Boolean
logic is the underlying logic for searching the Internet and electronic
databases
Many search
engines use the system of BOOLEAN
LOGIC to refine a search. This is helpful to know because
otherwise you could get thousands upon thousands of pages with little
useful information when you search.
The three main
logical operators – AND,
OR and NOT – allow
you to include or exclude terms in your search.
Example:
searching for information on the ozone layer in Australia and Antarctica.
·
If
we search “Australia” OR “Antarctica”, we’ll get general
information about both Australia and Antarctica.
OR
= either or both terms must be present in the document.
The result is
lots of documents.
·
If
we search “ozone layer” AND “Antarctica”, only documents with both
these terms in them are returned.
AND
=
both terms must be present in the document.
The result is
fewer and more relevant documents.
·
If
we search for “ozone layer” AND “Australia” NOT “Antarctica”,
the result is information about the ozone layer and Australia but all
documents that mention Antarctica will be excluded from the search.
NOT
= excludes document with this term.
The result is
that the numbers of documents are reduced but you could miss out on a
relevant one.
This can be
useful when you are searching for something like a “python” and enter
as your terms “python” NOT “Monty”
SHORTHAND
OPERATORS:
These can be
used with most search engines and are a shorthand form of Boolean
operators, e.g.
“+”
= ALL documents must have that word
“gun” + “control”
“-“
= NONE of the documents are to have that word
“python” – “Monty”
OTHER
SEARCH TIPS:
PHRASES:
Including a phrase in quotation marks reduces the documents to more
relevant ones, e.g. “Prime Minister of Australia”, “Brisbane Family
History Society”
TRUNCATION:
When you are looking for variations of a word, you can add an
asterisk (*) or a plus (+) to the root part of the word, e.g. “run*”
finds “run”, “runs” or “running”. This option only works with
some search engines.
CAPITALISATION:
Using a capital letter in a search forces
the search engine to find only an exact case match for the whole word,
e.g. “turkey” will match: turkey. Turkey, TURKEY – but “Turkey”
will retrieve only: Turkey.
SYNONYMS
AND OTHER SPELLINGS: Try these in
your searches. Also CHECK
your spelling!
USE
MORE THAN ONE SEARCH ENGINE:
Always use more than one!
CHECK
OUT THE SEARCH TIPS ON THE SEARCH ENGINES YOU CHOOSE.
TO
BROADEN A SEARCH:
(when you are not getting enough information)
TO
NARROW A SEARCH:
(when you are getting too much information)
-
·
Use very specific terms and phrases
-
·
Use Boolean AND between words and phrases
-
·
Request that the word or phrase occurs in the document title
-
·
Limit the domain, e.g. to “.edu”
-
Use
Advanced search features on a search engine
|
