EXERCISE 7.12 [extra - not in book]
What are the three main categories of
usability principle? Choose one of them, and define
three principles that are included within it.
answer available for tutors only
- predictability: support for the user
to determine the effect of future action based on
past interaction history.
- synthesizability: support for the
user to assess the effect of past operations on
the current state.
- familiarity: the extent to which a
user's knowledge and experience in other real-world
or computer-based domains can be applied when interacting
with a new system.
- generalizability: support for the
user to extend knowledge of specific interaction
within and across applications to other similar
- consistency: likeness in input-output
behaviour arising from similar situations or similar
- dialog initiative: allowing the user
freedom from artificial constraints on the input
dialog imposed by the system.
- multi-threading: ability of the system
to support user interaction pertaining to more than
one task at a time.
- task migratability: the ability to
pass control for the execution of a given task so
that it becomes either internalized by user or system
or shared between them.
- substitutivity: allowing equivalent
values of input and output to be arbitrarily substituted
for each other.
- customizability: modifiability of
the user interface by the user or the system.
- observability: ability of the user
to evaluate the internal state of the system from
its perceivable representation.
- recoverability: ability of the user
to take corrective action once an error has been
- responsiveness: how the user perceives
the rate of communication with the system.
- task conformance: the degree to which
the system services support all of the tasks the
user wishes to perform and in the way that the user
Other exercises in this chapter
ex.7.1 (ans), ex.7.2 (ans), ex.7.3 (open), ex.7.4 (ans), ex.7.5 (ans), ex.7.6 (ans), ex.7.7 (tut), ex.7.8 (tut), ex.7.9 (open), ex.7.10 (tut), ex.7.11 (tut), ex.7.12 (tut), ex.7.13 (tut)
all exercises for this chapter