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Introduction to the Shapiro Library

Use this research guide to learn about the Shapiro Library's services, tools and how to get started using the library.

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Boolean Operators/Boolean Searching

Boolean searching is a search technique which uses Boolean operators to help bring back search results faster and with more precision. The most common Boolean operators are AND, OR, and NOT. These are logic-based words that help search engines narrow down or broaden search results. 

Boolean Operators

AND

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.

OR

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.

NOT

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).

Uses

As with any search strategy, you may want to consider what Boolean operators/searching is most useful for and anything you should be cautious about when using this searching technique:

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.)

Check out the FAQ: What is Boolean searching and how can I use it? for additional information.