Main and interactive effects of weekly transformational and laissez‐faire leadership on followers’ trust in the leader and leader effectiveness

Leaders’ behaviour fluctuates over time, and leaders use different behaviours that impact their followers. Whereas transformational leadership is associated with positive outcomes, laissez‐faire leadership negatively affects followers. An important question that remains unanswered is how the joint use of both leadership behaviours relates to leader effectiveness. In this study, we answer this question by investigating the main and interactive effects of transformational and laissez‐faire leadership behaviours on perceived leader effectiveness. Specifically, we hypothesized that leaders are perceived as less effective by their followers when they use both transformational and laissez‐faire leadership, because it reduces followers’ trust in their leader. Data came from 59 employees who participated in a weekly diary study and provided 228 data points. Results showed that both weekly transformational and laissez‐faire leadership predicted trust in the leader assessed in the following week. Trust in the leader, in turn, positively predicted perceived leader effectiveness assessed one week later. Contrary to our predictions, we found that trust in the leader and perceived leader effectiveness were reduced when leaders showed a combination of less (−1 SD ) weekly transformational and more (+1 SD ) laissez‐faire leadership than usual. In the weeks that leaders showed more (+1 SD ) transformational leadership, followers had more trust in their leader and perceived their leader to be more effective regardless of the leader's use of laissez‐faire. These findings suggest that it is important to take interactions between different leadership behaviours into account when studying leadership effectiveness. Practitioner points Leaders should inspire, support, and intellectually challenge their followers on a weekly basis, because these transformational leadership behaviours enhance followers’ trust in the leader. Leaders should refrain from a passive approach towards their followers, especially in weeks when they do not show transformational leadership, because this approach reduces followers’ trust in the leader. Leaders use different leadership behaviours within the same week and the effects of these behaviours are rather short‐lived (i.e., within that week rather than across weeks). Followers’ trust in the leader positively predicts followers’ perceptions of leader effectiveness.