"Boolean logic" consists of three operators:
| Most Internet search fields include: |
| OR |
|
| AND |
|
| NOT |
|
| " " |
quotes (exact phase between quotation marks) |
| Several Internet search fields include |
| * |
asterisk ( truncation) - For example, econom* finds: economy, economic, economics, economist, etc. (Alta Vista, Yahoo, lii.org, Infomine) |
Training and Resource Center. Wild Cards and Truncation Changes (2004) http://training.proquest.com/trc/training/boolean.htm
What kind of "advanced search" does your preferred search engine offer?
Some Search Engines use "Full Boolean" terms, others use "Implied Boolean" terms.
| Search Engine |
Feature |
| (OR only), Ixquick, Dogpile |
Boolean Operators |
| AlltheWeb adv. search, AltaVista adv. search, Live Search, Ixquick |
Boolean with ( ) stings (bee OR wasps) |
Most search engines (e.g. Google by default adds +, you can add OR or -) |
Implied Boolean + or - |
Advanced search temaplates for:
AlltheWeb, AltaVista, Ask.com, Live Search, Ixquick, Google, Ixquick, Dogpile, Yahoo |
Template Terminology |
| Google , Ixquick |
Proximity Operators
(“cable NEAR modem” will instruct the search engine to look in documents for instances of the words “cable” and “modem” that are near each other.) |
Cohen, Laura. "Boolean Searching on the Internet". Jan 2008, University at Albany Libraries.http://library.albany.edu/internet/boolean.html
Google: Try this in Google, you will need to use the "Advanced Search" link. Google, by default uses the AND (+) operator. You can add the (-) operator to subtract a word. The advanced search tool does this for you.
Yahoo will accept Boolean terms.
| 1. |
I want an overview of the subject" bee stings". |
| |
This search will return all the web pages with at least one of the words bee or sting. |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS
(Google "Advanced Search" ) |
| |
bee OR sting |
162,000,000 |
| |
IN GOOGLE: bee OR sting |
|
|
Returns contain
a lot of information about bees - life cycle, behavioral patterns,
etc.
Problem: Returns contain a
lot ofextraneous information about insect and jellyfish stings,
Sting, the singer and "police stings".
Solution: Refine search to
include only pages containing both words. |
| 2. |
I would like information about only bee stings. |
| |
This search will return all the web pages with all of the words "bee" and "sting". |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS |
| |
bee AND sting |
1,170,000 (fewer returns is better!) |
| |
IN GOOGLE: bee sting |
|
|
Returns contain information about bees and stings.
Problem: returns stillcontain
a lot of information about insect and jellyfish stings, Sting,
the singer and "police stings". |
| |
bee sting (no operator, using engine's default method)
("AND" is the default operator if nothing is entered.) |
1,170,000
Note: When not specified Google and Yahoo automatically create an "AND"
relationship as default) |
| 3. |
I would like information only about bee stings with a focus on medication for treatment. |
| |
This search will return all the web pages with all of the words "bee", "sting" and "medication". |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS |
| |
bee AND sting AND medication |
98,700 Fewer, more relevant turns. |
| |
IN GOOGLE: bee sting medication |
|
| |
 |
Problem: returns for 'bee'
AND 'sting'lcontain a lot of information about insect and jellyfish
stings, Sting, the singer and "police stings".
Solution: Adding a 3rd keyword
greatly reduces the number of returns. Most pages contain information
about bee sting medication. |
| 4. |
I would like information only about bee stings, but not the singer Sting. |
| |
This search is intended to get pages returned with all of the words "bee", "sting" but without the word "singer". |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS |
| |
bee AND sting NOT singer |
774,000 |
| |
IN GOOGLE: bee sting -singer |
|
| |
 |
Problem: Entering 'bee' and
'sting' returns a lot of extraneous pages about Sting, the singer.
Solution: Use NOT to remove
unwanted subjects that may be included in keyword homonyms.
|
| 5. |
I would like information about only bee stings, but not the singer Sting. |
| |
This search is intended to get pages returned with all of the words "bee" and "sting" but without the words "singer" or "police". |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS |
| |
bee AND sting NOT singer NOT police |
702,000 |
| |
IN GOOGLE: bee sting -singer -police |
|
| |
 |
Problem: Entering 'bee' and
'sting' returns a lot of extraneous pages about Sting, the singer
and police sting operations
Solution: Use multiple NOTs
to remove unwanted subjects that may be included in keyword homonyms. |
| 6. |
I would like information about only "bee stings". |
| |
This search is intended to get pages returned with the phrase "bee stings" (both words occur together.) |
| |
KEYWORD ENTRIES |
NUMBER OF RETURNS |
| |
"bee
stings" |
677,000 |
| |
IN GOOGLE: "bee stings" |
|
| |
Returns:
Contains information about bee stings and Sting, the singer |
Summary of Results
Refining your research terms greatly diminishes the number of returns!
| KEYWORD ENTRIES |
NUMBER OF RETURNS Google "Advanced Search" |
| bee OR sting |
162,000,000 |
| bee AND sting |
1,170,000 |
| "bee stings" |
677,000 |
| bee AND sting NOT singer |
774,000 |
| bee AND sting NOT singer NOT police |
702,300 |
| bee AND sting AND medication |
98,700 fewest returns |
| "bee sting" NOT singer NOT police |
481,000 |
| "bee stings" NOT singer NOT police |
442,000 |
*If you do not use a Boolean word, most search engines
will add "AND" as the default operator. Check the search engine's
"help" pages if you wish to know the default operator.
Boolean Pactice 
Centers for Teaching and Learning, San Mateo Community College District, CA USA Updated 8/28/2008 by Sevastopoulos |
