Contemporary Ergonomics 1998

  • 63 652 9
  • Like this paper and download? You can publish your own PDF file online for free in a few minutes! Sign Up

Contemporary Ergonomics 1998

Proceedings of the Annual Conference of the Ergonomics Society Royal Agricultural College Cirencester 1–3 April 199

2,460 477 10MB

Pages 624 Page size 432 x 648 pts Year 2004

Report DMCA / Copyright

DOWNLOAD FILE

Recommend Papers

File loading please wait...
Citation preview

CONTEMPORARY ERGONOMICS 1998

CONTEMPORARY ERGONOMICS 1998

Proceedings of the Annual Conference of the Ergonomics Society Royal Agricultural College Cirencester 1–3 April 1998 Edited by

M.A.HANSON Institute of Occupational Medicine Edinburgh

THE

Ergonomics society

UK

Taylor & Francis Ltd, 1 Gunpowder Square, London EC4A 3DE

USA

Taylor & Francis Inc., 1900 Frost Road, Suite 101, Bristol, PA 19007–1598

This edition published in the Taylor & Francis e-Library, 2004. Copyright © Taylor & Francis Ltd 1998 except papers by P.J.Goillau et al., R.S.Harvey, and two papers by L.M.Bouskill et al. © British Crown Copyright 1998/DERA published with the permission of the Controller of Her Britannic Majesty’s Stationery Office. And except the paper by L.A.Morris © British Crown Copyright 1998 reproduced with the permission of the Controller of Her Britannic Majesty’s Stationery Office. The views expressed are those of the author and do not necessarily reflect the views or policy of the Health & Safety Executive or any other government department. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. A catalogue record for this book is available from the British Library. ISBN 0-203-21201-0 Master e-book ISBN

ISBN 0-203-26949-7 (Adobe eReader Format) ISBN 0-7484-0811-8 (Print Edition)

Cover design by Hybert Design

Preface Contemporary Ergonomics 1998 are the proceedings of the Annual Conference of the

Ergonomics Society, held in April 1998 at the Royal Agricultural College, Cirencester. The conference is a major international event for Ergonomists and Human Factors Specialists, and attracts contributions from around the world. Papers are chosen by a selection panel from abstracts submitted in the autumn of the previous year and the selected papers are published in Contemporary Ergonomics. Papers are submitted as camera ready copy prior to the conference. Each author is responsible for the presentation of their paper. Details of the submission procedure may be obtained from the Ergonomics Society. The Ergonomics Society is the professional body for Ergonomists and Human Factors Specialists based in the United Kingdom. It also attracts members throughout the world and is affiliated to the International Ergonomics Association. It provides recognition of competence of its members through the Professional Register. For further details contact: The Ergonomics Society Devonshire House Devonshire Square Loughborough Leicestershire LE11 3DW UK Tel/Fax (+44) 1509 234 904

Contents

HUGH STOCKBRIDGE MEMORIAL SESSION Ergonomics and Standards Introduction DM Anderson Ergonomics standards—the good, the bad and the ugly T Stewart International standardisation of graphical symbols for consumer products FR Brigham The UK human factors defence standard: past, present and future RS Harvey

2 3 8 13

STEPHEN PHEASANT MEMORIAL SESSION The Contribution of Ergonomics to the Understanding and Prevention of Musculoskeletal Disorders Introduction S Lee and D Stubbs The role of physical aspects PW Buckle The combined effects of physical and psychosocial work factors J Devereux The role of psychosocial factors AK Burton

20 21 25 30

MUSCULOSKELETAL DISORDERS Interpreting the extent of musculoskeletal complaints C Dickinson People in pain DM Anderson Prevention of musculoskeletal disorders in the workplace—a strategy for UK research LA Morris, R McCaig, M Gray, C Mackay, C Dickinson, T Shaw and N Watson A musculoskeletal risk screening tool for automotive line managers A Wilkinson, RJ Graves, S Chambers and R Leaver Risk assessment design for musculoskeletal disorders in healthcare professionals C Beynon, D Leighton, A Nevill and T Reilly Ergonomic microscopes—solutions for the cyto-screener? JL May and AG Gale Musculoskeletal discomfort from dancing in nightclubs SL Durham and RA Haslam

