More Illusion Than Reality? A Review of the State of Research on the Causal Effects of Servant Leadership, Recommendations, and an Exemplary Study

Causality is essential in informing science and policy. In the present study, we investigate the current state of research regarding causality in the field of servant (and authentic) leadership and provide recommendations on how causally identified studies can be conducted. After explaining the methodological problems that potentially prevent causal inferences (i.e., endogeneity bias and issues in experimental design), we provide two systematic literature reviews of servant and authentic leadership showing that these problems remain very prevalent. We then discuss two solutions on how causal effects of servant leadership or perceptions thereof can be established: randomized experiments and instrumental variable regression. To illustrate our recommendations, we report an experiment on the effect of a combination of two servant leadership dimensions (i.e., stewardship and authenticity) on follower performance and also investigate the effect of combined stewardship and authenticity perceptions using instrumental variable regression. The results do not indicate that combined stewardship and authenticity behavior or perceptions affect follower performance. Our study can serve as a roadmap, especially for servant leadership researchers, to address potential endogeneity and conduct causally identified research.