with whom CARPENETI, Justice, joins, dissenting.
I respectfully dissent. In my opinion, the board did not err in relying on Dr. Riederer's testimony in concluding that the employer successfully rebutted the presumption of compensability under AS1
1. The court's dismissal of Dr. Riederer's testimony as "predictive" is both factually incorrect and doctrinally troublesome.
Dr. Riederer testified that he did not observe the normal indicia of a serious ankle injury upon examining Wollaston seventy-two hours after the work-related accident. He repeatedly testified that Wollaston's ankle was weight-bearing, and not discolored or swollen. He further testified that while his physical examination revealed some tenderness on the inside of the ankle, it produced no objective indicia of the posterior ligament or tendon trauma that Wollaston claimed was the primary source of his permanent partial impairment. Based on these clinical observations, Dr. Riederer diagnosed Wollaston with a ligamentous injury on the inside of the ankle/foot structure-a mild to modest ankle sprain. There is nothing predictive or speculative about this diagnosis.
Further, there is nothing inherently insufficient about Dr. Riederer's estimation of Wollaston's likely recovery time. Dr. Ried-erer thought Wollaston would fully recover within one to two weeks. This estimation was based on Dr. Riederer's sound medical examination in combination with years of experience dealing with many types of ankle injuries of different levels of severity. His opinion should not be dismissed simply because Wollaston did not return for a checkup.
The court, however, dismisses Dr. Riederer's prognosis as "predictive based on a fixed past perspective,2" because Dr. Riederer's contemporaneous recovery estimation and subsequent testimony were based upon a single examination performed before Wollaston had fully recovered from his injury. Many recovery prognoses made by original treating physicians would be subject to the same criticism 3think it is undesirable to reject such evidence. Employees may not return for follow-up treatment or examination to the physicians who first treated them, or may still be in the early stages of recovery when they do so. But the original physician's observations, diagnoses, and prognoses are closest in time to the injury and least likely to be influenced by litigation strategy. By signaling that the board should disregard these physicians' analyses, the court unduly limits useful and relevant expert evidence of the employee's condition. This restriction may increase litigation costs by forcing par-
*1070ties to hire additional experts rather than rely on the opinions of the original treating physicians. And this limitation may disadvantage both employees and employers: an opinion favorable to the employee's claim would be entitled to little weight when the board determines whether the employee has proved his claim by a preponderance of the evidence.
2. Dr. Riederer's testimony is sufficient to rebut the presumption of com-pensability.
Dr. Riederer's testimony fits seamlessly with the surrounding evidence. Wollaston's non-work-related basketball injury-which occurred just seven months before his work-related injury-was tremendously destructive. The X-ray report of the basketball injury indicated "a complete dislocation at the ankle joint w{ith] the foot at right angles to the tibia."4 The treating physician, Dr. Catalanello, characterized the basketball injury as being as serious an injury as one could sustain without tearing the ankle open. Dr. Riederer testified that the basketball injury was "horrendous." Dr. Catalanello's emergency room report notes that he "warned patient that there is no guarantee that he will not experience a permanent dysfunction secondary to this lesion." The owner of Schroeder Cutting and two of his employees testified that Wollaston had still not recovered from the basketball injury when he returned to work over two months later.
Further, Wollaston's behavior after his work-related accident tends to confirm Dr. Riederer's diagnosis of a mild sprain. Wolla-ston did not seek further medical treatment until about a month after visiting Dr. Riederer. It is not surprising Wollaston did not return to Dr. Riederer because Wollaston had moved to Texas. But if his work-related injury had in fact been serious, one would expect him to have seen some physician for treatment sooner than he did.
