6. Usability
• Learnability: time to learn the application
• Efficiency: time to perform task
• Memorability: timethat users remember how and what
• Accuracy: number and kind of errors
• satisfaction: subjective feeling
Often a compromise - important to make explicit
7. •
tijdens het ontwikkelen
•
om te verbeteren
•
summatief
•
op het einde
•
om te bewijzen dat “het (niet) werkt”
•
formatief
11. Usability engineering
• ‘Think-aloud protocol‘
• Video recording with annotation
• Log, remarks, etc. for analysis
• ‘Discount usability engineering’
• Comparative test of user interface
12. By experts
•
•
•
•
in HCI or domain
very effective
delicate relation with developers
target
• identify problems
• suggest solutions
• through checklist of guidelines
14. Participants
• representative
• computer experience, language, task,
motivation, education, etc.
• gender, age
• have to know they are not being evaluated
• relationship
• colleagues, friends, family, ...
18. • every test user finds fraction L of usability
issues
• independent test users
n
n users find fraction 1-(1-L)
• L=31%
L=8%
85% for n=5, 99% for n=15
35% for n=5
