Tutorial 3:

Searching the Web

Objectives

• Session 3.1

– Determine whether a research question is specific or exploratory – Formulate an effective Web search strategy to answer research questions – Use Web search tools including search engines, Web directories, metasearch engines, and Web bibliographies effectively New Perspectives on the Internet, 9th Edition 2

Objectives

• Session 3.2

– Apply Boolean logic and filtering techniques to improve your Web searches – Perform complex searches in search engines – Use advanced search options in Web search engines – Assess the validity and quality of Web research resources New Perspectives on the Internet, 9th Edition 3

Session 3.1 Overview How a Search Engine Works

New Perspectives on the Internet, 9 th Edition 4

Types of Search Questions

• • A specific question is a question that you can phrase easily and one for which you will recognize the answer when you find it An exploratory question is an open-ended question that can be harder to phrase; it also is difficult to determine when you find a good answer New Perspectives on the Internet, 9th Edition 5

Types of Search Questions

• Finding Answers to Specific Questions – Can be answered with a single fact or set of information – The search for the answer involves a process of narrowing down the range of potential answers you examine in each step New Perspectives on the Internet, 9th Edition 6

Types of Search Questions

• Finding Answers to Specific Questions (continued) New Perspectives on the Internet, 9 th Edition 7

Types of Search Questions

• Finding Answers to Exploratory Questions – Cannot be answered with a single fact or set of information – Search starts with general questions that lead to other, less general questions – Scope broadens as you gather information pertinent to the exploratory question New Perspectives on the Internet, 9 th Edition 8

Types of Search Questions

• Finding Answers to Exploratory Questions (continued) New Perspectives on the Internet, 9th Edition 9

•

Formulating Effective Web Search Strategies

For specific questions: – Formulate and state your question – Select the appropriate tool(s) to use in your search – Translate your question into a search query – Run the query and evaluate your results – If results do not answer the question: • • Continue the search with a different search tool Revise and narrow the question and repeat the process New Perspectives on the Internet, 9 th Edition 10

•

Formulating Effective Web Search Strategies

For exploratory questions: – Formulate and state your question – Select the appropriate tool(s) to use in your search – Translate your question into a search query – Run the query and evaluate your results – If results do not answer the question, formulate and state additional questions and repeat the process until there is sufficient information to answer the question New Perspectives on the Internet, 9 th Edition 11

•

Formulating Effective Web Search Strategies

An important part of searching is evaluating the quality of the search results New Perspectives on the Internet, 9 th Edition 12

Web Search Tools

• Web search tools include four broad categories of sites: – Search engines – Directories – Metasearch engines – Other Web resources such as Web bibliographies New Perspectives on the Internet, 9th Edition 13

Web Search Tools

• Understanding Search Engines – A Web search engine is a Web site that finds other Web pages that match a word or phrase you enter – The word or phrase you enter in a search engine is called a search expression or a query – A search expression might also include instructions that tell the search engine how to search – A basic search page includes a text box for entering a search expression and a command button to begin the search New Perspectives on the Internet, 9th Edition 14

Web Search Tools

New Perspectives on the Internet, 9th Edition 15

Web Search Tools

• Understanding Search Engines (continued) – A Web robot, also called a bot or a spider, is a program that automatically searches the Web to find new Web sites and update information about old Web sites that are already in the database – – One of a Web robot’s more important tasks is to delete information in the database when a Web site no longer exists All search engines provide a series of results pages, which are Web pages that list hyperlinks to the Web pages containing text that matches your search expression New Perspectives on the Internet, 9th Edition 16

Web Search Tools

• Understanding Search Engines (continued) – A hit is a Web page that is indexed in the search engine’s database and that contains text that matches a specific search expression – – A hyperlink to a Web page that no longer exists or has been moved to another URL is called a dead link Web pages or Web sites that have a number of dead links are said to suffer from link rot – Most search engines label paid placement links as “sponsored,” and they are called sponsored links – If the advertising appears in a box on the page, it is usually called a banner ad New Perspectives on the Internet, 9th Edition 17

Web Search Tools

• Understanding Search Engine Databases – A meta tag is HTML code that a Web page creator places in the page header for the specific purpose of informing Web robots about the content of the page – Search engines that store a Web page’s full contents are called full text indexing engines – Many search engines omit stop words such as and, the, it, and by from their databases New Perspectives on the Internet, 9th Edition 18

Web Search Tools

• Understanding Search Engine Databases (continued) New Perspectives on the Internet, 9th Edition 19

Web Search Tools

• Search – Engine Features Page ranking is a way of grading Web pages by the – number of other Web pages that link to them Inbound links are the connections or links from – other pages Most search engines use stemming to search for variants of keywords automatically New Perspectives on the Internet, 9th Edition 20

Web Search Tools

New Perspectives on the Internet, 9 th Edition 21

Web Search Tools

• Search Engine Features (continued) – A natural language query interface allows users to enter a question exactly as they would ask a person that question – The procedure of converting a natural language question into a search expression is sometimes called

parsing

New Perspectives on the Internet, 9th Edition 22

Web Search Tools

• Using Directories and Hybrid Search Engine Directories – A Web directory is a listing of hyperlinks to Web pages that is organized into hierarchical categories – The combination of search engine and directory is sometimes called a hybrid search engine

directory

– Yahoo! Directory includes 16 main categories – The Open Directory Project uses the services of more than 40,000 volunteer editors who maintain listings in their individual areas of interest New Perspectives on the Internet, 9th Edition 23

