TY  - JOUR
AU  - Heckman,James J.
AU  - Vytlacil,Edward
TI  - Structural Equations, Treatment Effects and Econometric Policy Evaluation
JF  - National Bureau of Economic Research Technical Working Paper Series
VL  - No. 306
PY  - 2005
Y2  - April 2005
UR  - http://www.nber.org/papers/t0306
L1  - http://www.nber.org/papers/t0306.pdf
N1  - Author contact info:
James J. Heckman
Department of Economics
The University of Chicago
1126 E. 59th Street
Chicago, IL 60637
Tel: 773/702-0634
Fax: 773/702-8490
E-Mail: jjh@uchicago.edu

Edward J. Vytlacil
Department of Economics
New York University
19 West 4th Street, Sixth Floor
New York, NY 10012
Tel: 212/992-8682
Fax: 212/995-4186
E-Mail: vytlacil@nyu.edu
AB  - This paper uses the marginal treatment effect (MTE) to unify the nonparametric literature on treatment effects with the econometric literature on structural estimation using a nonparametric analog of a policy invariant parameter; to generate a variety of treatment effects from a common semiparametric functional form; to organize the literature on alternative estimators; and to explore what policy questions commonly used estimators in the treatment effect literature answer. A fundamental asymmetry intrinsic to the method of instrumental variables is noted. Recent advances in IV estimation allow for heterogeneity in responses but not in choices, and the method breaks down when both choice and response equations are heterogeneous in a general way.
ER  -