Download
1 / 15
170 likes | 394 Views
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. Cognitive Walkthrough.
E N D
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.
Cognitive Walkthrough • Evaluation by an expert, who goes through a set task while imitating user performance
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.
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:
Questions Cognitive Walkthrough • Is the next goal clear at this stage? • Is the appropriate action obvious? • Is it clear that this action leads to the goal? • What problems are there in performing the action?
Example: the Automatic Nail Painter • The automatic nail painter is a machine with which one can have one’s nails painted.
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
System DescriptionAutomatic 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
Task DescriptionAutomatic 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.
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
Actionlist 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.
Actionlist 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.
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 1:Is 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.
Step 1 - Questions 2, 3, and 4Automatic Nail Painter • Question 2:Is the appropriate action obvious? No.The system dos neither indicate that the user has to use the ‘+’ and ‘-’ buttons nor explain their use. • Question 3:Is 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.
