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D R . A N N N O S S E IR

Design Process

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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?

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People, Activities, Context, Technology (PACT)

People undertake activities, in contexts using technologies.

A student uses a phone to send a text message whilst sitting on a bus

Air traffic controllers work together using computers and flight strips to ensure smooth running of an airport in the air traffic control centre.

A 70-year-old woman presses various buttons to set the intruder alarm in her house.

It is the variety in each of the PACT elements - and their combination - that makes interactive systems design so fascinating

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What is a PACT Analysis?

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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).

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People

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.

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People

Physical differences:-Height, weight, different capabilities in sight, hearing, touch,…

Psychological differences”:-Different ways of working; different memory abilities, spatial ability; different amounts of attention at different times; ability to recognize things or remember things. Different „mental models‟

Usage differences:-Experts versus novices, discretionary users of technologies, differences in designing for a heterogeneous group or a homogeneous group

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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,

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Activities

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 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

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Activities

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,

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Activities

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

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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

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Context

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

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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?

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Technologies

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.

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Designing a ticket machine

Ramses station is introducing a new system of automatic barriers. Now everyone will have to buy a ticket before they travel. Write down the characteristics of this activity

Regular/infrequent? Peaks and troughs; interruptible? Response time; co-operation? Vague/well-defined? Safety critical? Errors? Data requirements; media

What mental model would you want to engender in people. How would you design for this?

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Different Contexts of Use

Activities always take place in some context

„Context‟ sometimes means things that surround an activity and sometimes what glues an activity together

Physical environment is one sort of context

ATM or ticket machine versus computer at home

Social context is important

Help from others, acceptability of certain designs

Organizational context

Power structure, changes in life style, de-skilling, etc.

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Different Technologies

Hardware and software to consider Input

How to enter data and commands into the system. Suitability of medium for different contexts/activities

Output Characteristics of displays - „streamy‟ media versus „chunky‟

media. Characteristics of the content. Also feedback is important

Communication Between person and technology. Bandwidth, speed.

communication between devices

Content Functional systems versus systems more focused on content

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Ticket Machine

So, taking into consideration the contexts of use, the activities and the people. What technology will you design for the new ticket machines? Consider

Input

Output

Communication

Content

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Ticket Machine ideas

Input - need to specify destination, need to provide payment, need to specify ticket type Press button (depending how many stations). Have touch screen

(gets greasy). Pay by mobile phone?

Output - need to specify options, need to provide a ticket,

need to say when complete. Ticket could be electronic or paper. Printing facility needed. Options

as buttons, or menu items? Need to provide change?

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Ticket Machine ideas

Communication - must be simple. Could be Bluetooth. Probably button presses are easiest

Content - need to specify stations, but it could have lots of local information. Help with travel planning?

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Design Process

Challenge: Think of decorating your house, flat or bedroom.

When could you start with requirements, conceptual design a physical design or a prototype/ envisionment?

What processes would you go through after you start?

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Re-decorating your flat

Start with requirements - e.g. I need a space to work in. I want to get rid of some clutter. I want the room to be lighter, fresher, cleaner…

Start with conceptual design - need to create an area for working in; need to build a cupboard to store things in; paint the walls a lighter colour.

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Re-decorating your flat

Start with a physical design - we could put a partition up in the corner of the bedroom; that cupboard I saw in Ikea could be used to store things in my flat; I am going to paint the walls „apple-white‟

Start with envisionment - look at this person‟s flat in this magazine with a neat working area; here‟s a sketch of my ideas for a cupboard; you know the colour of Rod‟s bedroom…

Then evaluate - that partition would be too expensive, that cupboard would get in the way; that colour would get dirty very quickly…

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The Classic Life Cycle for Software Development (Waterfall model) Sommerville, 1995.

Classic Life Cycle for Software Development

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Classic Life Cycle for Software Development

Traditionally, software developers have treated each phase of the software design life cycle as an

independent part of software development, which must be completely satisfied before moving on to the next phase.

It is linear, sequential, systematic.This view is simplistic.

In practice, however, the development stages

overlap and feed information to each other. Moreover, there are many iterations up and down between stages.

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Interface Design and Evaluation Process

Greenberg, 1996.

User-Centered Iterative Design

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User-Centered Iterative Design

The essential difference between the classic life cycle and user-centered interface design is that user interface design and development is based on the premise that users should be involved throughout the design life cycle.

Additionally, the process should be highly iterative, so that the design can be tested (or evaluated) with users to make sure it meets the users‟ requirements. Unlike this iterative design process, the waterfall life cycle generally leaves evaluation to the end.

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Star Life Cycle

Star Life Cycle (Evaluation-centered)

Hix and Hartson, 1993.

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Star Life Cycle - Key features

Evaluation is central to designing interactive systems. Everything gets evaluated at every step of the process

The process can start at any point – sometimes there is a conceptual design in place, sometimes we start with a prototype, sometimes we start with requirements

The activities can happen in any order, for example, requirements might be evaluated and a prototype built and evaluated and some aspect of a physical design might then be identified

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Star Life Cycle

the star life cycle is “intended to be equally supportive of both top-down and bottom-up development, plus inside-out and outside in development”

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