Functions of a Subject Authority File 

The functions of a subject authority file are discussed below: 

Cataloguing: The subject authority file serves as the source of indexing vocabulary and as the  means of verifying or  validating headings assigned to individual cataloguing records. It helps to ensure that a) the same heading is assigned to all works on the same subject, b) each heading represents only that particular subject, and c) all headings assigned to cataloguing records conform to the established forms. 

Maintenance: Necessary adjustments to cataloguing records are needed to be added from time to time as a result of changes in the indexing vocabulary. When existing subject headings are revised or new headings are  added; cross-references are  often affected and  should be adjusted. The subject authority file reflects the most current status of headings and cross-references and thus, serves as the source for verification and validation of subject headings as to the cataloguing records. It is also useful when a library converts its manual form to the online mode and wishes to have previously existing records reflect current practice.

Retrieval: Subject authority file helps the users in two ways. First, subject headings displayed in  the subject authority file  show the user the terminology and form of subject access points in the catalogue. Second, the cross-references guide the users to related headings when user's input terms fail to retrieve useful records.