2013년 2월 1일 금요일

[발췌: 일반이론 4/5장] The Choice of Units, Expectation as Determining Output and Employment

출처: The General Theory of Employment, Interest and Money (Keynes, 1936)


※ This is a reading note with excerpts taken, and with personal annotations and remarks added, in trying to understand the above text, so visit the source links to see the original.

※ 발췌(excerpts):

Chapter 4_ Choice of Units

I

In this and the next three chapters[4~6장] we shall be occupied with an attempt to clear up certain perplexities which have no peculiar or exclusive relevance to the problems which it is our special purpose to examine. Thus these chapters are in nature of a digression, which will present us for a time pursuing our main theme. Their subject-matter is only discussed here because it does not happen to have been already treated elsewhere in a way which I find adequate to the needs of my own particular enquiry.

The three perplexities which most impeded my progress in writing this book, so that I could not express myself conveniently until I had found some solution for them, are: 
  • firstly, the choice of the units of quantity appropriate to the problems of the economic system as a whole; 
  • secondly, the part played by expectation in economic analysis; and 
  • thirdly, the definition of income.

II

That the units, in terms of which economists commonly work, are unsatisfactory can be illustrated by the concepts of the national dividend, the stock of real capital and the general price-level:


(ⅰ) The national dividend, as defined by Marshall and Professor Pigou,[1] measures the volume of current output or real income and not the value of output or money-income.[2] Furthermore, it depends, in some sense, on ^net^ output;ㅡon the net addition, that is to say, to the resources of the community available for consumption or for retention as capital stock, due to the economic activities and sacrifices of the current period, after allowing for the wastage of the stock of real capital existing at the commencement of the period. On this basis an attempt is made to erect a quantitative science. But it is a grave objection to this definition for such a purpose that the community's output of goods and services is a non-homogeneous complex which cannot be measured, strictly speaking, except in certain special cases, as for example when all the items of one output are included in the same proportions in another output.

(ⅱ) The difficulty is even greater when, in order to calculate net output, we try to measure the net addition to capital equipment; for we have to find some basis for a quantitative comparison between the new items of equipment produced during the period and the old items which have perished by wastage. In order to arrive at the net national dividend, Professor Pigou[3] deducts such obsolescence, etc., 'as may fairly be called "normal"; and the practical test of normality is that the depletion is sufficiently regular to be foreseen, if not in detail, at least in the large'. But, since this deduction is not a deduction in terms of money, he is involved in assuming that there can be a change in physical quantity, although there has been no physical change; i.e. he is covertly introducing changes in value.

Moreover, he is unable to devise any satisfactory formula[4] to evaluate new equipment against old when, owing to changes in technique, the two are not identical. I believe that the concept at which Professor Pigou is aiming is the right and appropriate concept for economic analysis. But, until a satisfactory system of units has been adopted, its precise definition is an impossible task. The problem of comparing one real output with another and of then calculating net output by setting off new items of equipment against the wastage of old items presents conundrums which permit, one can confidently say, of no solution. 

(ⅲ) Thirdly, the well-known, but unavoidable, element of vagueness which admittedly attends the concept of the general price-level makes this term very unsatisfactory for the purpose of a causal analysis, which ought to be exact.

Nevertheless these difficulties are rightly regarded as 'conundrums'. They are 'purely theoretical' in the sense that they never perplex, or indeed enter in any way into, business decisions and have no relevance to the causal sequence of economic events, which are clear-cut and determinate in spite of the quantitative indeterminacy of these concepts. It is natural, therefore, to conclude that they not only lack precision but are unnecessary. Obviously our quantitative analysis must be expressed without using any quantitatively vague expressions. And, indeed, as soon as one makes the attempt, it becomes clear, as I hope to show, that one can get on much better without them.

The fact that two incommensurabe collections of miscellaneous objects cannot in themselves provide the material for a quantitative analysis need not, of course, prevent us from making approximate statistical comparisons, depending on some broad element of judgment rather than of strict calculation, which may possess significance and validity within certain limits.

But the proper place for such thing as net real output and the general level of prices lies within the field of historical and statistical description, and their purpose should be to satisfy historical or social curiosity, a purpose for which perfect precisionㅡsuch as our causal analysis requires, whether or not our knowledge of the actual values of the relevant quantities is complete or exactㅡis neither usual nor necessary. To say that net output to-day is greater, but the price-level lower, than ten years ago or one year ago, is a proposition of a similar character to the statement that Queen Victoria was a better queen but not a happier woman than Queen Elizabethㅡa proposition not without meaning and not without interest, but unsuitable as material for the differential calculus. Our precision will be a mock precision if we try to use such partly vague and non-quantitative concepts as the basis of a quantitative analysis.


