Resolving the Tension between Vertical and Shared Leadership in Construction Project Teams: A Congruence Perspective

Many existing studies have separately explored the effectiveness of vertical leadership (VL) and shared leadership (SL) in project teams. Despite the growing dual emphasis on VL and SL in the contemporary construction practice, little is known about whether and how these two mutually exclusive sources of leadership synergistically function. Grounded in social information processing theory, this study examines how VL and SL jointly affect project performance through a congruence framework. The proposed theoretical model is tested using two-wave time-lagged data from construction projects, employing polynomial regression and response surface analysis methods. The results indicate that the congruence of VL and SL leads to higher project performance compared to incongruence. Overall, project performance shows an upward trend as the level of VL-SL congruence increases. Intriguingly, the combination of low VL and high SL produces higher project performance than high VL and low SL, contrary to the assumption. This study further confirms that job crafting can transform the congruence of VL and SL into project performance. Additionally, as task uncertainty increases, the positive impact of VL-SL congruence on project performance is significantly amplified. These findings bridge the two streams of research on VL and SL, and offer informative insights on the effectiveness of the paradoxical leadership approach (i.e., simultaneously engaging VL and SL) in engineering project practice.