Binormal Precision-Recall Curves for Optimal Classification of Imbalanced Data

摘要

Binary classification on imbalanced data, i.e., a large skew in the class distribution, is a challenging problem. Evaluation of classifiers via the receiver operating characteristic (ROC) curve is common in binary classification. Techniques to developclassifiers that optimize the area under the ROC curve have been proposed. However, for imbalanced data, the ROC curve tends to give an overly optimistic view. Realizing its disadvantages of dealing with imbalanced data, we propose an approach based onthe Precision-Recall (PR) curve under the binormal assumption. We propose to choose the classifier that maximizes the area under the binormal PR curve. The asymptotic distribution of the resulting estimator is shown. Simulations, as well as real data results, indicate that the binormal Precision-Recall method outperforms approaches based on the area under the ROC curve.