Semi-Parametric Estimators of Truncated Regression Models

Estimators for semi-parametric linear regression models with truncated response variables (fixed truncation point). The estimators implemented are the Symmetrically Trimmed Least Squares (STLS) estimator introduced by Powell (1986) , the Quadratic Mode (QME) estimator introduced by Lee (1993) , and the Left Truncated (LT) estimator introduced by Karlsson (2006) .