The interaction of suffixing algorithms and ranking techniques in retrieval performance, particularly in an online environment, was investigated. Three general purpose suffixing algorithms were used for retrieval on the Cranfield 1400, Medlars, and CACM test collections, with no significant improvement in performance shown for any of the algorithms. A failure analysis suggested three modifications to ranking techniques: variable weighting of term variants, selective stemming depending on query length, and selective stemming depending on term importance. None of these modifications improved performance. Recommendations are made regarding the uses of suffixing in an online environment. introduction Traditional statistically based keyword retrieval systems have been the subject of experiments for over 30 years. The use of simple keyword matching as a basis for retrieval can produce acceptable results, and the addition of ranking techniques
based on the frequency of a given matching term within a document collection and/or within a given document adds considerable improvement (Sparck Jones, 1972;Salton, 1983).
The conflation of word variants using suffixing algorithms was one of the earliest enhancements to statistical keyword retrieval systems (Salton, 1971), and has become so standard a part of most systems that many system descriptions neglect to mention the use of suffixing, or to identify the algorithm was used. Suffixing was originally done for two principle reasons: the large reduction in storage required by a retrieval dictionary (Bell, 1979), and the increase in performance due to the use of word variants. Recent research has been more concerned with performance improvement than with storage reduction.
The NLM IRX (Information Retrieval Experiment) project (Benson,