Table Of ContentA guide to task analysis
A guide to task analysis
Edited by
B.Kirwan
(University of Birmingham)
and
L.K.Ainsworth
(Synergy)
UK Taylor & Francis Ltd., 11 New Fetter Lane, London EC4P 4EE
USA Taylor & Francis Inc., 325 Chestnut Street, 8th Floor, Philadelphia DA 19106
Copyright © Taylor & Francis Ltd 1992
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First published 1992.
Taylor & Francis is an imprint of the Taylor & Francis Group
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A catalogue record for this book is available from the British Library
ISBN 0-203-22145-1 Master e-book ISBN
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ISBN 0 7484 0057 5 (Print Edition) (cloth)
ISBN 0 7484 0058 3 (paper)
Library of Congress Cataloging in Publication Data is available
Cover design by Amanda Barragry
CONTENTS
Executive Summary vi
Preface viii
Acknowledgements ix
Introduction 1
Part I: The task analysis process
1 The task analysis process 14
Part II: Task analysis techniques
Introduction 32
2 Task data collection 37
3 Task description methods 79
4 Task simulation methods 1 45
5 Task behaviour assessment methods 1 68
6 Task requirements evaluation methods 2 21
Part III: Task analysis case studies
Introduction 2 39
7 Balancing automation and human action through task 2 44
analysis
8 A preliminary communications system assessment 2 54
9 A plant local panel review 2 69
10 A staffing assessment for a local control room 3 01
11 Task simulation to predict operator workload in a command 3 12
system
12 Analysis of operator safety actions 3 22
v
13 Maintenance training 3 39
14 A method for quantifying ultrasonic inspection effectiveness 3 52
15 Operational safety review of a solid waste storage plant 3 66
16 A task analysis programme for a large nuclear chemical plant 3 73
Appendix: Summary of task analysis techniques 4 01
Glossary of Terms 4 13
Acronyms 4 19
Subject Index 4 22
Executive Summary
Task Analysis is the name given in this Guide to any process that identifies and
examines the tasks that must be performed by users when they interact with
systems. It is a fundamental approach which assists in achieving higher safety,
productivity and availability standards.
This document describes the task analysis approach, and gathers together and
comprehensively describes the application of 25 major task analysis techniques,
organizing them into a practical user guide.
The Guide is aimed at industrial practitioners such as design engineers, safety
assessors, ergonomics practitioners, trainers, procedures writers, project
managers, etc., with or without previous task analysis experience, who have a
need to establish task requirements or to carry out task assessments for one or
more of the following topics:
• Allocation of function (between human and machine)
• Person specification
• Staffing and job organization
• Task and interface design
• Training
• Human reliability assessment
• Safety management
• Performance checking
• Problem investigation
Guidance is provided on which techniques to use to achieve human-system
performance goals (e.g. efficient and effective allocation of function) in the most
cost-effective manner. Application of this Guide will therefore assist
organizations in choosing and applying the most appropriate technique(s) to
meet their particular needs.
Examples from some of these topic areas of when and where Task Analysis
could usefully be applied are the following:
vii
• Where safety is important (e.g. accidents or near misses have occurred; the
technology is vulnerable to human error; or operator safety actions are
claimed as part of (the safety case)
• Where it is necessary to provide assurance that task allocation and feasibility
are appropriate
• When operational feedback raises concerns over a particular human-machine
interface
• When the requirements for productivity have changed
• Where personnel characteristics are different
• Where different crewing or organizational structure is intended
• Where a significantly different technology is being used
• Where the same task has to be performed in a different environment
This Guide to Task Analysis shows how and when various task analysis
techniques can be used to address the above issues, and also gives practical
insights into the use of these techniques. Additionally, the Guide assists in
planning task analysis applications during the life cycle of a system, at any stage
from early design onwards, to achieve cost-effective results. Finally, a number of
real case studies demonstrate how task analysis has actually been used in
practice, and the impact that task analysis has had in these industrial
applications.
G.Pendlebury
Chairman of Task Analysis
Working Group
Preface
This Guide was produced because of a perceived need to transmit knowledge of
techniques from practising ergonomists to others in industry who would benefit
from the application of formal task analysis methods and strategies. Task
analysis is fundamental to the analysis and enhancement of human-machine
systems, yet few documents exist which cover more than a small number of the
large range of tools available, and of these fewer still contain practical guidance.
A working group of interested members with appropriate expertise from a range
of UK industries, universities and consultancies, was therefore formed. This
working group originated from the Human Factors in Reliability Group which
had already developed two other guides, one on human reliability assessment and
one on human factors in the process industries. The Task Analysis Working
Group (TAWG) was then formed and worked as an independent group
attempting to explain the task analysis process and how it worked in industrial
systems design, development and assessment (the task analysis process, Part I of
the Guide). TAWG then defined a representative set of task analysis techniques
(25 in total, documented in Part II of the Guide), and supplemented this
information via a series of documented case studies from a range of industries,
exemplifying the different uses for which task analysis could be implemented.
This Guide is not a theoretical treatise on the nature of task analysis. Rather its
emphasis is on practical applications and insights that have been gained from
applying the techniques documented, whether aimed at solving a single aspect of
a human-machine-system problem, or a programme of task analysis and human
factors aimed at maximizing successful human performance in systems.
Whatever purpose the reader has in mind for task analysis, the developers of the
Guide believe it will be useful in achieving those goals, as this is fundamentally
what task analysis is all about.
Disclaimer
The contents of this report, including any opinions and/or conclusions expressed
are those of the authors, contributors and reviewers, and do not necessarily reflect
the views or policy of the parent organizations.
Acknowledgements
The need for a Guide to Task Analysis was identified by the Human Factors
Reliability Group (HFRG), who set up a Task Analysis Working Group
(TAWG). The TAWG then developed the specification for the Guide and
subsequently produced it.
The developers of the Guide thank five organizations in particular who have
sponsored the Guide, listed here in chronological order:
British Nuclear Fuels plc, Risley, UK—for sponsoring the development of
Part I
National Power—for sponsoring Part II
Nuclear Electric, Barnwood—for sponsoring Part III
ICI Engineering—for sponsoring the final but critical stages of the
Guide’s editorship and production
Synergy—for lending support in the word processing and final
production stages of the Guide
In addition the producers of the Guide wish to acknowledge the major
contractors involved in the development of the Guide:
Part I—Dr S.P.Whalley (R.M. Consultants Ltd) and Dr A.Shepherd
(Loughborough University)
Part II—Dr L.K.Ainsworth (Synergy) (technique write-ups—Dr L.K.
Ainsworth, Mr B.Kirwan, Mr A.Livingston, Mr D.Mullany, Dr A.
Shepherd, Dr R.B.Stammers, Mr D.Visick, Mr T.Waters and Dr S.P.
Whalley)
Part III—Ms J.Penington (W.S.Atkins Ltd)
Principal editorship/integration of the Guide—Mr B.Kirwan
(Birmingham University)
The Task Analysis Guide was produced from approximately 1989 to 1991. The
work was orchestrated by a main group who contributed to the Guide and
developed its concept, scope and over-saw its content; and a steering group (Task
Analysis Steering Group) who made executive decisions and over-saw the
