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Pacing stress, human adaptation and training in car production
Applied Ergonomics 1972, 3.3,142-146
Pacing stress, human adaptation and training in car production R.M. Belbin Consultant to the Industrial Training Research Unit. and D. Stammers Now with North Gloucestershire College of Technology.
Paced systems of production offer economic advantages but are often lacking in terms of ergonomic principles. Stress arises through forcing longer than standard work cycle times into a fixed time allowance. Operators adopt strategies to reduce these stresses, but where they persist, human reactions can include collective strikes, local unauthorised line stoppages, or transfer to other work. Problems include the lack of rest breaks and the desire for maximum earnings. The solutions proposed include off-track training, higher payment grades for trained workers, assured rest breaks, and removal of work from the line for fault rectification or for final assembly by older workers.
Under a paced system of working, an operator is obliged to complete each task within a rigidly fixed time cycle. Clearly anyone planning work with ergonomic principles in mind would not give such a system a moment's consideration. The fixed time cycle wastes tile savings in time which the skilled operator can achieve and causes mounting difficulty for the operator of lesser accomplishments or one who suffers a 'contingency' during tile cycle. On the other hand, the ergonomie deficiencies of pacing are counterbalanced by some intrinsic economic advantages. A paced system of production under which each unit passes directly from one operator to the next minimises stock in process; maximises the use of floor space; minimises the handling of materials; and, once the system has been laid out, simplifies tile organisational effort of supplying the right components to the right place at the right time. if pacing is to maintain its place in modern industry, how can the system be improved to offset some of its ill effects? In this article we have endeavoured to approach this question by examining the nature of the problems occurring on the factory floor of one large organisation. But before doing so we might take account of some of
the salient findings of previous studies of pacing, both of laboratory and industrial origin. Previous work The reasons underlying tile human difficulties associated with pacing have been revealed by Dudley (1962), who draws attention to tile difference between the natural distribution of work cycle times under the normal incentive conditions operating in a factory and the distribution found under paced conditions. With unpaced work there is a peak frequency around the standard time with skewing towards longer cycle times (Fig 1).
a
b
u
Lt.
III
This article has been published by the Industrial Training Research Unit as ResearchPaper TR2 in a series on selection and training in industry. 142
Applied Ergonomics September 1972
Operation time Fig 1 Distribution of cycle times: a) unpaceo work, b) paced work
The problem for pacing is to accommodate these few longer cycles within a time allowance. The longer cycles may be due to outside causes, eg a cross threaded screw, or be personal, a fumble or the infliction of damage. But when the cycle time is effectively lengthened under pacing, for whatever reason, some sort of 'breakdown' is bound to occur. There can be a 'miss' leading to an item of work being omitted or incomplete, the quality suffers (see Turner, 1963) or additional work is accomplished through increased human effort. The history of car assembly plants affords many instances of precipitous reactions by operators to even slight increases in working pressure (Walter and Guest, 1952). The longterm effect of exposure to this pressure is that only a small proportion of car assembly line workers stay in the job until retirement (Belbin, 1953). Most pacing is not totally rigid, however, and so there are possibilities for operators to use to best advantage whatever latitude the system offers. It is clear from several studies that operators try to build themselves a 'bank' of work on which they can draw, so creating a reserve of time (Van l~eck, 1961 ; Murrell, 1963; and Walker and Guest, 1952). All these studies recommend that, wherever possible, the 'bank' should be provided by management through design changes on the production lines. Where this is not possible, the evidence points to the fact that more time must be allowed for rigidly paced work than is needed for unpaced conditions of working, if maximum job accuracy is to be achieved (Murrell, 1963).
