Variable selection in additive models via hierarchical sparse penalty

As a popular tool for nonlinear models, additive models work efficiently with nonparametric estimation. However, naively applying the existing regularization method can result in misleading outcomes because of the basis sparsity in each variable. In this article, we consider variable selection in additive models via a combination of variable selection and basis selection, yielding a joint selection of variables and basis functions. A novel penalty function is proposed for basis selection to address the hierarchical structure as well as the sparsity assumption. Under some mild conditions, we establish theoretical properties including the support recovery consistency. We also derive the necessary and sufficient conditions for the estimator and develop an efficient algorithm based on it. Our new methodology and results are supported by simulation and real data examples.