Most researchers know that the terms AND, OR, and NOT are used to combine terms (you may be familiar with their formal name of "Boolean operators" or "Boolean logic"). However, it is common for beginning researchers to apply them incorrectly when formulating a search statement. Improper use of AND, OR, and NOT is the second largest cause of a failed search. This is how these terms should be used:
The chart below illustrates some examples of these terms "in action."
Search Statement |
Results |
|---|---|
online teaching AND higher education |
NARROWS the search results by eliminating online teaching in elementary or secondary schools |
higher education OR college OR graduate programs |
EXPANDS the search results by using synonyms for the concept of higher education |
higher education NOT graduate programs |
NARROWS the search results by eliminating 'graduate programs'. CAUTION: "NOT" can often eliminate results that are desirable. For example: "Anorexia NOT males" will eliminate articles that mention BOTH males and females. |
Now, to see how this all works in practice, click on the "Next" link (below) to take a look at constructing actual search statements.
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This document was created by Carol Wright, Associate Librarian at Penn State's University Libraries.
Instructional design assistance provided by Ann Luck, Senior Instructional Designer for Penn State's World Campus.
Copyright © June 2001, The Pennsylvania State University.
