Chapter 08 - Usability Studies & Usability Testing

Question 1

Usability Studies

Answer 1

help to make good initial decisions and may be collected any time in the design process.

Question 2

Usability Tests

Answer 2

used to evaluate design decisions after they are implemented.

Question 3

Methods for Usability Studies

Answer 3

Observations
Questionnaires
Interviews
   - Face to Face
   - Telephone

Question 4

Usability Testing method

Answer 4

Should evaluate human performance and user preference.

Question 5

Usability Engineering

Answer 5

combining prototyping and usability testing

1. Set acceptable usability levels (goals)
2. Conduct usability testing
3. Make required changes

Repeat until goals are met

Question 6

What is the relationship between Performance and

Preference?

Answer 6

71% perform well and like a system or perform poorly and dislike a system.

29% perform well and dislike a system or perform poorly and like a system. (Nielsen & Levy, 1994)

*** Preferences of system designers do not always lead  to the best performance-related design decisions.

Question 7

Preferences and Performance Scores for Alternative User Interfaces

Answer 7

A follow-up study reported similar results (Bailey, 1993). A study was conducted to determine the best screen-based control for a new application. Forty-six computer professionals practiced using four different methods and then selected the one that they thought would elicit the fastest performance.
The same people then participated in a performance test. The results are shown in Table 8-2. Again, a relatively large percentage of the designers preferences did not elicit the fastest performance.

Question 8

Types of Usability Tests

Answer 8

Formal = using theories to make predictions.

Inspection= walkthroughs, questionnaires

Performance = well-controlled simulations of people performing activities using system prototypes.

Operational = methods used after a product is delivered.

Question 9

Predicting Human Performance

Answer 9

Is the Principle purpose of usability testing.

• Fidelity= variable that largely determines the predictive power of a usability test.
• The fidelity of test conditions is directly related to cost and inversely related to the ease with which meaningful changes can be made to the system.

Question 10

System Performance

Answer 10

Accuracy Objective

Cost-effective performance

User acceptance