Mean and quantile boosting for partially linear additive models

Additive models are often applied in statistical learning which allow linear and nonlinear predictors to coexist. In this article we adapt existing boosting methods for both mean regression and quantile regression in additive models which can simultaneously identify nonlinear, linear and zero predictors. We use gradient boosting in which simple linear regression and univariate penalized spline are used as base learners. Twin boosting is applied to achieve better variable selection accuracy. Simulation studies as well as real data applications illustrate the strength of our proposed methods.