Boolean LogicUsing Boolean Logic

to more effectively search

the internet and databases

Karen Yurish

May 2004

What is Boolean Logic?

• George Boole, 19th century mathematician (Bopp and Smith 100)

• Form of symbolic logic which “uses common words . . . to create and manipulate sets” of information (Bopp and Smith 101)

Benefits of Boolean Logic

• Broaden Search

• Narrow Search

O R

T ru n c a tio n

L o g ic to B ro a d e n yo u r S e a rch

OR

• Will yield results that have either one search word OR the other

• hornets or wasps will give you results that contain either word

Truncation (*,!)• Shortens a word or eliminates characters to

search for many forms of a word

• Also called “wildcards” or “stemming”

• presiden* will search for president, presidents, presidential

• wom*n will search for woman and women

A N D

N O T

Q u o ta tio n M a rk s

P ro x im ity

L o g ic to N a rro w Y o u r S e a rch

AND (+)

• Will search for results which ONLY contain both of your search words

• harmony and hornets will only find results that contain BOTH words

NOT (-)• Will eliminate terms from your search

• rock not music will only search for physical rocks, not musical bands

Quotation Marks

• Quotation marks will search for the EXACT PHRASE in quotation marks

• In this way, you limit the search to an exact phrase

• “Harmony Intermediate School” will yield results with that exact phrase

Proximity• Proximity is a refinement of the Boolean

operator AND (Bopp and Smith 107)• A special operator is used for this search

such as adj (adjacent) or n (near)• harmony n/3 drama would give you a result

such as “Harmony Intermediate School Drama Club . . .” because drama is at most three words from harmony

Advanced Searches

• Still not finding what you need?

• Use the “Help” Section in any search engine or database to do an even more advanced search

Works Cited

Bopp, Richard E and Linda C. Smith. Reference and Information Services: An

Introduction, 3rd edition. Englewood, Colorado: Libraries Unlimited, 2001.