E.L. Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922
Substantial medical evidence must be based on reasonable medical probability, adequate examination and history, and not be speculative or erroneous.
Medical reports and opinions must be reliable and supported by reasoning to constitute substantial evidence.
From the decision · page 7Medical evidence is required if there is an issue regarding the compensability of the claim.
(Lab. Code, § 4060(c)(d), 4061(i), 4062.3(l).) A medical opinion must be framed in terms of
reasonable medical probability, it must be based on an adequate examination and history, it must
not be speculative, and it must set forth reasoning to support the expert conclusions reached. (E.L.
Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 928
[71 Cal.Comp.Cases 1687]; Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 620-621
(Appeals Bd. en banc).) "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].)
Hegglin v. Workmen's Comp. Appeals Bd. (1971) 4 Cal.3d 162
Medical opinion fails to support findings if based on surmise, speculation, conjecture or guess.
Medical opinions must not be speculative or conjectural to be substantial evidence.
From the decision · page 7Medical evidence is required if there is an issue regarding the compensability of the claim.
(Lab. Code, § 4060(c)(d), 4061(i), 4062.3(l).) A medical opinion must be framed in terms of
reasonable medical probability, it must be based on an adequate examination and history, it must
not be speculative, and it must set forth reasoning to support the expert conclusions reached. (E.L.
Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 928
[71 Cal.Comp.Cases 1687]; Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 620-621
(Appeals Bd. en banc).) "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].)