Area under the distance threshold curve as an evaluation measure for probabilistic classifiers

Evaluation for probabilistic multiclass systems has predominately been done by converting data into binary classes. While effective in quantifying the classifier performance, binary evaluation causes a loss in ability to distinguish between individual classes. We report that the evaluation of multiclass probabilistic classifiers can be quantified by using the area under the distance threshold curve for multiple distance metrics. We construct our classifiers for evaluation with data from the National Cancer Institute (NCI) Lung Image Database Consortium (LIDC) for the semantic characteristic of malignancy. We conclude that the area under the distance threshold curve can provide a measure of the classifier performance when the classifier has more than two classes and probabilistic predictions.