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The design of design teams in high-technology industries
AppliedErgonomies 1987, 18.2, 111-114
The design of design teams in high-technology industries W.T. Singleton Emeritus Professor University of Aston in Birmingham; Visiting Professor University of Geneva
Every design enterprise in high-technology involves a large multi-disciplinary team. In the context of man-machine interaction there are two related issues concerning the design system. Firstly, the team must be divided into sub-teams which can complete separate tasks within the context of the total system concept. Secondly, there are human factors design issues which often run across the work of the sub-teams. The division of a design effort into separate tasks is a considerable art but there are some general principles such as the minimisation of communication across interfaces and the standardisation of procedures for consolidating, communicating and recording design decisions. A human factors service must be available on a wide range of issues, including coding and storage of information concerning progress to date, the man-machine interfaces, work space and working environment design, and the design of instruction manuals. The ergonomist cannot confine his solutions within design. There are complementary issues of training which are usually organisationally separated. The ergonomist must cooperate with personnel specialists responsible for staffing levels and training. In recent years useful bridges have developed in the form of common interests in task analysis and simulation.
Keywords: Design, systems, communication Preamble High.technology design teams currently create complex man-ma0hine systems such as vehicles used in warfare, road, rail and air transport; industrial plants which produce manufactured goods, chemicals or electric power; distribution systems for water, gas, electricity, food and industrial products; and commercial systems essentially engaged in moymg money around. All such big systems involve elaborate data-processing and often also contain sub-systems such as missiles, machine-tools and powered handling devices from heavy lifting gear to micromanipulation which themselves require elaborate design effort. These systems and many sub-systems have in common the concept of a control centre where one or more human operators monitor and guide what is happening. This may be as elaborate as the main control room of a nuclear power station or as relatively straightforward as a pendant used to control a machine-tool. Usually there are also other operators in a maintenance role. Invariably the communication issues are not confined to man.machine interfaces, there are also man-man interfaces (Fig. 1). This paper surveys some of the problems in such design work and the methodology required to cope with them. In particular, it is emphasised that the design team itself is a system to which principles of effective communication can be applied.
The description and proposals in this paper are not based directly on any systematically obtained laboratory or field data (although these are in the background of the principles) but rather on the author's experience of nearly 40 years of involvemefit in a great variety of such systems. There is some danger in spreading ergonomics expertise as far as is implied here. On the negative side there is less back-up from reliable data obtained from anthropometric and psychometric measurements or human performance experiments, and there is some trespass into fields where others such as organisational psychologists and sociotechnical specialists have done the research. More positively,
co01(~ '
Management
Maintenance staff ~ - .~
Control
systems
Fig. 1
0003-6870/87/02 0111-04 $03.00 © 1987Butterworth& Co (Publishers)Ltd
Customers
systems
Operating
Technical experts
J
Machineand man interfaces with the control centre
Applied Ergonomics June 1987
111
these real problems are indivisible - someone has to contribute advice on decisions which involve all these issues and often the ergonomist is the only 'people representative' associated with the team.
I ntroduction Traditionally, technological design teams have operated on an autocratic basis with one person - the designer allocating tasks to other engineers and technologists. The designer was the centre of the communications network and he was thus in a position to deal with all problems of integration and compromise. Such a system is no longer feasible for several reasons. All systems are vulnerable to human error in design and operation; it is increasingly accepted that the human role in system performance should be considered systematically at the design stage. The criterion of effectiveness is no longer sufficient; all systems must be cost-effective, and also marketable. It follows that engineers must co-operate with ergonomists, accountants and marketeers. Technology itself has advanced to a level of speciality and complexity which makes it impossible for one person to have sufficient expertise to make a detailed Choice between all the possible processes and mechanisms. For these reasons, and because of trends arising from our more egalitarian societies, many decisions are now made by groups. The introduction of systems theory has resulted in more emphasis on functional as distinct from mechanistic approaches to design and as a consequence even strictly engineering problems are best dealt with by interdisciplinary groups. The introduction of ergonomics which centres on the activity of human operators cuts across many functions and mechanisms and further complicates the cross linkages in decision-making. These influences converge in impeding the progress of design unless considerable care is devoted to meeting the needs for elaborate intercommunication and accurate recording of the design progression. This is, in itself, an ergonomics problem because designers are one kind of human operator requiring well-structured information stores and interfaces.
