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Information Literacy: Boolean Searches & Nesting

Information Literacy

Boolean Operators

Use Boolean operators (AND, OR, NOT) to combine keywords in a search.

1.  Use AND to narrow a search. Both and/or all search terms must be present in all references retrieved.         Example:  global warming AND forests     


2.  Use OR to expand a search. Your search will retrieve records with EITHER of the terms.  OR is most      often used to combine synonyms or like terms.
      Example:  hyperactivity AND children or adolescents

3.  Use NOT to exclude a term. Records with the first term will be retrieved, but any records with the      second term will be eliminated.
     Example:  eating disorders NOT bulimia





Nesting is using parentheses ( ) to insure that Boolean operations are performed in the sequence you intend. Nesting synonyms can broaden your search. Nesting is typically used when you have only one search box.



will retrieve both of the following:        Smoking is on the rise in teenagers            Adolescents  turn to smoking to relieve stress