Library Tip #3

Boolean Searching

This guide will introduce you to the practice of Boolean searching and how you can use Boolean search techniques to search the library's online databases. Boolean searching allows you to create a very broad or narrow search. 

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What is Boolean Search?

What is Boolean Search? Boolean searches allow you to combine words and phrases using the words AND, OR, NOT and NEAR (otherwise known as Boolean operators) to limit, widen, or define your search.

Where does the term Boolean originate?

George Boole, an English mathematician in the 19th century, developed "Boolean Logic" in order to combine and exclude certain concepts when searching databases.

Keywords

Keywords are the important words that describe and are unique to your topic. Try to focus and use the most specific terms possible. Think of synonyms and related terms that could be used as well.  Avoid including very common words and articles (e.g., a, an, the, for, in, on).

Example topic: women’s involvement in unions in the United States

Keywords: women, unions, United States

Synonyms/Related terms: woman, labor unions, organized labor, America

Boolean Operators

Most search engines (Google, Yahoo, etc.)  and databases allow Boolean searching.  Three common Boolean operators are: AND, OR, and NOT.

AND: Will retrieve only records or documents that contain both the search terms. This operator narrows the scope of a search and is useful for combining unrelated concepts.      Example: women AND labor unions

OR:  Will retrieve all records or documents that contain either of the search terms. This operator broadens the scope of a search and is useful for combining related terms.     Example: labor unions OR organized labor

NOT: Will retrieve records or documents that contain the first search term(s) but will exclude records that contain the second search term(s). This operator is used to reduce the number of records retrieved or refine a search.    Example: labor NOT pregnancy

Boolean Searching/Operators Tutorials

Example of Boolean Searching in EBSCO:

Video Credit: Georgetown University Library   

 Last Updated: July 13, 2015

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