The structures of design teams Adequate exchange and storage of information is central to the smooth development of the design process. The design team structure should be considered from this viewpoint. Paradoxically, the aim is to separate the team into sub-teams which require the minimum information exchange. In this way each sub-team can get on with its task without the need for constant reference to others. Subdivision of design teams is still done on the basis of long experience in particular industries, but it is possible to enumerate standard symptoms which indicate that the subdivision was not optimal. They are: 1. Internal memoranda copied as a matter of routine to more than five colleagues 2. The setting up of internal (and interminable) working parties, sub-committees and task forces 3. Invitations to attend meetings, not because of any likelihood of a direct contribution but in a representational or liaison role
112
Applied Ergonomics June 1987
4. The setting up of committees which are allowed or even encouraged to write their own terms of reference 5. Jealousy between individuals or sections, particularly about demarcation 6. Reconsideration of matters about which firm decisions have already been made; possibly because the previous decision is not accepted, more usually because there are inadequate records and insufficiently structured access to details of decisions and reasons for decisions 7. Poor documentation and indexing of documents 8. Excessive reliance on the human memory 9. Secretiveness by teams to reduce the possibility of interference by others and by individuals to preserve personal power 10. Remoteness of leadership so that team members are insufficiently aware of their part in the total scheme of things. All team members should be familiar with what the leader's objectives are and also his style of approaching issues and obstacles. This reduces their need to consult him about minor problems and reduces friction between colleagues because all are working in line with the leader's efforts and therefore with each other. It should be emphasised that these symptoms and consequences are no more than exaggerations of what is the normal position. Every member of a design team will recognise these effects in his organisation; it does not necessarily mean that his team is very badly organised. It is quite normal for various symptoms of 'them' versus 'us' to develop and the higher the morale and motivation, the greater the tendency to see 'us' as superior in quality and importance to others. One of the skills required of project leaders is the ability to guide such positive thinking into productive rather than unproductive channels. The product from a design team which has not been well organised may be technically competent but will lack the subtle qualities of total coherence which indicate efficiency and also present an aesthetically satisfying product. There may also be questions of reliability laecause the integration of the sub-systems is not as tidy as it could be. The design process itself will have been more expensive a~,d more timeconsuming than was expected.
Team management So far this paper has centred on failings rather than remedies but identification of a problem is a necessary preliminary step towards a solution. There are no easy solutions to these intricate problems of social behaviour. At the technical level, systems thinking has been of some help in clarifying the importance of well-defined objectives and the need to separate functional thinking from thinking in terms of mechanisms. On the other hand, the greater the creative content of a design the less feasible it is to begin by defining objectives. Design thinking is always iterative. The designer has some ideas of what he has to do but this idea is always refined as the work proceeds. The solution invariably emerges in parallel with the process of attaining it. It has to be recognised also that original work can often get into a cul-de-sac. The art of recognising when retreat is a prerequisite for further progress is a crucial aspect of good design thinking. There are usually wide differences of opinion on such issues and the reactions of individuals are
