Education research increasingly includes “effect sizes” in discussions of findings from studies of policies, practices, interventions, programs, services, and curricula.

This infographic offers an introduction to effect size, discusses what factors influence reported effect sizes, and identifies how effect sizes can be interpreted to inform decisions.

It also 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.