36 41 46 51 56 61 66

MANUAL HANDLING Is the ergonomic approach advocated in the Manual Handling Regulations being adopted? KM Tesh Control of manual handling risks within a soft drinks distribution centre EJ Wright and RA Haslam Training and patient-handling: an investigation of transfer JA Nicholls and MA Life Risk management in manual handling for community nurses P Alexander Children’s natural lifting patterns: an observational study F Cowieson Manual handling and lifting during the later stages of pregnancy T Reilly and SA Cartwright Posture analysis and manual handling in nursery professionals JO Crawford and RM Lane

72 77 82 87 92 96 101

POSTURE Can orthotics play a beneficial role during loaded and unloaded walking? DC Tilbury-Davis, RH Hooper and MGA Llewellyn Investigation of spinal curvature while changing one’s posture during sitting FS Faiks and SM Reinecke The effect of load size and form on trunk asymmetry while lifting G Thornton and J Jackson The effect of vertical visual target location on head and neck posture R Burgess-Limerick, A Plooy and M Mon-Williams

108 113 118 123

OFFICE ERGONOMICS Is a prescription of physical changes sufficient to eliminate health and safety problems in computerised offices? RM Sharma An evaluation of a trackball as an ergonomic intervention B Haward Old methods, new chairs. Evaluating six of the latest ergonomic chairs for the modern office A Esnouf and JM Porter

130 135 140

NEW TECHNOLOGY Development of a questionnaire to measure attitudes towards virtual reality S Nichols Orientation of blind users on the World Wide Web MP Zajicek, C Powell and C Reeves “Flash, splash and crash”: Human factors and the implementation of innovative Web technologies A Pallant and G Rainbird

146 151 156

WORK STRESS Determining ergonomic factors in stress from work demands of nurses DW Jamieson and RJ Graves

162

A risk assessment and control cycle approach to managing workplace stress RJ Lancaster

167

TELEWORKING Teleworking: Assessing the risks M Kerrin, K Hone and T Cox Evaluating teleworking—case study S Campion and A Clarke

174 179

TEAM WORKING Team organisational mental models: an integrative framework for research J Langan-Fox, S Code and G Edlund The impact of IT&T on virtual team working in the European automotive industry C Carter and A May

186 191

WORK DESIGN The effect of communication processes upon workers and job efficiency A Dickens and C Baber A case study of job design in a steel plant HT Neary and MA Sinclair The effects of age and habitual physical activity on the adjustment to nocturnal shiftwork T Reilly, A Coldwells, G Atkinson and J Waterhouse Job design for university technicians: work activity and allocation of function RF Harrison, A Dickens and C Baber

198 203 208 213

SYSTEM DESIGN AND ANALYSIS Allocation of functions and manufacturing job design based on knowledge requirements CE Siemieniuch, MA Sinclair and GMC Vaughan The need to specify cognition within system requirements IS MacLeod Analysis of complex communication tasks J Wikman

220 225 230

INFORMATION SYSTEMS Health and safety as the basis for specifying information systems design requirements TG Gough Cognitive algorithms R Huston, R Shell and AM Genaidy

236 241

DESIGN METHODS Rapid prototyping in foam of 3D anthropometric computer models in functional postures S Peijs, JJ Broek and PN Hoekstra

248

The use of high and low level prototyping methods for product user interfaces JVH Bonner and P Van Schaik Creative collaboration in engineering design teams F Reid, S Reed and J Edworthy

253 258

DESIGN AND USABILITY Pleasure and product semantics PW Jordan and AS Macdonald A survey of usability practice and needs in Europe MC Maguire and R Graham Cultural influence in usability assessment A Yeo, R Barbour and M Apperley

264 269 274

INTERFACE DESIGN Interface display designs based on operator knowledge requirements F Sturrock and B Kirwan Understanding what makes icons effective: how subjective ratings can inform design SJP McDougall, MB Curry and O de Bruijn Representing uncertainty in decision support systems: the state of the art C Parker Representing reliability of at-risk information in tactical displays for fighter pilots M Piras, S Selcon, J Crick and IRL Davies Semantic content analysis of task conformance A Totter and C Stary

