No. 52	                        August 4, 2016	155

              IN THE SUPREME COURT OF THE
                    STATE OF OREGON

             In the Matter of the Compensation of
                 Roger J. Thompson, Claimant.
                    SAIF CORPORATION
            and Clackamas County Fire District #1,
                    Respondents on Review,
                               v.
                    Roger J. THOMPSON,
                     Petitioner on Review.
           (WCB 10-06391; CA A152618; SC S063020)

    On review from the Court of Appeals.*
    Argued and submitted November 12, 2015.
  Nelson R. Hall, Bennett Hartman Morris and Kaplan,
Portland, argued the cause for petitioner on review.
   Julie Masters, Appellate Counsel, SAIF Corporation,
Salem, argued the cause and filed the brief for respondents
on review.
   Sara Ghafouri, Haglund Kelley, LLP, Portland, filed the
brief for amicus curiae Oregon Trial Lawyers Association.
    Sarah K. Drescher, Tedesco Law Group, Portland,
filed the brief for amicus curiae International Association
of Fire Fighters. With her on the brief were Thomas A.
Woodley, David Ricksecker, and Sara A. Conrath, Woodley
& McGillivary, Washington, D.C.
  Before Balmer, Chief Justice, and Kistler, Walters,
Landau, Baldwin, Brewer, and Nakamoto, Justices.**
    KISTLER, J.
   The decision of the Court of Appeals is reversed. The
order of the Workers’ Compensation Board is affirmed.
______________
	**  On judicial review of an order of the Workers’ Compensation Board, dated
September 7, 2012. 267 Or App 356, 340 P3d 163 (2014).
	   **  Linder, J., retired December 31, 2015, and did not participate in the deci-
sion of this case.
156	                                                     SAIF v. Thompson

     Case Summary: Claimant, while employed as a firefighter, suffered a heart
attack caused by atherosclerosis. Claimant filed a claim for workers’ compensa-
tion benefits and relied on a statutory presumption that his condition was a com-
pensable occupational disease. According to the presumption, a worker who suf-
fers from certain diseases or conditions while employed as a firefighter is entitled
to workers’ compensation, unless an employer demonstrates that the disease or
condition is unrelated to employment. ORS 656.802(4). Claimant sought benefits
from his employer and employer’s insurer, SAIF, denied the claim. SAIF relied on
expert medical testimony; according to SAIF’s expert, the causes of atherosclero-
sis are not known, but atherosclerosis is not caused by firefighting. The Workers’
Compensation Board reversed, explaining that SAIF failed to meet its burden of
persuasion to prove by clear and convincing evidence that claimant’s condition
was unrelated to his employment. The Court of Appeals reversed and held that
the board impermissibly required SAIF to put on evidence of an alternative cause
of claimant’s atherosclerosis. Held: (1) Once a claimant establishes the predicate
facts giving rise to the firefighters’ presumption, the burdens of production and
persuasion shift to the employer to prove that the condition is unrelated to fire-
fighting; (2) the Court of Appeals erred in determining that the board required
proof of an alternative cause. The board reasonably determined that SAIF’s evi-
dence was not persuasive because it was inconsistent, not because SAIF failed to
offer evidence of an alternative cause.
   The decision of the Court of Appeals is reversed. The order of the Workers’
Compensation Board is affirmed.
Cite as 360 Or 155 (2016)	157