III

On every particular occasion, let it be remembered, an entrepreneur is concerned with decisions as to the scale on which to work a given capital equipment; and when we say that the expectation of an increased demand, i.e. a raising of the aggregate demand function, will lead to an increase in aggregate output, we really mean that the firms, which own the capital equipment, will be induced to associate with it a greater aggregate employment of labour. In the case of an individual firm or industry producing a homogeneous product we can speak legitimately, if we wish, of increase of decrease of output. But when we are aggregating the activities of all firms, we cannot speak accurately except in terms of quantities of employment applied to a given equipment. The concepts of output as a whole and it price-level are not required in this context, since we have no need of an absolute measure of current aggregate output, such as would enable us to compare its amount with the amount which would result from the association of a different capital equipment with a different quantity of employment. When, for purposes of description or rough comparison, we wish to speak of an increase of output, we must rely on the general presumption that the amount of employment associated with a given capital equipment[?, which] will be a satisfactory index of the amount of resulting output;ㅡthe two being presumed to increase and decrease together, though not in a definite numerical proportion.

In dealing with the theory of employment I propose, therefore, to make use of only two fundamental units of quantity, namely, quantities of money-value and quantities of employment. The first of these is strictly homogeneous, and the second can be made so. For, in so far as different grades and kinds of labour and salaries assistance enjoy a more or less fixed relative remuneration, the quantity of employment can be sufficiently defined for our purposes by taking an hour's employment of ordinary labour as our unit and weighting an hour's employment of special labour in proportion to its remuneration; i.e. an hour of special labour remunerated at double ordinary rates will count as two units. We shall call the unit in which the quantity of employment is measured the labour-unit; and the money-wage of a labour-unit we shall call the wage-unit.[5] Thus, if E is the wages (and salaries) bill, W the wage-unit, and N the quantity of employment, E=N×W.

This assumption of homogeneity in the supply of labour is not upset by the obvious fact of great differences in the specialised skill of individual workers and in their suitability for different occupations. For,[:]
  • if the remuneration of the worker is proportional to their efficiency, the differences are dealt with by our having regarded individuals as contributing to the supply of labour in proportion to their remuneration; 
  • whilst if, as output increases, a given firm has to bring in labour which is less and less efficient for its special purposes per wage-unit paid to it, this is merely one factor among others leading to a diminishing return from the capital equipment in terms of output as more labour is employed on it. 
We subsume, so to speak, the non-homogeneity of equally remunerated labour units in the equipment, which we regard as less and less adapted to employ the available labour units as output increases, instead of regarding the available labour units as less and less adapted to use a homogeneous capital equipment. Thus if there is no surplus of specialised or practicised labour and the use of less suitable labour involves a higher labour cost per unit of output, this means that the rate at which the return from the equipment diminishes as employment increases is more rapid than it would be if there were such a surplus.[6] Even in the limiting case where different labour units were so highly specialised as to be altogether incapable of being substitued for one another, there is no awkwardness; for this merely means that the elasticity of supply of output from a particular type of capital equipment falls suddenly to zero when all the available labour specialised to its use is already employed.[7] Thus our assumption of a homogeneous unit of labour involves no difficulties unless there is great instability in the relative remuneration of different labour-units; and even this difficulti can be dealt with, if it arises, by supposing a rapid liability to change in the supply of labour and the shape of the aggregate supply function.
[6] This is the main reason why the supply price of output rises with increasing demand even when there is still a surplus of equipment identical in type with the equipment in use. If we suppose that the surplus supply of labour forms a pool equally available to all entrepreneurs and that labour employed for a given purpose is rewarded, in part at least, per unit of effort and not with strict regard to its efficiency in it actual particular employment (which is in most cases the realistic assumption to make), the diminishing efficiency of the labour employed is an outstanding example of rising supply price with increasing output, not due to internal diseconomies.
It is my belief that much unnecessary perplexity can be avoided if we limit ourselves strictly to the two units, money and labour, when we are dealing with the behaviour of the economic system as a whole; reserving the use of units of particular outputs and equipments to the occasions when we are analysing the output of individual firms or industries in isolation; and the use of vague concepts, such as the quantity of output as a whole, the quantity of capital equipment as a whole and the general level of prices, to the occasions when we are attempting some historical comparison which is within certain (perhaps fairly wide) limits avowedly imprecise and approximate.

