TY  - JOUR
AU  - Meyer,Bruce D.
TI  - Natural and Quasi- Experiments in Economics
JF  - National Bureau of Economic Research Technical Working Paper Series
VL  - No. 170
PY  - 1994
Y2  - December 1994
UR  - http://www.nber.org/papers/t0170
L1  - http://www.nber.org/papers/t0170.pdf
N1  - Author contact info:
Bruce D. Meyer
Harris School of Public Policy
University of Chicago
1155 E. 60th Street
Chicago, IL 60637
Tel: 773/702-2712
Fax: 773/702-0926
E-Mail: bdmeyer@uchicago.edu
AB  - 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.
ER  -