Search strategies and search tools

How a search is constructed can determine what is retrieved or what is not retrieved. A thoughtful search strategy helps cull through the mass of information and retrieve targeted results. (Of course, even with a good strategy, a huge search result is possible and sometimes even likely.)

Steps to creating a search strategy

1. Identify topic concepts and keywords or terms
   
   
2. Determine synonyms or alternatives for concepts and/or keywords
   
   
3. Determine relationships between concepts and/or keywords
   • Do you need Boolean operators: or, and, not
   • Do you want words to appear within so many words of each other (proximity)?
     
     
4. Determine if truncation (stemming, rooting) would be useful.

Sample search strategy

Topic: How many American adults are classified as functionally illiterate?

Concepts: Adults, American, Functionally illiterate

Synonyms: American or United States

Relationships: adults and (American or United States) and functionally illiterate

Proximity: in this case, adjacency: adults and (American or United States) and "functionally illiterate"

Truncation: could be used here in various places: adult* and (american* or United States) and functional* and illitera*

• Subject directories are lists of Internet resources organized into a predefined classification scheme.

• Directories allow you to browse through categories to find resources on general topics. Some directories have quick lookup search features that allow you to search all categories for keywords.

How subject directories work

The creation of subject directories usually includes some human involvement. Internet Resources are selected and then placed under one or more subject categories. Searching the directory merely involves selecting the appropriate subject category and following the appropriate hyperlinks.

Advantages of using subject directories

• Less coverage means less to wade though
• Human selection can mean more wheat and less chaff

Disadvantages of using subject directories

• Smaller Coverage
• Human bias in selection

Example of a subject directory

Name: Yahoo

URL: http://www.yahoo.com/

General History: Developed by David Filo and Jerry Yang at Stanford. The name Yahoo! is supposed to stand for "Yet Another Hierarchical Officious Oracle" but Filo and Yang insist they selected the name because they considered themselves yahoos.

Size: Over 400,000 entries

Selection Method: Entries are added to Yahoo primarily through user submissions.

Other Information: One of the most popular of the subject directories. Yahoo also publishes a traditional magazine called "Internet Life."

Search engines constantly crawl the Web and generate huge catalogs of Web pages. Examples of popular search engines: Infoseek, AltaVista, Hotbot, Lycos, excite, and Northern Light.

Search engines have three major parts:

1. the spider or crawler;
2. the index or database;
3. and the search engine software.

The key difference between search engines and directories: Search engine databases are built by computers while directory databases are created by humans.

Differences between search engines

Consider some or all of these issues when selecting and using a search engine:

1. How large is the search engine database? AltaVista - 100 million pages; Infoseek - 30 million pages
   
   
2. What types of items are included in the database? AltaVista - Web pages, Usenet news; Infoseek - Web pages, Usenet news, company information, newswires
   
   
3. What options are available for searching the database?
   
   
   • Boolean operators? In AltaVista, use AND or &; in Infoseek, use a plus (+) sign
     
     
   • Truncation or stemming? In AltaVista, use an asterisk (*); Infoseek automatically stems words most of the time

   • Phrase searching (one type of proximity limit)? AltaVista and Infoseek both use quotation marks ("phrase searching")
     
     
   • Proximity operators? In AltaVista, use NEAR to search for terms within 10 words of each other; Infoseek does not support
     
     
   • Other filtering or limiting options? (for example, limiting by last modified date, domain, or words in document title)
     
     

Simultaneous search engines work by querying a number of other search engines at the same time, organizing the results, and then displaying them for you.

Examples of popular simultaneous search engines include MetaCrawler, SavvySearch, Profusion, DogPile.

Advantage of simultaneous search engines

One-stop shopping!

Limitations to keep in mind

1. Some of the busiest sites on the Net
2. May return few hits from each search engine
3. May be difficult to refine a query

Region- and subject-specific search tools

On the Web you can find directories and engines specific to both regions and disciplines. Here are a few:

Regional search tools

• AltaVista Europe (search engine; filters by language)
• Hola (search engine; search for Spanish and Portugese language pages, as well as those containing Latin American content)
• Simmany (Korean search engine)
• SAIR Search (South Asian Internet Resources - a search engine for India, Pakistan, Sri Lanka, Nepal, and Bangladesh)

Subject-specific search tools

• MathSearch (search engine)
• Diversity Database (directory)
• "All" Engineering Resources on the Internet (EELS) (search engine)
• James Kirk Search Engine (?)