affording himself a bank), he could be counted as being 'ahead of station'. But if he had difficulty in keeping up he would find himself working 'down from station'. The results of this analysis are shown in Figs 2 and 3. It will be seen tliat most gang members are able to work
Ahead of station Behind station
station Behind station
Most of the detailed observations were concentrated on one track and involved between 60 and 70 operators, two foremen, six inspectors and four rectifiers. The whole study covered a period of eighteen months. For the purpose of the study, we assumed the ideal position for each job on the conveyor line as occurring within a fixed territory. This was termed working 'at station'. If, however, the operator gained on the line (so
6
7
8
o~
n
2oFU
U u
40"
20 0 20 40 60
Day shift (180 observations per person)
H
(]
m
--
u
II
,_/ i_i a
n
n
uo
D
u
O/o Ahead of station
o 40
nl-IHnHn uu u
nrl
oUU
u
U
Night shift ( 50 observations i~zr p~rson ) Fig 2 Chart showing percentage of time operators work ahead of station or behind station
Qperators
Inspector
,o FFt-fl--n--H-ff-n--n--n-n---i-I-Day shift (180 observations per person} r ~
n,
Almost all of the work within the department entails the use of hand tools, some being pneumatic. The operators are not restricted to fixed work s t a t i o n s - a s is the case with, say, spot-welding equipment -- but are free to move up and down the track within a limited area until the car is hoisted out of reach.
5
Day shift (with trainees) (70 observations I~r person}
Problems on assembly lines
In this department, men work on what is known as the interior and exterior trim, fitting such items as carpets, seats, windscreens, handles and lamps. The components are transported in trolleys which move at the same speed as, and adjacent to, the appropriate body shell on the main track. There are five such tracks in the department. Each track has three inspection stations, the last of which is final inspection, which also acts as a check on rectification. Following final inspection, the completed body is lifted and transported to the final assembly lines where engine, gearbox and similar items are incorporated.
4
Inspector \ 9
Olo
I~zhind station
The assembly lines of motor car manufacture provide almost the classic example in industry of paced work on a large scale. The Industrial Training Research Unit study was carried out in an assembly plant in the Midlands in a department employing some 300 semi-skilled and unskilled operators.
Operators ~176 40 I 2 3
f
20
Trainees
,o n - f 1 .
_
-fin
....
Day shift (with trainees} ( 7 0 observations per person)
2O
,o
--fi-N-Tr-
....
Night shift (50 observations per I~rson} While some operators enjoy large amounts of relaxation others are not receiving o reasonable minimum Fig 3 Percentage relaxation other than official breaks
Applied Ergonomics September 1972
143
comfortably within their allotted time cycle. This may be shown by the bias towards working 'ahead of station' (Fig 2) and by the amount of relaxation time taken (Fig 3). The tendency to work ahead is not so marked on the night shift where informal breaks are fewer, but formal rest breaks are enjoyed due to the stopping of the line at set times. In spite of the fact that pacing operates under conditions of low stringency for most operators on the track, it is also true that s o m e operators are subject to appreciable stress. This can be seen from two criteria: working 'down from station' (Fig 2), and some low percentages in relaxation time (see Fig 3). These factors tend to be combined, because the operator who is under pressure, being either at station or behind station, is obliged to keep working aU the time. Where there are no formal rest breaks, the strain may be considerable. Fig 2 also shows chain reaction effects. On the shift with trainees, operators 6, 8 and 9 all work under pressure, due presumably to the difficulty trainees have in keeping up. On the night shift, operators I, 2 and 3 are under pressure. The fact that operator 1 is falling behind evidently affects operators 2 and 3. These various patterns show the interdependence of the men on the track. On the day shift without trainees, all the operators are on top of the job and no-one is working under pressure. The exception to the interdependence of the men in tile gangs seems to be tile inspectors. Their inspection tasks are ill-specified and largely discretionary. Even inspection items of high priority are easily and quite often omitted, especially if there is an operator in the way. Hence being located ahead of station or behind station does not appreciably affect the levels of stress to which inspectors are exposed. Stress then would seem to be confined to the operators and this stress fluctuates as the men spend some portion of their time ahead of station and some portion behind station due to intermittent pressures arising from three main sources. 1. One main source is operator intereference. Commonly a man fallsbehind station due to the repurcussion effect of someone higher up the track experiencing trouble, being temporarily absent or just being slow. In consequence an operator may be obstructed from getting into a vehicle which is already occupied until it is well down the line. 2. Fluctuations in the quality of materials or a shortage of components may disrupt the flow of working for prolonged periods. In effect, the time cycle of work is lengthened and this can only result in 'slipping down the track'. 3. Working behind station is sometimes due to undermanning. In this factory, piece work rates were agreed with a gang of men who by economising in labour on the line could increase their own earnings. This was usually achieved either by not replacing an absent worker or doing without additional help after some extra item of work had been negotiated.