280 285 290 295 300

WARNINGS Warnings: a task-oriented design approach JM Noyes and AF Starr Effects of auditorily-presented warning signal words on intended carefulness RS Barzegar and MS Wogalter Listeners’ understanding of warning signal words J Edworthy, W Clift-Matthews and M Crowther Perceived hazard and understandability of signal words and warning pictorials by Chinese community in Britain AKP Leung and E Hellier

306 311 316 321

VERBAL PROTOCOL ANALYSIS Thinking about thinking aloud MJ Rooden Adjusting the cognitive walkthrough using the think-aloud method M Verbeek and H van Oostendorp Verbal protocol data for heart and lung bypass scenario simulation “scripts” J Lindsay and C Baber Use of verbal protocol analysis in the investigation of an order picking task B Ryan and CM Haslegrave

328 333 338 343

PARTICIPATORY ERGONOMICS Selecting areas for intervention BL Somberg Participatory ergonomics in the construction industry AM de Jong, P Vink and WF Schaefer User trial of a manual handling problem and its “solution” D Klein, WS Green and H Kanis

350 355 360

INDUSTRIAL APPLICATIONS Case study: a human factors safety assessment of a heavy lift operation WI Hamilton and P Charles The application of ergonomics to volume high quality sheet printing and finishing ML Porter The application of human factors tools and techniques to the specification of an oil refinery process controller role J Edmonds and C Duggan Feasibility study of containerisation for Travelling Post Office operations G Rainbird and J Langford

366 371 376 381

MILITARY APPLICATIONS The complexities of stress in the operational military environment MI Finch and AW Stedmon The development of physical selection procedures. Phase 1: job analysis MP Rayson The human factor in applied warfare AE Birkbeck

388 393 398

AIR TRAFFIC MANAGEMENT Getting the picture—Investigating the mental picture of the air traffic controller B Kirwan, L Donohoe, T Atkinson, H MacKendrick, T Lamoureux and A Phillips Developing a predictive model of controller workload in air traffic management AR Kilner, M Hook, P Fearnside and P Nicholson Assessing the capacity of Europe’s airspace: The issues, experience and a method using a controller workload model A Majumdar Evaluation of virtual prototypes for air traffic control—the MACAW technique PJ Goillau, VG Woodward, CJ Kelly and GM Banks Development of an integrated decision making model for avionics application D Donnelly, JM Noyes and DM Johnson Psychophysiological measures of fatigue and somnolence in simulated air traffic control H David, P Cabon, S Bourgeois-Bougrine and R Mollard

404 409 414 419 424 429

DRIVERS AND DRIVING What’s skill got to do with it? Vehicle automation and driver mental workload M Young and N Stanton The use of automatic speech recognition in cars: a human factors review R Graham Integration of the HMI for driver systems: classifying functionality and dialogue T Ross Subjective symptoms of fatigue among commercial drivers PA Desmond How did I get here? Driving without attention mode JL May and AG Gale Seniors’ driving style and overtaking: is there a “comfortable traffic hole”? T Wilson Speed limitation and driver behaviour D Haigney and RG Taylor The ergonomics implications of conventional saloon car cabins on police drivers SM Lomas and CM Haslegrave The design of seat belts for tractors DH O’Neill and BJ Robinson

436 441 446 451 456 461 466 471 476

NOISE AND VIBRATION Auditory distraction in the workplace: a review of the implications from laboratory studies S Banbury and D Jones Transmission of shear vibration through gloves GS Paddan and MJ Griffin The effect of wrist posture on attenuation of vibration in the hand-arm system TK Fredericks and JE Fernandez

482 487 492

HAND TOOLS Criteria for selection of hand tools in the aircraft manufacturing industry: a review BP Kattel and JE Fernandez Exposure assessment of ice cream scooping tasks PG Dempsey, R McGorry, J Cotnam and I Bezverkhny