Taking Dr. Riederer's testimony in combination with the evidence of Wollaston's devastating prior injury and his behavior following his work-related injury, the board could reasonably conclude that the employer had rebutted the presumption of compensability either by providing an alternative explanation for Wollaston's disability-iLe., the bas-kethball infjury-or by "directly eliminat[ing] any reasonable possibility" that Wollaston's work-related injury was a "substantial cause of his disability" 5 beyond July 7, 1996.6
The court, however, faults Dr. Riederer's testimony for failing to explicitly opine that the work injury was not a substantial cause of Wollaston's disability.7 I think the board could permissibly disagree with the accuracy of this characterization of Dr. Riederer's testimony8 But in any event, there can be no serious doubt that Dr. Riederer believed Wollaston's work-related injury was probably not the cause of any impairment beyond the estimated one-to-two-week recovery period.9 Requiring medical experts to mold their opinions to fit legal formulae is unlikely to improve the accuracy of their testimony.
Likewise, it is of little significance that Dr. Riederer did not stridently disagree with Dr. Whittemore's diagnosis of a posterior liga*1071ment injury or Dr. Whittemore's assessment of permanent impairment when given the opportunity to do so by Schroeder's attorney. If anything, it may have bolstered his credibility before the board.
Because the court holds that Dr. Riederer's testimony was insufficient to rebut the presumption of compensability, it does not address whether substantial evidence supported the board's conclusion that Wollaston failed to prove his claim by a preponderance of the evidence.10I would hold that the evidence discussed above is sufficient to support the board's ultimate decision as well as its decision that the presumption was rebutted. I would therefore affirm the superior court's affirmance of the board's decision.
Tolbert v. Alascom, Inc., 973 P.2d 603, 611 (Alaska 1999) (employer must provide substantial evidence to rebut presumption of compensability); Veco, Inc. v. Wolfer, 693 P.2d 865, 869 (Alaska 1985) (same). "Substantial evidence is such relevant evidence as a reasonable mind might accept as adequate to support [the board's] conclusion." - Miller v. ITT Arctic Servs., 577 P.2d 1044, 1046 (Alaska 1978) (citations omitted).
Because the presumption shifts only the burden of production and not the burden of persuasion, we review any evidence tending to rebut the presumption in isolation, without reweighing the rebuttal evidence against the evidence tending to establish causation. Wolfer, 693 P.2d at 869.
. Op. at 1066.
. The court cannot intend to apply the "predictive" pejorative to all medical estimations of recovery periods. After all, permanent impairment determinations often involve a type of prediction-usually a prediction of the extent to which the patient will not fully recover.
. Dr. Catalanello attested that Wollaston's accident "flipped [his ankle] under completely 90 degrees."
. Grainger v. Alaska Workers' Comp. Bd., 805 P.2d 976, 977 (Alaska 1991).
. The board found that the presumption of com-pensability had not been rebutted for the period prior to July 7, 1996.
. Op. at 1067-1069.
. Dr. Riederer testified that based upon his examination of Wollaston, he "did not anticipate any permanent residual" impairment. Although Dr. Riederer stated that his recovery prognoses were not always correct, this was nothing more than a refreshingly candid admission of the uncertainty of medical practice. Dr. Riederer unequivocally stated that he would make the same diagnosis again if faced with a similar injury.
. Dr. Riederer did testify that he thought the work injury may have aggravated the previous injury. We have held that "(iin the case of a preexisting condition associated with a disability, a claim is compensable upon a showing that employment (1) aggravated, accelerated, or combined with a preexisting condition so as to be (2) a substantial factor in bringing about the disability." Estate of Ensley v. Anglo Alaska Constr., 773 P.2d 955, 958 (Alaska 1989) (citations omitted). But this theoretical avenue of recovery is not before us, because Wollaston claims he had completely recovered from his basketball injury before his work injury occurred.
. When we review the board's decision that the employee did or did not prove her claim, we apply the substantial evidence test. Wolfer, 693 P.2d at 870. As with our review of whether the evidence is sufficient to rebut the presumption of compensability, we do not reweigh the evidence or choose between competing inferences. Beauchamp v. Employers Liab. Assurance Corp., 477 P.2d 993, 997 (Alaska 170).