A Systematic Literature Review of Causal Mediation Analysis in Social Psychology

Mediation analysis has been widely used in social psychology to investigate the mechanisms linking independent and dependent variables. However, conducting a proper mediation analysis is challenging, as its causal interpretation requires strong assumptions and careful study design. This systematic literature review examined mediation studies published in the Journal of Personality and Social Psychology and provides recommendations for applied researchers conducting causal mediation analysis. Results revealed a near-exclusive reliance on linear regression frameworks, with no study incorporating treatment and mediator interactions or distinguishing between causally defined natural and controlled direct effects. Only a few studies conducted sensitivity analyses. Temporal ordering was also inconsistently reported, and in rare cases the order of mediator and dependent variable was reversed, raising concerns about the validity of the mediation model. These patterns highlight a persistent gap between methodological recommendations and current research practices. We provide recommendations to strengthen study design, clarify assumptions, and adopt more rigorous analytic strategies to enhance the credibility of mediation research.