Boolean Operators

What do you do after you've brainstormed for search terms? You'll need to combine them in a logical fashion so that the database understands the information you seek. Databases facilitate this type of search with the boolean operators AND, OR, and NOT. Here are some exampes of how to use them:


Makes the search more specific. Used to combine two or more key concepts. If the research question is "How does marijuana affect teenagers?" Construct the search with AND:

marijuana AND teenagers

Venn Diagram of Boolean Operator AND


Broadens a search. Used to combine synonymous or related terms together. Locates references that include any of the terms you enter, but not necessarily all:

therapeutic OR medicine

Venn Diagram of Boolean Operator OR
therapeutic OR medicine


Used to exclude documents that contain a certain term. It retrieves references that include the first term but not the second:

Mexico NOT new

Venn Diagram of Boolean Operator NOT
Mexico NOT new

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