	          KISTLER, J.
	        The question in this workers’ compensation case
is how a statutory presumption, colloquially known as the
“firefighters’ presumption,” applies. See ORS 656.802(4)
(stating that presumption).1 In this case, no one disputes
that claimant proved the predicate facts, which gave rise
to a presumption that his heart attack “result[ed] from” his
work as a firefighter and thus was an occupational disease.
See id. No one also appears to dispute that the effect of the
presumption was to shift the burden of persuasion to SAIF
to prove by clear and convincing evidence that “the cause
of [claimant’s] condition [wa]s unrelated” to his work as a
firefighter. See id. (stating that requirement).
	        After considering SAIF’s medical evidence, the
Workers’ Compensation Board (board) found that the evi-
dence did not satisfy SAIF’s burden of persuasion and
entered an order finding that claimant’s heart attack was
a compensable occupational disease. The Court of Appeals
reversed. SAIF v. Thompson, 267 Or App 356, 340 P3d 163
(2014). It reasoned that the board had implicitly and incor-
rectly concluded that only one type of medical evidence (evi-
dence of risk factors unique to the claimant and unrelated
to his work) would rebut the presumption. Id. at 364-65.
Having determined that the board applied an incorrect legal
rule, the Court of Appeals reversed its order. Id. at 367. We
allowed claimant’s petition for review and now conclude that
the Court of Appeals misperceived the basis for the board’s
order. We also conclude that the board reasonably found, on
the evidence before it, that SAIF had failed to satisfy its
	1
       ORS 656.802(4) provides:
    	 “Death, disability, or impairment of health of firefighters of any polit-
    ical division who have completed five or more years of employment as fire-
    fighters, caused by any disease of the lungs or respiratory tract, hypertension
    or cardiovascular-renal disease, and resulting from their employment as fire-
    fighters is an ‘occupational disease.’ Any condition or impairment of health
    arising under this subsection shall be presumed to result from a firefighter’s
    employment. However, any such firefighter must have taken a physical exam-
    ination upon becoming a firefighter, or subsequently thereto, which failed
    to reveal any evidence of such condition or impairment of health which pre-
    existed employment. Denial of a claim for any condition or impairment of
    health arising under this subsection must be on the basis of clear and con-
    vincing medical evidence that the cause of the condition or impairment is
    unrelated to the firefighter’s employment.”
158	                                                    SAIF v. Thompson

burden of persuasion. We accordingly reverse the Court of
Appeals decision and affirm the board’s order.
	        Before setting out the facts in this case, we first
describe the statutory context in which the case arises.
Ordinarily, workers seeking compensation for an “occupational
disease” must “prove that employment conditions were the
major contributing cause of the disease.” ORS 656.802(2)(a);
see also ORS 656.802(1) (defining “occupational disease”).
However, in 1961, the Oregon legislature adopted a statu-
tory presumption that, if the claimant established certain
predicate facts, the claimant’s condition resulted from his
or her employment and was an occupational disease. See Or
Laws 1961, ch 583, § 1. Proponents of the bill explained that,
according to statistical studies, firefighters are more likely
than other occupations to develop heart and lung diseases,
due to smoke and gas exposure in strenuous conditions, and
that firefighters should not bear the burden of demonstrat-
ing that a disease or condition was caused by firefighting.
See Minutes, Senate Labor and Industries Committee, HB
1018, Mar 8, 1961. The legislature accordingly established
a “disputable presumption” that firefighting causes certain
types of occupational diseases. See Minutes, House Labor
and Industries Committee, Feb 2, 1961, p 2. The legislature
amended the statute in 1977 by clarifying that a claim could
be denied “on the basis of medical or other evidence that
the cause of the fireman’s condition or impairment [was]
unrelated” to firefighting. See Or Laws 1977, ch 734, § 1 (so
providing).
	In Wright v. SAIF, 289 Or 323, 613 P2d 755 (1980),
this court explained that the statute, as amended in 1977,
created a disputable presumption, that the effect of the
presumption was to shift the burden of production to the
employer, and that, if an employer met its burden of produc-
tion, then the trier of fact had to determine which way the
evidence preponderated. Id. at 331-32.2 The court did not
decide whether the presumption also shifted the burden of
persuasion to the employer; rather, the court left open the
	2
       As we read Wright, the court used the phrase “disputable presumption” as
a synonym for “rebuttable presumption.” See Wright, 289 Or at 331-32; cf. State v.
Dahl, 336 Or 481, 486, 87 P3d 650 (2004) (discussing rebuttable presumptions).
Cite as 360 Or 155 (2016)	159