It follows that we shall measure changes in current output by reference to the number of hours of labour paid for (whether to satisfy consumers or to produce fresh capital equipment) on the existing capital equipment, hours of skilled labour being weighted in proportion to their remuneration. We have no need of a quantitative comparison between this output and the output which would result from associating a different set of workers with a different capital equipment. To predict how entrepreneurs possessing a given equipment will respond to a shift in the aggregate demand function it is not necessary to know how the quantity of the resulting output, the standard of life and the general level of prices would compare with what they were at a different date or in another country.


IV

It is easily shown that the conditions of supply, such as are usually expressed in terms of the supply curve, and the elasticity of supply relating output to price, can be handled in terms of our two chosen units by means of the aggregate supply function, without reference to quantities of output, whether we are concerned with a particular firm or industry or with economic activity as a whole. For the aggregate supply function for a given firm (and similarly for a given industry or for industry as a whole) is given by

Zr=Φr(Nr),

where Zr is the proceeds (net of user cost) the expectation of which will induce a level of employment Nr. If, therefore, the relation between employment and output is such that an employment Nr results in an output Or, where Or=ψr(Nr), it follows that

p={ Zr + Ur(Nr) }/ Or = { Φr(Nr) + Ur(Nr) }/ ψr(Nr)

is the ordinary supply curve, where Ur(Nr) is the (expected) user cost corresponding to a level of employment Nr.

Thus in the case of each homogeneous commodity, for which Orψr(Nr) has a definite meaning, we can evaluate ZrΦr(Nr) in the ordinary way; but we can then aggregate the Nr's in a way in which we cannot aggregate the Or's, since ΣOr is not a numerical quantity. Moreover, if we can assume that, in a given environment, a given aggregate employment will be distributed in a unique way between different industries, so that Nr is a function of N, further simplifications are possible.

주석..


Chapter 5_ Expectation as Determining Output And Employment


I

All production is for the purpose of ultimately satisfying a consumer. Time usually elapses, howeverㅡand sometimes much timeㅡbetween the incurring of costs by the producer (with the consumer in view) and the purchase of the output by the ultimate consumer. Meanwhile the entrepreneur (including both the producer and the investor in this description) has to form the best expectations he can as to what the consumers will be prepared to pay when he is ready to supply them (directly or indirectly) after the elapse of what may be a lengthy period; and he has no choice but to be guided by these expectations,[1] if he is produce at all by processes which occupy time.
[1] For the method of arriving at an equivalent of these expectations in terms of sales-proceeds see footnote (3) to p. 24 [?] above.
These expectations, upon which business decisions depend, fall into two groups, certain individuals or firms being specialised in the business of framing the first type of expectations and others in the business of framing the second. The first type is concerned with the price which a manufacturer can expect to get for his 'finished' output at the time when he commits himself to starting the process which will produce it; output being 'finished' (from the point of view of the manufacturer) when it is ready to be used or to be sold to a second party. The second type is concerned with what the entrepreneur can hope to earn in the shape of future returns if he purchase (or, perhaps, manufactures) 'finished' output as an addition to his capital equipment. We may call the former short-term expectation and the latter long-term expectation.

Thus the behaviour of each individual firm in deciding it daily[2] output will be determined by its short-term expectationsㅡexpectations as to the cost of output on various possible scales and expectations as to the sale-proceeds of this output; though, in the case of additions to capital equipment and even of sale to distributors, these short-term expectations will largely depend on the long-term (or medium-term) expectations of other parties. It is upon these various expectations that the amount of employment which the firms offer will depend. The actually realised results of the production and sale of output will only be relevant to employment in so far as they cause a modification of subsequent expectations. Nor, on the other hand, are the original expectations relevant, which led the firm to acquire the capital equipment and the stock of intermediate products and half-finished materials with which it finds itself at the time when it has to decide the next day's output. Thus, on each and every occasion of such a decision, the decision will be made, with reference indeed to this equipment and stock, but in the light of the current expectations of prospective costs and sale-proceeds.

Now, in general, a change in expectations (whether short-term or long-term) will only produce its full effect on employment over a considerable period. The change in employment due to a change in expectations will not be the same on the second day after the change as on the first, or the same on the third day as on the second, and so on, even though there be no further changes in expectations.
  • In the case of short-term expectations this is because changes in expectations are not, as a rule, sufficiently violent or rapid, when they are for the worse, to cause the abandonment of work on all the productive processes which, in the light of the revised expectation, it was mistake to have begun; whilst, when they are for the better, some time for preparation must needs elapse before employment can reach the level at which it would have stood if the state of expectation had been revised sooner. 
  • In the case of long-term expectations, equipment which will not be replaced will continue to give employment until it is worn out; whilst when the change in long-term expectations is for the better, employment may be at a higher level at first, than it will be after there has been time to adjust the equipment to the new situation.