144
Applied Ergonomics September 1972
These three reasons for intemfittent difficulties in keeping pace are also affected by the availability of skills on the line. There is no formal training for the new operator and tile newcomer merely works as a supernumerary alongside an experienced operator until, after a fixed period of time, he is counted as 'run-in'. There are no criteria of skill and no fixed methods of working. In consequence, the competence of operators varies considerably. Even the skills they do possess are not always used in the most equitable manner, for work is allocated by the gang and those higher in status, experience and skill tend to enjoy a greater hold on tile less demanding jobs at the expense of newcomers.
Human reaction of pacing One of the expectations about tile human operator under paced conditions of work is that sooner or later there is a breakdown of the system. In car assembly there are several ways in which this breakdown is observed to occur. There is a collective withdrawal of labout (a strike) which can act as a safety valve, showing itself as a temporary walkout (though wielded to the economic advantage of the men) rather than a prolonged dispute. There is unauthorised stopping of the line effected when an operator presses the emergency button: this enables people to catch up (get back to or ahead of station). Finally, there is voluntary transfer by individuals to other work: in tile trim shop tile loss of labour was generally high. For example, there was a 20% labour turnover amongst those employed in the late thirties and the forties, a figure more than twice the normal average for this age group. Some operators transfer to production work. Most inspectors on the line were exoperators, although the move involved a drop in earnings of between s - 9 per week. All these symptons of stress were noted during the period of study. The lightning strike was resorted to less frequently than might have been imagined by those acquainted with the car industry. One reason for this was that the men were themselves frequent victims of strikes by others, especially in component manufacture. While these disputes adversely affected their earnings and were sources of frustration, they had some positive merit in reducing excessive working pressure. These behavioural reactions to pacing stresses are in line with and supplement those found in previous studies. But a further means of asscssi~lg the reaction of operators to their conditions of work was to ask them open-ended questions. A very simple questionnaire was prepared which consisted of only two questions: 1. Would you recommend a man of over 40 to take a job like yours? If tile answer is 'yes' please say why. If the answer is 'no' please say why. 2. If you heard that somebody was leaving work similar to yours, what do you think would be his reasons?
Ten inspectors and 73 operators completed the questionnaire. Respondents were regarded as having negative
attitudes if they answered no to the first question and positive attitudes if they answered 'yes'. Some 90% of the inspectors showed positive attitudes against only 19% of the operatives. The two main reasons for not recommending the work were "speed too great" and "job too demanding physically". To the second question (asked of operators only) a different set of answers appeared at the top of the list. Here 40% of respondents suggested "to avoid nights" while " m o n o t o n y " was quoted by 17% and "strikes" by 16%; The discrepancy between these two sets of answers suggests that the men see work stresses exerting a harmful effect around the age of 40 but that where age is ignored a different set of frustrations are seen as causing men to leave work. While operators have generally negative attitudes to track work, those in the critical 3 5 - 4 0 age group seem to dislike the work more than other age groups. There were many spontaneously unfavourable comments, such as "the track is the boss' and "this is tile modern form of salvery". Some of these sentiments seem to brush off on to the firm itself and contribute to an atmosphere of antipathy towards the 'them' of higher management.
Conclusions Assembly line production in motor manufacture affords an example of the problems created by paced work although the physical constraints in comparison with the conditions produced in some laboratory experiments are not overstringent. What increases the stringency is a number of stresses which arise as by-products o f decisions reached both by management and men. One of these decisions, for which management must especially be held responsible, is the abolition on the day shift of formal rest breaks. It is true that the line may stop several times during the day for technical reasons and that these stops afford fortuitous rest breaks which may suffice for human needs, but the system is not geared for the uninterrupted day. Here, rest breaks can only be created to the extent that the operators succeed in working ahead of station, a condition which demands freedom from contingencies. Another human source of stress arises from the men's control over the work situation. Work study, which might ensure a fitting apportionment of work, is resisted in favour of ratefixing and the opportunity which this less accurate system creates for bargaining. Large earnings come high in the car worker's list of priorities and as a group they tend to opt, once the rate has been settled, for that minimum manning that offers maximum wages. The older worker is unlikely to be able to exercise his minority interest in exchanging a slightly lower payment for a lighter work load unless he resigns from the track. Just as the older worker may have difficulty in coping through lack of energy, so also the newcomer may have difficulty in coping for lack of skill. The effect is the same. An even allocation of tasks may allow most of the team to work within limits of comfort, while those who are less well equipped in energy and skill are subject to excessive pressures. Ironically, the bigger rest breaks are taken by those who need them less, while on a number of occasions it was observed that individual operators under pressure of the line could not afford to take test breaks at all! So the system imposes 'positive feedback' which makes it all the more susceptible to a breakdown.