not predictable. Sometimes those directly wrestling with the problem are most aware of the snags; at other times it is the supervisor who takes responsibility for stopping an approach to which those involved remain committed. However, if the troops have lost enthusiasm, this in itself is a good reason for considering another approach. The situation described by Macaulay is not a satisfactory one: But those behind cried 'Forward/' and those before cried 'Back!' For the most complex decisions - such as those made by governments in terminating the development of weapon systems - it is rarely clear even with hindsight whether the decision was appropriate or not. Recognition that design decisions are in practice extraordinarily muddled, with a large intuitive element, emphasises the importance of being clear about what decisions have been made and what the reasons were. This reduces the tendency for the most crucial decisions to emerge almost accidentally. For example, the decision on how large a crew should be in a tank, on a flight deck or in a control room, dominates subsequent features of the control system design as well as the control centre design. Incidentally, the basic principle of centralised control seems to have been adopted universally simply because the technology makes it possible; how far it is actually desirable is rarely explored. This is particularly true for military systems where the control centre is vulnerable to enemy attack. The case for distributed control is supported also by another general feature - namely, that much of the important evidence needed to control operations is impressionistic and not suitable for codification and entry into a data processing system. The following are indications that a design team is under competent management: 1. Each sub-team has directives which indicated an orientation if not a specific objective, and there is a very clear separation from the work of other sub-teams. 2. Each sub-team has been given a time scale, at the end of which it will be feasible to decide whether or not it has competently served its purpose. 3. There will be a notable absence of groups whose activities are mysterious but for which the purpose eventually emerges as some senior person setting up defences against any questioning of his own competence. 4. There is an efficient information circulation system and central filing system which team members can rely upon. 5. Funds will be available on a rational basis so that expensive manpower costs are not dissipated through lack of availability of relatively minor funds for other purposes. 6. Team leaders and committee chairmen have been trained in the elementary principles of adequate preparation for group activities and adequate recording of progress made. Action lists are necessary but not sufficient, decisions and the supporting evidence are also recorded. 7. Discussion leaders will have some acquaintance with group dynamics, not only in the political sense of detecting when some members are practising the black arts of manoeuvre and obfuscation, but also in the more technical sense of disagreements arising from the use of different models and different values.
8. Individuals will have developing task programmes which are not subject to erratic and apparently irrational switches in priorities. 9. Individuals will be aware of their specific place in the scheme of things and will be able to see avenues of progress for their own careers even when the design project has been completed. There are some fashionable principles of team design in widespread current use which are of dubious validity: I. Sub-teams should be problem-orientated but should be supported by discipline-orientated services. Such a matrix organisation leads to difficulties between group leaders on the two sides of the matrix, and to confused loyalties on the part of team members and supporters. 2. Problem-solving team performance should be monitored by an audit team. This can reduce the motivation for the highest quality in the initial problem-solving and can lead to time-wasting dialogue between initiators and auditors. 3. Sub-systems concerned with safety should receive more intensive monitoring than those concerned with achieving objectives. Superficially this would appear self-evident, but in practice it is very difficult to separate safety systems from others. 4. It is even more difficult to separate quality and speed of production by a design team. As in other kinds of work, urgency does not necessarily reduce quality. 5. Strategies for compensating for the incompetent by increasing manpower and by attempting to guide insufficiently skilled individuals by monitoring groups rarely succeed. The more senior the person, the more difficult it is to compensate for his inadequacies by the use of other channels. There is no escape from concepts such as morale and leadership. Fortunately, morale parallels efficiency. Clarification of objectives and extensive feed-back about progress towards meeting them reinforces both. Leadership also, in this context, involves clarifying issues and facilitating communication. Authority remains important and depends only partly on technical competence; it also depends on the social climate of the organisation and on features such as the maintenance of social distance. The overall authority gradient needs to be optimised in that too much will interfere with communication and too little will impede effective decision-making.
