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Users, tasks and environment

Howell IstanceSchool of Computing

(chapter 3.1 – 3.5 : McCracken and Wolfe )

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3. Know The User

In this chapter you will learn about:• User Analysis: what do you need to know about

the users?• Task Analysis: What are the user’s goals? What

tasks do they perform?• Environment analysis: What are the user’s

surroundings and what effect do they have on performing a task?

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Differences between user groups…

• Consider the design of a check-out system for a large supermarket and the design of a counter system for a high-street building society

• Talk to the person next to you and make a list of some of the differences between the groups of people who will use each system

• List also how these differences could affect design decisions about each system

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Primary and secondary users

• Primary user: the person who actively uses the site:– Airline reservation clerk– Help desk staff

• Secondary user: the person being served by a primary user:– Airline passenger– Customer who called the support line

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User characteristics: physical differences

• Age (use larger fonts for older people)

• Vision limitations, such as colour blindness• Other physical limitations that might restrict

movement (See Chapter 12)• Small children don’t have good fine-muscle

control: see big buttons on next slide

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Big buttons for little people

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User characteristics: cultural differences

• Language (how many languages should be supported)

• Education (reading level)• Profession (specialized vocabularies)• Attitude towards computer systems (e.g

technophobia amongst elderly users)• Corporate style: what are you trying to convey

to whom?

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High-fashion cosmetics have a style

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A bank site has a very different style

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Assumed knowledge: about task domain

• How much knowledge do you assume the user has about the task(s) that the system supports

• Determines how much support the interface should provide the user

• Determines the terminology used• Think about an air-traffic control application, a

statistics package, an internet banking site, a 3D modeling package (e.g. Maya or 3DS Max)

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Assumed knowledge: about computers

• How much knowledge do you assume the user group has about computers in general?

• Can you assume familiarity with graphical user interfaces (GUIs) – if not, don’t expect the user to know what a combo box and how to use it

• Can you assume familiarity with using the internet –if so, you can assume familiarity with conventions and common facilities, and with using GUIs

• Important particularly when designing for the (older) general public

• Increasing public awareness of internet and computer use (but this can’t be taken for granted yet)

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Assumed knowledge: application familiarity

• Novice– Faces a frightening unknown; timid, nervous, in no

mood to explore your goodies

• Advanced Beginner– Less fear: knows basics; still impatient at having to

learn how to do tasks.

• Competent Performer – Can diagnose simple problems and can perform a

complex series of tasks

• Expert– Small group. Can diagnose complex problems. Has a

mental model of the application. Not typical users.

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Summary of User Characteristics

• What characteristics can you expect of the users of your interface?– frequency of use– discretion to use the system– knowledge of the task which the system will support– knowledge of computers– experience of other similar systems– physical differences, e.g. literacy, vision– cultural differences– attitude towards computers (and your system)– existing skills (keyboard, mouse)

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Summary of Design Implications

• frequency of use: amount of skill building that takes place and knowledge user can be expected to retain

• discretion to use the system: impact of poor usability• knowledge of the task which the system will support:

level of support at interface provided for how to complete tasks

• knowledge of computers: level of guidance provided• experience of other similar systems: user expectations

and use of familiar interface conventions• Physical differences, assumptions made about

presentation of text and use of other modalities• cultural differences: attitude towards computers level

of help and guidance and way in which system is introduced to users

• existing skills (keyboard, mouse): choice of interaction style to use to exploit existing skills

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User characteristics: getting information

• How can you learn the characteristics of your users?

• Not managers. Managers are not users. They may think they know users, but they aren’t users.

• Not developers. The worst. Of course they can see that button the users can’t see: they put it there.

• Users themselves, preferably in their workplace are a good source of information.

