A subject heading is part of a systematic list of terms that describe a given subject matter, e.g. like in a library catalogue.
See also: controlled vocabulary
According to Reitz, a subject heading is “The most specific word or phrase that describes the subject, or one of the subjects, of a work, selected from a list of preferred terms (controlled vocabulary) and assigned as an added entry in the bibliographic record to serve as an access point in the library catalog. A subject heading may be subdivided by the addition of subheadings (example: Libraries--History--20th century) or include a parenthetical qualifier for semantic clarification, as in Mice (Computers).” (retrieved 15:08, 27 February 2009 (UTC))
The library of congress uses the term "authority record" to describe the “tool used by librarians to establish forms of names (for persons, places, meetings, and organizations), titles, and subjects used on bibliographic records. Authority records enable librarians to provide uniform access to materials in library catalogs and to provide clear identification of authors and subject headings. For example, works about "movies," "motion pictures," "cinema," and "films" are all entered under the established subject heading "Motion pictures."”.
“An index term, subject term, subject heading, or descriptor, in information retrieval, is a term that captures the essence of the topic of a document. Index terms make up a controlled vocabulary for use in bibliographic records.” (Wikipedia, retrieved 15:08, 27 February 2009 (UTC))
2.1 Marc / Library of Congress
The library of congress authorities returns many entries for search about "educational technology" within the "Subject authority headings". However, only a subset concerns authorized headings that are formally established in a retrievable authority record.
The main "educational technology" term (without subheadings) identifies the following "see from": Instructional technology, Technology in education It then defines "see also", such as "Audio-visual education" and "authorized see also" such as Technology, Educational innovation, instructional systesm, teaching - aids and devices.
Note: Understanding Marc would take some time. Didn't take it yet. So look at the spec yourself :) - Daniel K. Schneider 15:08, 27 February 2009 (UTC).
The Sears List of Subject Headings is much smaller than the library of congress one.
Subject headings can be quite formal
- Marc 21 Format for Authority Data's topical terms (X50)
- An XML version of Marc is under development.
- SKOS (Simple Knowledge Organization System)
- SKOS is based on RDF (XML) and “it is a family of formal languages designed for representation of thesauri, classification schemes, taxonomies, subject-heading systems, or any other type of structured controlled vocabulary.” (Simple Knowledge Organization System, Wikipedia)
- See SKOS
- Reitz, J.M. Online Dictionary for Library and Information Science, http://lu.com/odlis/odlis_g.cfm
- HW Wilson (2007). Sears List of Subject Headings®, 19th Edition Sears List of Subject Headings 19th Edition, HW Wilson. ISBN 978-0-8242-1076-2