Communication Good internal and external communication is central to effective performance and it is on this topic that more orthodox ergonomics can be extended to help cope with design team issues. Computer-based systems can be a considerable aid to mutual understanding across disciplines in the same group. The computer provides a common vehicle, and at times a common enemy, which contributes indirectly to the integration of the group as well as directly to the storage of information and its transmission to outsiders. The flexibility of computer graphics systems and potentiality for cross-referencing facilitates the use of block diagrams which are an important aid to mutual understanding. Spatial presentation avoids some of the difficulties of over-
Applied Ergonomics June 1987
113
~
I
-Docurnentation i~- Functional separation Design , ~-Internal communication ~- Feedbackfrom operations
[Simulation[ F~ontrol s ation ~I- Instruments Trai
L~°cumentati°n
~
-Access
I Maintenance~-~ Internal communications ' F Documentation Procedural updating
L_
Fig. 2
The central role of task analysis in system design
specialised jargon and clarifies interactive relationships within very complex concepts. In the disciplines related to human behaviour, Task Analysis provides common ground for the ergonomist, the personnel specialist and the producers of the many kinds of operating instructions (Fig. 2). Task descriptions are useful to the ergonomist, not only as a basis for interface designs but also as his evidence in debates on allocation of functions which incorporate safety as well as performance criteria. The contribution of human errors to estimates of system reliability are clearly an important issue but unfortunately not one where the ergonomist can make very confident predictions in the present state of the art. Developments in computers, particularly reduced cost, have also extended the application of simulation and computer assisted training more generally. One of the original claims for the systems approach was that it would be possible to conduct training and other personnel development and assessment in parallel with the development
114 Applied Ergonomics June 1987
of hardware. This is now more feasible with the potentialities for appropriate simulation. If a high-fidelity simulator is available, it can also be used for the evaluation of interface innovations and instructional formats. Such advantages were always important to military systems, but they are of increasing importance in civil systems because of the very high costs of commissioning time when the system has already been paid for but there is, as yet, no return on the investment, or worse still, if the system fails to meet expectations and accentuates other problems in the customer's organisation. Customers for high-technology systems are usually so tightly organised that any new system which does not perform as predicted is a disaster. The increased utilisation of computers in design processes disguises but does not avoid the traditional issues of documentation, which depend on integration and clarity of descriptions of problems and their solutions. Document integration is often neglected. If i.t is not made clear how a particular report derives from and relates to other reports, there will eventually be expensive confusion about the authority of different sources, perhaps even to the point of having to re-do work which has already been done. Maintenance operations also require attention to task design and documentation. There are particular problems in communication links and formal procedures between the maintenance staff and the operating staff. There are increasing overlaps between design and training. More precisely defined information presentations require complementary training systems and contain implicit assumptions about the expected level of technical expertise of maintenance and control operators.
Conclusion Following the enumeration of all these difficulties, one might wonder how these large-scale systems ever reach the stage of working satisfactorily. The fact that they do is a tribute to the skills of designers who function in spite of the limitations of their parent system. However, ergonomics is about recognising and compensating for human limitations as well as capitalising on human assets. It is often said that human operators are the glue that holds operating systems together, and this is true also for design systems.
The design of design teams in high-technology industries W.T. Singleton Emeritus Professor University of Aston in Birmingham; Visiting Professor University of Geneva
Every design enterprise in high-technology involves a large multi-disciplinary team. In the context of man-machine interaction there are two related issues concerning the design system. Firstly, the team must be divided into sub-teams which can complete separate tasks within the context of the total system concept. Secondly, there are human factors design issues which often run across the work of the sub-teams. The division of a design effort into separate tasks is a considerable art but there are some general principles such as the minimisation of communication across interfaces and the standardisation of procedures for consolidating, communicating and recording design decisions. A human factors service must be available on a wide range of issues, including coding and storage of information concerning progress to date, the man-machine interfaces, work space and working environment design, and the design of instruction manuals. The ergonomist cannot confine his solutions within design. There are complementary issues of training which are usually organisationally separated. The ergonomist must cooperate with personnel specialists responsible for staffing levels and training. In recent years useful bridges have developed in the form of common interests in task analysis and simulation.
Keywords: Design, systems, communication Preamble High.technology design teams currently create complex man-ma0hine systems such as vehicles used in warfare, road, rail and air transport; industrial plants which produce manufactured goods, chemicals or electric power; distribution systems for water, gas, electricity, food and industrial products; and commercial systems essentially engaged in moymg money around. All such big systems involve elaborate data-processing and often also contain sub-systems such as missiles, machine-tools and powered handling devices from heavy lifting gear to micromanipulation which themselves require elaborate design effort. These systems and many sub-systems have in common the concept of a control centre where one or more human operators monitor and guide what is happening. This may be as elaborate as the main control room of a nuclear power station or as relatively straightforward as a pendant used to control a machine-tool. Usually there are also other operators in a maintenance role. Invariably the communication issues are not confined to man.machine interfaces, there are also man-man interfaces (Fig. 1). This paper surveys some of the problems in such design work and the methodology required to cope with them. In particular, it is emphasised that the design team itself is a system to which principles of effective communication can be applied.
