Boolean Logic and Search Engine Math

Boolean logic involves using three basic Boolean operators (AND, OR , NOT) or symbols to link concepts in searching databases such as search engines. Not all search engines utilize Boolean logic in the same way.

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Search engines substitute symbols: + and -

Attaching a + (plus sign) to a word requires that the word be found in all the search results.

Example: police +sting.

Attaching a - (minus sign) in front of a word requires that the word not be found in any of the search results.

Example: python -monty.

Command	How	Supported By
Include Term	+	All
Exclude Term	-
Must Include Phrase	Advanced Search Page or Use " " (quotes)
Match All Terms	Automatic
OR	OR	AltaVista, AOL Search, Ask Jeeves, Google, HotBot, MSN Search, Teoma, Yahoo but must OR be done in ALL CAPS, and use ( ) parenthesis to group synonyms
NEAR	NEAR	AltaVista (10 words), Google use / for adjacency in exact order

Special thanks to Search Engine Watch and Search Engine Showdown for the information and ideas used to create this page.

Maintained by lib-webmaster@wpi.edu
Last modified: May 02, 2006, 12:30 EDT