Cognitive Walkthough

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Cognitive Walkthough

• Evaluation by simulating users

This material has been developed by Georgia Tech
HCI faculty, and continues to evolve.
Contributors include Gregory Abowd, Jim Foley,
Diane Gromala, Elizabeth Mynatt, Jeff Pierce,
Colin Potts, Chris Shaw, John Stasko, and Bruce
Walker. Comments directed to foley_at_cc.gatech.edu
are encouraged. Permission is granted to use with
acknowledgement for non-profit purposes. Last
revision February 2004.
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Cognitive Walkthrough (CW)

• Assess learnability and usability through
  simulation of way users explore and become
  familiar with interactive system
• A usability thought experiment
• Requires fairly detailed (paper) description of
  prototype
• Like code walkthrough (s/w engineering)
• From Polson, Lewis, et alat UC Boulder

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CW Process

• Construct carefully designed tasks from system
  spec or screen mock-up
• Walk through (cognitive operational) activities
  required to go from one screen to another
• Review actions needed for task, attempt to
  predict how users would behave and what problems
  theyll encounter

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CW Requirements

• Description of users and their backgrounds
• Description of task user is to perform
• Complete list of the actions required to complete
  task
• Prototype or description of system

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CW Assumptions

• User has rough plan
• User explores system, looking for actions to
  contribute to performance of action
• User selects action seems best for desired goal
• User interprets response and assesses whether
  progress has been made toward completing task

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CW Methodology

• Step through action sequence
• Action 1
• Response A, B, ..
• Action 2
• Response A
• ...
• For each one, ask four questions and try to
  construct a believability story

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CW Four Questions

• Will users be trying to produce whatever effect
  action has?
• Will users be able to notice that correct action
  is available?
• Once found, will they know its the right one for
  desired effect?
• Will users understand feedback after action?

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CW Question 1

• Will user be trying to produce whatever effect
  (ie, result) the action has?
• Typical supporting Evidence
• It is part of their original task
• They have experience using the system
• The system tells them to do it
• No evidence?
• Construct a failure scenario
• Explain, back up opinion

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CW Question 2

• Will the user notice action is available?
• Typical supporting evidence
• Known from use experience
• Visible device, such as a button
• Perceivable representation of an action such as a
  menu item

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CW Question 3

• Once user finds the correct action at the
  interface, will user know its the right one for
  creating the desired result?
• Typical supporting evidence
• Experience
• Interface provides a visual item (such as prompt)
  to connect action to result effect
• All other actions look wrong

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CW Question 4

• Will user understand the feedback?
• Typical supporting evidence
• Experience
• Recognize a connection between a system response
  and what user was trying to do

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Believability story summary

• 1. Will the user be trying to produce whatever
  effect the action has?
• 2. Will the user be able to notice that the
  correct action is available?
• 3. Once the user finds the correct action at the
  interface, will she know that it is the right one
  for the effect she is trying to produce?
• 4. After the action is taken, will the user
  understand the feedback given?

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Remember

• You can do this on paper prototypes
• Early in design process
• Use on multiple early designs
• Combine with simple action counts to begin
  assessing speed of use

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Do it Yourself - the VCR

• Program VCR
• List actions
• Ask questions