On the Expected Gain From Adjust ing Matched Term Retrieval Systems A file adjustment procedure based on maximizing the Bayes expected gain proposed for matched term retrieval systems. The expected gain and its probability distribution are derived as a function of: (1) the prior proportion of omitted terms, and (2) the coefficient of separation between two distributions corresponding to values of an adjustment statistic. An example evaluates the gain parameters for a typical information retrieval system. CACM November, 1967 Shumway, R. H. CA671106 JB February 26, 1978 2:59 PM 1514 5 1514 1514 5 1514 1514 5 1514