Natural and Quasi- Experiments in Economics
Bruce D. Meyer
University of Chicago - Irving B. Harris Graduate School of Public Policy Studies; National Bureau of Economic Research (NBER)
NBER Working Paper No. t0170
Using research designs patterned after randomized experiments, many recent economic studies examine outcome measures for treatment groups and comparison groups that are not randomly assigned. By using variation in explanatory variables generated by changes in state laws, government draft mechanisms, or other means, these studies obtain variation that is readily examined and is plausibly exogenous. This paper describes the advantages of these studies and suggests how they can be improved. It also provides aids in judging the validity of inferences they draw. Design complications such as multiple treatment and comparison groups and multiple pre- or post-intervention observations are advocated.
Number of Pages in PDF File: 44
Date posted: May 25, 2006