Mau, Peter2020-11-172020-11-172020-08https://hdl.handle.net/11299/217141University of Minnesota Ph.D. dissertation. July 2020. Major: Organizational Leadership, Policy, and Development. Advisor: Kyla Wahlstrom. 1 computer file (PDF); vi, 128 pages.This study investigated the impact of principal professional development on leaders’ self-efficacy in four domains of school leadership: Setting Directions, Developing People, Redesigning the Organization, and Managing the Instructional Program. Subjects in this study had participated in an 18-month principal leadership academy, with some of them also receiving coaching. In addition, this study sought to understand the relationships among principal self-efficacy, principal collective efficacy, and the possible effect of having fellow principals in a district previously participate in the principal leadership development academy. Evidence of impact was collected via a post hoc survey of principals who were past participants in Minnesota Principals Academy (MPA). The survey assessed their efficacy before and after the academy experience. In addition, individual interviews were conducted with a small purposive sample of academy participants. Respondents reported statistically significant higher levels of self-efficacy related to all four domains of school leadership after participating in MPA. Additionally, the effect size for the growth in principal self-efficacy was very large. Further, design elements such as a cohort-model and having a high-quality, research-based curriculum were critical components in supporting their growth. Findings from this study also show that critical colleagues (both within the cohort and from outside the cohort) supported growth in principal self-efficacy. Finally, this study also revealed a weak relationship between principal self-efficacy and principal collective efficacy, even when more than half the principals in a district had previously participated in MPA.enPrincipal leadershipPrincipal professional developmentPrincipal self-efficacyThesis or Dissertation