Escobedo — how-and-why apportionment

How later panels applied it

Newest released decisions whose legal-standard extraction named this holding. Each quotes the passage and links to the official PDF. The leading case is cited the way courts cite it; our own cards stay ADJ, date, and issue. Litigated tail — not a win rate.

• ADJ20322653 · 2026-10-16 · Santa Rosa OfficeEscobedo

  Determinative passage · p.16(Bolton) (1983) 34 Cal.3d 159 [48 Cal.Comp.Cases 566].) To constitute substantial evidence “…a medical opinion must be framed in terms of reasonable medical probability, it must not be speculative, it must be based on pertinent facts and on an adequate examination and history, and it must set forth reasoning in support of its conclusions.” (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board 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.

  The Appeals Board must judge the weight and credibility of medical opinions based on their factual basis.

  Official decision · page 16 →
• ADJ19474979 · 2026-10-16 · Sacramento District OfficeEscobedo

  Determinative passage · p.8In addition to the analyses offered by the WCJ, we offer the following. To constitute substantial evidence “… a medical opinion must be framed in terms of reasonable medical probability, it must not be speculative, it must be based on pertinent facts and on an adequate examination and history, and it must set forth reasoning in support of its conclusions.” (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board en banc).) Dr. Piciucco’s reporting is framed in terms of reasonable medical probability, is not speculative, is based on pertinent facts and on an adequate examination and history, and sets forth reasoning in support of its conclusions. As the WCJ observed, applicant presented no alternative, substantial medical evidence finding industrial psychiatric injury. Furthermore, the parties presumably choose an AME because of the AME’s expertise and neutrality. (Power v.

  Applied to evaluate Dr. Piciucco's reports as substantial medical evidence.

  Official decision · page 8 →
• ADJ10737010 · 2026-10-14 · Marina del Rey District OfficeEscobedo

  Determinative passage · p.13Specifically, applicant argues that his preexisting osteoarthritis of the right hip cannot support apportionment because there is no evidence that he would have required hip replacement surgery in the absence of industrial injury. In Escobedo the Appeals Board held that (1) section 4663 requires the reporting physician to make an apportionment determination; (2) apportionment to other factors allows apportionment to causation, including pathology, prior conditions, and retroactive work restrictions; (3) applicant holds the initial burden to prove industrial injury and also has the added burden of establishing the approximate percentage of permanent disability directly related to the industrial injury; (4) defendant has the burden of establishing the approximate permanent disability caused by other factors; and (5) a medical report addressing apportionment may not be relied upon unless it constitutes substantial evidence.

  Applied to evaluate medical evidence on apportionment and permanent disability.

  Official decision · page 13 →
• ADJ8492544 · 2026-09-29 · Salinas District OfficeEscobedo

  Determinative passage · p.9We cannot emphasize enough that to constitute substantial evidence “…a medical opinion must be framed in terms of reasonable medical probability, it must not be speculative, it must be based on pertinent facts and on an adequate examination and history, and it must set forth reasoning in support of its conclusions.” (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board en banc), (emphasis added).) The term ‘synergy’ is not a “magic word” that immediately rebuts the use of the CVC. Instead, a physician must set forth a reasoned analysis explaining how and why synergistic ADL overlap exists. If parties are searching for a magic word to use during a doctor’s deposition, that word is “Why?”. Rather than focusing on whether a specific term, including the term synergy, was used, it is imperative that parties focus on an analysis that applies critical thinking based on the principles articulated in Escobedo to support a conclusion based on the facts of the case. Such an analysis must include a detailed description of the impact of ADLs and how those ADLs interact.

  Applied to evaluate the sufficiency of QME opinions on industrial causation of diabetes and sleep loss.

