Most evaluations of education policies focus on their mean impacts; when distributional effects are investigated it is usually by comparing mean impacts across demographic subgroups. We argue that such estimates may overlook important treatment effect heterogeneity; in order to appreciate the full extent of a policy's distributional impacts one…

We discuss the evidence on the effectiveness of preschool programs using results from three well-known intervention studies: the Chicago Child-Parent Centers, High/Scope Perry Preschool Program, and the Carolina Abecedarian Project. Results from cost-benefit analyses of other programs for younger and older children also are reported. Given that…