Discussion of recall and precision of index terms focuses on an information-theoretic measure of term specificity. Term weighting schemes are described, including the inverse document frequency (IDF) and signal-noise ratio (S/N) approaches; term weighting by specificity is explained; and the need for experiments with test document collections is…

Presents a method of modeling the relevance relationship in information retrieval to answer the question of the theoretical limits of certain statistical methods. Hypergeometric probability distribution is used to construct an abstract model of a database of MEDLINE records, and results of tests of vector retrieval methods are reported. (28…