Regression Discontinuity Designs: A Guide to Practice
In Regression Discontinuity (RD) designs for evaluating causal effects of interventions, assignment to a treatment is determined at least partly by the value of an observed covariate lying on either side of a fixed threshold. These designs were first introduced in the evaluation literature by Thistlewaite and Campbell (1960). With the exception of a few unpublished theoretical papers, these methods did not attract much attention in the economics literature until recently. Starting in the late 1990s, there has been a large number of studies in economics applying and extending RD methods. In this paper we review some of the practical and theoretical issues involved in the implementation of RD methods.
This paper was prepared as an introduction to a special issue of the Journal of Econometrics on regression discontinuity designs. We are grateful for discussions with David Card and Wilbert van der Klaauw. Financial support for this research was generously provided through NSF grant SES 0452590 and the SSHRC of Canada. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research.