Interface evaluation
An application of evaluative methods
Today’s topics
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Research methods
Web application
Navigation
Link structure (see slides in week)
Image (see slides in week)
Interactivity
User Information Behavior and Design
Implications
• Artifact models
• Examples with questionnaires
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Research methods
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Survey
Interviews
Focus groups
Observations/Contextual Inquiry
Usage Statistics, Log Analysis
Usability Testing
Card Sorting
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Comparison (I)
Research Methods
Pros and Cons
Best Used for
Survey
Pros: Reach many people
without geographical barriers.
Cons: Low response rate.
Ambiguity in question and/or
answer. Subjective and
retrospective.
Collect preferences and
opinions from one or many
large group(s).
Interviews
Pros: No ambiguity, can ask
follow-up questions to probe
unexpected topics or clarify
issues. Easy to conduct.
Cons: Subjective and
retrospective.
Understand business
stakeholders and their
objectives. Gain quick
understanding about issue,
problems and questions
based on verbal report.
Source: Ding, W. & Lin, X. (2010). Information architecture: The design and integration
of information spaces. Morgan & Claypool Publishers.
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Comparison (II)
Research Methods
Pros and Cons
Best Used for
Focus Groups
Pros: Like a group interview.
Can reach multiple people at
the same time. Participants
may be inspired by each other
and provide more valuable
ideas.
Cons: Participants’ opinions
may be influenced by others.
Out of context of the task.
Collect opinions, ideas and
visioning data. Good for
high-level starting points and
trend data.
Observations/Contex
tual Inquiry
Pros: Data gathering takes
Understand user tasks based
place in the context of user’s
on behavior. Understand
work. Data is more concrete.
user’s working environment.
Data is more objective, natural.
Cons: Opportunistic, time
consuming, large amount of
data, analysis takes time.
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Comparison (III)
Research Methods
Pros and Cons
Best Used for
Usage Statistics, Log
Analysis
Pros: Data is objective and rich. Identify usage patterns and
May discover in-depth
find problems that need
information about user failure. research.
Cons: Sheer volume of data.
Need coding or special
software to do analysis.
Usability Testing
Pros: Rich data both verbal
and behavioral.
Cons: Lab setting and artificial
tasks may decrease the value
of the data.
Card Sorting
Pros: Powerful tool can be used Best used for studying
both qualitatively and
users’ mental models
quantitatively.
Cons: Results need to be
presented in a meaningful
way.
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Effective in identifying
design defects.
Three Generations of the Web (I)
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Three Generations of the Web (II)
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Web Applications
Source: Ding, W. & Lin, X. (2010). Information architecture: The design and integration
of information spaces. Morgan & ClaypoolS519
Publishers.
Web 2.0 applications
• Wiki, blog, and SNS
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Example: Campaign websites
Sum
Barack Obama
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Michele Bachmann
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Ron Paul
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Rick Perry
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Mitt Romney
Sum
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5
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7
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6
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5
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7
5
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2
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Navigation (I)
• Purpose of navigation
– Where am I? (orientation).
– What can I do? (content, interaction, search).
– Where can I go from here?
• Drill up via global navigation.
• Parallel move via local navigation.
• Drill down via associative navigation.
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Navigation (II)
• Navigation types
– Global navigation and sectional navigation
– Local navigation
– Supplemental navigation
– Process navigation
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Compare the two navigation systems
• http://www.libraries.iub.edu/index.php
• http://www.lis.illinois.edu/
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Interaction Design Principles
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Design for Fitts
Design for Color Blindness
Design for Affordance
Design for Efficiency
Design for Forgiveness
Design for User Perceptions
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Fitt’s law: Design for Fitts
• Fitts’ Law maintains that the time required to
move rapidly from a starting point to a final
target area is a function of the distance to the
target and the size of the target.
• Bigger is better: Important functions should be
presented with large objects (reasonably big).