  Official decision · page 9 →
• ADJ7316783 · 2026-09-24 · Goleta District OfficeEscobedo

  Determinative passage · p.16on an adequate examination and history, and it must set forth reasoning in support of its conclusions.” (Escobedo v. Marshalls (2005) 70 Cal.Comp.Cases 604, 621 (Appeals Board en banc).) “When the foundation of an expert’s testimony is determined to be inadequate as a matter of law, we are not bound by an apparent conflict in the evidence created by his bare conclusions.” (People v. Bassett (1968) 69 Cal.2d 122, 139.) In this case, QME Dr. Stanwyck has failed to assign applicant with any psychiatric work restrictions. In the alternative, Dr. Stanwyck discussed diminished and/or reduced ability to function. Work restrictions are not the same as diminished and/or reduced ability to function. Furthermore, the medical-legal opinions on CVC rebuttal do not constitute substantial medical evidence. To date, Dr. Ovadia continues to defer to Dr.

  Applied to assess the sufficiency of medical-legal opinions in the case.

  Official decision · page 16 →
• ADJ17215880 · 2026-09-18 · Goleta District OfficeEscobedo

  Determinative passage · p.5Marshalls (2005) 70 Cal.Comp.Cases 604, 611 (Appeals Board en banc).) The mere fact that a medical report assigns approximate percentages of industrial and nonindustrial causation does not make the report reliable medical evidence by itself. (E.L. Yeager Construction v. Workers' Comp. Appeals Bd. (Gatten) (2006) 145 Cal.App.4th 922, 927–928 [71 Cal.Comp.Cases 1687].) 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 that factors other than the industrial injury at issue caused permanent disability. (Escobedo, at p.

  The QME's opinion was found not to be substantial evidence because it relied on probability and mathematical division without adequate medical or factual support.

  Official decision · page 5 →
• ADJ6958667 · 2026-09-11 · Van Nuys District OfficeEscobedo

  Determinative passage · p.6Pursuant to Labor Code Section 4663, Defendant bears the burden of proving apportionment with substantial evidence. Under Escobedo v. Marshalls (2005) 70 CCC 604, such burden is met if apportionment is supported by substantial medical evidence that explains how and why nonindustrial factors caused a percentage of the applicant's permanent disability. A medical opinion based on materially inaccurate or unresolved historical facts is not substantial evidence. In Pan Pacific Printing Press, Inc. v. WCAB (Whitt) (2016) 81 CCC 744 (writ denied), the QME report could not be relied upon for conclusions dependent on the inaccurate history that applicant had no prior back symptoms. Specifically, in the case of Whitt, "the WCAB explained in its decision that Dr. Broderick's conclusion that Applicant suffered a specific injury on 1/4/2012 was not substantial evidence because it was based on an incorrect history of no prior back injury." Here, Defendant contends that the court erred in declining to apply a 10% non-industrial apportionment based upon the opinions of Dr. Bertoldi and Dr. Sones, which opine that 10% of Applicant's permanent disability should be apportioned to non-industrial factors.

  Defendant failed to meet burden due to inconsistent applicant history and speculative medical opinions.

  Official decision · page 6 →
• ADJ12141593 · 2026-09-11 · Los Angeles District OfficeEscobedo

  Determinative passage · p.10whether it developed from a congenital, developmental, pathological, or traumatic source. (Franklin, supra, at p. 238; see Escobedo v. Marshalls, CNA Ins. Co., (2005) 70 Cal.Comp.Cases 604, 619 (citing Subsequent Injuries Fund v. Workmen's Comp. Appeals Bd. (Talcott) (1970) 2 Cal.3d 56, 62 [35 Cal.Comp.Cases 80].) The first question before us, then, is whether applicant presented substantial medical evidence of preexisting permanent disability under these authorities. (Todd, supra.) To constitute substantial evidence "… a medical opinion must be framed in terms of reasonable medical probability, it must not be speculative, it must be based on pertinent facts and on an adequate examination and history, and it must set forth reasoning in support of its conclusions." (Escobedo, supra.) "Medical opinion … 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, 97].) In this regard, the parties framed the issues for trial to include whether apportionment applies to the 35% or 5% threshold and whether applicant had preexisting permanent disability of unspecified body parts 2 instead of applying the Todd analytical framework. (Minutes of Hearing (Reporter), August 5, 2025, p.

  The Board found Dr. Cortes's opinion met this standard and Dr. Minkstein's did not.

  Official decision · page 10 →