Condorcet Fusion For Improved Retrieval

Abstract

We present a new algorithm for improving retrieval results by combining document ranking functions: <i>Condorcet-fuse</i>. Beginning with one of the two major classes of voting procedures from Social Choice Theory, the Condorcet procedure, we apply a graph-theoretic analysis that yields a sorting-based algorithm that is elegant, efficient, and effective. The algorithm performs very well on TREC data, often outperforming existing metasearch algorithms whether or not relevance scores and training data is available. Condorcet-fuse significantly outperforms Borda-fuse, the analogous representative from the other major class of voting algorithms.