Answered By: Jennifer Harris
Last Updated: Jun 02, 2016     Views: 177

Boolean searching is used to help find search results faster and with more precision. Boolean searching uses operators: words like AND, OR, and NOT. These are logic-based words that help search engines narrow down or broaden search results.

The Boolean operator AND tells a search engine that you want to find information about two (or more) search terms. For example, cats and dogs. This will narrow down your search results because the search engine will only bring back results that include both search terms.

The Boolean operator OR tells the search engine that you want to find information about either search term you've entered. For example, cats or felines. This will broaden your search results because the search engine will bring back any results that have either search term in them.

The Boolean operator NOT tells the search engine that you want to find information about the first search term, but nothing about the second. For example, cats not dogs. This will narrow down your research results because the search engine will bring back only resources about the first search term (cats), but exclude any resources that include the second search term (dogs).

Most Useful For:
  • Narrowing down or broadening your search results by connecting search terms together using logic
  • Making connections between keywords or emphasizing relationships between keywords when searching
Cautions:
  • May bring back too many, too few, or irrelevant results if keywords are not carefully selected
  • Not all databases handle Boolean operators in the same way (e.g. some support nesting, some databases support symbols like "&", etc.)

The library has several books and eBooks in our collection which can help answer your questions about Boolean searching. Check out the books and web resources below for additional information.

Helpful Books from the Library:

 The Oxford Guide to Library Research Book Cover

The Oxford Guide to Library Research by Thomas Mann
Call Number: REF Z710 .M23 2005
ISBN: 9780195189971
Publication Date: 2005-11-01

 Decision Points : Boolean Logic for Computer Users and Beginning Online Searchers Book Cover

Decision Points : Boolean Logic for Computer Users and Beginning Online Searchers by Janaye Matteson Houghton and Robert S. Houghton
Call Number: [electronic resource]
ISBN: 9781563086724
Publication Date: 1999

To find more books and eBooks on Boolean searching, please search the Multi-Search or the Online Library Catalog.

These web resources may be helpful if you need help using Boolean searching. However, be sure to evaluate any sources you use--the Shapiro Library cannot vouch for the accuracy of information provided on external websites.

Still Need Help? Ask a Librarian!

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