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OCLC Support

What is the difference between WorldCat and What do I need to know about the central index?

Applies to
  • WorldCat Discovery

WorldCat is a database that represents the “collective collection” of the world’s libraries, built through the contributions of librarians, and expanded and enhanced through individual, regional, and national programs. WorldCat represents electronic and digital materials, including the important, unique items found only in local libraries. is a web destination that brings together the contents of the WorldCat database, including the multiple formats contributed through the WorldCat Digital Collection Gateway and more than 200 million article citations from many popular databases.

The central index is an index of metadata for e-content collections libraries often provide to their users. These include collections from well-known content providers.

What you need to know about the central index:

  • Central index databases contain article citations from non-OCLC databases.
  • Bibliographic records display key metadata such as title, author, and publication information
  • Articles from non-OCLC central index databases display the database name as the source of the citation
  • Your library must subscribe to a central index database to enable it
  • Database contents in OCLC’s central index are generic and not specific to your library
  • OCLC has no way of knowing from the central index databases what content falls within your actual subscription coverage
  • Articles display as held by your library based on the assumption that, because your library has holdings on the serial where the article is found, you have access to the articles within that serial
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