TY  - JOUR
AU  - Ichimura,Hidehiko
AU  - Taber,Christopher R.
TI  - Direct Estimation of Policy Impacts
JF  - National Bureau of Economic Research Technical Working Paper Series
VL  - No. 254
PY  - 2000
Y2  - June 2000
UR  - http://www.nber.org/papers/t0254
L1  - http://www.nber.org/papers/t0254.pdf
N1  - Author contact info:
Hidehiko Ichimura
Graduate School of Economics
University of Tokyo
Hongo 7-3-1
Tokyo 113-0033
Japan
E-Mail: ichimura@e.u-tokyo.ac.jp

Christopher R. Taber
Department of Economics
University of Wisconsin -Madison
1180 Observatory Dr
Social Sciences Building #6448
Madison, WI 53706-1320
Tel: (608) 263-7791
Fax: (608) 262-2033
E-Mail: ctaber@ssc.wisc.edu
AB  - This paper specifies a general set of conditions under which the impacts of a policy can be identified using data generated under a different policy regime.  We show that some of the policy impacts can be identified under relatively weak conditions on the data and structure of a model.  Based on the identification results we develop estimators of policy impacts.  We discuss a nonparametric method to implement the estimation but also discuss semiparametric methods in order to reduce the conditioning dimension.  We then provide an empirical example of the impact of tuition subsidies using the ideas.  While the framework used in this paper is fairly narrow, we believe this approach can be applied to a broad set of problems.
ER  -