Estimation of type 3 tobit models using symmetric trimming and pairwise comparisons

This paper considers estimation of the semiparametric Type 3 Tobit model. We construct two-step estimators that use the ideas of symmetric trimming and pairwise comparisons which have been proposed for the censored regression model by Powell (1986) and Honoré and Powell (1994). The estimators are consistent and asymptotically normal under two identifying assumptions: conditional symmetry and independence between the errors and regressors. The ideas and techniques are also implementable in other selection models that are variations of the basic Type 3 Tobit model. We demonstrate this by applying the proposed method in estimating an empirical model considered by Udry (1994).