for example , in one of the factories studied , which packed domestic goods , output per man hour increased by 75 per cent and earnings by 40 per cent , and the wages cost per unit was reduced by 20 per cent , in a period of two years following the introduction of the financial incentive scheme . although the Birmingham study suggests that financial incentives are effective in influencing the behaviour of workers , it also shows that the effects may vary a great deal from factory to factory . where high output is already being achieved , the introduction of a financial incentive may make little or no difference . in other circumstances , however , the effect may be quite marked . in yet others , there may be influences at work which prevent a scheme from having the intended effect . it is always difficult to anticipate precisely what the effect will be , or to make any useful statement about the relationship between the financial incentive on the one hand , and effort or output on the other , which would apply in all circumstances . but it is obviously useful to know what influences are likely to affect the success of financial incentive schemes , and to be aware of some of the practical difficulties which may arise . the evidence from intensive studies of workshop behaviour by social scientists in Britain and U.S.A will now be discussed briefly . the influence of the social group . observation of behaviour in workshops often reveals that levels of output and earnings under financial incentive schemes are controlled by groups of workers . this is possible because , by their very design , such schemes leave the worker some freedom to regulate the relationship between effort and reward , hence providing scope for manipulation . the extent of this , and the desire to manipulate , will vary from workshop to workshop , according to the degree of machine-pacing of work , and the effectiveness of other managerial controls . it will also depend on whether workers want to set their own standards of output and earnings . if they do , and if their standards are lower than those considered as reasonable by managers , such behaviour is usually called restriction of output . behaviour of this kind and the judgements which are made about it , reveal that the ideas of managers and workers will often differ about a fair day &apos;s work for a fair day &apos;s pay . the existence of such discrepant ideas has long been recognized . F W Taylor , a pioneer of scientific management , used the colourful term systematic soldiering to describe control over output by the working group , when the group &apos;s standards were lower than management hoped for or expected . he believed that this could be overcome by the scientific setting of standards , by more efficient methods of working and managerial control , and by the offer of cash incentives to workers , specially selected as suitable to perform certain tasks defined by management . in Taylor &apos;s scheme , which has been widely adopted in various forms , the onus is upon management to develop more effective techniques of control over the production process . often investigators , including Taylor himself , have argued that to change attitudes is equally important , if not more so . P E Vernon argued , for example , that the economic fallacy of restriction of output - i.e , that it is in the workers &apos; best interests - could be overcome if workers were better educated , and allowed a greater share in management . later researches suggest that these investigators over-stressed economic rationalism as a motive in worker behaviour . social scientists have pointed out that the behaviour of an individual is largely controlled by the rules and customs of society as a whole and of the groups within it to which he belongs . he is rewarded when he conforms to the rules , and punished when he deviates from them . a very powerful social sanction , for example , is sending to Coventry which cuts the deviant off from social communication with other members of his group . in a society like our own , which is highly differentiated along lines of occupation and social class , and which is built up of a multitude of interlinked groupings and specialized activities , it is not surprising that differing standards emerge , which are preserved and maintained in the processes of group life . all this was illustrated in the well-known Hawthorne experiments carried out in the U.S.A . the investigators , who watched the behaviour of the workers in the bank wiring room concluded that the workers kept output at a steady level below the limit set by normal fatigue , not because they were , as individuals , pursuing well-defined economic interests but because they feared that to behave otherwise would promote external pressure to break up the group . the workers explained their behaviour , it is true , by reference to their fear of rate-cutting , or working themselves out of a job , and so on . but these explanations seemed to the investigators to be rationalizations of behaviour which had itself arisen from deep-rooted psychological and social needs . there is much evidence which supports the view that workers may be willing to forgo greater cash rewards to maintain pleasant social relationships and other satisfactions , such as control over the working environment . if this is so the attempt to tighten management control over the behaviour of individual workers - by the techniques which Taylor , amongst others , advocated - may well be felt as a threat to the working group , and may generate sufficient resistance to nullify the intended effects of the techniques themselves . for a time after the classic Hawthorne studies , some observers of behaviour in workshops were so concerned to stress the importance of social satisfaction that they tended to ignore the continuing influence of economic needs on the behaviour of workers . recently some writers have suggested that a worker may gain both social and economic satisfaction , because controls over output and earnings maintained by the group may also be intended to serve economic objectives , and may consciously be designed to do so . a recent Manchester University study , supporting this kind of conclusion , was