User-Centred Design:

Task Analysis(lecture-5)

Prof. Dr. Matthias RauterbergFaculty Industrial Design

Technical University of Eindhoven

g.w.m.rauterberg@tue.nl

© M. Rauterberg, TU/e 2

Overview over this lecture

• Why history of Task Analysis?

• Task Analysis: Why is it important?

• Task Analysis Task Analysis

• What is a Task?

• Task Analysis Methods: Which to use?

• Hierarchical Task Analysis (HTA)

© M. Rauterberg, TU/e 3

Comments to these lecture notes:• All slides for this lecture about task analysis are not

as HTML files available.• If you contact me and ask for these files, I will send

you a hardcopy of all slides [don’t forget your postal address]

• All other slides of this lecture notes are not in the hardcopy included.

• Reference: B. Kirwan & L.K. Ainsworth (1992) A Guide to Task Analysis. Taylor & Francis

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The Basic Triangle: T-U-S

• user-oriented requirement analysis– know the user

– describe the context of use

– analyse the user‘s tasks

– decide for user-system function allocation

user system

task(s)

training

usability

task

des

ign autom

ation

functionalityqual

ifica

tion

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physical operation

feedback control of action

goal-, subgoal-setting

mental operation

task(s)

planning of execution selection of means

the complete action cycle

synchronisation in time

synchronisation in space

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The Task-Subtask Relationship• What is the scope of the whole

task?– This question is for any task relevant.

• How many subtasks are relevant to describe all important steps?– This question is especially important

for continuous task solving processes. If the task consists of discrete operations on the lowest level, this questions turns into “what is the appropriate level of abstraction?”.

• Exercise:– Try to find out, why there are six

subtasks to describe the preparation of Ravioli?

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Exercise: ATM scenario (1)

• The task “withdraw cash using a card” can be described in a structured diagram and/or in a table format.

• The table format allows the notation of additional information.

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• The textual notation describes the linear task solving process over time.

• The scope of the task description was enlarged and additional subtasks were included.

Exercise: ATM scenario (2)

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ISO Definition of Quality of Use

• The ISO 9241 standard defines three components of "quality of use" applicable to the design of user interfaces:

EffectivenessDoes the product do what the users require? Does it "do the right thing?"

EfficiencyCan the users learn the user interface quickly? Can they carry out their tasks with minimum expended effort, including a minimum of errors? Does it improve the productivity/effort ratio? Does it "do things right?"

SatisfactionDo users express satisfaction with the product? Does the new product reduce stress? Do the end users now have a more satisfying job?

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List of relevant books for the area of human-computer interaction (HCI)

• About HCI in general:– D. Norman, S. Draper: User centered system design. Lawrence Erlbaum, 1986.

– P. Booth: An introduction to Human-Computer Interaction. Lawrence Erlbaum, 1990.

– L. Barfield: The user interface - concepts & design. Addison Wesley, 1993.

– A. Dix, J. Finlay, G. Abowd, R. Beale: Human-Computer Interaction. Prentice, 1993.

– J. Preece, Y. Rogers, H. Sharp, D. Benyon, S. Holland, T. Carey: Human-Computer Interaction. Addison Wesley, 1994.

– L. Macaulay: Human-Computer Interaction for Software Designers. Thomson, 1995.

– B. Shneiderman: Designing the user interface. Addison Wesley, 1997, 3rd edition.

• About design principles:– C. Brown: Human-Computer Interface design guidelines. Ablex, 1989.

– W. Galitz: Handbook of screen format design. QED, 1989.

– D. Hix, R. Hartson: Developing user interfaces. Wiley, 1993.

– ISO 9241 (Part 10: Dialogue principles, Part 12: Presentation of information, Part 14: Menu dialogues, Part 15: Command dialogues, Part 16: Direct manipulation dialogues, Part 17: Form fill-in dialogues)

– D. Mayhew: Priniples and guidelines in software user interface design. Prentice, 1992.

– C. Gram, G. Cockton (eds.): Design priniples for interactive software. Capman & Hall, 1996.

• About usability evaluation methods:– D. Freedman, G. Weinberg: Walkthroughs, Inspections, and technical reviews. Dorset, 1990.

– J. Dumas, J. Redish: A practical guide to usability testing. Ablex, 1993.

– A. Monk, P. Wright, J. Haber, L. Davenport: Improving your Human-Computer Interface: a practical technique. Prentice Hall, 1993.

– ISO 9241 (Part 11: Guidance on usability, Part 13: User guidance)

– J. Nielsen, R. Mack (ed.): Usability inspection methods. Wiley, 1994.