• Closer is faster: The contextual action buttons or
links should be presented within the reasonable
proximity of user activities.
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An example
• Which one is better?
• What about this?
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Design for color blindness
• Besides color, they also use shapes to convey
the information.
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Design for affordance
• An affordance is whatever can be done to an
object
– a chair affords sitting
– a button affords pushing
– a handle afford turning or pulling
• To ensure perceived affordance, the design
should meet user expectations. Following
conventions usually gives good affordance
– Make sure people can easily tell which is clickable and
which is not
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Design for efficiency
• Efficiency allows the user to accomplish the
task more quickly
• Ways to ensure efficiency
– decreasing data entry (Amazon)
– limiting decision making on the user’s side
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Design for forgiveness
• Forgiveness allows the user to feel less anxiety
about making mistakes, and allows for
imperfections in human activity.
• There are different ways to offer forgiveness
– Easy reversal of actions ((are you sure?) dialogs)
– Error prevention
– Error handling
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Design for user perceptions
• User perceptions are not always right
• However, it is very important for designers to
be aware of it during the design process
• It is important to provide multiple ways to
accommodate different users so that they can
choose the preferred method to perform their
tasks
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An example
• A classic example occurred in the 1930s in New York City,
where “users” in a large new high-rise office building
consistently complained about the wait times at the
elevators. Engineers consulted concluded that there was no
way to either speed up the elevators or to increase the
number or capacity of the elevators. A designer was then
called in, and he was able to solve the problem.
• What the designer understood was that the real problem
was not that wait time was too long, but that the wait time
was perceived as too long. The designer solved the
perception problem by placing floor-to-ceiling mirrors all
around the elevator lobbies. People now engaged in
looking at themselves and in surreptitiously looking at
others, through the bounce off multiple mirrors. Their
minds were fully occupied and time flew by.
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How people use websites (I)
• Users first read in a horizontal movement,
usually across the upper part of the content
area. This initial element forms the F’s top bar.
Next, users move down the page a bit and
then read across in a second horizontal
movement that typically covers a shorter area
than the previous movement. This additional
element forms the F’s lower bar. Finally, users
scan the content’s left side in a vertical
movement.
http://www.useit.com/alertbox/reading_pattern.html.
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How people use websites (II)
• Users tend to sacrifice information quality for
easy access (e.g. Wikipedia vs. Encyclopedia)
• Relying more on web search engines than
individual websites
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Work models
• Work models
– Work models = a graphical language to capture
knowledge about work
– Models make concepts concrete, in order for the
team to share and discuss ideas
– Models can be used to communicate with clients
• Types of work models
– Flow model, sequence model, culture model,
artifact model, and physical model
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Artifact model
• Artifacts are tangible things people create or use
to help them get their work done
• Presentations
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Information presented by the object
Parts of the object
Structure of the parts
Annotations
Presentation
Additional conceptual distinctions
Usage
Breakdowns
• A few examples
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Questionnaires on interface evaluation
• http://oldwww.acm.org/perlman/question.html
Acronym
QUIS
Instrument
Questionnaire for User
Interface Satisfaction
Perceived Usefulness and
Ease of Use
Nielsen's Attributes of
Usability
Nielsen's Heuristic Evaluation
Reference
Institution
Chin et al, 1988 Maryland
Example
27 questions
Davis, 1989
IBM
12 questions
Nielsen, 1993
Bellcore
5 attributes
Nielsen, 1993
Bellcore
10 heuristics
CSUQ
Computer System Usability
Questionnaire
Lewis, 1995
IBM
19 questions
ASQ
After Scenario Questionnaire Lewis, 1995
IBM
3 questions
PHUE
Practical Heuristics for
Usability Evaluation
Purdue Usability Testing
Questionnaire
Perlman, 1997 OSU
13 heuristics
Lin et al, 1997
Purdue
100 questions
USE Questionnaire
Lund, 2001
Sapient
30 questions
PUEU
NAU
NHE
PUTQ
USE
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