The Proportion of NUC Pre-56 Titles Represented in OCLC WorldCat

Abstract

This article describes a research project that included a designed experiment and statistical analysis to sample and estimate the proportion of records in the 754 volumes of the National Union Catalog Pre-56 Imprints (Mansell) that also appear in OCLC WorldCat. The authors randomly selected a sample of records from Mansell and then searched the records in OCLC WorldCat. The results show that 72.2 percent of the records in Mansell were found in WorldCat and 27.8 percent of the sampled Mansell records were not (95% confidence interval [26%, 30%]). Because a significant proportion of works held by libraries is not found in OCLC WorldCat, Mansell remains a valuable library resource.