carried out in an engineering workshop , where a group of workers manipulated a complicated incentive scheme by an unofficial procedure which they described as cross-booking . the incentive scheme was designed to reward individual workers according to the proportion of time saved on allowed times based on time-study data . the workers found that some of these times were loose , that is , much time could be saved and bonus earned , with relatively little effort . other times were tight , requiring much effort to effect substantial saving and bonus . this group had devised a procedure which balanced the effects of tight and loose allowed times . a proportion of the time saved on loose jobs was not declared by the men when they filled in their time sheets . the men claimed that this procedure had two effects : the existence of loose times was concealed from the management , and the time which they had saved but had not declared , could be banked and then booked on to tight jobs to make them pay . the workers claimed that this procedure enabled them to stabilize effort and earnings and , at the same time , to protect themselves , by concealing the loose rates , from rate-cutting by management . to book straight , they argued , would have also led to wide fluctuations in their earnings since the proportions of tight and loose rates which would be allocated to them in any week could not be accurately predicted . to check the workers &apos; claim that cross-booking stabilized earnings , an investigation was made of the wages records . comparisons of the earnings of persons who cross-booked with those of the few deviants who booked straight seemed to support the claim , as the graph shows ( see p 14 ) . these and other similar studies suggest that the manipulation of incentive schemes by groups of workers is an attempt to put into effect their ideas of a fair day &apos;s work . if the ideas of managers and workers differ about what a worker ought to produce in a day , it is to be expected that both parties will try to express these ideas in behaviour : management by procedures of administrative control , and workers by individual or by group action . the question as to why ideas about a fair day &apos;s work should differ will be discussed in a later section . but the realization that ideas do differ and that financial incentive schemes offer scope to groups of workers for expression of their ideas has led to the emergence of other methods of wage payment which will encourage workers to aim for standards which managers regard as appropriate . group bonus and other schemes . it might appear that the use of group bonus schemes in place of individual incentive schemes would provide an answer to the problem of the influence of social groups on output . such schemes seem to offer no threat to group solidarity and social satisfaction . they may even enhance them . yet , at the same time , the group may behave as an individual is supposed to do - i.e to increase output and earn as much as possible . there is little in reason or experience , however , which lends support to this view . it is true that some processes lend themselves easily to systems of group payment as , for example , in the steel industry where many processes are operated by crews of men . but there is nothing in such schemes to ensure that output levels will meet management expectations if the crews decide otherwise . the scope for control still exists . group bonus schemes may or may not encourage a sense of common purpose , depending on other circumstances . group bonus schemes pose their own special problems . if workers perform different tasks , difficulties may arise over dividing the group earnings in accordance with the different contributions of individuals . even where workers perform similar tasks , individual differences in skill and application may make any simple division of earnings seem unfair , and may adversely affect relationships within the group . instances have been reported where workers have asked managers to replace group by individual incentives , for this very reason . in recent years the idea has been gaining ground that the kinds of financial incentive scheme discussed above are an inefficient means of managerial control . since they leave workers free to make individual or collective decisions about the relationships between effort and reward , they weaken managerial control over the productive process , and affect the capacity of the management accurately to set standards and to plan programmes of work . attention has therefore been turned to the development of systems of payment which offer a regular weekly sum to individuals in return for a consistent level of measured performance . in such schemes payment is not related directly to pieces produced or to time saved . they take the form of a contract in which the individual undertakes to maintain a certain pace of work in return for a weekly wage . one effect of this is that management is better able to predict and plan . another is that the onus is placed on managers and supervisors to see that workers have enough work to do to fulfil their obligations under the contract . some schemes provide that if a worker shows himself capable of reaching and maintaining a higher pace of work , he can be given a higher weekly wage . so there is still an incentive to increase output . schemes such as this , like individual and group piece-work or bonus schemes , raise practical problems of setting rates or measuring standards of performance , i.e the translation of ideas of a proper day &apos;s work into terms of physical output or effort . it will be argued here that procedures for setting rates , however refined , do not by themselves solve any of the problems raised by the existence of differing notions of a proper day &apos;s work . but it is necessary in any discussion of financial incentive schemes to describe and evaluate these procedures . the problem of rate setting . before the stop-watch was widely introduced for timing industrial work , piece-work schemes were usually based on times estimated by supervisors , who relied on personal judgement based on past experience . this method , sometimes referred to as guesstimating , is still employed . 