Editing Authority control (section)

==Examples==
===Diverse names describe the same subject===
[[File: Diana, Princess of Wales 1997 (2).jpg|thumb|upright|right|[[Diana, Princess of Wales|Princess Diana]] is described in one authority file as "Windsor, Diana, Princess of Wales" which is an official heading.]]
Sometimes within a catalog, there are diverse names or spellings for only one person or subject.<ref name=tws2NovYfuf/><ref name = tws2NovY909 />  This variation may cause researchers to overlook relevant information. Authority control is used by catalogers to [[collocation|collocate]] materials that logically belong together but that present themselves differently. Records are used to establish [[uniform title]]s that collocate all versions of a given work under one unique heading even when such versions are issued under different titles. With authority control, one unique preferred name represents all variations and will include different variations, spellings and misspellings, uppercase versus lowercase variants, differing dates, and so forth. For example, in Wikipedia, the first wife of [[Charles III]] is described by an article [[Diana, Princess of Wales]] as well as numerous other descriptors, e.g. [[Princess Diana]], but both ''Princess Diana'' and ''Diana, Princess of Wales'' describe the same person so they all redirect to the same main article; in general, all authority records choose one title as the preferred one for consistency. In an online library catalog, various entries might look like the following:<ref name=tws2NovY111 /><ref name="ALT-for-dead-link-footnote"/>

#Diana. (1)
#Diana, Princess of Wales. (1)
#Diana, Princess of Wales, 1961–1997. (13)
#Diana, Princess of Wales 1961–1997. (1)
#Diana, Princess of Wales, 1961–1997. (2)
#DIANA, PRINCESS OF WALES, 1961–1997. (1)

These terms describe the same person. Accordingly, authority control reduces these entries to one unique entry or officially authorized heading, sometimes termed an ''access point'': Diana, Princess of Wales, 1961–1997.<ref name=VIAF/>

{| class="wikitable" style="clear: right"
|-
! Authority file
! Heading / ID
|-
| style="font-weight:bold;" | {{nobr|[[Virtual International Authority File]]}}
|VIAF ID: 107032638
|-
| style="font-weight:bold;" | [[Wikipedia]]
|[[Diana, Princess of Wales]]<ref>Note: this is the article title as of March 12, 2013</ref>
|-
| style="font-weight:bold;" | [[Wikidata]]
|Wikidata identifier: [https://www.wikidata.org/wiki/Q9685 Q9685]
|-
| style="font-weight:bold;" | [[Integrated Authority File]] (GND)
|GND ID: 118525123
|-
| style="font-weight:bold;" | [[Library of Congress|U.S. Library of Congress]]
|Diana, Princess of Wales, 1961–1997
|-
| style="font-weight:bold;" | [[WorldCat]] Identities
|Diana Princess of Wales 1961–1997
|-
| style="font-weight:bold;" | [[National Library of Spain|Biblioteca Nacional de España]]
|Windsor, Diana, Princess of Wales
|-
| style="font-weight:bold;" | [[KANTO – National Agent Data]] (Finland)
|Diana, Walesin prinsessa / KANTO ID: 000104109
|-
| style="font-weight:bold;" | Getty Union List of Artist Names
|Diana, Princess of Wales English noble and patron, 1961–1997
|-
| style="font-weight:bold;" | {{nobr|[[National Library of the Netherlands]]}}
|Diana, prinses van Wales, 1961–1997<ref name=VIAF/>
|}
Generally, there are different authority file headings and identifiers used by different libraries in different countries, possibly inviting confusion, but there are different approaches internationally to try to lessen the confusion. One international effort to prevent such confusion is the [[Virtual International Authority File]] which is a collaborative attempt to provide a single heading for a particular subject. It is a way to standardize information from different authority files around the world such as the [[Integrated Authority File]] (GND) maintained and used cooperatively by many libraries in German-speaking countries and the United States [[Library of Congress]]. The idea is to create a single worldwide virtual authority file. For example, the ID for [[Princess Diana]] in the GND is ''118525123'' (preferred name: ''Diana &lt; Wales, Prinzessin&gt;'') while the United States Library of Congress uses the term ''Diana, Princess of Wales, 1961–1997'';  other authority files have other choices. The Virtual International Authority File choice for all of these variations is ''VIAF ID: 107032638'' — that is, a common number representing all of these variations.<ref name="VIAF">[[viaf:107032638/|Virtual International Authority File]]. Records for Princess Diana, Retrieved on 12 March 2013</ref>

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.

===Same name describes two different subjects===
Sometimes two different authors have been published under the same name.<ref name=tws2NovYfuf/> This can happen if there is a title which is identical to another title or to a collective uniform title.<ref name=tws2NovYfuf/> This, too, can cause confusion. Different authors can be distinguished correctly from each other by, for example, adding a middle initial to one of the names; in addition, other information can be added to one entry to clarify the subject, such as birth year, death year, range of active years such as 1918–1965 when the person [[Floruit|flourished]], or a brief descriptive epithet. When catalogers come across different subjects with similar or identical headings, they can [[Word-sense disambiguation|disambiguate]] them using authority control.