Authorities as the decision cited them, with how this panel applied each one.
Labor Code sections 5903, 5952(d); Lamb v. Workmen's Comp. Appeals Bd. (1974) 11 Cal.3d 274; Garza v. Workmen's Comp. Appeals Bd. (1970) 3 Cal.3d 312; LeVesque v. Workers' Comp. Appeals Bd.
A decision must be based on admitted evidence and supported by substantial evidence.
The decision must be supported by substantial evidence in the record.
From the decision · page 7A decision must be based on admitted evidence in the record and must be supported by
substantial evidence. (Lab. Code, § 5903, 5952(d); Lamb v. Workmen's Comp. Appeals Bd.
(1974) 11 Cal.3d 274, 281 [39 Cal.Comp.Cases 310]; Garza v. Workmen's Comp. Appeals Bd.
(1970) 3 Cal.3d 312, 317 [35 Cal.Comp.Cases 500]; LeVesque v. Workers' Comp. Appeals Bd.
McAllister v. Workers' Comp. Appeals Bd. (1968) 69 Cal.2d 408
Medical evidence that industrial injury was reasonably probable constitutes substantial evidence for injury AOE/COE.
Medical expert opinion is required to establish injury causation.
From the decision · page 8Medical evidence that industrial injury was reasonably probable, although not certain,
constitutes substantial evidence for a finding of injury AOE/COE. (McAllister v. Workers' Comp.
Appeals Bd. (1968) 69 Cal.2d 408, 417 [33 Cal.Comp.Cases 660].) Although the factual issue of
the occurrence of the alleged incident is a determination for the WCJ, the issue of injury is a
medical determination, which requires expert medical opinion. As the Court of Appeal explained
in Peter Kiewit Sons v. Industrial Acc. Com. (1965) 234 Cal.App.2d 831, 838 [30 Cal.Comp.Cases
188]: "Where an issue is exclusively a matter of scientific medical knowledge, expert evidence is
essential to sustain a [WCAB] finding; lay testimony or opinion in support of such a finding does
not measure up to the standard of substantial evidence. Expert testimony is necessary where the
truth is occult and can be found only by resorting to the sciences."
Peter Kiewit Sons v. Industrial Acc. Com. (1965) 234 Cal.App.2d 831
Expert medical opinion is essential where the issue is exclusively scientific medical knowledge.
Expert testimony is necessary to sustain a finding of injury.
From the decision · page 8Medical evidence that industrial injury was reasonably probable, although not certain,
constitutes substantial evidence for a finding of injury AOE/COE. (McAllister v. Workers' Comp.
Appeals Bd. (1968) 69 Cal.2d 408, 417 [33 Cal.Comp.Cases 660].) Although the factual issue of
the occurrence of the alleged incident is a determination for the WCJ, the issue of injury is a
medical determination, which requires expert medical opinion. As the Court of Appeal explained
in Peter Kiewit Sons v. Industrial Acc. Com. (1965) 234 Cal.App.2d 831, 838 [30 Cal.Comp.Cases
188]: "Where an issue is exclusively a matter of scientific medical knowledge, expert evidence is
essential to sustain a [WCAB] finding; lay testimony or opinion in support of such a finding does
not measure up to the standard of substantial evidence. Expert testimony is necessary where the
truth is occult and can be found only by resorting to the sciences."
Hegglin v. Workmen's Comp. Appeals Bd. (1971) 4 Cal.3d 162
Medical reports and opinions are not substantial evidence if based on erroneous facts, inadequate histories, or incorrect legal theories.
Medical opinions of record were found flawed due to lack of review of prior conditions and inadequate history.
From the decision · page 9"Medical reports and opinions are not substantial evidence if they are known to be
erroneous, or if they are based on facts no longer germane, on inadequate medical histories and
examinations, or on incorrect legal theories. Medical opinion also fails to support the Board's
findings if it is based on surmise, speculation, conjecture or guess." (Hegglin v. Workmen's Comp.
Appeals Bd. (1971) 4 Cal.3d 162, 169 [36 Cal.Comp.Cases 93].