Exploring systematic and unsystematic change of dynamic leader behaviours: a weekly diary study on the relation between instrumental leadership, stress, and health change

Diary studies in the leadership literature have linked leader behaviours to several outcomes of followers. As a side effect, they demonstrated that leaders show a certain degree of dynamism of their behaviours across time. Building on conservation of resources theory, we put leader dynamism and its influence on followers into focus and develop a theoretical model integrating two forms of dynamic instrumental leadership - systematic and unsystematic leadership change - to explore how these two forms of leadership dynamism are related to linear change of followers' stress and health over time. It is also tested whether these relationships are moderated by workload change. We collected data from 234 employees over nine weeks (N = 2,327 measurement points) in a weekly diary study. Results showed that systematic instrumental leadership change was positively related to health change, but not to stress change. Unsystematic instrumental leadership change was neither related to linear change in stress nor health. Different forms of workload change moderated the relation between both components of leadership change with stress and health. Our work provides answers to detrimental effects of dynamic leader behaviours on health-related follower outcomes over time by highlighting the dynamism of these relationships.