498 503

THERMAL ENVIRONMENTS The effect of clothing fit on the clothing Ventilation Index LM Bouskill, N Sheldon, KC Parsons and WR Withey A thermoregulatory model for predicting transient thermal sensation F Zhu and N Baker The user-oriented design, development and evaluation of the clothing envelope of thermal performance D Bethea and KC Parsons A comparison of the thermal comfort of different wheelchair seating materials and an office chair N Humphreys, LH Webb and KC Parsons

510 515 520 525

The effect of repeated exposure to extreme heat by fire training officers JO Crawford and TJ Milne 530 The effects of self-contained breathing apparatus on gas exchange and heart rate during fire-fighter simulations KJ Donovan and AK McConnell 535 The effect of external air speed on the clothing ventilation index LM Bouskill, R Livingston, KC Parsons and WR Withey 540 COMMUNICATING ERGONOMICS Commercial planning and ergonomics J Dillon Human factors and design: Bridging the communication gap AS Macdonald and PW Jordan Guidelines for addressing ergonomics in development aid T Jafry and DH O’Neill Determining and evaluating ergonomic training needs for design engineers J Ponsonby and RJ Graves Ergonomic ideals vs genuine constraints D Robertson, S Layton and J Elder

546 551 556 560 565

GENERAL ERGONOMICS Another look at Hick-Hyman’s reaction time law TO Kvålseth Design relevance of usage centred studies at odds with their scientific status? H Kanis The integration of human factors considerations into safety and risk assessment systems JL Williamson-Taylor The use of defibrillator devices by the lay public T Gorbell and R Benedyk Occupational disorders in Ghanaian subsistence farmers M McNeill and DH O’Neill

572 577 582 587 592

AUTHOR INDEX

599

SUBJECT INDEX

603

HUGH STOCKBRIDGE MEMORIAL SESSION: ERGONOMICS AND STANDARDS

HUGH STOCKBRIDGE MEMORIAL LECTURES Ergonomics and Standards

Introduction Towards the end of his career, Hugh Stockbridge became known for, amongst other things, his keen interest in ergonomics standards, but he was not originally a ‘standards man’. In fact his individualistic style was very far from standard. In the days before the publication of Murrel’s book Ergonomics (Chapman and Hall, 1965), we had only one ‘cookbook’ published in the UK that could be seen as a standard. This was the 1960 publication from the MRC/RNPRC: Human Factors in Design and Use of Naval Equipment, intended for use by Royal Navy designers. Hugh, however, was ever the innovative experimenter in the grand tradition of Cambridge psychologists, and where ergonomics data was lacking, produced some of his own. An example was the designs for micro shape coded knobs, intended to be used on the old ‘Post office keys’, published internally at Farnborough in 1957. His continuing interest in factors affecting the design of indicators and such controls was later reflected in a paper with Bernard Chambers in the Journal Ergonomics (Taylor and Francis, 1970). By the end of the ‘60s, Hugh was already involved in his great project, as a member of a working party of the RNPRC to carry out a revision of the earlier handbook. The working party carried out a thorough review of the proliferating, human engineering handbooks and surveys, and by consideration of best ergonomics principles, conceived a new publication of 11 Chapters, to be produced in a ring binding to facilitate updating and additions. But that is the subject of Roger Harvey’s paper in this memorial session. Hugh also made a particularly interesting, and still valid, critique of ergonomics handbooks and journals to Human Engineering, by Kraiss and Moraal (Verlag TüV Rheinland Gmbh, 1975). Much later, Hugh became secretary of the Study Group concerned with the creation of DBF STAN 00–25, and to quote from a contemporary colleague, ‘…his cryptic minutes were a work of art—inimitable, yet very informative once decoded and embellished with the knowledge of those who had the need to know.’ The other two papers are complementary in many ways. Tom Stewart covers the considerable time he has spent developing and using more general International Standards in ergonomics. It will be especially interesting to hear his comments on the application of ergonomics principles to creating standards—and the standards he considers have made a negative contribution to ergonomics! The final paper, contributed by Fred Brigham, illustrates amongst other things the particular problems encountered in the development of quite specific standards for graphical symbols for use on consumer products intended for an international market. The promotion of appropriate testing procedures to ensure usability of such symbols must be a very important and interesting part of the standard making process. Hugh would have been proud of this session.

