This article describes the analysis of regression-discontinuity designs (RDDs) using the R packages rdd, rdrobust, and rddtools. We discuss similarities and differences between these packages and provide directions on how to use them effectively. We use real data from the Carolina Abecedarian Project to show how an analysis of an RDD can be…

Notes that the article reviewed contributes to the expanding literature on noncompliance by explicating the assumptions involving covariates that can be used to identify maximum likelihood estimates in place of exclusion restrictions. Notes points that require further discussion. (SLD)