Title: Identification of treatment effects using control functions in models with continuous, endogenous treatment and heterogeneous effects
Description: "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"--National Bureau of Economic Research web site.