Recommendations A paced production line is continuously producing problems that originate in work stress and which fluctuate with changing conditions in ways that are not always rcalised. For example, under boom conditions the introduction of additional labour with the agreement of the men, and the speeding up of tile tracks (there is no other way of increasing production), can only result in the allocation of a small number of tasks per man, an accentuation of rigid pacing and an increase in operator interference effects. Human problems also originate in undermanning as the men thin their ranks as a means of maximising individual take-home pay. The main need on a paced line would seem to be one of establishing a fine balance in the allocation of manpower and of developing human flexibility to counteract the mechanical rigidities of file system. The optimisation in the manpower loading on the line is an ergonomic study in itself. Other more simple ergonomic measures can be recommended as follows: !. Newcomers might be trained in the basic skills o f assembly work off the track. Toye and Hogan of ITRU, working in the same factory as this study, trained two groups of operators in assembly skills, one by a general discovery method and the other by a procedural method. One month later they compared the performance of both groups on a 'new' assembly task with operators who also had received no training but who had accumulated work experience. Both trained groups performed better than the untrained on the new task. The effect of training would seem to be one of improving the flexibility of operators in coping with the diverse range of tasks that characterise the assembly line and thereby lowering the pacing stringencies accentuated by deficient operator skill (Toye, 1971). 2. An emphasis on the training of assembly workers carries with it implications of payment for skill. Intermittent training.during working life might be used as a means of qualifying operators for higher basic grades. Such a programme would encourage versatility, protect the older worker from the consequences of a failure to adapt to new techniques on the production line, and reduce operator interference effects. 3. Manned test breaks and relief must be assured for all those who are subject to paced working. There are two ways of approaching this. One method is to depend as at present on chance mechanical stoppages to offer periodic rest breaks but to top these up occasionally by planned stoppages where the lines would otherwise run intermittently. The other approach is to employ a group of float workers from those in the highest skill grades to offer planned relief to all those working on the line. Other approaches to the resolution of the conflict between the ergonomic use of operators and the economic needs of the paced production line would involve some modification of the latter. The provision of the acknowledged benefits of a bank of work would have the effect of lengthening the production line. The pacing element might be largely removed, however, if cars could be
Applied Ergonomics September 1972
145
slipped off the line at set points into bays where skilled older workers could finish assembly operations. Such provision would also allow for proper rectification of faults, many of which are due in themselves to hurried work in assembling slightly off-tolerance components. In other words, some of the economic advantages of paced work become more practicable and acceptable if provision can be made for treatment of irregularities in a system free from time stress.
Sequel to the study A report on the study was submitted to management and the recommendations on the development of training were put to a meeting of the Works Council. This Council was receptive to the package proposals for relieving stress on the line but one representative of the production workers saw the proposal to study assembly skills and to develop operator training as an implied threat to the sanctity of the piecework system. In effect, this opposition led to a cessation of the development work proposed. Perhaps it is only experience of pilot demonstration projects that will enable men working under arduous and stressful conditions to judge where their true interests lie.
146
AppliedErgonomics September 1972
References Belbin, R.M. 1957 OccttpationalPsychology, 27, 177-190, Difficulties of older people in industry. Dudley, N.A. 1962 hzternationalJournal of Production Research, 1.2,60, The effect of pacing on operator performance. Van Beck, H.G. 1961 Report from the Psychological Department o f N.V. Philips Gloeilampenfabrieken, Eindhoven. Working on assembly lines. Murrell, K.F.H. 1963 hzternationalJournal of Production Research, 2, 169-185. Laboratory studies in paced work, 1 and 2. Walker, C.R., and Guest, R.It. 1952 The man on the assembly line. Harvard University Press. Toye, M.H. 1971 hzdustrialandConmlercial Trahfing, 3 588/589. To educate or to instruct. Turner, G. 1963 Why the quality of our cars suffers. In "The Car Makers", Eyre and Spottiswode.
