- Profile. A typical user’s prerequisite skills and experience.
- Effort. A limit on the number of user gestures (keystrokes, mouse clicks, etc.) it should take to accomplish a functional task.
- Duration. A limit on the amount of time that it will take a typical user to perform the functional task.
Ideally, the product manager addresses ease of use for the full continuum of skill and experience levels, but such metrics may not be realistic to formulate. It may suffice to specify metrics for a finite set of user levels, e.g.: