Design Considerations
Requirements Gathering
Envisionment Methods
Evaluation
Other
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PACT Analysis
What is a PACT Analysis?
- People: relevant user characteristics and skills
- Activities: how is the activity currently carried out?
Why? What can be improved?
- Context: the environment of the activity
- Technologies: what tools are used now, and how might
new developments be used?
People
- Cognitive characteristics - level and duration of attention, perception,
memory, learning abilities, cognitive capabilities,
fears, personality characteristics
- Physical characteristics - age differences,
physical abilities,
- What motivates, pleases and engages - affect
- Experience & expectations - novice v's expert
- Language
- Culture - For example, in Microsoft Excel there are two buttons, one labeled with a cross and the other a tick. In the US a tick is used for acceptance and the cross rejection, but in Ireland a tick or a cross can be used to show acceptance (e.g. a cross on a ballot paper).
- Special needs - blindness, colour blindness, deafness, wheel chair user
- Homogenous vs heterogeneous user groups - website site users are (normally) heterogeneous - many different types of people; users of a company's intranet are (generally) homogenous
- Discretionary vs committed users - does the user have a choice? if yes, then you need to encourage them to return
- Infrequent vs frequent users - if users are normally infrequent, then interface must be particularly 'helpful' as users will forget how to complete complicated tasks.
Activities
- Goals, tasks and actions
- Regular or unusual, weekly? Yearly? - frequent tasks should be easy to do; infrequent tasks should be easy to learn or remember
- Well-defined or vague
- Continuous or interrupted - user may need to 'find their place' again
- Current task practices
- Individual vs co-operative work
- Multi-tasking vs serial tasks
- Passive vs active,
- Quality vs quantity trade-off
- Data input requirements
- Length of time on tasks - peaks and troughs of working, need for fast
response
- Coping with errors - presentation of error messages, how to deal with
them, how the system accommodates them, significance of errors, safety
critical errors
Context
- Physical environments - noisy, cold, wet, dirty, stressful, uses dangerous
materials, sunny
- Social environments - channels of communication, structure,centralisation vs decentralisation, home, mobile, training materials
- Organisational context - relationships with customers, other staff, effect
on work practices and job content, role, deskilling, job loss, shift in
power
- Circumstances under which activities happen (time, place, pressure of
work/time)
- Amount and type of support for activities - tuition, manuals, demonstrations,
new knowledge, new skills
Technologies
- Input - Getting data in; getting commands; security
- Output - Characteristics of different displays (e.g. video vs. photographs;
speech vs. screen)
- Communications - Between people, between devices, speed, etc. - What
is connected to what?
- Size of screen
- GUI or not?
- Sound?
- Networked or stand alone.
- Always on or dial in?
- Real-time systems;
- Safety critical systems;
- Walk-up-and-use systems (e.g. kiosks) / Office systems / Palm pilot
application / Web site.
Why Use it?
- More detailed design brief
- And/or specification
- And/or user requirements document
- Key points for evaluation
Participants Needed
One or more experts needed
Task List
- Brainstorm the variety of P, A, C and Ts that are possible
- Explore design implications
- Look for trade-offs between combinations of PACT
- Think about how these might effect design
Conditions required
- Some information about (similar) system is required
- Marketing personnel may be involved also
Example
- PACT analysis for a tourism website
Exercise
In groups of 2/3 identify
- People, activities, contexts, technologies of an in-flight entertainment
system using the pointers above.
- What are the design implications?