Cognitive Walkthrough

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Cognitive Walkthrough

• Evaluation method based on the idea that
• the user learns about the interface in an
  exploratory way,
• the user has goals,
• the user is applying simple means-ends reasoning.

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Cognitive Walkthrough

• Evaluation by an expert, who goes through a set
  task while imitating user performance

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Preparation We need four things

• User description including level of experience
  with computers and any assumptions made by the
  designer
• System description including operations and
  performance (e.g. paper design)
• Task description specifying the task that the
  expert has to carry out from users point of view
• Action sequence describing the system display and
  the user actions needed to complete the given
  task. One system display and one user action
  together are one step.

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Process of carrying out a Cognitive Walkthrough

• Prototype, user description, system description,
  task description and action list has to be
  prepared by the designer/developer
• Designer gives these document to an expert.
• The expert reads the descriptions.
• The expert carries out the task by following the
  action list.
• The expert asks the following questions with EACH
  step of the action list

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Questions Cognitive Walkthrough

1. Is the next goal clear at this stage?
2. Is the appropriate action obvious?
3. Is it clear that this action leads to the goal?
4. What problems are there in performing the action?

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Example the Automatic Nail Painter

• The automatic nail painter is a machine with
  which one can have ones nails painted.

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User Description Automatic Nail Painter

• The users are assumed to have no prior knowledge
  of how to operate the Automatic Nail Painter.
  However, they are assumed to have experience in
  putting nail varnish on nails manually

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System Description Automatic Nail Painter

• The system allows one finger to be placed into
  the machine at a time. The user programmes the
  machine for use by choosing- the number of
  fingers to be varnished- the colours of the
  varnish to be used- the number of coatings to be
  applied

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Task Description Automatic Nail Painter

• The user must get all ten fingers varnished with
  one coat of purple varnish. The system is already
  switched on when the user begins his/her task.
  The task is completed, when the tenth fingernail
  is varnished.

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Action list Automatic Nail Painter

• System System displays How many fingers do you
  want to varnish?User action user selects
  number 10 by pressing the or the - button until
  the appropriate number is shownSystem System
  responds by displaying the current number of
  fingers selected to be varnished.User action
  User presses ok when the correct number has been
  displayed

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Action list Automatic Nail Painter (cont.)

• System System displays choose the colour of
  varnish you wish to apply.User action User
  must select the colour purple by choosing from
  the colour menu. This includes scrolling up and
  down until s/he finds purple. S/he then has to
  press the OK button.System Systems displays
  how many coats do you want to apply?User
  action User selects the number of coats by
  pressing the or - button until the 1 is
  shown.

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Action list Automatic Nail Painter (cont.)

• System System displays the number of fingers to
  be varnished, the colour of the varnish and the
  number of coats to be applied. System asks for
  confirmationUser action User presses OK to
  confirmSystem System displays Press start to
  begin varnishing.User action User presses
  start buttonetc.

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Step 1- Question 1 Automatic Nail Painter

• From the action list Step 1System System
  displays How many fingers do you want to
  varnish?User action user selects number 10 by
  pressing the or the - button until the
  appropriate number is shown
• Question 1Is the goal clear at this stage? Not
  completely.The user is asked to state the
  number of fingers to be varnished. He could be
  thinking that the system deals with one hand at a
  time.

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Step 1 - Questions 2, 3, and 4Automatic Nail
Painter

• Question 2Is the appropriate action obvious?
  No.The system dos neither indicate that the user
  has to use the and - buttons nor explain
  their use.
• Question 3Is it clear that this action leads to
  the goal? YesIf the user presses the and -
  button the numbers are clearly displayed.
• Question 4
• What problems are there in performing the
  action?The action is simple to perform once the
  user has discovered the use of the buttons.

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Step 2 Question 1Automatic Nailpainter

• ?