Information scent

1
Information scent

• Kathryn Summers
• 2003

2
Information scent

• The visual and linguistic cues that enable a
  searcher to determine whether a source,
  particularly a Web site, has the information they
  seek, as well as to navigate to the desired data.

3
Research Foundations

• Work on information foraging and information
  scent started in the 1990s (part of work on
  information visualization)
• Xerox PARC (Peter Pirolli, Stuart Card, Ed Chi,
  among others)
• Additional researchers (e.g., George Furnas, UM
  School of Information)

4
Information Scent

• Furnas (1997)--representational object holds a
  residue of what lies behind it.
• Residue recast and refined by Pirolli (1997) as
  information scent and defined in Card et al.
  (2001)
• profitability of an information source-- the
  value of information gained per unit cost of
  processing the source.

5
Dr. Ed Chi

• Start with a search engine, then "hub-and-spoke"
  surfing begin center, follow trail based on
  information scent.
• Continue on trail if scent is strong
• If trail is or becomes weak, go back to hub
• Continue until satisfied
• Users may switch strategies
• Go to a different search engine
• Quit if too many trails, too many choices

6
Information scent and usability

• Usability increases as the cognition necessary to
  find information decreases
• Make information trails so clear that users can
  follow them with less cognitive effort
• Revenue increases as usability increases (ideally)

7
Why It Matters to Get Scent Right

• Saved time
• Saved patience
• Increased productivity
• Increased satisfaction
• Increased usability

8
Cost of information foraging

• Cost
• time spent,
• resources utilized
• opportunities lost when pursuing this strategy
  instead of others. (Russell, 1993)

9
How much information is enough?

• Satisficing versus optimal foraginguser
  testing shows that users have different
  aspiration levels (Krug, 2000, p.24)
• Pirolli--satisficing can often be characterized
  as localized optimization (e.g., hill climbing)
  with resource bounds and imperfect information as
  included constraints.

10
Staying on the path

• Informavores will keep clicking as long as they
  feel like they're "getting warmer" -- the scent
  must keep getting stronger and stronger, or
  people give up.
• Progress must seem rapid enough to be worth the
  predicted effort required to reach the
  destination.

11
Cost-benefit analysis for navigatin

• What gain can I expect from a specific
  information nugget (such as a Web page)?
• What is the likely cost to discover and consume
  that information? (typically time and effort, or
  even money in micropayment system.)
• Users make estimates to answer these questions,
  based on their experience or on design cues

12
Abandoning the path

• Reasons to change sites
• Too many links
• Confusing page layouts
• Users "decide to quit not because the information
  isn't there, but because the amount of cognition
  it would take is so high," Chi said.

13
Foraging for food

• Animals make decisions on where, when, and how to
  eat.
• Suboptimal behaviors result in starvation, and
  thus fewer offspring that follow those behaviors
  in subsequent generations.
• After thousands of generations, optimal
  food-gathering behavior is all that's left.

14
Patch foraging theory

• Information foraging predicts that the easier it
  is to find good patches, the quicker users will
  leave a patch.
• Googleemphasizes quality in sorting search
  results. Its easy for users to find other good
  sites. Thus, the less time users will spend on
  any one site.
• Broadband means internet connection is always
  onfacilitates information snacking rather than
  extended foraging

15
How things change

• Moving between sites has always been easy. But,
  from an information foraging perspective, it used
  to be best if users stayed put because the
  probability that the next site would be any good
  was extremely low.
• Jakobs advice to early website designers
• Convince users that the site is worthy of their
  attention. (good information, easy to find)
• Make it easy for users to find even more good
  stuff so that they stay rather than go elsewhere.
  (sticky sites)

16
Jakobs advice now

• Google and always-on connections have changed the
  most fruitful design strategy to one with three
  components
• Support short visits be a snack
• Encourage users to return use mechanisms such as
  newsletters as a reminder
• Emphasize search engine visibility and other ways
  of increasing frequent visits by addressing
  users' immediate needs

17
Sites with good information scent

• Good content
• Easy to find
• links and category descriptions explicitly
  describe what users will find at the destination
  (Top level labels/categories provide scent for
  everything under them

18
Understanding Information Scent

• Each label on a website has a semantic
  relationship with the links to which it leads
• Think of the top-level label as carrying a
  residue of the lower-level labels. This residue
  is the scent we follow.
• Careers carries a strong, distinct residue for
  the Open Positions and Employee Benefits
  subnavigation links.

19
Scent and Information Processing

• Choosing among information scents seems to
  involve preconscious processing
• Scent draws on our existing semantic networks,
  vast numbers of nodes (with one node per concept)
  interconnected in various relationships

20
Semantic Networks
Tie
Fire
Pants
Shirt
Red
Blue
Clouds
Plants
Sky
Green
Airplane
Grass
21
Spreading Activation

• Activation of one node spreads down the paths to
  related nodes, in a ripple effect
• As the activation spreads further from the
  source, it decreases in strength
• Distance of nodes from one another, as well as
  the weight (strength) of the connection, is based
  on how closely related they are in your experience

22
Spreading Activation and Scent

• The labels chosen for links activate these nodes
  and cause the spreading activation
• We choose the link label with the strongest
  relationship to what we are seeking, based on
  what we have encoded in our semantic networks

23
Determining Good Scent

• Browsing The user starts at the home page and
  arrives at the desired information simply by
  choosing the best link at each level of the
  site.
• Search The user searches and either finds the
  desired information or arrives at a page where
  local navigation conveys sufficient scent to
  reach the goal.

24
Facet-Based Browsing

• Rather than trying to capture the whole scent in
  one label, another option is to allow browsing by
  facet
• A facet is an aspect or dimension of an object or
  piece of information
• Each facet is a scent trail that can lead to the
  object or information

25
Three Indicators of Poor Scent

• Indecision (Which path to take? More than one
  looks like a possibility.)
• Frustration (None of these look good)
• Confusion (What does this word mean?)

26
Qualitative User Test Metrics

• User comments
• both written and verbal
• Signs of indecision
• hovering back and forth between two global
  navigation links
• Indications of frustration and confusion

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Quantitative User Test Metrics

• Path directness
• determine optimal path and number of clicks
• calculate number of clicks it takes user to reach
  destination and compare
• Path frequency
• which paths are chosen most frequently?
• Time Completion Rate
• Satisfaction

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Stress Test Criteria

• Looking at the subpage, identify the following
  items
• The name of the website
• The title of the page
• The section of the website you are in
• The path from the home page to your location
• Other pages at the same level
• Pages further down from your location