Keyword vs. Subject Searching

Sometimes it is beneficial to try a Subject Search on your topic, which can give you more precise results.

What is the difference between Keyword and Subject searching?

Keyword Search uses any words/phrases that you choose

Subject Heading search uses a "controlled vocabulary"

— also known as a descriptor, thesaurus term, or subject heading created by the Library of Congress system; article databases might also have their own unique subject headings


  • Allows natural language searching

  • Searches anywhere in the record

  • Created by you, the user

  • Don't need to know the "controlled vocabulary"


  • Computer interprets your search — by matching your search with an organized list of subjects

  • Better, more precise results because it only searches the Subject field in the record


  • Results can be messy because some of them are irrelevant to your needs

  • Risky: Garbage in, garbage out; what you type is what you get; — there is no interpretation


  • Subject headings are not flexible because they must be selected from a "controlled" list of words

  • Requires thesaurus or index

  • No guessing allowed

Examples of Keyword Terms

  • Native Americans

  • Cars

  • Movies or films

  • United States and civil war

Examples of Library of Congress Subject Headings

  • Indians of North America

  • Automobiles

  • Motion pictures

  • United States—History—Civil War, 1861-1865

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