Lexical-Statistical Systems

8.5 Summary

This chapter has summarized the major research carried out under the guise of “automated information retrieval.” The common thread has been a focus on algorithmic approaches to improving indexing and retrieval, with a particular focus on techniques that utilize words in documents and statistical measures applied to them. The evaluative results, mostly coming from the TREC initiative, show consistent benefit for a variety of approaches, such as certain types of term weighting, passage retrieval, and query expansion. However, the sections describing the results of Web and interactive searching results should temper those conclusions, since it is not clear that the approaches studies provide much benefit for real users. Continued user-oriented evaluation must take place to define the optimal uses of these techniques.