Boolean Logic Computer Technology PVMS ©2012 Searching on the Internet…

What is Boolean Logic? Refers to the logical relationship among search terms Allows you to combine words and phrases into search statements to retrieve documents from searchable databases. Is named for the British-born Irish mathematician George Boole.

Boolean logic consists of three logical operators: OR OR AND AND NOT NOT

AND retrieves pages where both terms occur Query: I’m interested in the relationship between poverty and crime. Search termsResults poverty76,342 crime348,252 poverty AND crime12,998

Search terms Resultscollege396,482 university590,791 college OR university 819,214 OR allows pages with at least one of the terms Query: I would like information about college.

NOT excludes documents containing whatever follows it Query: I want information about cats, but I want to avoid anything about dogs. Search termsResults cats86,747 dogs130,424 cats NOT dogs65,223

Quotation Marks “ ” Requires words to be searched as a phrase, in the exact order you type them. Search terms Results working mothers 12,600,000 “working mothers” 905,000 Query: I want information on working mothers. Information on working and mothers Information on working mothers only

Truncation searching allows you to retrieve documents containing variations on a search term. To execute a truncation search, type the first few letters (stem) of the keyword followed by an asterisk (*). For example: This search would retrieve entries for all documents containing the words: creature, creation, create, creating, creator, creaturely, etc. When executing a phrase truncation search, only the final word in the phrase can be truncated Truncation For example: creat*

Try using Boolean logic for the following statements…

Boolean logic: OR Search: cats OR felines Query: I need information about cats

Boolean logic: AND Search: dyslexia AND adults Query: I’m interested in dyslexia in adults.

Boolean logic: NOT Search: radiation NOT nuclear Query: I’m interested in radiation, but not nuclear radiation

Boolean logic: OR, AND Search: (cats OR felines) AND behavior Query: I want to learn about cat behavior

Summary Boolean logic consists of three operators: or, and, not To search words as a phrase use quotation marks Truncation searching allows you to retrieve documents containing variations on a searched item.

References Joe Barker, Teaching Library, University of California, Berkley help/ab_trunc.htm help/ab_trunc.htm