HKUST
Feature selection is an important component of text categorization. This technique can both increase a classifier's computation speed, and reduce the overfitting problem. Several feature selection methods, such as information gain and mutual information, have been widely used. Although they greatly improve the classifier's performance, they have a common drawback, which is that they do not consider the mutual relationships among the features. In this situation, where one feature's predictive power is weakened by others, and where the selected features tend to bias towards major categories, such selection methods are not very effective. In this paper, we propose a novel feature selection method for text categorization called conditional mutual information maximin (CMIM). It can select a set of individually discriminating and weakly dependent features. The experimental results show that CMIM can perform much better than traditional feature selection methods.