1. Lecture 8
Searching Part 2

2. Descriptive Terms
“Hit” on a page means search term is “associated” with the page
Does not mean word is “on” the page
Tags helps to identify descriptive text

3. Descriptive Terms Descriptive text Title—from <title> tag
Anchor text—from <a> tag
Meta—A <meta > tag in the head section
Alt attributes—from the <img > tag

4. Page Rank Top ten hits usually contain our “answer”
Order of hits is based on a number: PageRank

5. Links to Other Pages Google pioneered page ranking
PageRanking works like a voting system
Page A “votes” for B if it links to it
More links to page ==> higher ranking

6. Links to Other Pages Ranking is weighted too
PageRank is computed by the crawler
Looks at page A
Notices the links to page B
Scores one for B
More than counting links, though

7. Links to Other Pages After crawling, PageRank is computed
Query processor forms hit list
URLs are sorted by their page ranking

8. human AND powered AND flight
Advanced Searches
human AND powered AND flight
Logical Operator AND
Default query
Logical operators determine truth of a whole based on parts

10. human AND powered AND flight
Advanced Searches
human AND powered AND flight
Logical Operator AND
Three independent words
Words can appear anywhere on the page in any order
Use quotes for phrase

11. marshmallow OR strawberry OR chocolate
Complex Queries
marshmallow OR strawberry OR chocolate
OR-queries
At least 1

12. tigers AND NOT baseball
Complex Queries
tigers AND NOT baseball
Logical operator NOT
Above is combination of AND and NOT query

13. Combining Logical Operators
(marshmallow OR strawberry) AND sundae
Logical operators work like arithmetic
Can be combined and grouped using parentheses
Google also uses a minus for NOT

14. Restricting Searches Can perform a site search Search for phrase
biology site:millersville.edu
Search for phrase
“detroit tigers”

15. Filtered Searches
Other constraints can be used on advanced search

16. Web Searching Strategy for research on the web
Choose good search terms
Know the Anatomy of a Hit
Skim Hit List
Pick a Hit and locate info on page

17. 1. Selecting Search Terms
Determining precise terms
Advanced Search
General Topic
Descriptive Terms
Refining (Adding Words)
Avoiding Over Constraining
Removing Words

18. 1. Selecting Search Terms
Use Advanced Search
Lots of control
Google’s Advanced Search
language, region, last update, number ranges, etc.

19. 1. Selecting Search Terms
Begin with the General Topic
Suppose we want to find volume of boxcar
Try “boxcar volume”
Boxcar Willie’s Best Loved Favorites, Volume 2
Boxcar Willie’s Songbook, a three volume set
Volume Consultants vs. … at Boxcar Marketing
etc.
Add topic word “train”

20. 1. Selecting Search Terms
Choose Descriptive Words
Be precise
Your computer has Intel graphics
To learn more
Try “Intel cpu”
Try “Intel gpu”
comparison of Intel GPUs, GPU tools

21. 1. Selecting Search Terms
Refine by Adding Words
Try “Intel gpu Haswell”
Iris, reviews of Intel GPUs
Initial list suggests adding Iris (which you remember from your computer’s specs)
Iris Pro 5200 Review at AnandTech

23. 1. Selecting Search Terms
Avoid Over Constraining
Add more words one at a time
Bad: “Intel gpu Dell”
Be sure the word is necessary for result

24. 1. Selecting Search Terms
Remove Specific Words (Minus or NOT)
Often useful to eliminate pages with certain words
“Intel gpu Iris –iMac”

25. 2. Anatomy of a Hit What is displayed with each hit? Title Snippet
From tag
Snippet
Preview of what might be on the page
Usually short phrases from the page containing the search terms

26. 2. Anatomy of a Hit What is displayed with each hit? URL
Associated with title
Possibly Site Links
Shortcut links from the site
Not “sponsored” links
“Intel”
Jobs, Download Center, Company Overview

27. 3. Using the Hit List Skim top level Dig deeper if promising
Otherwise, continuing skimming

28. 3. Using the Hit List “Looking deeper” ranks the information Title
Snippet
Context
URL
Authoritative source?
Page itself

29. 4. Once You Find a Likely Page
A likely page has
Suggestive title
Promising snippet
Reliable domain
How close are we to what is wanted?
Skim page
Check date
Find keywords

30. 4. Once You Find a Likely Page
May have to return to hit list
May want to cross-check info
Find corroborating information!

31. Authoritative Information
Don’t Believe Everything You Read!
Facebook
Shark’s Love!
“A shark developed an affection for the fisherman who saved her life.”
“Once I stop the boat she comes to me, she turns on her back and let [sic] me pet her belly and neck, she grunts, …”
Read more on snopes.com
Blogs

32. Wikipedia Articles created by users Good starting point for research
Anyone can add/edit
Good starting point for research

33. Using the Web for Research
Apply good research practices
Question the information
Sensible? Believable? Consistent? Fit what you already know?
Use multiple sources
Off-line too
Assess the site’s authoritativeness

34. What Is Authoritative?
Authoritative means that we are looking for what experts say
Experts usu. well-informed
Usu. source of truth
Best we can do

35. Respected Sources Look for respected organizations Universities
Leading newspapers, magazines
Government

36. Primary Sources Primary source has direct knowledge of the information
People who interview primary sources are secondary sources
People who watch journalists on TV or read newspaper reports are tertiary sources

38. Primary Sources No guarantees even from primary sources
Perception bias

39. Authoritative Sources
Go to authoritative sites
NASA, USDA, Census Bureau, IRS, etc.
Dihydrogen Monoxide (
“DHMO is present in high levels nearly every creek, stream, pond, river, lake and reservoir in the U.S. and around the world.”

40. Site Analysis… Good? Bad?
Possible issues for bad sites
Broken links
Failure to give contact information
Failure to have a non-Web identity
Simplistic design
No recent updates or blog entries
Spelling mitsakes

41. Summary How search engines work How to use search engines effectively
Evaluating info on Internet