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Types of Search Tools

here are SIX major types of search tools on the Web. While each in them have its own features relevant to its collection, collection development system/technique and its presentation method.

        This is the most commonly used type of tool for finding information on the internet. Search engines utilize software to automatically generate a database of websites and pages loaded on the web. Search engines generally have three major parts: first is 'spider' or 'crawler'; it crawls and visits web pages continuously to create the database with new uploaded web pages. Second is database, also sometimes called a catalogue or index, which contains a copy of every web page that the spider finds. and third is the search engine, the program that answer our queries by sifting though its huge collection of pages to find matches to our queries. While to update its collection normally spider crawls weekly to find updates of existing pages and new web pages.

         However search engines are problematic because being machines they do not think of quality, anyone, anywhere can publish information. Here in search engines is the lack of quality control, means that the vast quantities of retrieved information can range from potentially high quality sources to highly dubious information.

Ranking: 

Normally search engines like Northern Light ranks the result through most relevance, it shows percentage against each searched record while listing most relevant first. The higher the figure more relevant a site is deemed to be. It assumes more relevant where your searched terms appear in the title of the page, near the top of the page, or appear frequently in the text. Remember you should not assume the ranking is always successful.

You may also wish to consult "What Makes a Search Engine Good?" - a table (PDF file) summarizing the factors I use to evaluate search engines overall.

In a meta-search engine, you submit keywords in its search box, and it transmits your search simultaneously to several individual search engines and their databases of web pages. Within a few seconds, you get back results from all the search engines queried. Meta-search engines do not own a database of Web pages; they send your search terms to the databases maintained by search engine companies.

Smarter Meta-Search Engines

There are two families of smarter meta-search engines at this time:

• Meta-searchers that search good databases, accept complex searches, integrate results well, eliminate duplicates, and offer additional features such as clustering by subjects within your search results. Some of the famous names are; Vivisimo (www.vivisimo.com) Metacrawler & Dogpile (metacrawler.com) (dogpile.com).
  

• Tools for serious digging in many resources, with powerful abilities to help you find what you seek within search results. These are appropriate for very serious researchers to use for in depth probing of a topic. Some of the famous names are; SurfWax (www.surfwax.com), Copernic Agent (www.copernic.com)

Subject Catalogs & Directories:

Like gateways and Virtual Libraries, Subject catalogues or directories are created manually. Sites are submitted by the authors or developers, and then assigned to an to an appropriate subject category or categories by the catalogue or directory maintainers. However, unlike gateways and virtual Libraries, there is no selection and evaluation of the information to access its quality and authenticity of the material.

To confuse matters, many search engines like Google also include subject catalogue element and many real catalogues connect users automatically to a search engine to expand their search results.
 

Selected Subject Catalogs & Directories
Subject Directories	Librarians' Index www.lii.org	Infomine infomine.ucr.edu	Academic Info www.academicinfo.net Recommend Browsing	About.com www.about.com	Yahoo! dir.yahoo.com
Size, type	Over 13,000 Compiled by public librarians in information supply business. Highest quality sites only. Great, reliable annotations.	Over 115,000 Great, reliable annotations. Cooperatively compiled by university & college-level, academic librarians of the UC campuses.	Rich selection of about 25,000 pages, selected as "college and research level Internet resources" aimed at "at the undergraduate level or above." Brief annotations.	Over 1 million Generally good annotations done by "Guides" with various levels of expertise.	About 2 million. Scarce descriptions and annotations. Often useful, especially for popular and commercial topics.
Phrase searching (term definition)	Yes. Use " "	Yes. Use " " |term term| requires exact match	No. " " make searches fail.	Yes. Use " "	Yes. Use " "
Boolean logic (term definition)	AND implied between words. Also accepts OR and NOT, and (   ).	AND implied between words. Also accepts OR.	OR implied between words. Accepts AND, OR, NOT and (  ) Recommend AND between words in most searches.	No.	No.
Truncation (term definition)	Use *. Also stems. Can turn stemming off on Advanced Search page.	Automatically expands words. Can turn stemming off. Use " " to search exact terms.	No.	Use *. Not accepted consistently.	No.
Field searching	Advanced Search allows Boolean searching within subject, titles, description, parts of URLs, and more.	Select boxes under search box to limit to KW (keyword) SU (subject) TI (title) AU (author) AN (annotation)	No.	No.	t:requires terms in title field u:requires terms in URL

Invisible Web:

The "invisible web" is what you cannot retrieve ("see") in the search results and other links contained in these types of tools.

• Searchable Databases. Most of the invisible web is made up of the contents of thousands of specialized searchable databases that you can search via the Web. The search results from many of these databases are delivered to you in web pages that are generated just in answer to your search. Such pages very often are not stored anywhere: it is easier and cheaper to dynamically generate the answer page for each query than to store all the possible pages containing all the possible answers to all the possible queries people could make to the database. Search engines cannot find or create these pages.

• Excluded Pages. There are some types of pages that search engine companies exclude by policy. There is no technical reason they could not include them if they wanted. It's a matter of selecting what and what not to include in databases that are already huge, expensive to operate, and whose search function is a low revenue producer.

