Collection Overlap as a Function of Library Size: A Comparison of American and Canadian Public Libraries

Random samples of monographic materials from American and Canadian public libraries were matched with the collections of similar libraries of different sizes. Materials with a publication date earlier than 1970 were excluded in order to reduce the sample size, to minimize the effects of comparing older and newer libraries, and to increase the relevance of the findings for resource sharing through contemporary on-line computer-based networks. A strong positive correlation appears to exist between percentage find rate and target library size, with regression analysis suggesting linearity over a wide range of collection sizes.