In a traditional regression-discontinuity design (RDD), units are assigned to treatment on the basis of a cutoff score and a continuous assignment variable. The treatment effect is measured at a single cutoff location along the assignment variable. This article introduces the multivariate...

This paper analyzes 12 recent within-study comparisons contrasting causal estimates from a randomized experiment with those from an observational study sharing the same treatment group. The aim is to test whether different causal estimates result when a counterfactual group is formed, either...

Since 1980, the number of state pre-kindergarten (pre-K) programs has more than doubled, with 38 states enrolling more than one million children in 2006 alone. This study evaluates how five state pre-K programs affected children's receptive vocabulary, math, and print awareness skills. Taking...

This paper reviews the literature on whether regression-discontinuity studies reproduce the results of randomized experiments conducted on the same topic. After briefly reviewing the regression-discontinuity design and its history, we explicate the general conditions necessary for a strong test...