SEARCH ENGINE (ASAS)

SEARCH ENGINES

Search engines are very different from subject directories. While humans organize and catalog subject directories, search engines rely on computer programs called spiders or robots to crawl the Web and log the words on each page. With a search engine, keywords related to a topic are typed into a search "box." The search engine scans its database and returns a file with links to websites containing the word or words specified. Because these databases are very large, search engines often return thousands of results. Without search strategies or techniques, finding what you need can be like finding a needle in a haystack.

To use search engines effectively, it is essential to apply techniques that narrow results and push the most relevant pages to the top of the results list. Below are a number of strategies for boosting search engine performance.
PREPARING YOUR SEARCH
By spending a few minutes clarifying your search, you can increase your chances of finding what you need fast and effectively.

STEP 1: STATE WHAT YOU WANT TO FIND
First, in one or two sentences, state what you want to find on the Internet. For example:

What are the characteristics to look for when purchasing a computer?

STEP 2: IDENTIFY KEYWORDS
When conducting a search, break down the topic into key concepts. For example,

What are the characteristics to look for when purchasing a computer?

Boolean AND

Connecting search terms with AND tells the search engine to retrieve web pages containing ALL the keywords.

characteristics and purchasing and computer

The search engine will not return pages with just the word characteristics. Neither will it return pages with the word characteristics and the word purchasing. The search engine will only return pages where the words characteristics, purchasing and computer all appear somewhere on the page. Thus, AND helps to narrow your search results as it limits results to pages where all the keywords appear.

STEP 3: SELECT SYNONYMS AND VARIANT WORD FORMS
List synonyms, alternate spellings, and variant word forms of each keyword.

computer desktop notebook

purchase buy

STEP 4: COMBINE SYNONYMS, KEYWORDS, AND VARIANT WORD FORMS
Combine synonyms with Boolean OR.

Boolean OR
Linking search terms with OR tells the search engine to retrieve web pages containing ANY and ALL keywords.

(characteristics or purchasing or computer)

When OR is used, the search engine returns pages with a single keyword, several keywords, and all keywords. Thus, OR expands your search results. Use OR when you have common synonyms for a keyword.

Surround OR statements with parentheses for best results. To narrow results as much as possible, combine OR statements with AND statements.

NOTE: Place parentheses around OR statements.

(buy or purchase)

(computer or notebook)

Use truncation with an asterisk symbol (*) to combine variant word forms.

(computer* or notebook*)

Combine keywords with Boolean AND.

(buy or purchase) and

(computer* or notebook*) and

For example:

characteristics and (buy or purchase) and (computer or notebook)

Boolean AND NOT
AND NOT tells the search engine to retrieve web pages containing one keyword but not the other.

manchester and not united

The above example instructs the search engine to return web pages about manchester but not web pages about the "Manchester United" football team. Use AND NOT when you have a keyword that has multiple meanings. The need for AND NOT often becomes apparent after you perform an initial search. If your search results contain irrelevant results (e.g., Saturn the car rather than Saturn the planet), consider using AND NOT to filter out the undesired websites.

Implied Boolean: PLUS & MINUS
In many search engines, the plus and minus symbols can be used as alternatives to full Boolean AND and AND NOT. The plus sign (+) is the equivalent of AND, and the minus sign (-) is the equivalent of AND NOT. There is no space between the plus or minus sign and the keyword.

NOTE: AltaVista's Simple Search requires the use of plus and minus rather than AND, OR, and AND NOT.

+computer +characteristics

IMPORTANT: Use AltaVista's Simple Search for implied Boolean (+/-) searches, and use AltaVista's Advanced Search for full Boolean (AND, OR, AND NOT) searches.

STEP 5: CHECK YOUR SPELLING
Search engines return websites with words that match your keywords. If you misspell a keyword, your results will contain websites where that word is also misspelled.