concurring.
I concur in the majority opinion’s decision to vacate and remand in this case, but not in its reasoning for doing so. In particular, I disagree that the board’s opinion indicates that it misunderstood the nature of a claimant’s “burden of eliminating idiopathic causes” under Phil A. Livesley Co. v. Russ, 296 Or 25, 32, 672 P2d 337 (1983) (Livesley), in a case in which a claimant seeks to establish the compen-sability of a workplace fall under the “unexplained fall” doctrine. Under that doctrine, as articulated in Livesley, where a fall in the workplace in unexplained — that is, the cause of the fall “cannot be directly established” — a claimant may nonetheless prove indirectly that the fall was caused by the work environment (and, therefore, arose from the work environment) by “eliminating idiopathic causes” for the fall. Id. A claimant may do so by producing “affirmative evidence to exclude idiopathic factors as the cause of her injury.” Id. If that evidence persuades the factfinder (by the applicable standard of proof) that idiopathic factors did not cause the claimant’s injury, then “the inference arises that the fall was traceable to some ordinary risk, albeit unidentified, to which the employment premises exposed the employee.” Id.
*572From the board’s explanation of its reasoning in the order on review, I am not inclined to think that the board misunderstood a claimant’s burden to eliminate idiopathic factors of causation in the context of a claim litigated under the unexplained fall doctrine. I would not, therefore, remand on that basis. I would, however, remand for a different reason: that the board erred by invoking the “unexplained fall” doctrine in this case, where claimant presented direct evidence of causation, and did not seek to prove causation indirectly by invoking the unexplained fall doctrine.
Claimant’s first assignment of error raises this point. Claimant points out that her theory all along has been that her fall was caused by a tripping hazard in the lobby of her workplace, and contends that the unexplained fall doctrine is inapplicable where, as here, a claimant seeks to establish causation directly rather than indirectly. In her briefing before the ALJ, she urged the ALJ to find that the fall was “explained” by the fact that she had tripped over uneven tile. In its briefing, employer urged the ALJ to find affirmatively to the contrary that claimant’s fall was caused by idiopathic factors and not the tile. In other words, both parties asserted that the fall’s cause was known or explained, but provided conflicting theories of causation. Consistent with those competing theories, a fair portion of the hearing before the ALJ centered on the condition of the lobby floor and, in particular, on how pronounced the uneven portion of the tile was, and also on how claimant’s idiopathic medical conditions may have contributed to the fall.
As to the floor’s role in claimant’s injury, claimant testified under oath at the hearing that she fell when, as she walked across the lobby while wearing Birkenstocks, her foot “caught on something,” causing her to trip and fall. Claimant thought her foot caught on a lip of tile. Although she admitted on cross-examination that she did not know “what her foot got caught on,” she testified that she believed it was the lip of tile because “[t] hat’s the only thing that I know that it could have been.” She testified further that the lip was not “real big,” but that it was visible “and if you run your foot against [it], you can definitely feel it.” Another worker in the building corroborated claimant’s testimony that the floor was not completely flush, and that there was *573a “dip” between the tiles. He thought that it would be “difficult” to catch one’s foot in the lip or dip, explaining that he had run his foot over the tiles while wearing dress shoes, but had not caught his foot on anything when he was doing that. Everyone seemed to agree that the lip measured around l/16th of an inch, although no one had measured it. Claimant’s medical records, as well as the report of the employer’s investigator, were also introduced. Those records reflect that, with minor exceptions,1 claimant consistently has reported that the fall resulted from her foot catching on something, probably tile, which then caused her to trip. The investigator’s report notes, consistent with the testimony at the hearing, that “[t]here is a tile with the slightest of a lip, about 1/16 of an inch perhaps.”
The ALJ ultimately resolved the parties’ dispute on causation in favor of claimant. The ALJ credited claimant’s “tripping” explanation of the fall as the more likely explanation than the idiopathic theory of causation advanced by employer: “Since the alleged personal/idiopathic risks offered are speculative, they are less than equally likely to have caused the fall as Claimant’s explanation of a tripping incident.”2 In addition to finding claimant’s explanation of the fall more persuasive than employer’s explanation, the ALJ also found that claimant had persuasively eliminated all idiopathic factors of causation, apparently in response to employer’s argument that claimant needed to do so.
Before the board, claimant reiterated the same points that she made to the ALJ, again contending (among other things) that the unexplained fall doctrine should not *574apply to the case because she had supplied an explanation for the fall.3 Claimant acknowledged that there were some “minor” inconsistencies in her explanations for her fall, but argued that the gist of her explanation has always been the same. The board nonetheless treated the case as an “unexplained fall” case, and did not address claimant’s argument that her fall had been caused by the uneven tile, except to state in a footnote that “[claimant does not contend that an employment risk contributed to her injury. Moreover, our review finds no such employment contribution.”
