The purpose of this study was to identify the factors that contributed to vocational rehabilitation assessment of earning capacity. Rehabilitation professionals who attended a national forensic rehabilitation conference were asked to rate the importance of 26 variables in development of opinions of earning capacity. Exploratory factor analysis revealed four themes in the responses: intrinsic characteristics of the worker, transferable skills components, worker traits, and labor market conditions. Multivariate analysis of variance found no significant differences in mean importance of the factors among forensic rehabilitation professionals practicing in different legal forums or in retention by plaintiff, defense, or neutral status, as well as no significant interactions. The results of this study will assist in the establishment of a standardized methodology for developing opinions of earning capacity consistent between forums of practice and competing parties in adjudication of vocational disability claims.