This chapter highlights the significance of impact measurement in informing strategic decisions in education. It presents impact assessments as tools for measuring change and providing insights that influence planning, resource allocation, and policy decisions. Key principles include setting impact-oriented goals aligned with priorities, selecting relevant indicators, and ensuring data transparency to build trust and support informed decision-making. A seven-question framework clarifies the purpose, scope, method, timing, interpretation, and application of assessments, ensuring they address both immediate and long-term needs. Examples show how various evaluation methods—quantitative, qualitative, and mixed—are suitable for specific decision contexts. The chapter stresses translating findings into clear, actionable decisions through effective communication, transparency, and fostering a culture that values evidence. It advocates for impact assessments that are closely linked to decision-making processes, driving meaningful institutional change.