Search Engine Overview
Basic Search Strategies
Advanced Search Techniques
Best Search Tool
Evaluating Websites
 

Search Engine Overview

Popular search engines today: 

 What do search engines do? 

• They search the Internet, or some portion of it, generally the World Wide Web,
  based on keywords.

• They index words they find and where they found them.

• They index hundreds of millions of individual web pages.

Limitations

• No one search engine captures the entire contents of the Internet

• Some content can not be searched with a general search engine, such as
  the "invisible web" or "deep web", which requires passwords/logins/authentication.

• The Internet is a fluid environment- things changes constantly. What you find
  today may be gone tomorrow.

How They Search and Retrieve Results

• Spider: Program that traverses the Web from link to link, identifying and reading
  pages (sometimes called web crawler)
• Index: Database containing a copy of each Web page gathered by the spider
• Search engine mechanism: Software that enables users to query the index and that usually returns results in relevancy ranked order
• Meta tags: The <META> tag is important HTML code that allows your site to be found and indexed according to your site content and then included in the search engine database.  The number of times a search words appears on a page can also make that word a search priority.

Basic Search Strategies

1. More or Less?  Expanding and Restricting Your Search

Using Google, the largest and most commonly used search engine, and the subject venomous frogs let's explore different ways to expand or restrict your search.

If you typed in both words in the Google search box Google assumes you wanted documents that include both those words, as if you typed an AND between them. 

venomous AND frogs

It's important to know if the search engine you use assumes you want an AND between your words.  Otherwise it might be using an OR.

venomous OR frogs

TRY THIS:   Type these 3 searches into Google and see how many results you get for each one.  Which one returns more results or fewer results?

1. venomous frogs

2. venomous OR frogs

3. frogs NOT venomous

To learn more about how some common search engines use AND, OR, NOT (Boolean operators) view the charts on these two sites.

• Recommended Search Engines, UC Berkeley http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/
  SearchEngines.html

• Best Search Tools Chart, InfoPeople http://www.infopeople.org/search/chart.html

2. Using Plus and Minus

Most search engines handle AND and NOT by letting you add a plus sign (+) directly in front of a word you want to include. This acts as the Boolean AND.

OR by adding a minus sign (-) directly in front of a word you want to exclude.  This acts as the Boolean NOT.

CAUTION: Search engines may or may not recognize Boolean operators (AND, OR, NOT) or the plus and minus signs.  Sometimes it is better to simply rely on their built in algorithms and see the initial results you get. And what works one day may change overnight.

Example:  greyhound -bus

3. How Many Ways Can You Describe That Topic?

• If you are looking for information about venomous frogs you might want to think of other terms to use when searching if you aren't finding what you want.

venomous ≈ poisonous

frogs ≈ amphibian

• Be specific. The World Wide Web is huge.  It is better to search using specific words to describe your topic rather than be too general. If your results are poor you can always expand your search by using more general or broader words.
   

• Finding alternative search terms (to include or exclude). Words found in search results will often suggest new ways of searching your topic.  
  
  For example:
  1.  When searching for venomous frogs you may discover the term poison dart frogs and retry your search with that phrase.
   
  2. When search for information about making apple pies you may need to exclude the word computers and include the word recipe.

4. Phrase vs. Word Searching

• Typing  frogs venomous or venomous frogs means you want your search to return BOTH terms on the web page(s) that is retrieved.
   

• But typing the search in quotes "venomous frogs" means you want the page to have this exact phrase with the words in this order.  This is a more precise and limiting search.
   

• Google ignores common words like "the" "of" but if the word is essential to your search than you should try to use phrase searching. 
  
  Example: "city of trees"

Advanced Search Techniques

1. Limiting your search to specific types of websites or domains.

Websites come from different sources. Knowing that source can help you evaluate the quality of the information.  Look at the top level domain (TLD) in their web address/URL.

• com - commercial businesses; this is the most common TLD
• gov - U.S. government agencies
• edu - Educational institutions such as universities
• org - Organizations (mostly nonprofit)
• mil - Military
• net - Network organizations

Read more about Top Level Domains at:  http://en.wikipedia.org/wiki/Top-level_domain

Example: If you're searching for health information you may want to limit your search to education (edu) or government (gov) sites to be assured of high quality information.  To do that you can use Google's Advanced Search page to limit your search to those sites.

Below you can see I am searching for west nile virus and limiting my search to a government website.  I could also have put quotes around the phrase "west nile virus" to insure that I didn't get websites that mentioned these words individually but were not related to this illness.

NOTE: You can also limit your search to a specific website, such as microsoft.com or idaho.gov

2. Limit your search to specific file types

By using Google Advanced Search you can limit you search to specific types of files:  [File type] - such as PDF, Microsoft Powerpoint, Word, Excel, etc.

3. Capitals or lower case?
   
   Google searches are NOT case sensitive. George Washington, GEORGE WASHINGTON, and george Washington will produce the same results. If in doubt about the search engine you are using type in all lower case.

    

4. Limit your search to specific languages or using the translation feature.

• Use Google Advanced Search to limit search results to a specific language.

• If you find a page of interest in another language you can click on "Translate this page"

Example: Search these key words official site eiffel tower

Starting with the Best Search Tool

Don't use a general search engine when you need something very specific. Although Google
is excellent at offering many different types of searches sometimes it saves time to go to a specialized search site.

1. General Search Tools
   Our selection of search tools to try - all on one page.
   http://www.boisepubliclibrary.org/Research/websearch.shtml
    

2. Looking for a multimedia file, image, sound or video? 
   Search the image page on Google http://images.google.com/ or
   Yahoo images at http://images.search.yahoo.com/images or
   use one of multimedia search sites on this page: http://www.boisepubliclibrary.org/Research/images/imagesearch.shtml
    

3. Trying to find a person or business?
   Use a directory like www.anywho.com,  www.switchboard.com 
   Find more directories on this page http://www.boisepubliclibrary.org/eCollections/Websites/directories.shtml
    

4. Looking for breaking news?
   Go to the News section of Google news.google.com  or
   Yahoo News news.yahoo.com/

Evaluating Website Quality

Because anyone can post anything on the Internet it is important that you remain critical of what you read.  Here are some key elements you should look at to ascertain
if this website is provide useful and valid information.

1. Purpose -What is the purpose of the web site? 

2. Authority - Who created it and maintains it and vouches for its content?

3. Currency - Is the site out of date?

4. Objectivity/bias - Are they trying to sell you something?

5. Appropriateness - What audience are they writing for?

For more discussion about evaluating websites visit:

• www.virtualchase.com/quality/checklist.html

• lib.nmsu.edu/instruction/evalcrit.html 

Website Evaluation Form from U.C. Berkeley tutorials

• http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/
  evaluation_checklist_2008_spring.pdf
   

Medical and health websites - look to see if it has the HON seal, which indicates they adher to the HONcode of ethical standards.

Look at these websites and decide if they are real or fake.

http://www.mcwhortle.com/index.htm      

http://www.dhmo.org      

http://www.accessidaho.org  

http://haggishunt.scotsman.com            

Last Updated: 08/24/2009  grr/AS