Advanced Searching : Boolean Searches

What is Boolean Searching?

Boolean searching is an implementation of Boolean logic and set theory.

Boolean operators, such as AND, OR and NOT, are used to combine search sets in a variety of ways.

AND Example: technology and education

This operator narrows your search by looking for only web pages on which both terms appear.

This combination of words with the "and" Boolean operator means "find web pages in which the term technology and the term education occur."

OR Example: technology or education

This operator allows you to include synonyms and it broadens your search by looking for web pages on which either one or the other term appears or both terms appear together.

This combination of words with the "or" Boolean operator means "find web pages in which either the term technology or the term education occur."

NOT Example: technology not computers

This operator allows you to exclude terms from your results. It is helpful when your search terms have more than one meaning.

This combination of words with the "not" Boolean operator means "find web pages in which the term technology appears but not the term computers."

Search engines typically have an "Advanced" search function for searching with Boolean operators.You may be able to search using the symbols + (must include) or -(exclude) from the "Basic" search interface.

What are "Proximity Operators"?
Proximity operators are Boolean operator like NEAR or ADJ, and they are used to control how closely the terms occur in the web document retrieved in a search.

NEAR/x Example: Technology NEAR/3 education

This operator narrows your search by looking for only web pages on which both terms appear within a specified distance of each other.

This combination of words with the "near/3" Boolean operator means "find web pages in which the term technology appears within three words of the term education."

ADJ Example: Technology ADJ education

This operator narrows your search by looking for only web pages on which both terms appear next to each other. (exact phrase)

This combination of words with the "adj" Boolean operator means "find web pages in which the term technology appears next to the term education."

For More Information:

Boolean Searching on the Internet
(http://library.albany.edu/internet/boolean.html)
An explanation of Boolean logic with diagrams

Search Tools Chart
(http://www.infopeople.org/search/chart.html)
Information about major search engines

Search Engine Math
(http://searchenginewatch.com/facts/math.html)
Effective search techniques


A source for some of this content: http://www.thelearningsite.net/cyberlibrarian/searching/lesson4.html