The present article considers a fundamental question in evaluation research: "By how much do program effects vary across sites?" The article first presents a theoretical model of cross-site impact variation and a related estimation model with a random treatment coefficient and fixed site-specific intercepts. This approach eliminates…

A fundamental issue for theories of human induction is to specify constraints on potential inferences. For inferences based on shared category membership, an analogy, and/or a relational schema, it appears that the basic goal of induction is to make accurate and goal-relevant inferences that are sensitive to uncertainty. People can use source…

Individual differences in response to a given treatment have been a longstanding interest in education. While many evaluation studies focus on average treatment effects (i.e., the effects of treatments on the levels of outcomes of interest), this paper additionally considers estimating the effects of treatments on the dispersion in outcomes.…