Pacing stress, human adaptation and training in car production R.M. Belbin Consultant to the Industrial Training Research Unit. and D. Stammers Now with North Gloucestershire College of Technology.
Paced systems of production offer economic advantages but are often lacking in terms of ergonomic principles. Stress arises through forcing longer than standard work cycle times into a fixed time allowance. Operators adopt strategies to reduce these stresses, but where they persist, human reactions can include collective strikes, local unauthorised line stoppages, or transfer to other work. Problems include the lack of rest breaks and the desire for maximum earnings. The solutions proposed include off-track training, higher payment grades for trained workers, assured rest breaks, and removal of work from the line for fault rectification or for final assembly by older workers.
Under a paced system of working, an operator is obliged to complete each task within a rigidly fixed time cycle. Clearly anyone planning work with ergonomic principles in mind would not give such a system a moment's consideration. The fixed time cycle wastes tile savings in time which the skilled operator can achieve and causes mounting difficulty for the operator of lesser accomplishments or one who suffers a 'contingency' during tile cycle. On the other hand, the ergonomie deficiencies of pacing are counterbalanced by some intrinsic economic advantages. A paced system of production under which each unit passes directly from one operator to the next minimises stock in process; maximises the use of floor space; minimises the handling of materials; and, once the system has been laid out, simplifies tile organisational effort of supplying the right components to the right place at the right time. if pacing is to maintain its place in modern industry, how can the system be improved to offset some of its ill effects? In this article we have endeavoured to approach this question by examining the nature of the problems occurring on the factory floor of one large organisation. But before doing so we might take account of some of
the salient findings of previous studies of pacing, both of laboratory and industrial origin. Previous work The reasons underlying tile human difficulties associated with pacing have been revealed by Dudley (1962), who draws attention to tile difference between the natural distribution of work cycle times under the normal incentive conditions operating in a factory and the distribution found under paced conditions. With unpaced work there is a peak frequency around the standard time with skewing towards longer cycle times (Fig 1).
a
b
u
Lt.
III
This article has been published by the Industrial Training Research Unit as ResearchPaper TR2 in a series on selection and training in industry. 142
Applied Ergonomics September 1972
Operation time Fig 1 Distribution of cycle times: a) unpaceo work, b) paced work
The problem for pacing is to accommodate these few longer cycles within a time allowance. The longer cycles may be due to outside causes, eg a cross threaded screw, or be personal, a fumble or the infliction of damage. But when the cycle time is effectively lengthened under pacing, for whatever reason, some sort of 'breakdown' is bound to occur. There can be a 'miss' leading to an item of work being omitted or incomplete, the quality suffers (see Turner, 1963) or additional work is accomplished through increased human effort. The history of car assembly plants affords many instances of precipitous reactions by operators to even slight increases in working pressure (Walter and Guest, 1952). The longterm effect of exposure to this pressure is that only a small proportion of car assembly line workers stay in the job until retirement (Belbin, 1953). Most pacing is not totally rigid, however, and so there are possibilities for operators to use to best advantage whatever latitude the system offers. It is clear from several studies that operators try to build themselves a 'bank' of work on which they can draw, so creating a reserve of time (Van l~eck, 1961 ; Murrell, 1963; and Walker and Guest, 1952). All these studies recommend that, wherever possible, the 'bank' should be provided by management through design changes on the production lines. Where this is not possible, the evidence points to the fact that more time must be allowed for rigidly paced work than is needed for unpaced conditions of working, if maximum job accuracy is to be achieved (Murrell, 1963).