question of what effect the presumption would have if the
evidence were in equipoise. Id. at 331 n 5. It noted that the
members of what was in that case a four-person court were
equally divided on that question. Id.
	        In 1983, the legislature addressed the question
that the court had left open in Wright. At the request of
the Oregon State Fire Fighters Council, Representatives
Whallon and Gold introduced House Bill (HB) 2700 (1983).
As originally introduced, HB 2700 would have made the
firefighters’ presumption conclusive; that is, if a firefighter
suffered from a heart or lung condition, established that he
or she had served as a firefighter for at least five years, and
proved that a physical examination failed to reveal that the
condition preexisted the firefighter’s employment, then it
would be conclusively presumed that the condition resulted
from employment. Bill File, HB 2700, Mar 30, 1983.
	        A representative of the Oregon State Fire Fighters
Council explained that the presumption should be conclusive
because some “medical practitioners * * * do not believe that
physical and mental stress causes heart disease.” Testimony,
House Committee on Labor, HB 2700, Mar 30, 1983, Ex E
(statement of Tom Whelan). In the Council’s view, employers
could defeat the current presumption by simply finding “one
or more physicians to say that in their opinion the condition
did not result from the workplace.” Id.
	        Representatives from local governments opposed
making the presumption conclusive. The personnel director
for the City of Salem testified that a conclusive presump-
tion would increase the number of compensable claims
because cities and other employers would be unable to show
that a firefighter’s cardiovascular or pulmonary disease
was “primarily the result of non-firefighting employment
related risk factors such as outside employment, smoking,
hypertension, heredity, [gender], obesity, sedentary life-
style and age.” Testimony, House Committee on Labor, HB
2700, Apr 13, 1983, Ex E (statement of Darrell Dearborn).
He explained that “[o]ur princip[al] concern with this bill
is that it removes in total any possibility that medical evi-
dence can be introduced to challenge compensability.” Id.
Similarly, the Assistant City Attorney for the City of Salem
160	                                                    SAIF v. Thompson

argued that a conclusive presumption would establish “a
rule of law, not a factual presumption[,] * * * [meaning that
an] employer can submit no evidence of any other contribut-
ing factors to the firefighter’s condition, such as heredity, or
a lifetime of heavy smoking to support a denial of the claim.”
Testimony, House Committee on Labor, HB 2700, Apr 13,
1983, Ex F (statement of Jeannette Launer).
	        In response to those concerns, the Oregon State
Fire Fighters Council offered an amendment to “clarify the
bill and deal with the concerns of the opponents.” Minutes,
House Committee on Labor, Subcommittee on Workers’
Compensation Benefits, HB 2700, Apr 20, 1983, p 2. The
amended bill no longer made the presumption conclusive. It
provided that, if the claimant proved certain predicate facts,
it would be presumed that the claimant’s condition resulted
from his or her employment as a firefighter. Employers could
deny a claim only “on the basis of clear and convincing med-
ical evidence that the cause of the condition or impairment
is unrelated to the [firefighter’s] employment.” Bill File, HB
2700, A-Engrossed Bill, Apr 19, 1983. The bill, as amended,
passed both houses and was signed by the governor.
	         The 1983 amendment made two propositions clear.
First, if a claimant proved the predicate facts, then the
presumption shifted both the burden of production and
the burden of persuasion to the employer to prove that the
claimant’s “condition or impairment is unrelated to the fire-
fighter’s employment.” Second, the employer must prove that
fact by clear and convincing evidence.3 The text and the leg-
islative history, however, do not provide as clear an answer
to the question that the Court of Appeals addressed in this
case—whether only evidence of individual risk factors that
are unrelated to employment may be offered to meet the
employer’s burden.4
	3
       In increasing the standard of proof to clear and convincing evidence, the
1983 amendment did not change the type of the evidence necessary to satisfy the
burden of persuasion. For a cogent explanation of how standards of proof allocate
risk and the public policies underlying those choices, see In re Winship, 397 US
358, 368-372, 90 S Ct 1068, 25 L Ed 2d 368 (1970) (Harlan, J., concurring).
	4
       The usual sources of legislative intent look in different directions on that
issue. On one hand, the text of the amended statute refers to “medical evidence”
without limitation. On the other hand, the employers’ testimony that persuaded
Cite as 360 Or 155 (2016)	161

