Expertise Ill-Defined: A Preliminary Exploration of Its Variability in Definition and Use in Research

While “expertise” is frequently used as a variable in human factors research, the criteria for defining this construct often lack clarity and consistency. This article briefly reviews common definitions of expertise and how it has been operationalized in research, highlighting the need for more nuanced categorization of expertise. We posit that expertise is multifaceted and propose a dichotomy that distinguishes “system expertise” from “task expertise,” with recency and frequency of task performance playing crucial roles alongside traditional metrics.