The board’s conclusion that “[claimant does not contend that an employment risk contributed to her injury” does not square with the record in this case. Claimant’s theory all along has been that something in the lobby, most likely the uneven tile, caught her foot and tripped her. Claimant testified under oath in support of that theory, describing on the stand how her fall happened. The ALJ addressed that theory and found that, on this record, claimant’s theory provided the more likely explanation for her fall than did employer’s speculative theory of idiopathic causation. Under those circumstances, the board erred when it determined that claimant was not contending that her fall was caused by an employment risk and decided to resolve the case under the unexplained fall doctrine. In my view, that error constitutes a procedural error that warrants a remand to permit the board to address claimant’s actual theory of the case. ORS 656.298(7) (providing that review of board orders “shall be as provided in ORS 183.482(7) and (8)”); ORS 183.482(7) (providing for a remand where “the fairness of the proceedings or the correctness of the action may have been impaired by a material error in procedure”). The board misapprehended claimant’s claim in an essential way and, based on that misapprehension, failed to address it.
I recognize that the board also stated that “our review finds no such employment contribution,” after it concluded that claimant was not advocating that her work *575environment caused her fall. That statement creates the possibility that the board’s error did not impair the fairness of the proceedings before it. If the board, in fact, gave due consideration to the role that the uneven floor may have played in claimant’s fall, then the board’s failure to understand the gravamen of claimant’s claim could not have impaired the fairness or correctness of the board’s decision. However, ORS 183.482(7) directs us to remand where the fairness or correctness of the proceedings “may have been impaired” as a result of a procedural error; we need not be certain of that impairment. (Emphasis added.)
The majority opinion concludes that the board’s error did not impair the fairness or correctness of the proceedings, because it “assume [s] that the board did what it said” in examining the record to determine whether an employment risk was present. 281 Or App at 565 n 3. Ordinarily, that would be my approach too. However, in this case, I am persuaded otherwise that, notwithstanding the board’s statement, the board’s misunderstanding of claimant’s theory of the case “may” have impaired the fairness or correctness of the proceedings for three reasons. First, the board did not discuss specifically the role the floor tile may have played in claimant’s fall, despite the direct evidence that the tile did play a role, and the centrality of that evidence to claimant’s case. Second, the board did not discuss the ALJ’s finding that claimant’s explanation of the fall should be credited over employer’s competing explanation for the fall, although caselaw indicates that the board should afford some deference to an ALJ’s demeanor-based credibility findings. See Erck v. Brown Oldsmobile, 311 Or 519, 528, 815 P2d 1251 (1991) (“[T]he Board should seriously consider the testimony [the ALJ] believes to be reliable.”). Given that claimant testified in person about how the fall occurred, it is hard not to think that claimant’s appearance on the stand had some bearing on the ALJ’s assessment of the evidence supporting the competing explanations for the fall, yet the board did not address this point. Third, the board’s decision to apply the unexplained fall doctrine in a case in which the claimant has not invoked that doctrine to prove causation — and in which there is direct evidence of causation — appears to depart from the usual circumstances in which the doctrine *576has been applied.4 This also suggests to me that the board might have seen this case differently if it had understood claimant’s theory correctly.
Those circumstances convince me that the board’s misunderstanding of claimant’s theory of the case may have caused it to overlook the direct evidence of causation that supports claimant’s theory and to apply the unexplained fall doctrine in a case in which the fall at issue is not so much “unexplained” as it is the subject of factual dispute over causation. Although the majority opinion concludes that a remand is warranted for a different reason, I do not understand that opinion to foreclose the board from taking these considerations into account on remand.
For these reasons, I concur in the decision to vacate and remand to the board.
One medical record states that claimant reported that her foot rolled and she tripped; another states that claimant reported that she “slipped.” When cross-examined on those records, claimant testified that her foot did not roll, that she tripped not slipped, and that she did not think that she would have told doctors otherwise, because “[t]here was nothing to slip on,” and because she had tripped.
The majority opinion reads this statement by the ALJ differently than I do, concluding that the ALJ did not credit claimant’s testimony that the fall was caused by the tripping incident. 281 Or App at 565 n 3. Although the sentence is worded awkwardly, a finding that the idiopathic factors of causation were speculative, and, therefore, less than equally likely to have caused the fall than the tripping incident to which claimant testified under oath is, in my view, the equivalent of a finding that, on this record, claimant’s explanation of the fall is the likely one.
Claimant also argued that, if the unexplained fall doctrine applied, then the board should find that she had eliminated idiopathic factors of causation for the fall.
See, e.g., Livesley, 296 Or at 27 (defining the scope of the unexplained fall doctrine in a case where there was no evidence to explain fall, and the claimant “was unable himself to offer a cause for the fall, however, and admitted that all he could remember of the incident was simply falling”); Blank v. US Bank of Oregon, 252 Or App 553, 557-58, 287 P3d 1272 (2012) (applying unexplained fall doctrine where the claimant could not recall the reason for her fall, and there was no other evidence of potential causes); McTaggart v. Time Warner Cable, 170 Or App 491, 494, 16 P3d 1154 (2000), rev den, 331 Or 663 (2001) (applying unexplained fall doctrine where claimant “[did] not know the reason for her fall,” and there was no other evidence of cause of fall).