The description and proposals in this paper are not based directly on any systematically obtained laboratory or field data (although these are in the background of the principles) but rather on the author's experience of nearly 40 years of involvemefit in a great variety of such systems. There is some danger in spreading ergonomics expertise as far as is implied here. On the negative side there is less back-up from reliable data obtained from anthropometric and psychometric measurements or human performance experiments, and there is some trespass into fields where others such as organisational psychologists and sociotechnical specialists have done the research. More positively,
co01(~ '
Management
Maintenance staff ~ - .~
Control
systems
Fig. 1
0003-6870/87/02 0111-04 $03.00 © 1987Butterworth& Co (Publishers)Ltd
Customers
systems
Operating
Technical experts
J
Machineand man interfaces with the control centre
Applied Ergonomics June 1987
111
these real problems are indivisible - someone has to contribute advice on decisions which involve all these issues and often the ergonomist is the only 'people representative' associated with the team.
I ntroduction Traditionally, technological design teams have operated on an autocratic basis with one person - the designer allocating tasks to other engineers and technologists. The designer was the centre of the communications network and he was thus in a position to deal with all problems of integration and compromise. Such a system is no longer feasible for several reasons. All systems are vulnerable to human error in design and operation; it is increasingly accepted that the human role in system performance should be considered systematically at the design stage. The criterion of effectiveness is no longer sufficient; all systems must be cost-effective, and also marketable. It follows that engineers must co-operate with ergonomists, accountants and marketeers. Technology itself has advanced to a level of speciality and complexity which makes it impossible for one person to have sufficient expertise to make a detailed Choice between all the possible processes and mechanisms. For these reasons, and because of trends arising from our more egalitarian societies, many decisions are now made by groups. The introduction of systems theory has resulted in more emphasis on functional as distinct from mechanistic approaches to design and as a consequence even strictly engineering problems are best dealt with by interdisciplinary groups. The introduction of ergonomics which centres on the activity of human operators cuts across many functions and mechanisms and further complicates the cross linkages in decision-making. These influences converge in impeding the progress of design unless considerable care is devoted to meeting the needs for elaborate intercommunication and accurate recording of the design progression. This is, in itself, an ergonomics problem because designers are one kind of human operator requiring well-structured information stores and interfaces.
The structures of design teams Adequate exchange and storage of information is central to the smooth development of the design process. The design team structure should be considered from this viewpoint. Paradoxically, the aim is to separate the team into sub-teams which require the minimum information exchange. In this way each sub-team can get on with its task without the need for constant reference to others. Subdivision of design teams is still done on the basis of long experience in particular industries, but it is possible to enumerate standard symptoms which indicate that the subdivision was not optimal. They are: 1. Internal memoranda copied as a matter of routine to more than five colleagues 2. The setting up of internal (and interminable) working parties, sub-committees and task forces 3. Invitations to attend meetings, not because of any likelihood of a direct contribution but in a representational or liaison role
112
Applied Ergonomics June 1987
4. The setting up of committees which are allowed or even encouraged to write their own terms of reference 5. Jealousy between individuals or sections, particularly about demarcation 6. Reconsideration of matters about which firm decisions have already been made; possibly because the previous decision is not accepted, more usually because there are inadequate records and insufficiently structured access to details of decisions and reasons for decisions 7. Poor documentation and indexing of documents 8. Excessive reliance on the human memory 9. Secretiveness by teams to reduce the possibility of interference by others and by individuals to preserve personal power 10. Remoteness of leadership so that team members are insufficiently aware of their part in the total scheme of things. All team members should be familiar with what the leader's objectives are and also his style of approaching issues and obstacles. This reduces their need to consult him about minor problems and reduces friction between colleagues because all are working in line with the leader's efforts and therefore with each other. It should be emphasised that these symptoms and consequences are no more than exaggerations of what is the normal position. Every member of a design team will recognise these effects in his organisation; it does not necessarily mean that his team is very badly organised. It is quite normal for various symptoms of 'them' versus 'us' to develop and the higher the morale and motivation, the greater the tendency to see 'us' as superior in quality and importance to others. One of the skills required of project leaders is the ability to guide such positive thinking into productive rather than unproductive channels. The product from a design team which has not been well organised may be technically competent but will lack the subtle qualities of total coherence which indicate efficiency and also present an aesthetically satisfying product. There may also be questions of reliability laecause the integration of the sub-systems is not as tidy as it could be. The design process itself will have been more expensive a~,d more timeconsuming than was expected.
