Estimation of Limited Dependent Variable Models With Dummy Endogenous Regressors
针对含二元内生回归元的模型，提出将估计目标从结构参数转向处理效应，并介绍两阶段最小二乘、乘法模型、分位数回归等简单策略，用多胞胎数据估计生育对就业的影响。
Applied economists have long struggled with the question of how to accommodate binary endogenous regressors in models with binary and nonnegative outcomes. I argue here that much of the difculty with limited dependent variables comes from a focus on structural parameters, such as index coefcients, instead of causal effects. Once the object of estimation is taken to be the causal effect of treatment, several simple strategies are available. These include conventional two-stage least squares, multiplicative models for conditional means, linear approximation of nonlinear causal models, models for distribution effects, and quantile regression with an endogenous binary regressor. The estimation strategies discussed in the article are illustrated by using multiple births to estimate the effect of childbearing on employment status and hours of work.