ERGONOMICS STANDARDS— THE GOOD, THE BAD AND THE UGLY Tom Stewart Managing Director System Concepts Limited 2 Savoy Court, Strand London WC2R OEZ www.system-concepts.com Hugh Stockbridge was an active supporter of ergonomics standardisation. In this presentation, I will draw some conclusions about the process of developing standards (particularly International Standards) and about the usefulness and usability of the resulting standards themselves. As the title suggests, there can be major problems with both the process and the standards (the Ugly) or there can be minor problems with both (the Bad). However, most of the time, the process works well and the resulting standards have improved the ergonomics quality of products and systems and are well received by industry and users (the Good).

Introduction One of Hugh Stockbridge’s most endearing qualities (apart from his sense of humour) was his enthusiasm for irreverence. I believe he would have approved of my choice of title and been pleased that his memory was being cherished in this session although he was also at home on the stage. This session is like a posthumous award for Hugh and it is clear that there are some similarities between standards and show business. Just as awards ceremonies often seem rather incestuous, esoteric and irrelevant to the real world, many standards seem to be aimed more at ergonomists and their concerns (in their terminology, structure and emphasis) than at standards users in the real world. Taking the analogy of awards a step further, I will therefore review ‘The Good, The Bad and The Ugly’ aspects of ergonomics standardisation in reverse order. These observations are based on my own experience as Chairman of ISO/TC 159/SC 4 Ergonomics of Human System Interaction and as an active developer of ergonomics standards for more than 15 years. But before exposing the sordid side of standards making, I would like to explain what the process of International Standardisation should involve.

The process of International Standardisation International standards are developed over a period of several years and in the early stages, the published documents may change dramatically from version to version until consensus is reached (usually within a Working Group of experts). As the standard becomes more mature (from the Committee Draft Stage onwards), formal voting takes place (usually within the

T Stewart

4

parent sub-committee) and the draft documents provide a good indication of what the final standard is likely to look like. Table 1 shows the main stages.

Table 1 The main stages of ISO standards development

The Ugly side of standards Although ergonomics standards are generally concerned with such mundane topics as keyboard design or menu structures, they nonetheless generate considerable emotion amongst standards makers. Sometimes this is because the resulting standard could have a major impact on product sales or legal liabilities. Other times the reason for the passion is less clear. Nonetheless, the strong feelings may result in what I have called the ugly side of standards. In terms of the standardisation process, the ugly side includes:

u large multinational companies exerting undue influence by dominating national committees. Although draft standards are usually publicly available from national standards bodies, they are not widely publicised. This means that it is relatively easy for well informed large companies to provide sufficient experts at the national level to ensure that they can virtually dictate the final vote and comments from a country.

u end user’s requirements being compromised as part of ‘horse trading’ between conflicting viewpoints. In the interests of reaching agreement, delegates may resort to making political trade-offs largely independent of the technical merits of the issue.

u national pride leading to uncritical support for a particular approach or methodology. In theory, participants in Working Group meetings are experts nominated by member bodies in the different countries. They are not there to represent a national viewpoint but are supposed to act as individuals. However, as one disillusioned expert explained to me ‘sometimes the loudest noise at a Working Group meeting is the grinding of axes’

Ergonomics standards—the good, the bad and the ugly

5

However, it is not just the process which is ugly. The standards themselves can leave much to be desired in terms of brevity, clarity and usability as a result of:

u stilted language and boring formats. The unfriendliness of the language is illustrated by the fact that although the organisation is known by the acronym ISO, its full English title is the International Organisation for Standardisation. The language and style are governed by a set of Directives and these encourage a wordy and impersonal style.

u problems with translation and the use of ‘Near English’. There are three official languages in ISO—English, French and Russian. In practice, much of the work is conducted in English, often by non-native speakers. As someone who only speaks English, I have the utmost respect for those who can work in more than one language. However, the result of this is that the English used in standards is often not quite correct— it is ‘near English’. The words are usually correct but the combination often makes the exact meaning unclear. These problems are exacerbated when the text is translated.