affording himself a bank), he could be counted as being 'ahead of station'. But if he had difficulty in keeping up he would find himself working 'down from station'. The results of this analysis are shown in Figs 2 and 3. It will be seen tliat most gang members are able to work
Ahead of station Behind station
station Behind station
Most of the detailed observations were concentrated on one track and involved between 60 and 70 operators, two foremen, six inspectors and four rectifiers. The whole study covered a period of eighteen months. For the purpose of the study, we assumed the ideal position for each job on the conveyor line as occurring within a fixed territory. This was termed working 'at station'. If, however, the operator gained on the line (so
6
7
8
o~
n
2oFU
U u
40"
20 0 20 40 60
Day shift (180 observations per person)
H
(]
m
--
u
II
,_/ i_i a
n
n
uo
D
u
O/o Ahead of station
o 40
nl-IHnHn uu u
nrl
oUU
u
U
Night shift ( 50 observations i~zr p~rson ) Fig 2 Chart showing percentage of time operators work ahead of station or behind station
Qperators
Inspector
,o FFt-fl--n--H-ff-n--n--n-n---i-I-Day shift (180 observations per person} r ~
n,
Almost all of the work within the department entails the use of hand tools, some being pneumatic. The operators are not restricted to fixed work s t a t i o n s - a s is the case with, say, spot-welding equipment -- but are free to move up and down the track within a limited area until the car is hoisted out of reach.
5
Day shift (with trainees) (70 observations I~r person}
Problems on assembly lines
In this department, men work on what is known as the interior and exterior trim, fitting such items as carpets, seats, windscreens, handles and lamps. The components are transported in trolleys which move at the same speed as, and adjacent to, the appropriate body shell on the main track. There are five such tracks in the department. Each track has three inspection stations, the last of which is final inspection, which also acts as a check on rectification. Following final inspection, the completed body is lifted and transported to the final assembly lines where engine, gearbox and similar items are incorporated.
4
Inspector \ 9
Olo
I~zhind station
The assembly lines of motor car manufacture provide almost the classic example in industry of paced work on a large scale. The Industrial Training Research Unit study was carried out in an assembly plant in the Midlands in a department employing some 300 semi-skilled and unskilled operators.
Operators ~176 40 I 2 3
f
20
Trainees
,o n - f 1 .
_
-fin
....
Day shift (with trainees} ( 7 0 observations per person)
2O
,o
--fi-N-Tr-
....
Night shift (50 observations per I~rson} While some operators enjoy large amounts of relaxation others are not receiving o reasonable minimum Fig 3 Percentage relaxation other than official breaks
Applied Ergonomics September 1972
143
comfortably within their allotted time cycle. This may be shown by the bias towards working 'ahead of station' (Fig 2) and by the amount of relaxation time taken (Fig 3). The tendency to work ahead is not so marked on the night shift where informal breaks are fewer, but formal rest breaks are enjoyed due to the stopping of the line at set times. In spite of the fact that pacing operates under conditions of low stringency for most operators on the track, it is also true that s o m e operators are subject to appreciable stress. This can be seen from two criteria: working 'down from station' (Fig 2), and some low percentages in relaxation time (see Fig 3). These factors tend to be combined, because the operator who is under pressure, being either at station or behind station, is obliged to keep working aU the time. Where there are no formal rest breaks, the strain may be considerable. Fig 2 also shows chain reaction effects. On the shift with trainees, operators 6, 8 and 9 all work under pressure, due presumably to the difficulty trainees have in keeping up. On the night shift, operators I, 2 and 3 are under pressure. The fact that operator 1 is falling behind evidently affects operators 2 and 3. These various patterns show the interdependence of the men on the track. On the day shift without trainees, all the operators are on top of the job and no-one is working under pressure. The exception to the interdependence of the men in tile gangs seems to be tile inspectors. Their inspection tasks are ill-specified and largely discretionary. Even inspection items of high priority are easily and quite often omitted, especially if there is an operator in the way. Hence being located ahead of station or behind station does not appreciably affect the levels of stress to which inspectors are exposed. Stress then would seem to be confined to the operators and this stress fluctuates as the men spend some portion of their time ahead of station and some portion behind station due to intermittent pressures arising from three main sources. 1. One main source is operator intereference. Commonly a man fallsbehind station due to the repurcussion effect of someone higher up the track experiencing trouble, being temporarily absent or just being slow. In consequence an operator may be obstructed from getting into a vehicle which is already occupied until it is well down the line. 2. Fluctuations in the quality of materials or a shortage of components may disrupt the flow of working for prolonged periods. In effect, the time cycle of work is lengthened and this can only result in 'slipping down the track'. 3. Working behind station is sometimes due to undermanning. In this factory, piece work rates were agreed with a gang of men who by economising in labour on the line could increase their own earnings. This was usually achieved either by not replacing an absent worker or doing without additional help after some extra item of work had been negotiated.
