violation of illegal drug use, the court continued probation, rather than revoking it. The fact that the judge conditioned continued probation on refraining from further drug use does not mean the judge would automatically have revoked for a second slip, without regard to circumstances.7
“Both the probationer ... and the State have interests in the accurate finding of fact and the informed use of discretion.” Gagnon, 411 U.S. at 785, 93 S.Ct. at 1761. Because the trial court did not follow constitutionally required procedures, it erroneously found that appellant committed an armed assault (by less than clear and convincing evidence, which may be necessary to satisfy due process, see supra note 2). Because the court premised its probation revocation order primarily upon that erroneous finding, it did not exercise its discretion in an “informed” manner. Id.
For the foregoing reasons, I vote to reverse and remand for a new final revocation hearing on the commission of the armed assault offense and for a new exercise of the trial court’s discretion.8
. The trial court also must hold a preliminary hearing to determine “whether there is probable cause or reasonable ground to believe that the arrested [probationer] has committed acts which would constitute a violation of [probation] conditions.” Morrissey v. Brewer, 408 U.S. 471, 485-86, 92 S.Ct. 2593, 2602, 33 L.Ed.2d 484 (1971); see Smith v. United States, 454 A.2d 1354, 1355 n. 1 (D.C.1983); Super.Ct.Crim.R. 32.1(a)(1) (listing due process requirements at preliminary revocation hearing).
. I join the section of Part III of the majority opinion, adopting the preponderance standard as the evidentiary burden the government must meet to prove "technical” or "substantive” violations of probation. Contrary to the majority, however, I believe this court cannot properly avoid reviewing the trial court's finding that appellant committed a new criminal offense while on probation. It follows that this court should answer the question left open by the majority: should the "preponderance” or the "clear and convincing evidence” standard apply when the issue at a probation revocation hearing is whether the probationer has committed a crime while on probation? See ante note 7. Because I dissent on other grounds, however, I also do not address that question.
. I am not persuaded by the analysis in Part II.B. of the majority opinion, which concludes that the probation officer’s testimony, on which the trial judge relied to find appellant had used illegal drugs, was "reliable hearsay.” The probation officer's testimony referred primarily to the ADASA form, not to the drug tests themselves. Furthermore, the government moved neither the probation file nor any official lab test results into evidence. Only the ADASA form, a kind of summary, was admitted. Thus, this case is not the same as Patterson v. United States, 570 A.2d 1198 (D.C.1990), where the probation officer testified using a probation violation report that was "an official record kept in the ordinary course of business.” Id. at 1199. Such official records typically include indicia of reliability such as signatures. While an official, signed report or a signed lab test would meet the requirements of "reliable hearsay" under Patterson, I do not think the ADASA form, standing alone, does.
. Thus, the majority's assertion and premise that "appellant’s revocation was based ... upon a substantive violation,” ante note 7, is simply false. The trial court based its (step two) revocation of probation upon finding both a substantive violation (use of illegal drugs) and the commission of a new offense. The majority belated*211ly recognizes this obvious fact on page 208 of its opinion, where it acknowledges "the trial judge found two 'first step’ violations: the commission of the new offense and the renewed drug use.” And yet back on page 201, the majority had already foreclosed meaningful analysis of appellant’s constitutional claim challenging the trial court’s finding that appellant committed armed assault, by stating: "Since [the illegal drug use] is sufficient to allow revocation of probation, we do not reach the contentions raised by appellant with respect to the new offense.” The majority, therefore, catches itself in a non sequitur, for if the revocation decision was based on "two ‘first step’ violations,” not on the drug use alone, then the majority must “reach the contentions raised by appellant with respect to the new offense.”
. Although the prosecutor indicated he was going to recall Drake, he never did so.
. The government is correct in pointing out that the Sixth Amendment’s confrontation clause imposes a higher constitutional standard of admissibility at trial than the due process clause imposes at a probation revocation hearing. Contrary to the government’s conclusion, however, that does not mean the government has no burden to overcome before offering hearsay testimony in place of testimony from declarants themselves. Because London’s statement to the police and identification of appellant as the shooter incriminated appellant, I believe that due process balancing — to determine whether there is good cause for denying appellant his right to confront and cross-examine London— requires the government to proffer a sufficient explanation of London's unavailability and to show why Detective Taylor’s hearsay testimony is sufficiently reliable. Without such a requirement, the government, as a matter of tactical course, may choose to put more credible police officers on the stand at probation revocation hearings instead of taking a chance with less credible eyewitnesses (subject to in-court scrutiny and cross-examination) to a probationer's alleged criminal offense. Furthermore, we have no evidentiary principle suggesting that a police officer’s hearsay testimony is inherently reliable. For example,
[w]hile police reports may be demonstrably reliable evidence of the fact that an arrest was made, they are significantly less reliable evidence on whether the allegations of criminal conduct they contain are true. We note that *214Congress exhibited similar doubts about the reliability of [police] reports when it specifically excluded them from the public records exception in criminal cases. See Fed.R.Evid. 803(8)(B).
United States v. Bell, 785 F.2d 640, 644 (8th Cir.1986) (citation omitted).
. The trial court would have been free, in the exercise of its discretion, to leave the probation sentence undisturbed. Alternatively, it could have imposed new conditions of probation rather than revoking probation altogether. The trial court followed this latter course in this case after appellant had failed his first drug test; the court restored appellant to probation on the condition that he participate in the ADASA drug treatment program.
. The majority postulates that the exercise of discretion I would have the trial judge undertake on remand would "be identical to the exercise which he previously undertook.” Ante at 209. That, again, is simply wrong. I would remand for a new probation revocation hearing, including the nondiscretionary (first step) violation analysis to afford appellant his constitutional rights under Gagnon and Morrissey pursuant to the Peters procedures. If the government fails to meet the "good cause” requirement for dispensing with appellant's right to confront and cross-examine adverse witnesses, or if the government produces those witnesses and they fail to withstand the scrutiny of testifying in court (causing the government’s failure to meet its burden, see supra note 2), the trial court — in discretionary step two — has authority, and may decide, not to revoke appellant’s probation, despite the fact of appellant’s illegal drug use and even if the government produces reliable hearsay evidence of the armed assault. It is not for this court to say what the trial court would do in the exercise of discretion on a new record.
It may be — and perhaps the majority thinks— that the trial court on remand would choose to base its (step one) violation finding solely on appellant’s renewed drug use and simply save the new crime evidence exclusively for use in the (step two) sanction decision. If so, that would be another case, unlike the one before us now.