	        In summary, ORS 656.802(4), as amended in 1983,
provides that a claimant must prove three predicate facts to
establish the firefighters’ presumption: (1) the claimant was
employed for five or more years as a firefighter for a political
division; (2) the claimant’s death, disability, or impairment
of health was caused by one of the listed diseases; and (3) a
physical exam failed to reveal that the condition or impair-
ment preexisted employment. If a claimant proves those
predicate facts, then the statute establishes a rebuttable
presumption that the condition or impairment “result[ed]
from [the] firefighter’s employment” and is an “occupational
disease.” ORS 656.802(4). The burden of both production
and persuasion then shifts to the employer to prove by “clear
and convincing medical evidence that the cause of the condi-
tion or impairment is unrelated to the firefighter’s employ-
ment.” Id.
	        With that background in mind, we turn to the facts
in this case. Claimant began working as a firefighter in
1991. In 2010, at the age of 44, claimant felt chest discom-
fort while using a treadmill and an elliptical machine at the
fire station. Two days later, while off duty, he experienced
muscular discomfort in his chest and neck, which prompted
him to seek medical treatment. Claimant’s cardiologists
concluded that he had had a heart attack, and they deter-
mined that the heart attack was caused by atherosclerosis—
essentially, a blocked artery due to coronary artery disease.
The cardiologists successfully treated claimant with angio-
plasty and stenting of the artery.
	       Claimant had no prior indication of cardiovas-
cular disease. He had had a physical examination before
his employment as a firefighter and also periodic physical
examinations after he began working as a firefighter. None
of those examinations revealed evidence of cardiovascular
disease. Furthermore, claimant’s cardiologists determined
that he had no known family history of cardiovascular dis-
ease or common risk factors for cardiovascular disease,

the 1983 legislature to make the presumption rebuttable focused on the need to
present one type of medical evidence—individual risk factors unrelated to work—
to rebut the presumption. However, no witness expressly addressed whether that
type of medical evidence was the only medical evidence that an employer could
use to rebut the presumption.
162	                                               SAIF v. Thompson

such as diabetes, obesity, high cholesterol, hypertension, or
tobacco use.
	         Following his heart attack, claimant filed a work-
ers’ compensation claim on the ground that his underlying
cardiovascular condition—atherosclerosis—resulted from
his employment as a firefighter and was a compensable
occupational disease. Claimant did not offer any medical
evidence to prove that his work caused his atherosclerosis.
Rather, he relied on the firefighters’ presumption. See ORS
656.802(4). Claimant contended, and SAIF did not dispute,
that claimant had established the predicate facts: he had
been employed for at least five years as a firefighter; he had
a cardiovascular disease; and his physical examinations
failed to reveal that his condition preexisted his employment.
	       After receiving his claim, SAIF asked claimant to
undergo an independent medical examination by Dr. Semler.
Semler examined claimant and also reviewed his medical
records. Semler issued a report that began by setting out
the question that Semler understood he had been asked to
address:
   “Because this worker is filing a claim for an occupational
   disease, he must establish that his life long work exposure
   is the most significant factor in the development of his con-
   dition. In other words, work by itself must outweigh the
   significance of all other pertinent factors combined. We are
   asking you to determine the major cause of the condition[.]”5
In answering that question, Semler explained that “[t]he
exact etiology for atherosclerosis is not definitely known.”
He noted that, in reviewing the medical literature, he had
“not found any scientific evidence that firefighting per se
leads to atherosclerosis or hardening of the arteries.” He
identified certain “theories” as to why a person’s arteries
might become blocked but found that none applied in claim-
ant’s case. After observing that “[a]therosclerosis is more
in keeping with the aging process in [claimant’s] case,” he
concluded that “it is highly probable that [claimant’s] work
as a firefighter is not the major contributing cause of his
cardiac condition.”
	5
     Semler’s report appears to be paraphrasing a legal standard supplied to
him by the entity that had requested the report.
Cite as 360 Or 155 (2016)	163

