Maurel, Arnaud; D'Haultfoeuille, Xavier - Duke University, Department of Economics - 2011
It is often believed that without instrument, endogenous sample selection models are identified only if a covariate with a large support is available (see, e.g., Chamberlain, 1986, and Lewbel, 2007). We propose a new identification strategy mainly based on the condition that the selection...