Web Search Tools

• Using Metasearch Engines – A metasearch engine is a tool that combines the power of multiple search engines New Perspectives on the Internet, 9th Edition 24

Web Search Tools

• Using Web Bibliographies – The Web includes Web bibliographies, another category of resource for searching the Internet – Web bibliographies are also called resource lists, subject guides, clearinghouses, and virtual

libraries

– Can be very useful when you want to obtain a broad overview or a basic understanding of a complex subject area New Perspectives on the Internet, 9th Edition 25

Session 3.2 Visual Overview Evaluating Web Sites

New Perspectives on the Internet, 9 th Edition 26

Using Logical Operators and Filtering Techniques in Complex Searches

• • • Logical operators specify the relationship between the elements they join The most commonly used logical operators in complex Web searching are Boolean operators, named for George Boole, a nineteenth-century British mathematician who developed a system of logic called Boolean algebra Boolean algebra is the branch of mathematics and logic in which all values are reduced to one of two values (usually true or false) New Perspectives on the Internet, 9th Edition 27

Using Logical Operators and Filtering Techniques in Complex Searches

New Perspectives on the Internet, 9th Edition 28

Using Logical Operators and Filtering Techniques in Complex Searches

• Other Search Expression Operators – A precedence operator, also called an inclusion operator or a grouping operator, establishes grouping levels within a complex expression New Perspectives on the Internet, 9th Edition 29

Using Logical Operators and Filtering Techniques in Complex Searches

• • Other Search Expression Operators (continued) – A location operator, or proximity operator, lets you search for terms that appear close to each other in the text of a Web page Wildcard Characters – A wildcard character allows you to omit part of a search term – The asterisk (*) is the most common wildcard character New Perspectives on the Internet, 9th Edition 30

Using Logical Operators and Filtering Techniques in Complex Searches

• Search Filters – Many search engines allow you to restrict your search by using search filters – A search filter eliminates Web pages from search results – Filter criteria can include such Web page attributes as language, date, domain, host, or page component (URL, hyperlink, image tag, or title tag) New Perspectives on the Internet, 9th Edition 31

Performing Complex Searches

• • Most search engines implement many operators and filtering techniques; the way in which they are applied differs Using Exalead to Perform a Boolean Search – Exalead is a search engine that allows the use of several Boolean and precedence operators – To create an effective search expression, you must identify search terms that might lead you to appropriate Web pages New Perspectives on the Internet, 9 th Edition 32

Performing Complex Searches

• Using Exalead to Perform a Boolean Search (continued) New Perspectives on the Internet, 9 th Edition 33

Performing Complex Searches

• Filtered Search in Google New Perspectives on the Internet, 9 th Edition 34

Performing Complex Searches

• Using Search Engines with Clustering Features – Some search engines group their search results into clusters – The clustering of results is similar to a filtering effect; however, the filtering is done automatically by the search engine after it runs the search – None of the search results are discarded; they are simply sorted into multiple categories, or clusters – Clustering can be especially effective when a word in the search expression has multiple meanings New Perspectives on the Internet, 9 th Edition 35

Exploring the Deep Web

• • • • A static Web page is an HTML file that exists on a Web server computer Many Web sites store information in a database, and when a user submits a query, the site’s Web server searches the database and generates a Web page on the fly that includes information from the database These generated pages are called dynamic Web

pages

Deep Web, hidden Web, and invisible Web are terms for the information contained in the databases that some Web sites use to generate dynamic pages New Perspectives on the Internet, 9th Edition 36

• •

Evaluating Web Research Resources

When you are searching the Web for an answer to a serious research question, the risks of obtaining and relying on inaccurate or unreliable information can be significant Reduce risks by evaluating carefully the quality of any Web resource; you can evaluate four elements of any Web page: – Authorship – Ownership – Content – Appearance New Perspectives on the Internet, 9th Edition 37

• •

Evaluating Web Research Resources

Authorship, Expertise, and Objectivity – Consider whether the qualifications presented pertain to the material that appears on the Web site – Author info should include the author’s affiliations with organizations related to the site information Web Site Ownership and Objectivity – – Most Web sites include information about ownership on their About pages Examine the domain identifier in the URL New Perspectives on the Internet, 9th Edition 38

Evaluating Web Research Resources

• Accuracy, Relevance, Scope, and Objectivity of Content – Determine the timeliness of the content – Read with a critical eye and evaluate whether the included topics are relevant – Evaluate the scope of the site; determine whether important topics or considerations are omitted – Confirm the Web page content’s objectivity • Form and Appearance – A legitimate source of accurate information usually presents its information in a professional form New Perspectives on the Internet, 9th Edition 39

• •

Evaluating Web Research Resources

Evaluating the Quality of a Web Page – Identify the author, and his or her credentials and objectivity – Examine Web site content for accuracy, relevance, – scope, and objectivity Evaluate the site’s form and appearance to determine quality and appropriateness Evaluating Wikipedia Resources – Wikipedia is a Web site that hosts a community edited set of online encyclopedias New Perspectives on the Internet, 9th Edition 40