Recommended methods: 3. Task scenarios

Cost-effective User Centred Design

Recommended methods: 3. Task scenarios

Methods
– Basic
– Recommended
   0. Maturity assessment
   1. Stakeholder meeting
   2. Context of use
   3. Task scenarios
   4. Test existing system
   5. Usability requirements
   6. Paper prototyping
   7. Style guides
   8. Evaluate prototype
   9. Usability testing
10. Collect feedback
      Specialised methods

– Satisfaction questionnaires
– Web site design
– Instructional systems design
– List of methods
– Integration with development

Purpose

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 are used.

Benefits

•It encourages designers to consider the characteristics of the intended users, their tasks and their environment.

•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 design approach.

•Scenarios can also be used to generate contexts for evaluation studies.

•Only minimal resources are required to generate scenarios.

•The technique can be used by developers with little or no human factors expertise.

Method

An experienced moderator is recommended for the sessions in which the scenario is explored.

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 development team.
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 usability targets.
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.

Practical guidelines

• 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.

More information

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 be operated.

Next steps

Use the scenarios as a basis for developing more specific usability requirements.

Last updated 19-Nov-00