Program Evaluation With Nonexperimental Data

Statistical methods for program evaluation with nonexperimental data have been studied by economists and econometricians over the last 20 years. These methods are concerned with laying out the precise circumstances under which valid nonexperimental estimates of the effects of an intervention can be obtained, and then with methods for determining when and if those circumstances hold. This article provides a simple exposition of the methods of identification that have been developed and draws the lessons of those methods for future evaluation designs, data collection, and analysis.