Authorities as the decision cited them, with how this panel applied each one.
Hamilton v. Lockheed Corporation (2001) 66 Cal.Comp.Cases 473
Decisions of the Appeals Board must be based on admitted evidence in the record and supported by substantial evidence.
The Appeals Board reviewed the record and found the medical evidence insufficient to support the WCJ's decision.
From the decision · page 4Decisions of the Appeals Board "must be based on admitted evidence in the
record." (Hamilton v. Lockheed Corporation (Hamilton) (2001) 66 Cal.Comp.Cases 473, 476
(Appeals Board en banc).) The Appeals Board has a constitutional mandate to "accomplish
substantial justice" in all cases. (Kuykendall v. Workers' Comp. Appeals Bd. (2000) 79 Cal.App.4th
396, 403 [65 Cal.Comp.Cases 264].) The Board has "a duty to develop an adequate record" and
"it is well established that the WCJ or the Board may not leave undeveloped matters which its
acquired specialized knowledge should identify as requiring further evidence." (Id., at pp. 403-
404.)
E.L. Yeager Construction v. Workers' Comp. Appeals Bd. (2006) 145 Cal.App.4th 922
A medical opinion must be predicated on reasonable medical probability and disclose reasoning to constitute substantial evidence.
The Appeals Board emphasized that medical reports must include reasoning and not be based on speculation.
From the decision · page 4It is well established that decisions by the Appeals Board must be supported by substantial
evidence. (Lab. Code, § 5903, 5952(d); Lamb v. Workmen's Comp. Appeals Bd. (1974) 11 Cal.3d
274 [39 Cal.Comp.Cases 310]; Garza v. Workmen's Comp. Appeals Bd. (1970) 3 Cal.3d 312 [35
Cal.Comp.Cases 500]; LeVesque v. Workmen's Comp. Appeals Bd. (1970) 1 Cal.3d 627 [35
Cal.Comp.Cases 16].) To constitute substantial evidence "a medical opinion must be predicated
on reasonable medical probability." (E.L. Yeager Construction v. Workers' Comp. Appeals Bd.,
(2006) 145 Cal.App.4th 922, 928 [71 Cal.Comp.Cases 1687], citing McAllister v. Workmen's
Comp. App. Bd. (1968) 69 Cal.2d 408, 413, 416§ 417, 419.) A medical opinion "is not substantial
evidence if it is based on facts no longer germane, on inadequate medical histories or
examinations, on incorrect legal theories, or on surmise, speculation, conjecture, or guess." (Id.,
Labor Code section 4663
Apportionment of permanent disability must be based on causation and include approximate percentages of industrial and non-industrial causes.
The Appeals Board reviewed the requirements for apportionment under Labor Code section 4663.
From the decision · page 5Section 4663, regarding apportionment of permanent disability, provides, in relevant part:
(a) Apportionment of permanent disability shall be based on causation.
Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604
A physician's report must disclose familiarity with apportionment concepts and set forth the basis for the opinion to be substantial evidence.
The Appeals Board requires detailed explanation in apportionment reports to rely on them as substantial evidence.
From the decision · page 5To comply with section 4663, a physician's report in which permanent disability is
addressed must also address apportionment of that permanent disability. (Escobedo v. Marshalls
(Escobedo) (2005) 70 Cal.Comp.Cases 604 [2005 Cal. Wrk. Comp. LEXIS 71] (Appeals Bd. en
banc).) However, the mere fact that a physician's report addresses the issue of causation of
permanent disability and makes an apportionment determination by finding the approximate
respective percentages of industrial and non-industrial causation does not necessarily render the
report substantial evidence upon which we may rely. Rather, the report must "disclose familiarity
with the concepts of apportionment, describe in detail the exact nature of the apportionable
disability, and set forth the basis for the opinion, so that the Board can determine whether the
physician is properly apportioning under correct legal principles." (Id. at p. 621.)