Interpreting Effect Sizes of Education Interventions

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Researchers commonly interpret effect sizes by applying benchmarks proposed by Cohen over a half century ago. However, effects that are small by Cohen’s standards are often large in the context of field-based education interventions. This focus on magnitude also obscures important differences in study features, program costs, and scalability. In this paper, I propose a new framework for interpreting effect sizes of education interventions, which consists of five broadly applicable guidelines and a detailed schema for interpreting effects from causal studies with standardized achievement outcomes. The schema introduces new effect-size and cost benchmarks, while also considering program scalability. Together, the framework provides scholars and research consumers with an empirically-based, practical approach for interpreting the policy importance of effect sizes from education interventions.