Efficient AUC maximization with regularized least-squares

Tapio Pahikkala, Antti Airola, Hanna Suominen, Jorma Boberg, Tapio I. Salakoski

Research output: A Conference proceeding or a Chapter in BookConference contributionpeer-review

7 Citations (Scopus)


Area under the receiver operating characteristics curve (AUC) is a popular measure for evaluating the quality of binary classifiers, and intuitively, machine learning algorithms that maximize an approximation of AUC should have a good AUC performance when classifying new examples. However, designing such algorithms in the framework of kernel methods has proven to be challenging. In this paper, we address AUC maximization with the regularized least-squares (RLS) algorithm also known as the least-squares support vector machine. First, we introduce RLStype binary classifier that maximizes an approximation of AUC and has a closedform solution. Second, we show that this AUC-RLS algorithm is computationally as efficient as the standard RLS algorithm that maximizes an approximation of the accuracy. Third, we compare the performance of these two algorithms in the task of assigning topic labels for newswire articles in terms of AUC. Our algorithm outperforms the standard RLS in every classification experiment conducted. The performance gains are most substantial when the distribution of the class labels is unbalanced. In conclusion, modifying the RLS algorithm to maximize the approximation of AUC does not increase the computational complexity, and this alteration enhances the quality of the classifier.

Original languageEnglish
Title of host publicationProceedings of the 2008 Conference on 10th Scandinavian Conference on Artificial Intelligence: SCAI 2008
EditorsAnders Holst, Per Kreuger, Peter Funk
Place of PublicationUnited States
PublisherIOS Press
Number of pages8
ISBN (Print)9781586038670
Publication statusPublished - 2008
Externally publishedYes
Event10th Scandinavian Conference on Artificial Intelligence - Stockholm, Stockholm, Sweden
Duration: 26 May 200828 May 2008

Publication series

NameFrontiers in Artificial Intelligence and Applications
ISSN (Print)09226389


Conference10th Scandinavian Conference on Artificial Intelligence
Abbreviated titleSCAI 2008


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