City of Philadelphia v. Workers' Compensation Appeal Board

OPINION

Justice ORIE MELVIN.

We granted review to determine whether an opinion rendered by a medical expert is sufficient to rebut the presumption of disease causation under the Pennsylvania Workers’ Compensation Act (“Act”), 77 P.S. §§ 1-1041.4; 2501-2626. For the reasons that follow, we hold that an expert’s opinion does not constitute substantial competent evidence where it is based on a series of assumptions that lack the necessary factual predicate. Since the medical opinion in the instant case is based upon unfounded supposition, it is legally insuffi cient to overcome the presumption of…