The purpose of these three parallel mixed method studies was to measure the effectiveness of an urban school district's 2011 Preparing New Principals Program (PNPP). Results supported the premise that preparing principals for school leadership in 2013 must develop them as instructional leaders who can improve teacher performance and student achievement. The recommendations are useful to any school district or institution of higher education implementing leader preparation programs. Improvements to principal preparation programs supported by the results of these studies include a longer principal internship, a strong mentor relationship with an effective principal, a structured process of initial entry into the program, differentiated principal preparation experiences, and an increased focus on teacher effectiveness.