Usability Evaluation (Week 4) Flashcards
Five Components of Usability (according to Nielson)
- Learnability
- Efficiency
- Memorability
- Errors
- Satisfaction
Learnability
How easy is it for users to accomplish basic tasks the first time they encounter the design?
Efficiency
Once users have learned the design, how quickly can they perform tasks?
Memorability
When users return to the design after a period of not using it, how easily can they reestablish proficiency?
Errors
How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
Satisfaction
How pleasant is it to use the design?
Usability
How well a system satisfies its intended use.
Usefulness
How much value a system offers to its user.
Desirability
How desirable the system is for its user.
Why Things are not usable (according to Rubin & Chisnell)
- Development focuses on the machine or system.
- Target audiences change and adapt.
- Designing usable products is difficult.
- Team specialists don’t always work in integrated ways.
- Design and implementation don’t always match.
How to make things usable (according to Rubin & Chisnell)
- Early focus on users and their tasks
- Evaluation and measurement of product usage
- Iterative design
Empirical Methods of Usability Evaluation
- Usability Testing
- Performance Evaluation
- Behavior Evaluation
- Measuring Satisfaction
Non-empirical methods of Usability Evaluation
- Cognitive modeling
- Heuristic evaluation
- Cognitive walkthrough
Five Characteristics of Usability Evaluation according to Dumas and Redish (1999)
- The goal is to improve usability
- The participants represent real users.
- The participants do real tasks.
- You observe and record what the participants do and say.
- You analyze the data, diagnose the real problems, and recommend changes to fix the problems.
Why usability evaluation is NOT a scientific experiment
- Experimental control is not as necessary
- Data measurement is not as precise
- Changes can be made mid-test to explore alternatives
- The exact same test does not have to be repeated precisely for each user.
- The number of participants is fewer in usability testing than in scientific experiments.
- Hypotheses and inferential statistics are used less often.