Bias Transmission and Variance Reduction in Two-Stage Quantile Regression

Tae-Hwan Kim (1) , Christophe Muller (2)

1 School of Economics, Yonsei University
2 GREQAM - Groupement de Recherche en Économie Quantitative d'Aix-Marseille

In this paper, we propose a variance reduction method for quantile regressions with endogeneity problems. First, we derive the asymptotic distribution of two-stage quantile estimators based on the fitted-value approach under very general conditions on both error terms and exogenous variables. Second, we exhibit a bias transmission property derived from the asymptotic representation of our estimator. Third, using a reformulation of the dependent variable, we improve the efficiency of the two-stage quantile estimators by exploiting a trade-off between an asymptotic bias confined to the intercept estimator and a reduction of the variance of the slope estimator. Monte Carlo simulation results show the excellent performance of our approach. In particular, by combining quantile regressions with first-stage trimmed least-squares estimators, we obtain more accurate slope estimates than 2SLS, 2SLAD and other estimators for a broad range of distributions.

Mots clés: Asymptotic Bias; Two-Stage Estimation; Variance Reduction; Quantile Regression

Domaines: Economies et finances

Tae-Hwan Kim, Christophe Muller. Bias Transmission and Variance Reduction in Two-Stage Quantile Regression. 2012. ⟨halshs-00793372⟩