	        Based on Semler’s report, SAIF denied the claim.
Claimant requested a hearing before the Hearings Division
of the Workers’ Compensation Board. Semler testified at
that hearing.6 Much of his testimony was devoted to pro-
viding background information regarding atherosclerosis
and heart attacks. Beyond that, his testimony reduced to
three propositions. First, Semler explained that atheroscle-
rosis starts as “a fatty deposit called a ‘fatty streak.’ ” The
appearance of a fatty streak indicates the existence of a dis-
ease process or an injury to the inner lining of the artery.
However, what causes the injury to the artery or the disease
process to begin is not known.7 Once the streak appears
plaque attaches to it and builds up over time. The plaque
can cause a heart attack either because it builds up to such
an extent that it obstructs the artery (as in claimant’s case)
or because a piece of the plaque breaks off and blocks the
artery that way.
	        Second, Semler testified that there are risk factors
that contribute to the development of atherosclerosis. They
include obesity, smoking, high blood pressure, high choles-
terol, diabetes, and family history. Claimant did not exhibit
any of those risk factors. Rather, Semler concluded in his
report that “[a]therosclerosis is more in keeping with the
aging process in [claimant’s] case.” As noted, claimant was
44 years old when he suffered a heart attack.
	       Third, Semler testified that he could not say, based
on the medical evidence, that firefighting caused atheroscle-
rosis. Alternatively, he testified that firefighting “did not
play any role in [claimant’s] development of atherosclerosis.”
He explained the basis for that opinion:
    “I’ve never seen a paper that said firefighting caused ath-
    erosclerosis. It’s not one of the things that doctors or cardi-
    ologists would list. I just listed all of the potential causes;

	6
       Claimant’s treating cardiologist, Dr. Dawley, also testified at the hearing.
The board reasonably found that Dawley’s testimony was equivocal regarding the
cause of claimant’s atherosclerosis and thus insufficient to rebut the presump-
tion. Accordingly, we summarize only Semler’s testimony, which was the focus of
the Court of Appeals’ reasoning.
	7
       In addition to stating in his report that the exact etiology of atherosclerosis
is not definitely known, Semler agreed on cross-examination that “the cause of
laying down of the fatty streaks * * * [is] still unknown.”
164	                                           SAIF v. Thompson

   diabetes, obesity, hypertension, high cholesterol, family
   history. But firefighting, I’ve never seen a paper that said
   firefighting caused atherosclerosis.”
Given the foregoing reasoning, Semler agreed on direct
examination that claimant’s condition was “unrelated to his
employment as a firefighter.”
	       The Administrative Law Judge (ALJ) found that
SAIF had “presented sufficient evidence to overcome the
presumption by clear and convincing evidence” and upheld
SAIF’s denial of the claim. The board reversed. We quote
the board’s reasoning in full because the Court of Appeals
concluded that, in finding that SAIF had not met its burden
of persuasion, the board applied an incorrect legal standard.
The board reasoned:
   “Dr. Semler was unaware of ‘any scientific evidence that
   firefighting per se leads to atherosclerosis * * *.’ Dr. Semler
   conceded that the ‘cause [of] atherosclerosis is still debat-
   able,’ but asserted that the ‘current consensus’ related
   atherosclerosis to ‘a multitude of factors[,] such as choles-
   terol disorder, diabetes, smoking, hypertension, family his-
   tory and other factors * * * [,] including being sedentary.’
   Dr. Semler ultimately opined that claimant’s employment
   as a firefighter played ‘no role whatsoever’ in his athero-
   sclerosis and heart attack.
   	 “We are not persuaded, however, that Dr. Semler’s opin-
   ion satisfies SAIF’s ‘clear and convincing’ burden to over-
   come the statutory presumption. Dr. Semler conceded that
   the cause of atherosclerosis is unknown. Despite that con-
   cession, Dr. Semler ruled out any contribution from claim-
   ant’s employment as a firefighter. Dr. Semler did not per-
   suasively explain, however, how he was able to make such
   a categorical exclusion, given that the causes of that condi-
   tion were unknown. The lack of such a persuasive explana-
   tion is particularly significant, given that the record does
   not establish that claimant had any identified ‘risk factors’
   for atherosclerosis.
   	 “In sum, after weighing the evidence, we find that SAIF
   has not established, by clear and convincing medical evi-
   dence, that the cause of claimant’s heart attack is unre-
   lated to his employment.”
(Ellipses and brackets in original; citations omitted.)
Cite as 360 Or 155 (2016)	165

