 |
|
| Information Literacy Guide | Locating Information | Electronic Searching | Resources | Site Outline |
Locating Information: Electronic Searching: Boolean Operators |
|
| Boolean logic is named for British mathematician George Boole, and it refers to creating relationships between search terms (or keywords). Boolean logic consists of three operators--AND, OR, and NOT. These operators can be used to narrow or broaden searches. (NOTE: Some search engines may require slightly different forms of these operators, or may even use symbols to replace them. Check the "Help" or "Tips" section of the database or search engine you're using.) |
|
Boolean Operators |
The results of performing Boolean searches are sometimes illustrated by the diagrams below (called Venn diagrams.) The diagrams show graphically how using the AND operator NARROWS a search, using the OR operator BROADENS a search, and using the NOT operator EXCLUDES material from a search.
Operator Example search The search will find... Venn diagram
results shown in green
AND
north carolina AND prohibitionitems containing "North Carolina" and "prohibition." AND narrows a search, resulting in fewer hits.
zimbabwe OR rhodesia
items containing either "Zimbabwe" or "Rhodesia" or both.
OR broadens a search, resulting in more hits.
NOT*
mexico NOT new mexico
items containing "Mexico" but not "New Mexico."
NOT narrows a search. Caution! It's easy to exclude relevant items.
*NOTES: Some systems use AND NOT or ANDNOT in place of NOT. While most systems are case insensitive, a few systems, such as Britannica Online, require you to type Boolean operators in upper case.
On to the next section... Truncation & Wildcard
| Defining | Locating | Selecting | Organizing | Presenting | Evaluating |
Please send comments or questions to the 4J
Web Team.
Eugene School District 4J
200 North Monroe Street, Eugene, Oregon 97402
Phone: 541.687.3123 [TTD 541.687.3447]
Last modified: October, 2003 by Steinke, Ague, Feuerhelm, Maxwell, and Warburg