The PACT framework

PACT turns a vague design brief into four sets of questions

Intuition

Before sketching an expense app you need to know who will use it, what they are trying to do, where they are, and what devices they hold. PACT is that checklist.

PACT (People, Activities, Contexts, Technologies): people use technologies to undertake activities in certain contexts. It is a series of questions to identify areas for investigation or to focus the design. The outcome is what you think users do to reach their goal, ideas for what the application should do, and a list of unanswerable questions to investigate. Revisit the analysis if needed.

People differ physically, psychologically and culturally

Everyone is different. Physical differences include physical characteristics and variation in the five senses. Psychological differences include spatial awareness, attention span and memory. There are also language and cultural differences, differences in experience and personality, and different goals, needs, reasons and motivations for using systems.

Activities have five perspectives, each with a design note

Start with the overall purpose, then detail it from these perspectives.

Mechanism

• Temporal: how often, when, continuous or interrupted, expected response time. Frequent activities should be easy to do, infrequent ones easy to remember, and interrupted ones should let users find their place again.
• Cooperative or not: can it be done alone, and who is involved? Collaborative activities need awareness of others, communication and coordination.
• Complexity: well-defined steps or vague? Vague activities need a different design from well-defined ones.
• Safety-critical: are mistakes allowed, and what are the critical consequences? Be careful where errors put lives at risk.
• Data and content: what information is needed, does it change with time, where does it come from? This affects the choice of input and output devices and communication technology.

Context has three useful types

All activities happen in context, so analyse activity and context together. Organisational context is how an organisation’s rules and procedures affect the activity. Social context is the social setting. Physical context is the physical circumstances.

Technology covers input, output and communication

Mechanism

• Input: alphanumeric (QWERTY physical or virtual, handwriting), numeric only (keypads), selections via indirect pointing devices (mouse, joystick, pointing stick) or direct pointing devices (touch-sensitive screen, stylus), speech, sensors for motion, air pressure and vibration, eye tracking, brain activity.
• Output: screen or monitor, multi-touch surface, printers, sound (earcons, speech output such as satellite navigation, text to speech) and haptics (force feedback in game consoles, phone vibration for silent alert or key presses).
• Communication: between people and between devices. Consider bandwidth and speed, depending on the data and content.

Exam detail

Output is primarily designed for three perceptual abilities: vision, hearing and touch, which link back to Lecture 2. Input should let people enter data and instructions securely and safely.

Pitfall

Keep temporal under Activities, not Contexts. The three contexts are organisational, social and physical only.

Try it: worked example

Apply PACT briefly to an expense-tracking mobile app (Lecture 3 activity).

Show answer and steps

AnswerPeople: students and workers who track spending. Activity: log and review spending. Context: on the move, social settings. Technology: touch screen and notifications.

1. People: describe users and differences in goals and experience (for example a student with a tight budget and a professional with many receipts).
2. Activities: logging an expense is frequent and short, so it must be easy to do. Reviewing monthly spending is infrequent, so it must be easy to remember. Entering expenses is interrupted often, so users must find their place again.
3. Contexts: physical (on a train, one hand free), social (paying in a group), organisational (employer expense rules).
4. Technologies: touch input, possibly a camera for receipts, notification output, and data needs such as saved categories.
5. List the unanswered questions to investigate, for example how users currently track spending. These answers are illustrative, not from the lecture slides.

Recall

Name the five perspectives on an activity and the three kinds of context.

Temporal, cooperative, complexity, safety-critical, data and content. Organisational, social, physical.