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Advanced Library Research Techniques: Subject Headings (Broad or Narrow)

This guide will help you improve your research skills and develop expertise in evaluating, comparing, and selecting reliable and credible sources of information.

Broader or Narrower Terms


Every database has subject headings in some form. Some subject headings have narrower terms and/or broader terms.

Exploding a term takes all of the broader terms that accompany your term and add them to your search. It can be a great way to find more relevant subject terms and, therefore, relevant results.


  • In a ProQuest database, go to the advanced search option in the ribbon at the top of the screen. (Stay away from Command Line unless you really know what you're doing.)
  • Click the "Thesaurus" link above the search box. A pop-up will come up.
  • Select the thesaurus you want to use (probably the most general one, the Proquest Platform Thesaurus)
  • Search or browse for the subject terms you want; select terms by clicking the checkbox next to it.
  • Once you click the subject terms you want, ProQuest remembers which ones you've checked, so even if you go to a different entry in the thesaurus, you will still keep your previous subject terms.
  • Add to search, combining with OR to keep it wide.
  • Now execute the search.
  • In EBSCO's Academic Search Complete database, a similar subject search can be done by clicking on "Subject Terms."


Selecting a Topic: You want to select a topic that is neither too broad or to narrow. See if you can select topics with a "just right" scope from the options below.

Air pollution in urban areas
Too Broad: 4 votes (3.85%)
Too Narrow: 0 votes (0%)
Just Right: 100 votes (96.15%)
Total Votes: 104
Respiratory diseases in children
Too Broad: 0 votes (0%)
Too Narrow: 6 votes (4.92%)
Just Right: 116 votes (95.08%)
Total Votes: 122
Sierra Club Campaign to close down 1980's-era coal plants in Texas
Too Broad: 0 votes (0%)
Too Narrow: 6 votes (4.8%)
Just Right: 119 votes (95.2%)
Total Votes: 125

Answers (Key)

1. Air pollution in urban areas

Too Broad -  need to identify an aspect of air pollution in order to narrow the scope

2. Respiratory diseases in children

Just Right - enough information to get started and you can continue to refine your topic

3. Sierra Club Campaign to close down 1980's-era coal plants in Texas

Too Narrow - Information will be to hard to find on just one event


Broader, Narrower, Related, Used For Terms


Library of Congress Subject Headings (LCSH): Explanations of BT=Broader Terms, NT=Narrower Terms, RT=Related Terms, UF=Used For

And, see example below for Core Term = Fringe benefits