u confusions between requirements and recommendations. In ISO standards, there are usually some parts which specify what has to be done to conform to the standard. These are indicated by the use of the word ‘shall’. However, in ergonomics standards, we often want to make recommendations as well. These are indicated by the use of the word ‘should’. Such subtleties are often lost on readers of standards, especially those in different countries. For example, in the Nordic countries, they follow recommendations (shoulds) as well as requirements (shalls), so the distinction is diminished. In the USA, they tend to ignore the ‘shoulds’ and only act on the ‘shalls’.

The Bad side of standards I used the expression ‘ugly’ to describe the result of extreme passion in the development of standards. In this part of the paper, I discuss what might be seen as the result of too little passion. The bad side is that standardisation is very slow as a result of :

u an apparently leisurely pace of work. One of the reasons is that there is an extensive consultation period at each stage with time being allowed for national member bodies to circulate the documents to mirror committees and then to collate their comments. Another reason is that Working Group members can spend a great deal of time working on drafts and reaching consensus only to find that the national mirror committees reject their work when it comes to the official vote. It is particularly frustrating for project editors to receive extensive comments (which must be answered) from countries who do not send experts to participate in the work. Of course, the fact that the work is usually voluntary means that it is difficult to get people to agree to work quickly.

u too many experts. This might sound like an unlikely problem but given the long timescale mentioned above it can be a significant factor in slowing down the process. The reason is that many experts are only supported by their organisations for a relatively short time and are then replaced by other experts. Every time a new expert joins the Working

T Stewart

6

Group, there is a tendency to spend a lot of time explaining the history and to some extent starting the process again. Similarly, each expert feels obliged to make an impact and suggest some enhancement or change in the standard under development. Since the membership of Working Groups can change at virtually every meeting (which are usually three or four months apart), it is not uncommon for long standing members finding themselves reinstating material which was deleted two or three meetings previously (as a result of a particularly forceful individual). While I do not accept that we have produced bad standards (at least in our committee), our standards have been criticised for being too generous to manufacturers in some areas and too restrictive in other areas. The ‘over-generous’ criticism misses the point that most standards are setting minimum requirements and in ergonomics we must be very cautious about setting such levels. However, there certainly are areas where being too restrictive is a problem. Examples include:

u ISO 9241–3:1992 Ergonomics requirements for work with VDTs: Display Requirements. This standard has been successful in setting a minimum standard for display screens which has helped purchasers and manufacturers. However, it is biased towards Cathode Ray Tube (CRT) display technology. An alternative method of compliance based on a performance test (which would be technology independent) is still under development and is unlikely to be finalised in the near future.

u ISO CD 9241–9 Ergonomics requirements for work with VDTs: Non keyboard input devices. This standard is suffering because technological development is faster than either ergonomics research or standards making. Although there is an urgent need for a standard to help users to be confident in the ergonomic claims made for new designs of mice and other input devices, the lack of reliable data forces the standards makers to slow down or run the risk of prohibiting newer, even better solutions.

The Good side of standards I would not spend my time (largely unfunded) developing standards if I did not believe that they are largely good for ergonomics. Major strengths in the process are that it is:

u based on consensus. Manufacturers (and ergonomists) make wildly different claims about what represents good ergonomics. This is a major weakness for our customers who may conclude that all claims are equally valid and there is no sound basis for any of it. Standards force a consensus and therefore have real authority in the minds of our customers. Achieving consensus requires compromises, but then so does life.

u international. Although there are national and regional differences in populations, the world is becoming a single market with the major suppliers taking a global perspective. Variations in national standards and requirements not only increase costs and complexity, they also tend to compromise individual choice. Making standards international is one way of ensuring that they have impact and can help improve the ergonomics quality of products for everyone.