	         The Court of Appeals reversed. It recognized that
the board had stated that SAIF had failed to meet its burden
of persuasion. 267 Or App at 363. The court concluded, how-
ever, that the board implicitly had applied an incorrect legal
rule. The court reasoned that, “because [Semler’s] explana-
tion was not met with contrary evidence or criticized by the
board,” the board must have “viewed Semler’s opinion as
inadequate to overcome the presumption because it lacked
proof of the ultimate cause of claimant’s atherosclerosis.” Id.
at 364. That is, the Court of Appeals read the board’s order
as requiring proof of individual risk factors unrelated to the
claimant’s work, such as diabetes, tobacco use, or high cho-
lesterol, to rebut the presumption. That legal rule, the Court
of Appeals reasoned, was at odds with its decision in Long v.
Tualatin Valley Fire, 163 Or App 397, 987 P2d 1267 (1999).8
The court accordingly reversed the board’s order. Thompson,
267 Or App at 367.9
	        On review, the parties raise two related but sepa-
rate issues. Relying primarily on cases from other states,
claimant and his amici argue that SAIF may not rely on
medical evidence that, as a general matter, atherosclerosis
is unrelated to firefighting to rebut the firefighters’ pre-
sumption. They contend that SAIF may rebut the presump-
tion only with evidence that claimant’s atherosclerosis was
caused by individual risk factors unrelated to his work, such
as diabetes, high cholesterol, or obesity. Under that stan-
dard, claimant contends, we should affirm the board’s order.
Alternatively, claimant argues that, even if SAIF may rely
on testimony that atherosclerosis generally is unrelated to

	8
      In Long, three doctors had testified that the cause of the firefighter’s
heart condition was not known but that the condition was not related to his
work. 163 Or App at 399, 401. The board found that that evidence rebutted the
presumption, and the Court of Appeals upheld its order. Id. Because the board
upheld the employer’s denial, the only question before the court in Long was
whether the employer’s evidence was sufficient to meet the employer’s burden
of production. The Court of Appeals limited its holding to that question. See id.
at 401.
	9
       Ordinarily, if the board applied an incorrect legal standard, the appropri-
ate disposition would be to reverse the board’s order and remand the case to the
board to apply the correct standard. The Court of Appeals, however, concluded
that Semler’s unrebutted testimony necessarily established by clear and convinc-
ing evidence that claimant’s condition was unrelated to his work. See Thompson,
267 Or App at 367.
166	                                                      SAIF v. Thompson

