We use the control function approach to identify the average treatment effect and the effect of treatment on the treated in models with a continuous endogenous regressor whose impact is heterogeneous. We assume a stochastic polynomial restriction on the form of the heterogeneity but, unlike alternative nonparametric control function approaches, our approach does not require large support assumptions.
The research activities of the NBER are funded by grants from federal research agencies, by private foundations, and by generous donations from our corporate associates and from private individuals. The NBER is a non-profit, 501(c)(3) organization. For information on supporting the NBER, please contact:
Mr. Denis Healy, Director of Development
1050 Massachusetts Avenue
Cambridge, MA 02138-5398