144
Applied Ergonomics September 1972
These three reasons for intemfittent difficulties in keeping pace are also affected by the availability of skills on the line. There is no formal training for the new operator and tile newcomer merely works as a supernumerary alongside an experienced operator until, after a fixed period of time, he is counted as 'run-in'. There are no criteria of skill and no fixed methods of working. In consequence, the competence of operators varies considerably. Even the skills they do possess are not always used in the most equitable manner, for work is allocated by the gang and those higher in status, experience and skill tend to enjoy a greater hold on tile less demanding jobs at the expense of newcomers.
Human reaction of pacing One of the expectations about tile human operator under paced conditions of work is that sooner or later there is a breakdown of the system. In car assembly there are several ways in which this breakdown is observed to occur. There is a collective withdrawal of labout (a strike) which can act as a safety valve, showing itself as a temporary walkout (though wielded to the economic advantage of the men) rather than a prolonged dispute. There is unauthorised stopping of the line effected when an operator presses the emergency button: this enables people to catch up (get back to or ahead of station). Finally, there is voluntary transfer by individuals to other work: in tile trim shop tile loss of labour was generally high. For example, there was a 20% labour turnover amongst those employed in the late thirties and the forties, a figure more than twice the normal average for this age group. Some operators transfer to production work. Most inspectors on the line were exoperators, although the move involved a drop in earnings of between s - 9 per week. All these symptons of stress were noted during the period of study. The lightning strike was resorted to less frequently than might have been imagined by those acquainted with the car industry. One reason for this was that the men were themselves frequent victims of strikes by others, especially in component manufacture. While these disputes adversely affected their earnings and were sources of frustration, they had some positive merit in reducing excessive working pressure. These behavioural reactions to pacing stresses are in line with and supplement those found in previous studies. But a further means of asscssi~lg the reaction of operators to their conditions of work was to ask them open-ended questions. A very simple questionnaire was prepared which consisted of only two questions: 1. Would you recommend a man of over 40 to take a job like yours? If tile answer is 'yes' please say why. If the answer is 'no' please say why. 2. If you heard that somebody was leaving work similar to yours, what do you think would be his reasons?
Ten inspectors and 73 operators completed the questionnaire. Respondents were regarded as having negative
attitudes if they answered no to the first question and positive attitudes if they answered 'yes'. Some 90% of the inspectors showed positive attitudes against only 19% of the operatives. The two main reasons for not recommending the work were "speed too great" and "job too demanding physically". To the second question (asked of operators only) a different set of answers appeared at the top of the list. Here 40% of respondents suggested "to avoid nights" while " m o n o t o n y " was quoted by 17% and "strikes" by 16%; The discrepancy between these two sets of answers suggests that the men see work stresses exerting a harmful effect around the age of 40 but that where age is ignored a different set of frustrations are seen as causing men to leave work. While operators have generally negative attitudes to track work, those in the critical 3 5 - 4 0 age group seem to dislike the work more than other age groups. There were many spontaneously unfavourable comments, such as "the track is the boss' and "this is tile modern form of salvery". Some of these sentiments seem to brush off on to the firm itself and contribute to an atmosphere of antipathy towards the 'them' of higher management.
Conclusions Assembly line production in motor manufacture affords an example of the problems created by paced work although the physical constraints in comparison with the conditions produced in some laboratory experiments are not overstringent. What increases the stringency is a number of stresses which arise as by-products o f decisions reached both by management and men. One of these decisions, for which management must especially be held responsible, is the abolition on the day shift of formal rest breaks. It is true that the line may stop several times during the day for technical reasons and that these stops afford fortuitous rest breaks which may suffice for human needs, but the system is not geared for the uninterrupted day. Here, rest breaks can only be created to the extent that the operators succeed in working ahead of station, a condition which demands freedom from contingencies. Another human source of stress arises from the men's control over the work situation. Work study, which might ensure a fitting apportionment of work, is resisted in favour of ratefixing and the opportunity which this less accurate system creates for bargaining. Large earnings come high in the car worker's list of priorities and as a group they tend to opt, once the rate has been settled, for that minimum manning that offers maximum wages. The older worker is unlikely to be able to exercise his minority interest in exchanging a slightly lower payment for a lighter work load unless he resigns from the track. Just as the older worker may have difficulty in coping through lack of energy, so also the newcomer may have difficulty in coping for lack of skill. The effect is the same. An even allocation of tasks may allow most of the team to work within limits of comfort, while those who are less well equipped in energy and skill are subject to excessive pressures. Ironically, the bigger rest breaks are taken by those who need them less, while on a number of occasions it was observed that individual operators under pressure of the line could not afford to take test breaks at all! So the system imposes 'positive feedback' which makes it all the more susceptible to a breakdown.
