Answered By: Terra Rogerson
Last Updated: Apr 02, 2020     Views: 330

Boolean operators are the words "AND", "OR" and "NOT".  When used in library databases (typed between your keywords) they can make each search more precise - and save you time!  

AND narrows a search by telling the database that ALL keywords used must be found in an article in order for it to appear in your results list. Search for two or more concepts that interest you by combining descriptive keywords with AND. 

For instance, if you're interested in reading articles about how young people feel about politics, you can search for youth AND politics.  All articles in your results will include both keywords.  Often, databases will allow you to specify where in the article you want those keywords to appear (title, abstract, full text, etc.).



OR broadens a search by telling the database that any of the words it connects are acceptable. This is particularly helpful when you are searching for synonyms, such as “death penalty” OR “capital punishment.” 

So, if you type in death penalty OR capital punishment, your results will include articles with either term, but not necessarily both.


NOT narrows your search by telling the database to eliminate all terms that follow it from your search results. This can be useful when:

  • you are interested in a very specific aspect of a topic (letting you weed out the issues that you're not planning to write about)
  • when you want to exclude a certain type of article (book reviews, for instance, aren't typically helpful when writing a college-level paper)

Use NOT with caution as good items can be eliminated from the results retrieved. 

In the example below, searching for sex education NOT abstinence-only will return articles on sex ed, but not those dealing with abstinence-only approaches.


Courtesy of American Public University librarians. 

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