New Leaders is a nonprofit organization with a mission to ensure high academic achievement for all students by developing outstanding school leaders to serve in urban schools. Its premise is that a combination of preparation and improved working conditions for principals, especially greater autonomy, would lead to improved student outcomes. Its approach involves both preparing principals and partnering with school districts and charter management organizations (CMOs) to improve the conditions in which its highly trained principals work. As part of the partnerships, New Leaders agrees to provide carefully selected and trained principals who can be placed in schools that need principals and to provide coaching and other support after those principals are placed. The districts and CMOs agree to establish working conditions that support, rather than hinder, the principals' efforts to improve student outcomes. This report describes how the New Leaders program was implemented in partner districts, and it provides evidence of the effect that New Leaders has on student achievement. [The research in this report was produced within RAND Education. For the appendices that accompany this report, see ED561154. For the research brief, "Principal Preparation Matters: How Leadership Development Affects Student Achievement. Research Brief," see ED561155.]