Answered By: Judith Jablonski
Last Updated: Apr 28, 2017     Views: 42

A controlled vocabulary is a list of standardized subject headings used by catalogers and database indexers to describe what a source (e.g. an article or book) is about. These subject headings may also be referred to as subject terms, preferred terms, index terms, system keywords or descriptors.

Why use controlled subject terms?

  • Using a controlled vocabulary helps you to quickly identify relevant sources.
  • Because catalogers/indexers are trained to assign the most accurate terms to each source, using a controlled subject heading can make your search more precise. This is one of the benefits of using a library database instead of a search engine!

Do all databases use controlled vocabularies?

While all academic libraries use subject headings in their cataloging (the controlled vocabulary known as the Library of Congress Subject Headings), not all databases do. Those that do typically have a subject field listed in the advanced search options.  They may also link to their vocabulary list (i.e., Thesaurus or Subject Headings). Our librarians can help you determine if a specific database has a controlled vocabulary or not.

How is a controlled vocabulary term different from a keyword?

Keywords are words and phrases found within the text of the source itself (that is, the author's words). Keyword searching is sometimes called "natural language searching," and is particularly useful if a concept is fairly recent or uses specialized jargon.

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