Recommendations A paced production line is continuously producing problems that originate in work stress and which fluctuate with changing conditions in ways that are not always rcalised. For example, under boom conditions the introduction of additional labour with the agreement of the men, and the speeding up of tile tracks (there is no other way of increasing production), can only result in the allocation of a small number of tasks per man, an accentuation of rigid pacing and an increase in operator interference effects. Human problems also originate in undermanning as the men thin their ranks as a means of maximising individual take-home pay. The main need on a paced line would seem to be one of establishing a fine balance in the allocation of manpower and of developing human flexibility to counteract the mechanical rigidities of file system. The optimisation in the manpower loading on the line is an ergonomic study in itself. Other more simple ergonomic measures can be recommended as follows: !. Newcomers might be trained in the basic skills o f assembly work off the track. Toye and Hogan of ITRU, working in the same factory as this study, trained two groups of operators in assembly skills, one by a general discovery method and the other by a procedural method. One month later they compared the performance of both groups on a 'new' assembly task with operators who also had received no training but who had accumulated work experience. Both trained groups performed better than the untrained on the new task. The effect of training would seem to be one of improving the flexibility of operators in coping with the diverse range of tasks that characterise the assembly line and thereby lowering the pacing stringencies accentuated by deficient operator skill (Toye, 1971). 2. An emphasis on the training of assembly workers carries with it implications of payment for skill. Intermittent training.during working life might be used as a means of qualifying operators for higher basic grades. Such a programme would encourage versatility, protect the older worker from the consequences of a failure to adapt to new techniques on the production line, and reduce operator interference effects. 3. Manned test breaks and relief must be assured for all those who are subject to paced working. There are two ways of approaching this. One method is to depend as at present on chance mechanical stoppages to offer periodic rest breaks but to top these up occasionally by planned stoppages where the lines would otherwise run intermittently. The other approach is to employ a group of float workers from those in the highest skill grades to offer planned relief to all those working on the line. Other approaches to the resolution of the conflict between the ergonomic use of operators and the economic needs of the paced production line would involve some modification of the latter. The provision of the acknowledged benefits of a bank of work would have the effect of lengthening the production line. The pacing element might be largely removed, however, if cars could be
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slipped off the line at set points into bays where skilled older workers could finish assembly operations. Such provision would also allow for proper rectification of faults, many of which are due in themselves to hurried work in assembling slightly off-tolerance components. In other words, some of the economic advantages of paced work become more practicable and acceptable if provision can be made for treatment of irregularities in a system free from time stress.
Sequel to the study A report on the study was submitted to management and the recommendations on the development of training were put to a meeting of the Works Council. This Council was receptive to the package proposals for relieving stress on the line but one representative of the production workers saw the proposal to study assembly skills and to develop operator training as an implied threat to the sanctity of the piecework system. In effect, this opposition led to a cessation of the development work proposed. Perhaps it is only experience of pilot demonstration projects that will enable men working under arduous and stressful conditions to judge where their true interests lie.
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References Belbin, R.M. 1957 OccttpationalPsychology, 27, 177-190, Difficulties of older people in industry. Dudley, N.A. 1962 hzternationalJournal of Production Research, 1.2,60, The effect of pacing on operator performance. Van Beck, H.G. 1961 Report from the Psychological Department o f N.V. Philips Gloeilampenfabrieken, Eindhoven. Working on assembly lines. Murrell, K.F.H. 1963 hzternationalJournal of Production Research, 2, 169-185. Laboratory studies in paced work, 1 and 2. Walker, C.R., and Guest, R.It. 1952 The man on the assembly line. Harvard University Press. Toye, M.H. 1971 hzdustrialandConmlercial Trahfing, 3 588/589. To educate or to instruct. Turner, G. 1963 Why the quality of our cars suffers. In "The Car Makers", Eyre and Spottiswode.