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Research Process: Boolean Operators

This tutorial aims to help develop effective library research skills and critical thinking skills in all courses at Prince George's Community College.

Boolean Operators

One of the basic techniques for searching is using the Boolean Operators. Boolean searching is a symbolic logic system that creates relationships between concepts and words.

Use BOOLEAN OPERATORS to relate the terms in specific ways that will affect the results of a search. Boolean operators are terms that create relationships between concepts and words: 



Retrieves only articles that contain all the terms and will narrow the search. Examples:

“child obesity” AND Maryland
“child obesity” AND “eating disorder”
“video games” AND children
“attention deficit disorder” AND children


Retrieves articles with any of the terms and will broaden the search. Examples:


“child obesity” OR “overweight children”
children OR juveniles
“attention deficit hyperactive disorder” OR hyperactivity


Eliminates articles containing the second term even when the first term is present. This will narrow the search. Examples:

obesity AND children NOT adults
depression AND teen NOT adults
“video games” AND teenagers NOT children

Using Nesting with Operators

Use nesting to build a more complex search by putting keywords and/or phrases in parentheses to determine their relationship when more than one operator is used. Examples:

(children AND teenagers) AND (ADHD OR hyperactivity)
(children AND “video games”) NOT (teens OR adults)

Key Concepts

USE QUOTATION MARKS (" ") before and after a phrase, two or more words that must be together in a defined order. This lets the database know that you want to search for this phrase, and not the individual words that make up the phrase. Examples:

“African American”
“eating disorder”
“obsessive compulsive disorder”
“video games”

boolean operators infographic

This video demonstrate how to use Boolean operators when searching in library subscribed databases. (Video created by the Franklin D. Schurz Library at Indiana University South Bend.)