Authority control

[7][8] Each controlled entry is described in an authority record in terms of its scope and usage, and this organization helps the library staff maintain the catalog and make it user-friendly for researchers.

[10] The unique header can guide users to all relevant information including related or collocated subjects.

Traditionally, one of the most commonly used authority files globally are the subject headings from the Library of Congress.

According to one view, authority control is not about creating a perfect seamless system but rather it is an ongoing effort to keep up with these changes and try to bring "structure and order" to the task of helping users find information.

Authority control is used by catalogers to collocate materials that logically belong together but that present themselves differently.

[18] The English Wikipedia prefers the term "Diana, Princess of Wales", but at the bottom of the article about her, there are links to various international cataloging efforts for reference purposes.

Although practices vary internationally, authority records in the English-speaking world generally contain the following information: Since the headings function as access points, making sure that they are distinct and not in conflict with existing entries is important.

Cataloguers [sic] have to decide which name the public would most likely look under, and whether to use a see also reference to link alternative forms of an individual's name.For example, the Irish writer Brian O'Nolan, who lived from 1911 to 1966, wrote under many pen names such as Flann O'Brien and Myles na Gopaleen.

Catalogers at the United States Library of Congress chose one form—"O'Brien, Flann, 1911–1966"—as the official heading.

[20] The example contains all three elements of a valid authority record: the first heading O'Brien, Flann, 1911–1966 is the form of the name that the Library of Congress chose as authoritative.

If a user queries the catalog under one of these variant forms of the author's name, he or she would receive the response: "See O'Brien, Flann, 1911–1966."

There is an additional spelling variant of the Gopaleen name: "Na gCopaleen, Myles, 1911–1966" has an extra C inserted because the author also employed the non-anglicized Irish spelling of his pen-name, in which the capitalized C shows the correct root word while the preceding g indicates its pronunciation in context.

With the advent of automated database technologies, catalogers began to establish cooperative consortia, such as OCLC and RLIN in the United States, in which cataloging departments from libraries all over the world contributed their records to, and took their records from, a shared database.