Simplified Similarity Scoring Using Term Ranks

Vo Ngoc Anh
Department of Computer Science and Software Engineering, The University of Melbourne, Victoria 3010, Australia.

Alistair Moffat
Department of Computer Science and Software Engineering, The University of Melbourne, Victoria 3010, Australia.

Status

Proc. 28th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, Salvador, Brazil, August 2005, pages 226-233.

Abstract

We propose a method for document ranking that combines a simple document-centric view of text, and fast evaluation strategies that have been developed in connection with the vector space model. The new method defines the importance of a term within a document qualitatively rather than quantitatively, and in doing so reduces the need for tuning parameters. In addition, the method supports very fast query processing, with most of the computation carried out on small integers, and dynamic pruning an effective option. Experiments on a wide range of TREC data show that the new method provides retrieval effectiveness as good as or better than the Okapi BM25 formulation, and variants of language models.