RANK: Large-Scale Inference with Graphical Nonlinear Knockoffs
This work addresses the need for reliable variable selection in big data applications, offering a robust method for scientists and researchers, though it builds incrementally on existing knockoffs frameworks.
The paper tackles the problem of ensuring power and reproducibility in high-dimensional nonlinear models by providing theoretical foundations for the model-free knockoffs procedure, showing that the power asymptotically approaches one under mild conditions and proposing a modified method (RANK) that controls false discovery rate at the target level with similar power.
Power and reproducibility are key to enabling refined scientific discoveries in contemporary big data applications with general high-dimensional nonlinear models. In this paper, we provide theoretical foundations on the power and robustness for the model-free knockoffs procedure introduced recently in Candès, Fan, Janson and Lv (2016) in high-dimensional setting when the covariate distribution is characterized by Gaussian graphical model. We establish that under mild regularity conditions, the power of the oracle knockoffs procedure with known covariate distribution in high-dimensional linear models is asymptotically one as sample size goes to infinity. When moving away from the ideal case, we suggest the modified model-free knockoffs method called graphical nonlinear knockoffs (RANK) to accommodate the unknown covariate distribution. We provide theoretical justifications on the robustness of our modified procedure by showing that the false discovery rate (FDR) is asymptotically controlled at the target level and the power is asymptotically one with the estimated covariate distribution. To the best of our knowledge, this is the first formal theoretical result on the power for the knockoffs procedure. Simulation results demonstrate that compared to existing approaches, our method performs competitively in both FDR control and power. A real data set is analyzed to further assess the performance of the suggested knockoffs procedure.