“…Both computational speed and classification accuracy are also expected to be taken into account. For categorical features, statistical test (e.g., Chi-square test) [ 8 , 9 ], information theory (e.g., information gain, mutual information, cross entropy) [ 10 , 11 , 12 , 13 ], and Bayesian methods [ 14 , 15 ] are usually used for feature screening, especially in the field of text classification. In this study, we propose a novel model-free feature screening method called weighted mean squared deviation (WMSD), which can be considered as a simplified version of Chi-square statistic and mutual information.…”