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A0335
Title: Concordance measure-based feature screening and variable selection Authors:  Yunbei Ma - Southwestern University of Finance and Economics (China) [presenting]
Abstract: The C-statistic, measuring the rank concordance between predictors and outcomes, has become a standard metric of predictive accuracy and is therefore a natural criterion for variable screening and selection. However, as the C-statistic is a step function, its optimization requires brute-force search, prohibiting its direct usage in the presence of high-dimensional predictors. We develop a smoothed version of the C-statistic to facilitate variable screening and selection. Specifically, we propose a smoothed C-statistic sure screening (C-SS) method for screening ultrahigh-dimensional data, and a penalized C-statistic (PSC) variable selection method for regularized modeling based on the screening results. We have shown that these two coherent procedures form an integrated framework for screening and variable selection: the C-SS possesses the sure screening property, and the PSC possesses the oracle property. Specifically, the PSC achieves the oracle property if $m_n=O(n^{1/4})$, where is the cardinality of the set of predictors captured by the C-SS. Our extensive simulations reveal that, compared to existing procedures, our proposal is more robust and efficient. Our procedure has been applied to analyze a multiple myeloma study, and has identified several novel genes that can predict patients response to treatment.