Two factors of expertise? Excellence and professionalism of environmental experts

The aim of this article is to empirically clarify factors and conditions of expertise. In addition to the core concept of expertise as excellence, a second factor needs to be taken into account: professionalism, or professional engagement. This hypothesis was tested and confirmed using data obtained from a survey on Swiss environmental professionals (n = 3514). The empirical test was based on factor analyses (Study 1) and a structural equation model (Study 2). The expertise scale consisted of nine items for self‐assessed perceived expertise amongst professional peers (α = .78). Excellence turned out to be a logarithmic function of years of practice (Study 3). Professionalism prevailed in domains where standards for best practices still needed to be established (Study 4).