Team management So far this paper has centred on failings rather than remedies but identification of a problem is a necessary preliminary step towards a solution. There are no easy solutions to these intricate problems of social behaviour. At the technical level, systems thinking has been of some help in clarifying the importance of well-defined objectives and the need to separate functional thinking from thinking in terms of mechanisms. On the other hand, the greater the creative content of a design the less feasible it is to begin by defining objectives. Design thinking is always iterative. The designer has some ideas of what he has to do but this idea is always refined as the work proceeds. The solution invariably emerges in parallel with the process of attaining it. It has to be recognised also that original work can often get into a cul-de-sac. The art of recognising when retreat is a prerequisite for further progress is a crucial aspect of good design thinking. There are usually wide differences of opinion on such issues and the reactions of individuals are
not predictable. Sometimes those directly wrestling with the problem are most aware of the snags; at other times it is the supervisor who takes responsibility for stopping an approach to which those involved remain committed. However, if the troops have lost enthusiasm, this in itself is a good reason for considering another approach. The situation described by Macaulay is not a satisfactory one: But those behind cried 'Forward/' and those before cried 'Back!' For the most complex decisions - such as those made by governments in terminating the development of weapon systems - it is rarely clear even with hindsight whether the decision was appropriate or not. Recognition that design decisions are in practice extraordinarily muddled, with a large intuitive element, emphasises the importance of being clear about what decisions have been made and what the reasons were. This reduces the tendency for the most crucial decisions to emerge almost accidentally. For example, the decision on how large a crew should be in a tank, on a flight deck or in a control room, dominates subsequent features of the control system design as well as the control centre design. Incidentally, the basic principle of centralised control seems to have been adopted universally simply because the technology makes it possible; how far it is actually desirable is rarely explored. This is particularly true for military systems where the control centre is vulnerable to enemy attack. The case for distributed control is supported also by another general feature - namely, that much of the important evidence needed to control operations is impressionistic and not suitable for codification and entry into a data processing system. The following are indications that a design team is under competent management: 1. Each sub-team has directives which indicated an orientation if not a specific objective, and there is a very clear separation from the work of other sub-teams. 2. Each sub-team has been given a time scale, at the end of which it will be feasible to decide whether or not it has competently served its purpose. 3. There will be a notable absence of groups whose activities are mysterious but for which the purpose eventually emerges as some senior person setting up defences against any questioning of his own competence. 4. There is an efficient information circulation system and central filing system which team members can rely upon. 5. Funds will be available on a rational basis so that expensive manpower costs are not dissipated through lack of availability of relatively minor funds for other purposes. 6. Team leaders and committee chairmen have been trained in the elementary principles of adequate preparation for group activities and adequate recording of progress made. Action lists are necessary but not sufficient, decisions and the supporting evidence are also recorded. 7. Discussion leaders will have some acquaintance with group dynamics, not only in the political sense of detecting when some members are practising the black arts of manoeuvre and obfuscation, but also in the more technical sense of disagreements arising from the use of different models and different values.
