Effect Size Basics: Understanding the Strength of a Program's Impact

Education research increasingly includes "effect sizes" in discussions of findings from studies of policies, practices, interventions, programs, services, and curricula. Accordingly, it is helpful for educators to understand the definition of effect size, what factors influence reported effect sizes, and how effect sizes can be interpreted. This infographic serves as a companion to the REL West guide, The Basics of Reviewing a Research Study, to assist state education agency staff, school district staff, and school staff as they review research to identify high-quality, evidence-based programs that meet their needs.