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3.3 Task Analysis: Overview• Goals, tasks, and actions• Workflow Analysis• Job analysis• Task list• Task sequence• Task hierarchies• Procedural analysis• Techniques for observing and listening to

users

Requirements for a task analysis method

• a structure to represent goals, subtasks, procedures, objects and actions

• a means of collecting data from experts in the task domain

• a means of representing the analysis to– check validity of the analysis back with experts– communicate with others in design team

• guidance for mapping the analysis to the design

• Hierarchical Task Analysis enables procedural descriptions of tasks to be captured and for objects and actions to be extracted

Hierarchical task analysis (HTA)

Originally devised to define training requirements in process industry - method needs additionally– descriptions of information requirements for lowest

level sub-operations– dictionary of objects and associated actions

• Representation– tree diagram or tabular format

• Advantages of HTA– simple, informal notation– but still requires considerable skills on part of

analyst.

Hierarchical task analysis (HTA)

Structural components• goal - statement of a desired state to be

achieved– e.g. visualise a design of a garment

• tasks - things done in order to achieve goals– e.g. produce a paper copy showing a given view

• sub-tasks- subordinate tasks to attain main task

• plan - specifies when the conditions when each sub-operation will be carried out

Example of HTA:Delete block of text in a word processor

1.Deleteblock of text Goal

2) Select 'cut' from Edit menu

1) Select block of text

or 2) Select cut icon from toolbar

or 2) Press 'delete' key

then

Tasks

HTA representation

1.Deleteblock of text

1. Selecttext block

2. Press‘delete’

3. Select cutfrom edit menu

4. Select cut iconfrom toolbar

Plan 1: 1-2 or 1-3 or 1-4

HTA representation

1.Deleteblock of text

1. Selecttext block

2. Press‘delete’

3. Select cutfrom edit menu

4. Select cut iconfrom toolbar

Plan 1: 1-2 or 1-3 or 1-4

1) Anchor the start of the block

2) adjust the extent of the block

3) Anchor end of the block

then

then

Subtasks

HTA representation of tasks and subtasks

1.Deleteblock of text

1. Selecttext block

2. Press‘delete’

3. Select cutfrom edit menu

4. Select cut iconfrom toolbar

1.Define start of textselection

2. Adjust lengthof text selection

3. Define end oftext selection

Plan 1: 1-2 or 1-3 or 1-4

Plan: 1.2 1-2-3

HTA representation of tasks and subtasks

1.Deleteblock of text

1. Selecttext block

2. Press‘delete’

3. Select cutfrom edit menu

4. Select cut iconfrom toolbar

1.Define start of textselection

2. Adjust lengthof text selection

3. Define end oftext selection

Plan 1: 1-2 or 1-3 or 1-4

Plan: 1.2 1-2-3

Procedure

1) position text insertion in front of first character of block2) ...

How far to decompose tasks?

1.Deleteblock of text

1. Selecttext block

2. Press‘delete’

3. Select cutfrom edit menu

4. Select cut iconfrom toolbar

1.Define start of textselection

2. Adjust lengthof text selection

3. Define end oftext selection

Plan 1: 1-2 or 1-3 or 1-4

Plan: 1.2 1-2-3

.. as far as is useful for the analysis

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3.4 Environment Analysis

• Where do people use your interface? Many variations:– An outdoor ATM in a cold location where people wear

gloves while using it (need huge buttons)– On a combination cell phone/wireless browser, with a

tiny display (need tiny fingers!)– In a location where direct sun can hit your display,

making it hard to read– In an extremely noisy factory, where any sound you

add would be impossible to understand

• Observe your users in their own setting

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3.5 Recruiting Users

• If product is in use, test with real current users:– Employees– Customers

• Temp agencies• In college, post notice or ask a professor to

announce• Provide incentives:

– Coffee mugs, T-shirts– $$$

• Not family or friends: they won’t be critical enough

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Summary

In this chapter you have learned that:– It is hard to over-emphasize the importance of a

user-centric approach to website development – It is important to focus very early on-

• Users & User Characteristics• The Task• The Environment