Understanding Variation in Treatment Effects in Education Impact Evaluations: An Overview of Quantitative Methods.

Variation in treatment effects has important implications for education practice—and for facilitating the most efficient use of limited resources—by informing decisions about how best to target interventions and how to improve the design or implementation of interventions. Understanding variation in effects is also critical to assessing how study findings may be generalized to other education environments. A new report, co-authored by Mathematica's education experts, can help researchers understand which methods to use to examine how much treatment effects vary across students, educators, and sites. The report summarizes the complex research literature on quantitative methods for assessing variation in treatment effects and provides technical guidance about the use and interpretation of these methods.