Contents Boolean Logic Truncation Phrase Searching

the THEORY Boolean logic allows users to combine search terms. Boolean logic allows users to both expand or limit their search. Boolean Logic

This is achieved by using Boolean operators AND, OR and NOT (always in caps), to link the search terms in searches. Boolean logic is used in many computer applications including search engines, web directories, databases and some CD ROMS. Boolean Logic the THEORY

An example will explain how the operators (or link words) work to limit or expand your search. The question for this search is: How are students affected by computers? Boolean Logic the THEORY

First it is necessary to isolate the major words from the question to use as search terms. These terms are referred to as keywords. E.g. The keywords from this example are STUDENTS and COMPUTERS. Boolean Logic the THEORY

The first operator (or link word) to investigate is OR. How will it affect the search on students and computers? Will the search expand or will OR limit the search? the THEORY Boolean Logic

When you use the OR operator in “students OR computers” the documents retrieved have either of the keywords in them. Using OR highest retrieval students & computers Boolean Logic

The second operator (or link word) to investigate is NOT. How will it affect the search on STUDENTS and COMPUTERS? Using NOT Boolean Logic

When you use the NOT operator in “students NOT computers” the items retrieved refer to students only. Using NOT students NOT Pages contain one but not the other term Boolean Logic

The third operator (or link word) to investigate is AND. How will it affect the search on STUDENTS and COMPUTERS? Using AND Boolean Logic

When you use the AND operator in “students AND computers” only items containing references to both students and computers are retrieved. Using AND students & computers AND narrows the search Boolean Logic

Some search engines have additional boxes or links which allow you to further narrow the results of your search. Google has a search within results link at the bottom of their results page. E.g.- search students AND computers - click on search within results - type in effects and press enter Try this: Boolean Logic GOOGLE TIP

Some search engines and databases require users to click on Advanced Search to use Boolean searching. Individual engines and directories use different Boolean operators. The examples of how different engines use Boolean logic will explain this further. Search HINTS Boolean Logic

the + (plus) symbol is used instead of AND. Place immediately before all terms to be included in the search. E.g. +animals +endangered the - (minus) symbol is used instead of NOT. Place immediately before all terms to be excluded. E.g. +animals –mammals the OR is not available. Boolean Logic – Basic Search Using DirectHit Try it : With Boolean searching on DirectHit:

the AND is implied. Type in all terms to be included in the search. E.g. animals endangered the - (minus) symbol is used instead of NOT. Place immediately before all terms to be excluded. E.g. animals –mammals the OR operator (in capitals) is placed between terms. E.g. astronomy OR planets Boolean Logic – Basic Search Using GOOGLE Try it : With Boolean searching on Google:

+ (plus) is used instead of AND. Place immediately before all terms to be included in the search. E.g. +animals +endangered - (minus) is used instead of NOT. Place immediately before all terms to be excluded. E.g. +animals –mammals () (parentheses) are used instead of OR. Place all terms in parentheses. E.g. (astronomy planets) Boolean Logic – Basic Search Using AllTheWeb Try it : With Boolean searching on AllTheWeb:

Truncation is a tool which can broaden a search. Users enter part of a word in order to ensure retrieval of all documents containing variations of the word. Not all search engines allow truncation. Try the next example using Yahoo. Truncation Search HINTS

Tool to broaden searches: 1.Right hand truncation with * Type sight * You will retrieve documents with sights, sightseeing, sighted etc. Using YAHOO Try it : Truncation

2.Internal “wild-card” truncation with * Type colo*r You will retrieve documents containing both colour and color. Using IXQUICK Try it : Truncation

Phrase searching offers another tool which will contribute to a successful search on the Internet. Try the following examples: Phrase Searching SEARCH HINTS

Enclose terms to be searched as a phrase in quotes “The Gettysburg Address” “The Battle of Trenton” The phrase will be retrieved exactly as keyed in. Try it: Phrase Searching Using GOOGLE

Works Cited Henninger, M. Don’t Just Surf. Effective Research Strategies for the Net. Sydney: U of New South Wales, Barlow, Linda. “How Search Engines Work.” The Spider’s Apprentice: A Helpful Guide to Web Search Engines.” 22 Sept Monash Information Services. 4 Oct Tyner, Ross. “Internet Search Tools and Techniques.” Electronic Information Literacy: Library and Internet Research. 25 Aug Okanagan U Coll. 4 Oct

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