Analysis of a random sample of bibliographic records from OCLC WorldCat finds that the great majority of items in WorldCat are held by very few participating libraries, and that an inverse geometric relationship exists between the number of libraries holding an item and the number of items with a given level of shared holdings. The findings provide a context for interpreting holding levels in WorldCat with regard to the proportion of widely shared items and the characteristics of items at various ranges of holdings. Used with other quantitative and evaluative measures, these findings will assist libraries in assessing their collections.
Bernstein, J. H. (2006). From the ubiquitous to the nonexistent: A demographic study of OCLC WorldCat. Library Resources & Technical Services 50 (2), 79-90.