ANOTHER LOOK AT THE IDENTIFICATION AT INFINITY OF SAMPLE SELECTION MODELS
重新审视样本选择模型的无穷远识别
It is often believed that without instruments, endogenous sample selection models are identified only if a covariate with a large support is available (see, e.g., Chamberlain, 1986, Journal of Econometrics 32, 189–218; Lewbel, 2007, Journal of Econometrics 141, 777–806) . We propose a new identification strategy mainly based on the condition that the selection variable becomes independent of the covariates for large values of the outcome. No large support on the covariates…