Meta-analysis can be used to estimate the true magnitude of the role of transformational leadership in performance and its generalizability across studies in several ways. First, at the most basic level, meta-analysis allows us to estimate the more precise magnitude of the relationship between transformational leadership and follower individual performance than any of the primary studies included in the meta-analysis. While theory suggests that transformational leadership is associated with higher levels of performance from followers, prior meta-analyses have provided limited information about the size of this relationship.
Thus, the first purpose of our article is to provide a more precise estimate of the relationship between transformational leadership and follower individual performance and to examine the generalizability of this relationship across settings. Second, when Bass (1985) initially suggested that transformational leadership motivates followers to perform beyond expectations, researchers were only beginning to differentiate between various types of performance criteria (Austin & Villanova, 1992). Thus, the exact meaning of performance beyond expectations was not clearly specified.
On one hand, transformational leadership may motivate followers to work harder, exerting more effort than would be expected from transactional leadership and resulting in higher levels of task performance. On the other hand, Podsakoff, MacKenzie, and Bommer (1996) have proposed that transformational leadership motivates followers to go beyond the minimum requirements of their job descriptions, resulting in higher levels of contextual performance. Finally, the focus of transformational leaders on challenging the status quo suggests that performance beyond expectations may result in higher levels of creativity and innovation among followers.
Despite the fact that primary studies have examined the relationship of transformational leadership with task, contextual, and creative performance, none of the prior meta-analyses on transformational leadership have estimated the magnitude of these relationships. Thus, the second purpose of our meta-analysis is to investigate the relative impact of transformational leadership on follower task, contextual, and creative performance. Third, transformational leadership theory suggests that transformational leadership is related not only to individual follower performance but also to erformance at the group and organization levels (Bass, 1985; Conger & Kanungo, 1998; Shamir, House, & Arthur, 1993). However, no previous meta-analysis has provided a comparison of the relationship of transformational leadership with performance at all three levels. DeGroot et al. (2000) provided initial evidence that transformational leadership is positively related to team performance, but this analysis was based on a limited number of primary studies on team performance (k = 7).
Judge and Piccolo (2004) identified a larger number of primary studies examining the relationship between transformational leadership and performance at the group and organizational levels (k = 41), but they combined these studies in Downloaded from gom. sagepub. com at PORTLAND STATE UNIV on December 5, 2012 Wang et al. 229 their meta-analysis, reporting the relationship between transformational leadership and group/organization performance. However, individual, group, and organization performance is likely influenced by different factors and through different mechanisms (Dansereau, Cho, & Yammarino, 2006).
As a result, the magnitude of the relationships of transformational leadership with performance at the three levels of analysis may differ (Yammarino et al. , 2005). Thus, a third purpose of our study is to estimate and compare the relationship of transformational leadership with individual, group, and organization performance. Finally, one of the most interesting theoretical claims of Bass (1997) is that transformational leadership has one-way augmentation effects over transactional leadership.
That is, transformational leadership is hypothesized to predict follower performance beyond the effects of transactional leadership. Yet this proposition has not been systematically examined in predicting follower performance across performance criteria and levels of analysis. A small number of primary studies by Bass and his colleagues (Bass, Avolio, Jung, & Berson, 2003; Howell & Avolio, 1993) examined and found support for the augmentation effects at the group and organizational levels. Furthermore, Judge and
Piccolo (2004) showed that transformational leadership had an augmentation effect on employee attitudes over contingent reward but no effect on leader job performance, suggesting the existence of possible boundary conditions of the augmentation hypothesis. Judge and Piccolo did not test the augmentation hypothesis for follower performance. Accordingly, the generalizability of the augmentation effect remains unclear across levels of analysis and across various performance criteria (task and contextual performance).
Thus, the fourth purpose of our research, testing the generalizability of the augmentation effect, will allow us to not only test the overall validity of transformational leadership but also potentially make critical refinements to the theory. In sum, after decades of research on transformational leadership, the number of primary studies that link transformational leadership and performance is sufficient to allow us to better understand this relationship across criterion type and levels of analysis.
This research has the potential to clarify the precise ways in which transformational leadership impacts performance and may increase the practical utility of transformational leadership theory (Corley & Gioia, 2011). Moreover, by comparing the relative effects of transformational and transactional leadership on different types and levels of performance, we can learn more about how these two types of leadership may work together to facilitate both effective performance across types and levels. Downloaded from gom. sagepub. com at PORTLAND STATE UNIV on December 5, 2012 30 Group & Organization Management 36(2) Hypotheses Transformational Leadership and Follower Performance at the Individual Level According to Bass (1985), transformational leaders exhibit four primary behaviors. First, through the behavior of inspirational motivation, transformational leaders develop and articulate a shared vision and high expectations that are motivating, inspiring, and challenging. Second, transformational leaders exhibit the behavior of idealized influence, serving as a role model by acting in ways that are consistent with the articulated vision.
Third, transformational leaders intellectually stimulate their followers to challenge existing assumptions and solicit followers suggestions and ideas. Finally, through the behavior of individualized consideration, transformational leaders attend to the needs of their followers and treat each follower as a unique individual, thereby fostering feelings of trust in and satisfaction with the leader (Podsakoff, MacKenzie, Moorman, & Fetter, 1990). Taken together, these transformational leadership behaviors are expected to motivate followers to perform at higher levels.