8. Individuals will have developing task programmes which are not subject to erratic and apparently irrational switches in priorities. 9. Individuals will be aware of their specific place in the scheme of things and will be able to see avenues of progress for their own careers even when the design project has been completed. There are some fashionable principles of team design in widespread current use which are of dubious validity: I. Sub-teams should be problem-orientated but should be supported by discipline-orientated services. Such a matrix organisation leads to difficulties between group leaders on the two sides of the matrix, and to confused loyalties on the part of team members and supporters. 2. Problem-solving team performance should be monitored by an audit team. This can reduce the motivation for the highest quality in the initial problem-solving and can lead to time-wasting dialogue between initiators and auditors. 3. Sub-systems concerned with safety should receive more intensive monitoring than those concerned with achieving objectives. Superficially this would appear self-evident, but in practice it is very difficult to separate safety systems from others. 4. It is even more difficult to separate quality and speed of production by a design team. As in other kinds of work, urgency does not necessarily reduce quality. 5. Strategies for compensating for the incompetent by increasing manpower and by attempting to guide insufficiently skilled individuals by monitoring groups rarely succeed. The more senior the person, the more difficult it is to compensate for his inadequacies by the use of other channels. There is no escape from concepts such as morale and leadership. Fortunately, morale parallels efficiency. Clarification of objectives and extensive feed-back about progress towards meeting them reinforces both. Leadership also, in this context, involves clarifying issues and facilitating communication. Authority remains important and depends only partly on technical competence; it also depends on the social climate of the organisation and on features such as the maintenance of social distance. The overall authority gradient needs to be optimised in that too much will interfere with communication and too little will impede effective decision-making.
Communication Good internal and external communication is central to effective performance and it is on this topic that more orthodox ergonomics can be extended to help cope with design team issues. Computer-based systems can be a considerable aid to mutual understanding across disciplines in the same group. The computer provides a common vehicle, and at times a common enemy, which contributes indirectly to the integration of the group as well as directly to the storage of information and its transmission to outsiders. The flexibility of computer graphics systems and potentiality for cross-referencing facilitates the use of block diagrams which are an important aid to mutual understanding. Spatial presentation avoids some of the difficulties of over-
Applied Ergonomics June 1987
113
~
I
-Docurnentation i~- Functional separation Design , ~-Internal communication ~- Feedbackfrom operations
[Simulation[ F~ontrol s ation ~I- Instruments Trai
L~°cumentati°n
~
-Access
I Maintenance~-~ Internal communications ' F Documentation Procedural updating
L_
Fig. 2
The central role of task analysis in system design
specialised jargon and clarifies interactive relationships within very complex concepts. In the disciplines related to human behaviour, Task Analysis provides common ground for the ergonomist, the personnel specialist and the producers of the many kinds of operating instructions (Fig. 2). Task descriptions are useful to the ergonomist, not only as a basis for interface designs but also as his evidence in debates on allocation of functions which incorporate safety as well as performance criteria. The contribution of human errors to estimates of system reliability are clearly an important issue but unfortunately not one where the ergonomist can make very confident predictions in the present state of the art. Developments in computers, particularly reduced cost, have also extended the application of simulation and computer assisted training more generally. One of the original claims for the systems approach was that it would be possible to conduct training and other personnel development and assessment in parallel with the development
114 Applied Ergonomics June 1987
of hardware. This is now more feasible with the potentialities for appropriate simulation. If a high-fidelity simulator is available, it can also be used for the evaluation of interface innovations and instructional formats. Such advantages were always important to military systems, but they are of increasing importance in civil systems because of the very high costs of commissioning time when the system has already been paid for but there is, as yet, no return on the investment, or worse still, if the system fails to meet expectations and accentuates other problems in the customer's organisation. Customers for high-technology systems are usually so tightly organised that any new system which does not perform as predicted is a disaster. The increased utilisation of computers in design processes disguises but does not avoid the traditional issues of documentation, which depend on integration and clarity of descriptions of problems and their solutions. Document integration is often neglected. If i.t is not made clear how a particular report derives from and relates to other reports, there will eventually be expensive confusion about the authority of different sources, perhaps even to the point of having to re-do work which has already been done. Maintenance operations also require attention to task design and documentation. There are particular problems in communication links and formal procedures between the maintenance staff and the operating staff. There are increasing overlaps between design and training. More precisely defined information presentations require complementary training systems and contain implicit assumptions about the expected level of technical expertise of maintenance and control operators.
Conclusion Following the enumeration of all these difficulties, one might wonder how these large-scale systems ever reach the stage of working satisfactorily. The fact that they do is a tribute to the skills of designers who function in spite of the limitations of their parent system. However, ergonomics is about recognising and compensating for human limitations as well as capitalising on human assets. It is often said that human operators are the glue that holds operating systems together, and this is true also for design systems.