1. Usability
ECE 695
Alexander J. Quinn
3/21/2016

2. Today
Midterm
Review 5 facets of usability

5. Five facets of usability
Learnability
Efficiency
Memorability
Errors
Satisfaction

6. learnability “The system should be easy to learn so that the user can begin working quickly.”
Credit: Jakob Nielsen, Usability Metrics: Tracking Interface Improvements, Interface, November 1996

7. efficiency “The system should be efficient so that once the user has learned it, high productivity is possible.”
Credit: Jakob Nielsen, Usability Metrics: Tracking Interface Improvements, Interface, November 1996

8. memorability “The system should be easy to use and remember, so that the casual user can return to it after not using it for a time and still know how it works.”
Credit: Jakob Nielsen, Usability Metrics: Tracking Interface Improvements, Interface, November 1996

9. errors “The system should have a low error rate, so users will encounter few errors; those they do encounter should be easy to recover from. Further, catastrophic errors mus not occur.”
For our purposes, we will focus on human errors.
Is it structured to mitigate inevitable limitations in human cognition and memory?
Can you gracefully recover from a human error?
Credit: Jakob Nielsen, Usability Metrics: Tracking Interface Improvements, Interface, November 1996

10. satisfaction “The system should be pleasant to use.”
Credit: Jakob Nielsen, Usability Metrics: Tracking Interface Improvements, Interface, November 1996