A Practical Guide to Causal Mediation Analysis: Illustration With a Comprehensive College Transition Program and Nonprogram Peer and Faculty Interactions

Abstract

Experimental and quasi-experimental designs have been increasingly employed in education. Mediation analysis has long been used to measure the role of mediators. Causal mediation analysis provides a modern approach to evaluate potential causal roles of mediators. Compared with conventional mediation analysis, causal mediation analysis has several advantages, e.g., by enabling us to evaluate necessary assumptions to establish a valid causal role of the mediator of interest. Despite these advantages and the availability of various software programs, causal mediation analysis has not been employed frequently in educational research. In this paper, we provide a step-by-step guide to causal mediation analysis using the free R package mediation in order to promote the more frequent application of causal mediation analysis in education, with an accessible data example from a Comprehensive College Transition Program (CCTP).