In public schools across the country, student needs are both diversifying and intensifying. At the same time, public school districts are facing increasing resource constraints, including declining enrollment, teacher workforce shortages, and reduced federal funding. These conditions make the need to prioritize the most effective strategies for improving student outcomes more pressing than ever. In the traditional, siloed budgeting approach, leaders reduce existing spending without considering the cost, the impact, or how the pieces fit together at the school level. This approach no longer suffices--if it ever did. Districts need a new approach that centers evidence-based strategies, school-level coherence, and optimized spending. The System Strategy Return on Investment (SSROI) approach supports systems leaders in making strategic decisions about resource allocation and system organization. This report presents a guide to a systems strategy approach.