TABLE 9-1: REVIEW OF EMPIRICAL STUDIES ON (SHARED) LEADERSHIP IN TEAMS
Avolio et al. (1996) studied the relationship between leadership behavior performed by the team as a
whole and team effectiveness. Later studies (Ensley et al., 2006; Pearce & Sims, 2002; Pearce et al.,
2003; Sivasubramaniam et al., 2002) applied similar research designs. Most studies used survey
methods to measure leadership behaviors at the level of the team. The primary aim was to differentiate
the impact of vertical and shared leadership on team effectiveness. Pearce and Sims (2002) for
instance, found that for teams, dealing with change management, shared leadership held more
explanatory value than vertical leadership. They defined vertical leadership as leadership behavior
performed by the formal team leader. Shared leadership was defined as a form of distributed
leadership that emerges from team dynamics. The empirical findings showed that shared leadership
had a strong impact on perceived team effectiveness. Moreover, vertical leadership also played an
important role, suggesting that these two alternate sources of leadership are not mutually exclusive but
rather can be perceived as complementary. Ensley et al. (2006) analyzed the role of vertical and
shared leadership within two different samples of startup firms. Their results showed that shared
leadership among top management team members held more explanatory variance for performance