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Subject Heading and Term Source Codes

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Metadata Examiner
The Library of Congress Subject Headings (LCSH).
The Library of Congress Subject Headings (LCSH).
Photo credit: 
Jeffrey Beall

Most academic libraries in the United States use the Library of Congress Subject Headings  (LCSH) as their standard for subject metadata.

However, there are dozens of different standards in use. Many are highly specialized and pertain only to a particular field of study. An example is a subject heading scheme called SHE: Subject Headings for Engineering.

Naturally, a thesaurus is language-specific. So there are multiple thesauri by language. So there might be an engineering thesaurus in English and Italian, and in many other languages. There are also general thesauri in most languages.

Many subject thesauri are open access. However, there are still a few that are proprietary. You have to either buy the book or license online access to be able to search and use the particular thesaurus.

The Library of Congress maintains an official list of the major thesauri in use around the world. Each thesaurus is assigned a code, and the list contains codes for over one hundred different indexes. Here are a few examples:
 

  • ilpt = Index to legal periodicals: thesaurus. (New York, NY: H.W. Wilson)
  • lcstt = List of Chinese subject terms (Taipei: National Central Library)
  • mesh = Medical subject headings (Bethesda, MD: National Library of Medicine)
  • qlsp = Queens Library Spanish language subject headings (Queens, New York: Queens Library)
  • ram = RAMEAU: répertoire d'authorité de matières encyclopédique unifié (Paris: Bibliothèque nationale)

The list from which I selected these thesauri is located here: http://www.loc.gov/standards/sourcelist/subject.html It is called "Subject Heading and Term Source Codes ."


Each thesaurus has a code, and the code cannot be longer than 12 characters. The codes are used in metadata to show the source of the subject metadata. Here's an example from a bibliographic record:
 

  • 650_7 Hispanoestadounidenses $z Colorado $x Historia $v Recursos bibliotecarios. $2 qlsp

In this example, the subfield 2 shows the source of the subject terms; in this case it's the Queens Library Spanish language subject headings.
 

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, Metadata Examiner

Jeffrey Beall works as Metadata Librarian at the University of Colorado Denver's Auraria Library. He earned a master of library science degree from the University of North Carolina at Chapel Hill, and he also holds an M.A. degree in English from Oklahoma State University. He has worked as an...

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