Ergonomics standards—the good, the bad and the ugly

7

We have produced a number of useful standards over the past few years. These are not only useful in providing technical information in their own right but serve to ensure that ergonomics issues are firmly placed on management agendas. Many organisations feel obliged to take standards seriously and therefore even if they were not predisposed towards ergonomics initially, the existence of International Standards ensures that they are given due consideration. As consultants, we know that basing our recommendations on agreed standards gives them far greater authority than citing relevant research. There is not space in this paper to list all the relevant standards but a few key examples include three from the ISO 9241 series and ISO 13407.

u ISO 9241–2:1992 Guidance on Task Requirements. This standard sets out key points on job and task design and provides a sound basis for persuading managers and system developers that such issues require proper attention if systems are to be successful.

u ISO 9241–3:1992 Visual Display Requirements. This standard allows purchasers to have some confidence in the ergonomic quality of computer displays. This is particularly important for managers who wish to meet their obligations under the European Directive on work with display screen equipment.

u ISO 9241–10:1996 Dialogue Principles. This standard sets out some key principles of dialogue design and gives useful examples to illustrate how the relatively simple principles apply in practice. The European Directive also requires employers to ensure that systems meet the principles of software ergonomics. This standard gives them an external benchmark which they can incorporate in procurement specifications.

u ISO DIS 13407 Human Centred Design for Interactive Systems. This standard is an attempt to solve the problem of developing ergonomics standards quickly enough in a fast changing technical environment. The standard provides guidance for project managers to help them follow a human-centred design process. By undertaking the activities and following the principles described in the standard, managers can be confident that the resulting systems will be usable and work well for their users. If their customers require evidence of humancentredness, the standard gives guidance on how to document the process.

The way forward Although I believe standards are an important tool for the ergonomist, many people find them difficult to understand and use. In part, this is because people sometimes expect too much from standards. They cannot represent the latest ideas and they are not going to help much with the more creative parts of design. However, they often represent important constraints and may give some guidance on what has worked in the past. The best way to really understand what is going on in standards is to get involved. This will give you advance warning of future standards, the opportunity to influence the content of standards and an understanding of the context in which they have been developed. You will then find it much easier to make effective use of standards. If you do not know who to contact, let me know what you are interested in helping with (email [email protected]) and I’ll send you details.

INTERNATIONAL STANDARDISATION OF GRAPHICAL SYMBOLS FOR CONSUMER PRODUCTS Fred Brigham Philips Design, Building HWD, PO Box 218, 5600 MD Eindhoven, The Netherlands

The paper discusses international activities concerned with the standardisation of graphical symbols and complementary activities in a major electronics company focussing on symbols used for consumer products. Issues relating to the practical application of symbols in an industrial setting are described, including procedures for new symbols and tools to provide worldwide access. Results from user tests of a proposal for international symbols are presented to illustrate some of the problems involved in designing comprehensible symbols. The paper concludes by stressing the need to focus on the communicative processes involved.

Introduction The main organisations concerned with the international standardisation of graphical symbols are as follows:

International Organization for Standardization (ISO) The main ISO technical committee dealing with graphical symbols is ISO TC145, which has three subcommittees dealing with public information symbols (SC1), safety signs and symbols (SC2), and graphical symbols for use on equipment (SC3). The main publication containing graphical symbols for use on equipment is ISO 7000. The symbols for use on equipment are developed by the technical committee responsible for the equipment following the rules in ISO 3461–1 (General principles for the creation of graphical symbols) and ISO 4196 (Use of arrows).

International Electrotechnical Commission (IEC) The IEC committee responsible for graphical symbols for use on electrotechnical equipment is IEC SC3C. New symbols are proposed by technical committees or by national standardisation organisations, and SC3C plays an active role in the approval procedure. The main publication containing graphical symbols for use on electrotechnical equipment is IEC 60417. This document is produced electronically from a database. The database may be linked to a web site in the near future allowing users to search for suitable symbols and either download the drawings or order them on CD-ROM.

Standardisation of graphical symbols for consumer products

9

ISO/IEC Joint Technical Committee 1 This joint technical committee is concerned with information technology and, because of its size and importance, can be considered separately from the two parent organisations. JTC1 Working Group 5 is responsible for graphical symbols for office equipment and also icons. A collective standard containing graphical symbols for office equipment is being prepared.

