In quantile regressions, we continue in the same way. We replace the scalar § in equation (3) by the parametric function %<Xj, /?) The Blinder-Oaxaca (bo) decomposition divides the wage differential between two groups into a portion that is “explained” by groups’ dissimilarities in productivity characteristics and an “unexplained” residual portion, which is typically used as a measure of discrimination (Jann, 2008).