Contents Boolean Logic Truncation Phrase Searching

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

This is achieved by using Boolean operators AND, OR and NOT to link the search terms in searches. Boolean logic is used by search engines on the Internet 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 children affected by television? Boolean Logic the THEORY

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

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

Type in “children OR television” Documents retrieved have either of the key words on them. Boolean Logic Using OR Highest retrieval Television & children

The second operator (or link word) to investigate is AND How will it affect the search on CHILDREN and TELEVISION Boolean Logic Using AND

Type in “children AND television” Items retrieved only where children and television both appear on the pages. Boolean Logic Using AND Television & children AND narrows the search

The third operator (or link word) to investigate is NOT How will it affect the search on CHILDREN and TELEVISION? Boolean Logic Using NOT

Type in “television NOT children” Items retrieved refer to television only. Boolean Logic Using NOT Items on television Not Pages contain one but not the other term

Search engines require users to click on advanced search to use boolean searching. Individual engines use boolean slightly differently. The example of how Alta Vista uses boolean logic will explain further. Boolean Logic Using ALTA VISTA

Boolean searching with search engine Alta Vista requires the + (plus) symbol to be placed before all terms if they are to be included. (+ replaces AND) E.g. +china +plate will result in both terms being somewhere in all documents retrieved. Boolean Logic Using ALTA VISTA Try it :

Boolean search with Alta Vista requires the – (minus) symbol to be placed before terms which are to be excluded. (- replaces NOT) E.g. china –plates retrieves all documents with China but excludes documents containing plates. Boolean Logic Using ALTA VISTA Try it :

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. Try the next examples using Alta Vista. Truncation Using ALTA VISTA

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

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

Phrase searching offers another tool which will contribute to a successful search on the Internet. Try the following examples - Phrase Searching Using GOOGLE

Enclose terms to be searched as a phrase in quotes “children’s book week” “The capital city of India” The phrase will be retrieved exactly as keyed in. Try it: Phrase Searching Using GOOGLE

References Henninger, M. (1999). Don’t Just Surf. Effective research strategies for the net. University of New South Wales Press Ltd., Sydney. Tyner, R. (1999). Internet Search Tools & Techniques. M.L.S.Okanagan University College. Available from Barlow, L.( ). The Spider’s Apprentice: A Helpful Guide to Search Engines. Monash Information Services. Available from:

Created & Designed by Syba Signs P/L C 2001 Syba Signs