Studies in medical education can serve a variety of purposes. Studies that have a predominantly quantitative orientation may focus on estimating relations between variables, on estimating effects of one or more variables on some other variable(s), or on series of causal relations or mechanisms. Which is the focus of a particular study depends on the theoretical framework and research questions of that study. However, theory is of fundamental importance to medical education research, and studies focusing on series of causal relations or mechanisms can contribute greatly to the advancement of medical education research. This paper presents the potential benefits which result from adopting a path analysis perspective on the estimation of causal relations and conceptualization of mechanisms in medical education research.