firefighting, the board reasonably found that Semler’s testi-
mony did not meet SAIF’s burden of persuasion.
	        We read the board’s order differently from the Court
of Appeals. As we read its order, the board did not rule that
only evidence of individual risk factors unrelated to claim-
ant’s employment may be used to rebut the firefighters’ pre-
sumption. Rather, the board recognized that Semler’s tes-
timony was sufficient to meet SAIF’s burden of production;
however, it found that Semler’s testimony was internally
inconsistent and, for that reason, failed to meet SAIF’s bur-
den of persuasion. It follows that this case does not pres-
ent the first issue that claimant and his amici raise. It only
presents the second.10
	         In explaining why we read the board’s order differ-
ently from the Court of Appeals, we begin by identifying the
legal standard that the board applied. In its order, the board
started its analysis by explaining, “We are not persuaded
* * * that Dr. Semler’s opinion satisfies SAIF’s ‘clear and con-
vincing’ burden.” The board explained why it was not per-
suaded and then concluded by stating, “In sum, after weigh-
ing the evidence, we find that SAIF has not established, by
clear and convincing evidence, that the cause of claimant’s
heart attack is unrelated to his employment.”
	        Taking the board at its word, we find it difficult
to say that the board did anything other than what ORS
656.802(4) directed it to do once claimant established, by
means of the firefighters’ presumption, that his atheroscle-
rosis “result[ed]” from his employment as a firefighter: The
board asked whether SAIF had persuaded it by clear and
convincing medical evidence that claimant’s atherosclerosis
was “unrelated” to his employment. The board neither said
nor intimated that only evidence of individual risk factors
unrelated to claimant’s work could be considered in finding
whether SAIF had met its burden of persuasion.
	10
       Even though this case does not require us to reach the first issue that
claimant raises, we note that the answer to that issue turns primarily on the
text, context, and legislative history of ORS 656.802(4). That is, whether ORS
656.802(4) limits the type of medical evidence that employers may use to rebut
the presumed fact is first and foremost a question of legislative intent. Cf. State v.
Stockfleth/Lassen, 311 Or 40, 50, 804 P2d 471 (1991) (explaining when cases from
other jurisdictions will be context that bears on a statute’s meaning).
Cite as 360 Or 155 (2016)	167

	       The Court of Appeals, however, reasoned that,
given Semler’s unrebutted testimony, the board must have
rejected that testimony because Semler had not identified
any individual risk factor (hypertension, diabetes, etc.) as
the cause of claimant’s condition. In our view, the Court of
Appeals gave too much credit to Semler and too little credit
to the board. Put differently, the board reasonably could
(and did) find that Semler’s report and his testimony were
not persuasive, without resorting to the legal rule that the
Court of Appeals attributed to it.
	        In explaining why we reach that conclusion, we
begin with Semler’s report. As discussed above, Semler
issued a written report in which he opined that firefighting
was not the major contributing cause of claimant’s athero-
sclerosis. The primary difficulty with Semler’s report is that
he asked and answered the wrong question. Because claim-
ant proved the predicate facts necessary to establish the
firefighter’s presumption, ORS 656.802(4) presumed that
his atherosclerosis “resulted from” his employment and was
an occupational disease. The question accordingly was not
whether claimant’s employment was the major contribut-
ing cause of his condition; it was whether his condition was
“unrelated to [his] employment.” ORS 656.802(4). Those are
two separate questions. The fact that claimant’s employ-
ment was not the major contributing cause of his condition,
as Semler concluded in his report, does not mean that his
condition was unrelated to his employment.11 For that rea-
son alone, the board reasonably could have discounted the
persuasive value of Semler’s report.
	        The board also had Semler’s testimony before it. As
noted, that testimony reduced to three propositions. The first
proposition that Semler identified—that the causes of ath-
erosclerosis are unknown—provides no persuasive evidence
	11
         The same problem filtered through Semler’s testimony. Not only did Semler
repeat once in his testimony before the ALJ that the medical literature did not
establish that firefighting was the major contributing cause of atherosclerosis,
but even his more carefully articulated conclusions suffered from a similar logi-
cal flaw. The fact that, as Semler repeatedly stated, the medical literature did not
prove that firefighting causes atherosclerosis does not necessarily mean that it
proves that firefighting is “unrelated” to atherosclerosis. The former proposition
may give rise to a weak inference of the latter, but Semler repeatedly appeared to
equate the two.
168	                                                    SAIF v. Thompson

