Ch 11 Cognitive Walkthroughs
and Heuristic Evaluation
Yonglei Tao
School of Computing and Info Systems
GVSU
Heuristic Evaluation
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Usability experts evaluates an interface
according to a set of criteria
• Follow a scenario through the design
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Identify problem users would have when
interacting with the interface
• Make recommendations
•
Nielsen’s ten huristics
www.useit.com/papers/heuristic/heuristic_list.html
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Empirical Data
Factor 1:Visibility of system status
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Feedback: keep user informed about what goes on
Provide status information
Feedback: show that input has been received
Features change as user carries out task
Feedback provided for all actions
Feedback timely and accurate
Indicate progress in task performance
Direct manipulation: visible objects, visible results
Identity cues system response vs. user’s goals
Show icons and other visual indicators
WYSIWYG: do not hide features
What incorrect inferences are most likely
Empirical Data (Cont.)
Factor 2: Match between system and real world
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Speak the user’s language
Contains familiar terms and natural language
Speak the user’s language
Metaphors from the real world
Familiar user’s conceptual model
Use of user’s background knowledge
Learnable through natural, conceptual model
Follow real-world conventions
Screen representation matches non-computer
Encourage users to import pre-existing tasks
Identity cues between actions and user’s goals
Understand the user’s language
Empirical Data (Cont.)
Factor 3: User control and freedom
Undo and redo should be supported
 Obvious way to undo actions
 Forgiveness: make actions reversible
 Ability to undo prior commands
 Clearly marked exits
 Ability to re-order or cancel tasks
 Modeless interaction
 User control: allow user to initiate/control actions
 Modelessness: allow users to do what they want
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Empirical Data (Cont.)
Factor 4: Consistency and standards
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Consistency: express same thing same way
Consistency
Consistency: same things look the same
Uniform command syntax
Conform to platform interface conventions
Consistent key definitions throughout
Universal commands: a few, generic commands
Show similar info at same place on each screen
Empirical Data (Cont.)
Factor 5: Error prevention
◦ Prevent errors from occurring in the first
place
◦ System designed to prevent errors
◦ Understand the user’s language
◦ What planning mistakes are most likely?
◦ What slips are most likely?
◦ Identity cues between actions and user’s goals
Empirical Data (Cont.)
Factor 6: Recognition rather than recall
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See-and-point instead of remember-and-type
Make the repertoire of available actions salient
Seeing and pointing: objects and actions visible
All user needs accessible through the GUI
What features often missed and at what cost?
Provide lists of choices and picking from lists
Minimize the users’ memory load
Direct manipulation: visible objects, visible results
Easy or difficult to perform (execute) task?
Evoke goals in the user
Allow access to operations from other apps.
Clearly marked exits
Show icons and other visual indicators
Integrated with the rest of the desktop
Empirical Data (Cont.)
Factor 7: Flexibility and efficiency of use
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Accelerators should be provided
Shortcuts: Accelerators to speed up dialogue
User tailorability to speed up frequent actions
User control: allow user to initiate/control actions
System should be efficient to use
User interface should be customizable
Ability to re-order or cancel tasks
Keyboard core functions should be supported
Physical interaction with system feels natural
Interactive Heuristic
Evaluation Toolkit
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Allows you to do either of the following:
- View a list of the suggested heuristics for a
particular type of electronic device, or
- Select your own heuristics for a type of device
and then compare your selections against a list
of suggested heuristics
http://www.id-book.com/catherb/
Cognitive Walkthroughs
An evaluator steps through the action
sequence for a task and check the design
for potential usability problems
 Role-plays the part of a typical user and
tries to accomplish that user’s tasks
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Cognitive Walkthroughs
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Questions to ask at each step
◦ Will users know what to do?
◦ Will users see how to do?
◦ Will users understand from feedback whether
the action was correct or not?
Example of Cognitive Walkthroughs
Example of Cognitive Walkthroughs
A Scenario – Read Poems from
Multiple Issues
From the Home page, click on the Issues
link
2. From the Issues page, decide on an issue to
look at
3. Click on the appropriate issue link
4. Scan the TOC for a poem
5. Click on the poem’s link
6. Read the poem
7. Click on the global Issues link
8. Repeat steps 2-6
1.