Authorities as the decision cited them, with how this panel applied each one.
Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604
A report must set forth reasoning in support of its conclusions to constitute substantial evidence.
Applied to evaluate the sufficiency of vocational expert reports and medical opinions.
From the decision · page 2To constitute substantial evidence, among other things, a report "must set forth reasoning
in support of its conclusions." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621
(Appeals Board en banc).) It is well established that in order to constitute substantial evidence, a
medical opinion must be predicated on reasonable medical probability. (McAllister v. Workmen's
Comp. App. Bd. (1968) 69 Cal.2d 408, 413, 416-417, 419 [33 Cal.Comp.Cases 660].) Also, a
medical report is not substantial evidence unless it sets forth the reasoning behind the expert's
opinion, not merely the conclusions. (Granado v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d
399, 407 [33 Cal.Comp.Cases 647].) "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].)
McAllister v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d 408
A medical opinion must be predicated on reasonable medical probability to constitute substantial evidence.
Applied to assess the validity of medical opinions in the Findings and Award.
From the decision · page 2To constitute substantial evidence, among other things, a report "must set forth reasoning
in support of its conclusions." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621
(Appeals Board en banc).) It is well established that in order to constitute substantial evidence, a
medical opinion must be predicated on reasonable medical probability. (McAllister v. Workmen's
Comp. App. Bd. (1968) 69 Cal.2d 408, 413, 416-417, 419 [33 Cal.Comp.Cases 660].) Also, a
medical report is not substantial evidence unless it sets forth the reasoning behind the expert's
opinion, not merely the conclusions. (Granado v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d
399, 407 [33 Cal.Comp.Cases 647].) "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].)
Granado v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d 399
Medical reports must set forth reasoning, not just conclusions, to be substantial evidence.
Applied to determine the evidentiary value of medical reports in the case.
From the decision · page 2To constitute substantial evidence, among other things, a report "must set forth reasoning
in support of its conclusions." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621
(Appeals Board en banc).) It is well established that in order to constitute substantial evidence, a
medical opinion must be predicated on reasonable medical probability. (McAllister v. Workmen's
Comp. App. Bd. (1968) 69 Cal.2d 408, 413, 416-417, 419 [33 Cal.Comp.Cases 660].) Also, a
medical report is not substantial evidence unless it sets forth the reasoning behind the expert's
opinion, not merely the conclusions. (Granado v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d
399, 407 [33 Cal.Comp.Cases 647].) "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 opinions based on surmise, speculation, conjecture or guess are not substantial evidence.
Applied to reject medical opinions lacking a proper evidentiary basis.
From the decision · page 2To constitute substantial evidence, among other things, a report "must set forth reasoning
in support of its conclusions." (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621
(Appeals Board en banc).) It is well established that in order to constitute substantial evidence, a
medical opinion must be predicated on reasonable medical probability. (McAllister v. Workmen's
Comp. App. Bd. (1968) 69 Cal.2d 408, 413, 416-417, 419 [33 Cal.Comp.Cases 660].) Also, a
medical report is not substantial evidence unless it sets forth the reasoning behind the expert's
opinion, not merely the conclusions. (Granado v. Workmen's Comp. App. Bd. (1968) 69 Cal.2d
399, 407 [33 Cal.Comp.Cases 647].) "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].)
Labor Code section 5313
Labor Code section 5313 requires a WCJ to state reasons or grounds for determinations.
Applied to require clear articulation of decision bases in the WCJ's opinion on decision.
From the decision · page 3Labor Code section 5313 requires a WCJ to state the "reasons or grounds upon which the
determination was made." The WCJ's opinion on decision "enables the parties, and the Board if
reconsideration is sought, to ascertain the basis for the decision, and makes the right of seeking
reconsideration more meaningful." (Hamilton v. Lockheed Corporation (Hamilton) (2001) 66
Cal.Comp.Cases 473, 476 (Appeals Board en banc), citing Evans v. Workmen's Comp. Appeals
Bd. (1968) 68 Cal.2d 753, 755 [33 Cal.Comp.Cases 350, 351].) A decision "must be based on
admitted evidence in the record" (Hamilton, supra, at p. 478), and 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].) As required by section 5313 and explained in Hamilton, "the WCJ is
Hamilton v. Lockheed Corporation (2001) 66 Cal.Comp.Cases 473
A decision must be based on admitted evidence and supported by substantial evidence.
Applied to ensure the WCJ's decision was supported by the record evidence.
From the decision · page 3Labor Code section 5313 requires a WCJ to state the "reasons or grounds upon which the
determination was made." The WCJ's opinion on decision "enables the parties, and the Board if
reconsideration is sought, to ascertain the basis for the decision, and makes the right of seeking
reconsideration more meaningful." (Hamilton v. Lockheed Corporation (Hamilton) (2001) 66
Cal.Comp.Cases 473, 476 (Appeals Board en banc), citing Evans v. Workmen's Comp. Appeals
Bd. (1968) 68 Cal.2d 753, 755 [33 Cal.Comp.Cases 350, 351].) A decision "must be based on
admitted evidence in the record" (Hamilton, supra, at p. 478), and 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].) As required by section 5313 and explained in Hamilton, "the WCJ is
Vocational evidence must be submitted to the physician for consideration and cannot substitute for medical apportionment.
Applied to clarify the role of vocational evidence in apportionment determinations.
From the decision · page 2In the en banc decision in Nunes v. State of California, Dept. of Motor Vehicles (June 22,
2023) 2023 Cal. Wrk. Comp. LEXIS 30 [88 Cal.Comp.Cases 741] ("Nunes I"), the Appeals Board
held that Labor Code section 4663 requires a reporting physician to make an apportionment
determination and prescribes the standard for apportionment, and that the Labor Code makes no
Kuykendall v. Workers' Comp. Appeals Bd. (2000) 79 Cal.App.4th 396
The Appeals Board has a constitutional mandate to ensure substantial justice and may require further evidence development.
Applied to justify remanding the case for further proceedings and evidence development.