that claimant’s condition was unrelated to his employment,
or so the board could find. As this court explained in Wright,
a diagnosis that a “claimant’s condition is ‘idiopathic,’ or of
unknown origin” is “simply a confession of an inability to
identify a cause of [the] claimant’s impairments rather than
evidence that [the] claimant’s condition or impairment is
unrelated to his [or her] employment.” 289 Or at 332 (empha-
sis in original).
	        The second proposition that Semler identified is
equally unavailing. As noted, Semler explained that cardiol-
ogists had identified some risk factors that are related to the
development of atherosclerosis.12 Semler testified, however,
that claimant did not exhibit those risk factors, which sim-
ply ruled out the possibility that those risk factors (rather
than claimant’s work) were the cause of his atherosclerosis.
The board reasonably could find that the second proposition
that Semler identified provided no persuasive evidence that
claimant’s condition was unrelated to his work. Contrary
to the Court of Appeals’ reasoning, we do not understand
the board, in ruling out those factors, to have held that only
those factors could be used to rebut the presumption that
claimant’s atherosclerosis resulted from his work.
	         Finally, Semler opined that atherosclerosis is unre-
lated to firefighting. In large part, Semler based that opinion
on the fact that he could not find in the medical literature a
proven connection between firefighting and atherosclerosis.
Even if we assume that Semler’s opinion was sufficient to
meet SAIF’s burden of production, the board was not per-
suaded by his opinion. As the board explained, Semler also
testified that the causes of atherosclerosis are not known.
The board reasoned that, if cardiologists cannot identify the
causes of atherosclerosis, as Semler testified, and if claim-
ant had no apparent risk factors that were unrelated to his
work, as Semler also testified, then the basis for Semler’s
opinion that claimant’s atherosclerosis was unrelated to his
work was not apparent and, for that reason, was not suffi-
ciently persuasive to meet SAIF’s burden of persuasion.

	12
        Sometimes, Semler referred to the factors as risk factors. Other times, he
referred to them as causes of atherosclerosis. Given his testimony that the etiol-
ogy of atherosclerosis is unknown, we refer to them as risk factors.
Cite as 360 Or 155 (2016)	169

	        As we read the board’s opinion, the board evaluated
the persuasive value of Semler’s opinion and found it lack-
ing. As the board explained, Semler’s opinion that athero-
sclerosis is unrelated to firefighting was at odds with his
testimony that the causes of atherosclerosis are unknown.
The latter testimony undercut the former, or so the board
reasonably could find. As a result, the board permissibly
concluded that SAIF had not met its burden of persuasion
by clear and convincing evidence. Contrary to the Court of
Appeals conclusion, we do not understand the board to have
sub silentio faulted SAIF for failing to prove that claimant’s
atherosclerosis was caused by individual risk factors (such
as diabetes, high blood pressure, and the like) unrelated to
his work.
	        SAIF, however, argues on review that Semler offered
a cogent and clear opinion, which “was legally sufficient to
rebut the presumption.” We assume that Semler’s opinion
met SAIF’s burden of production. However, we cannot say
that the board was required to conclude that Semler’s opin-
ion met SAIF’s burden of persuasion. There is a difference
between saying that there is sufficient evidence to permit
the board to find that SAIF met its burden of persuasion
and saying that the board was required to make that find-
ing. To put the point in a familiar context, there is a differ-
ence between saying that a party has put on sufficient evi-
dence to submit a claim to the jury and directing a verdict in
a party’s favor on that claim. In this case, even if we assume
that Semler’s testimony was sufficient to meet SAIF’s bur-
den of production, the board reasonably could find, for the
reasons the board stated, that Semler’s testimony did not
meet SAIF’s burden of persuasion.13 The Court of Appeals
erred in concluding otherwise.
	       The decision of the Court of Appeals is reversed.
The order of the Workers’ Compensation Board is affirmed.



	13
       It follows that we need not decide the first issue that claimant raises—
whether SAIF may rebut the firefighters’ presumption only with medical evidence
of individual risk factors unrelated to work—to resolve this case. We express no
opinion on that issue.
