The job of the school principal has become much more complex and demanding over the past several decades. Many university-based principal preparation programs--which prepare the majority of school principals--have struggled with how to make the fundamental changes needed to prepare principals for today's schools. To test a path forward, The Wallace Foundation provided grants to seven universities and their partners to redesign their principal preparation programs in line with research-supported practices. This targeted report shares findings from the RAND Corporation's five-year study of The Wallace Foundation's University Principal Preparation Initiative (UPPI), with an emphasis on findings for other principal preparation programs. [For "Redesigning University Principal Preparation Programs: A Systemic Approach for Change and Sustainability--Report in Brief. RAND Principal Preparation Series. Volume 3, Part 2. Research Report. RR-A413-4," see ED620468.]