How to Find the Invisible Web

Simply think "databases" and keep your eyes open. You can find searchable databases and other invisible web stuff in the course of routine searching in most general web directories. Of particular value in academic research are

• Librarians Index

• AcademicInfo

• Infomine

Use Google and other search engines to locate searchable databases by searching a subject term and the word "database".
To see some invisible web portals click here
 

Selected Directories of Searchable Databases
The Invisible Web Directory www.invisible-web.net	Directory of searchable databases. Use by browsing subjects; not searchable. "This site is a companion to The Invisible Web: Finding Hidden Internet Resources Search Engines Can't See, by Chris Sherman and Gary Price."
Direct Search www.freepint.com /gary/direct.htm	Several long pages listing and describing searchable databases on many academic topics. Pick the section or page from the links near the top. If you search, keep searches simple, because the search tool is not very good. Done by Gary Price, an academic librarian with research experience. HARD TO USE. Except in Business and Economics, I would use the other directories above.

Beyond Web:

      This is the most important portion of scholarly and quality information on the web, but usually researcher is not conversant with these mines of resources available.

      These resources may be virtual libraries and/or highly classified web catalogs etc. having specific information. These resources have their collection development policy and charges fee from the authors of the sources they are indexing and making part of their libraries. These libraries are manually constructed where each source is evaluated and rated. For theses selection reasons the sources like these have very less collections normally about three to fifty thousand.

Five-Step Search 

Step #2. Pick the right starting place using this table

Step #3. Learn as you go & VARY your approach with what you learn

Step #4. Don't bog down in any strategy that doesn't work.

Step #5. Return to previous strategies better informed

Bad Strategies

 Because of their inefficiency and often haphazard and frustrating results, we do not recommend either of the following two approaches to finding Web documents:

• Do not BROWSE searchable directories. If you can find a search box, then search a directory. BROWSING is a sometimes fun rarely as efficient. The term "directories" refers here to any collection of web resources organized into subject categories. Browsing locates documents by trying to match your topic in first that will lead you to your target. Browsing encounters the difficulty of guessing under which subject category your topic is classified. The category "health" may contain documents on medicine, homeopathy, psychiatry, and fitness in one directory. Searching (typing keywords in a search box) retrieves occurrences of your words no matter where they may be classified by subject. Use broad terms in searching any directory.
• Do not FOLLOW links. Often in search engine results, you will see links to sites that are selected based on how often they are visited by others, or based on fees paid to the browser.  Or you may see recommended "cool" sites.  Use these with caution!   Others may visit sites for reasons having no relation to your information interests, and the best sites for you may still be largely undiscovered by the vast public searching the Web.  Taste varies and should vary.  Make your own evaluations.

Quest for Quality

       There are few things that can help you in determining and searching the quality information on the Web.

• Learn to use Resources like search engines, meta search engines, gateways and virtual libraries  effectively, using search facilities to maximize quality information retrieval.
• Use virtual libraries and subject catalogues for quality information, Reason is that these are selected and evaluated resources by Librarians and Subject specialists. These resources have smaller collections but have quality.
• Avoid using search engines in the quest of quality only if you don't know effective searching strategies.
• Determine the perfect source for your information need
• Determine the best keywords or phrase as per your information need.
• After accessing the source though search engine or any where else assess the quality of the information source by:

Identifying the purpose of a source by clicking hyperlinks like ABOUT, SCOPE, PURPOSE etc

Assess the coverage of the source

Assess the authority and reputation of the source: Several techniques can be used to ascertain the authority and reputation. For academic works, literature search could be conducted to determine whether he or she has published in the field before, and whether he or she has published in refereed journals. Whether he or she is a professional working in the field or lay person with passing interest in a subject. 

There are some other alternatives to individual or institutional authority: one consideration is the address of the source, for example, .gov.uk and .gov in an address indicate governmental sites in the UK and the USA respectively, and .ac.uk and .edu indicate academic institutions. Web citation searching techniques can also be used to indicate authority. One further consideration is the use of counters - these often appear at the end of the home page or the first page of the site, and indicate how many people have visited the site during a specified period. But a site's popularity does not necessarily equate with its quality.

Assessing accuracy: Mathematical information can be either correct or incorrect, whereas theories can be subjective and there may be no right or wrong answer. surgical-tutor.org.uk includes the following questions for the critical appraisal for the paper: Who wrote the paper? do they or the institution have a proven academic record? is the paper interesting and relevant? did the study introduction address the relevant points? were the aims clearly stated? was an appropriate group of subjects studied? was the sample size justified? was the study design appropriate? are the conclusion of the paper justified? 

Assessing the currency and maintenance of a Source: Check its maintenance frequency means how often it is updated. how update and current is the information etc.

Make a comparison with other sources

Check kite marks, meta data and seals of approval: META DATA is Data about data. Meta data describes how and when and by whom a particular set of data was collected, and how the data is formatted. Meta data is essential for understanding information stored in data warehouses. BENCHMARKS are badge or logo displayed these are standards or averages by which similar items can be compared. it consists of symbols like stars, tick marks etc.

Choose the Best Search for your Information Need

For more information, please visit 

http://www.tempweb61.nic.in/tutGen1.htm

http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/Strategies.html

Note: If you experience some interesting techniques, share with us to share with others through this site