To provide examples of usage as an input to design, and to provide
a basis for subsequent usability testing. Scenarios specify how
users carry out their tasks in a specified context. To maintain
design flexibility, they should not specify what product features
It encourages designers to consider
the characteristics of the intended users, their tasks and their
Usability issues can be explored at a very early stage in
the design process (before a commitment to code has been made).
Scenarios can help identify usability targets and likely
task completion times.
The method promotes developer buy-in and encourages a user-centred
Scenarios can also be used to generate contexts for evaluation
Only minimal resources are required to generate scenarios.
The technique can be used by developers with little or no
human factors expertise.
moderator is recommended for the sessions in which the scenario
- Gather together the development team and other relevant
stakeholders under the direction of an experienced facilitator.
- Identify intended users, their tasks and the general
context. This information will
provide the basis for the scenarios to be created by the
- Functionally decompose user goals into the operations
needed to achieve them.
- Consider which activities should be performed by the user
and which by the computer.
- Assign task time estimates and completion criteria as
- The session can be videotaped for later review or transcribed
for wider distribution.
- The results from scenario building sessions can be used
to plan user-based evaluations.
Try to generate scenarios to cover
a wide range of situations, not just the most common ones or those
of most interest to the design team.
Try to include problem situations
that will test the system concept, not just straightforward scenarios.
Work through the scenarios fully and
judge the system on that basis rather than trying to change the
system half way through.
Scenarios are most useful when produced early in development as
specific realistic and detailed examples of what a user would do,
but without making any reference what user interface features that
would be used. See the examples.
Scenarios can also be used later to explore how the interface would
Use the scenarios as a basis for developing more specific usability