International Telecommunication Union (ITU) Graphical symbols to assist users of telephone services are published in ITU-T Recommendation E.121. This document includes symbols for videotelephony which have been developed by The European Telecommunication Standards Institute (ETSI) using the Multiple Index Approach which is described in ETSI Technical Report ETR 070 (1993).

Use of graphical symbols for consumer products Philips is a multinational company which produces a wide range of consumer products. As most of the products are electrotechnical, IEC 60417 is the major source of symbols. Figure 1 shows examples of symbols from IEC 60417 adapted for use within Philips. Many of the symbols are also used as icons.

Figure 1. Some graphical symbols used by Philips A major concern of Philips Design is the usability of products and this is taken into account in the policy with regard to the use of graphical symbols and the development of new symbols. Some of the practical issues arising are as follows:

Symbols or text In general, text describing a function in the user’s native language is likely to be understood better than a graphical symbol. Where there is no compelling reason to use graphical symbols it is better to use text. However, graphical symbols are useful where there is insufficient space to use text, eg. on a remote control, or where use of the equipment must be language independent.

Pictogram or abstract symbol The symbols on the left of Figure 1 are pictograms, i.e. they depict an object. Those on the right are abstract symbols. It might be thought that the pictograms can be more easily understood than the abstract symbols. The meaning of abstract symbols has to be learned but some are well understood, eg. the arrows used for “play”, “fast forward” etc. on tape players. Furthermore a pictorial representation may limit the application of the symbol or may become out of step with developments in technology.

Approval of new symbols In a company as diverse as Philips with relatively independent lines of business operating in all parts of the world, it is necessary to control the use of graphical symbols. This is done in

10

FR Brigham

the consumer products area by means of a company standard containing “approved” symbols. Where no appropriate symbol can be found either in the company standard or in relevant international standards, a new symbol must be developed. The Philips internal procedure involves submitting the proposed new symbol for immediate comment by an expert panel followed by circulation to a wider group of interested parties prior to publication in the standard. Wherever possible, new symbols are tested as part of the user interface.

Accessing the information The printed company standard for symbols is in the process of being replaced by a web site on the Philips intranet. This has the advantage that the up-to-date collection of approved symbols and new proposals under consideration can be accessed from anywhere in the world. The database can be searched using keywords and, when appropriate symbols have been found, the drawings can be downloaded as electronic files for immediate use. The approval procedure for new symbols has also been made more effective and efficient by linking this to the web site.

Testing graphical symbols It has been noted above that symbols should be tested wherever possible to ensure that their meaning will be understood. The following example illustrates some of the issues involved in developing symbols which can be reliably comprehended and distinguished. The testing of symbols is part of the Philips quality policy for consumer products which is committed to putting in place processes and tools which enable quality of use to be managed in a systematic way.

Symbols for timer functions In response to the needs of the electrotechnical industry, an IEC proposal was circulated containing symbols for the time functions “elapsed time”, “remaining time”, “programmable start” and “programmable stop”. The symbols concerned are shown as Set 1 in Table 1. Although the functions may initially appear complex, they are all functions which may be found on consumer equipment in the living room, bedroom or kitchen. Philips was concerned about the comprehensibility of the proposed symbols and decided to test them.

Testing procedure The test of pictogram associativeness from the ETSI Multiple Index Approach, ETR 070 (1993), provided the basis for the test method. The procedure was as follows: • One of the functions was described and drawings for all four functions presented. Subjects were asked to choose the drawing which best represents the function. • This was repeated for all four functions with the order randomised between subjects and stressing that each choice should be independent. • Subjects were typical users of consumer equipment (N≥24 for full test). Two further sets of symbols were tested at separate times. Set 2 was used in a pilot test conducted by Philips to explore possible alternatives to Set 1. Set 3 was circulated in the most recent IEC draft.

Results The number of correct selections of the symbols (hit rate) is shown in Table 1. The figure in brackets is the percentage of subjects correctly selecting the symbol concerned. Where the hit

Standardisation of graphical symbols for consumer products

11

ate differs significantly from that expected by chance (25%), this is indicated by the asterisks. (Chi-square goodness of fit test, **=α