This document discusses the multi-year partnership approach of Partners in School Innovation to transform low-performing schools. It focuses on building adult capacity in three domains - results-oriented leadership, systems for professional learning, and strengthening the core instructional program. The organization works shoulder-to-shoulder with school staff for 3-5 years to develop these areas through continuous support and monitoring of implementation. The report then describes results from three schools that partnered with the organization, finding improvements in two schools that confirm the theory of impact but mixed results in one school despite implementing the approach comprehensively.