If we suppose a state of expectation to continue for a sufficient length of time for the effect on the employment to have worked itself out so completely that there is, broadly speaking, no piece of employment going on which would not have taken place if the new state of expectation had always existed, the steady level of employment[3] thus attained may be called the long-period employment corresponding to that state of expectation. It follows that, although expectation may change so frequently that the actual level of employment has never had time to reach the long-period employment corresponding to the existing state of expectation, nevertheless every state of expectation has its definite corresponding level of long-period employment.
[3] It is not necessary that the level of long-period employment should be constant, i.e. long-period conditions are not necessarily static. For example, a steady increase in wealth or population may constitute a part of the unchanging expectation. The only condition is that the existing expectations should have been foreseen sufficiently far ahead.
Let us consider, first of all, the process of transition to a long-period position due to a change in expectation, which is not confused or interrupted by any further change in expectation. We will first suppose that the change is of such a character that the new long-period employment will be greater than the old. Now, as a rule, it will only be the rate of input which will be much affected at the beginning, that is to say, the volume of work on the earlier stages of new processes of production, whilst the output of consumption-goods and the amount of employment on the later stages of processes which were started before the change will remain much the same as before. In so far as there were stocks of partly finished goods, this conclusion may be modified; though it is likely to remain true that the initial increase in employment will be modest. As, however, the days pass by, employment will gradually increase. Moreover, it is easy to conceive of conditions which will cause it to increase at some stage to a ^higher^ level than the new long-period employment. For the process of building up capital to satisfy the new state of expectation may lead to more employment and also to more current consumption that will occur when the long-period position has been reached. Thus the change in expectation may lead to a gradual crescendo in the level of employment, rising to a peak and then declining to the new long-period level. The ^same^ thing may occur even if the new long-period level is the same as the old, if the change represents a change in the direction of consumption which renders certain existing processes and their equipment obsolete. Or again, if the new long-period employment is less than the old, the level of employment during the transition may fall for a time ^below^ what the new long-period level is going to be. Thus a mere change in expectation is capable of producing an oscillation of the same kind of shape as a cyclical movement, in the course of working itself out. It was movements of this kind which I discussed in my ^Treatise on Money^ in connection with the building up or the depletion of stocks of working and liquid capital consequent on change.

An uninterrupted process of transition, such as the above, to a new long-period position can be complicated in detail. But the actual course of events is more complicated still. For the state of expectation is liable to constant change, a new expectation being superimposed long before the previous change has fully worked itself out; so that the economic machine is occupied at any given time with a number of overlapping activities, the existence of which is due to various past states of expectation.


II


This leads us to the relevance of this discussion for our present purpose. It is evident from the above that the level of employment at any time depends, in a sense, not merely on the existing state of expectation but on the states of expectation which have existed over a certain past period. Nevertheless past expectations, which have not yet worked themselves out, are embodies in the to-day's capital equipment with reference to which the entrepreneur has to make to-day's decisions, and only influence his decisions in so far as they are so embodied. It follows, therefore, that, in spite of the above, to-day's employment can be correctly described as being governed by to-day's expectations taken in conjunction with to-day's capital equipment.

Express reference to current long-term expectations can seldom be avoided. But it will often be safe to omit express reference to ^short-term^ expectation, in view of the fact that in practice the process of revision of short-term expectation is a gradual and continuous one, carried on largely in the light of realised results; so that expected and realised results run into and overlap one another in their influence. For, although output and employment are determined by the producer's short-term expectations and not by past results, the most recent results usually play a predominant part in determining what these expectations are. It would be too complicated t work out the expectations ^de novo^ whenever a productive process was being started; and it would, moreover, be a waste of time since a large part of the circumstances usually continue substantially unchanged from one day to the next. Accordingly it is sensible for producers to base their expectations on the assumption that the most recently realised will continue, except in so far as there are definite reasons for expecting a change. Thus in practice there is a large overlap between the effects on employment of the realised sale-proceeds of recent output and those of the sale-proceeds expected from current input; and producers' forecasts are more often gradually modified in the light of results than in anticipation of prospective changes.[4]

Nevertheless, we must not forget that, in the case of durable goods, the producer's short-term expectations are based on the current long-term expectations of the investor; and it is of the nature of long-term expectations that they cannot be checked at short intervals in the light of realised results. Moreover, as we shall see in Chapter 12, where we shall consider long-term expectations in more detail, they are liable to sudden revision. Thus the factor of current long-term expectations cannot be even approximately eliminated or replaced by realised results.

주석..



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