Beyond measuring average program impacts, it is important to understand how impacts vary. This paper gives a broad overview of the conceptual and statistical issues involved in using multisite randomized trials to learn about and from variation in program effects across individuals, across subgroups of individuals, and across program sites.
This paper provides a detailed discussion of the theory and practice of modern regression discontinuity. It describes how regression discontinuity analysis can provide valid and reliable estimates of general causal effects and of the specific effects of a particular treatment on outcomes for particular persons or groups.
This paper provides practical guidance for researchers who are designing studies that randomize groups to measure the impacts of educational interventions.