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1、微观经济理论-基本模型和扩展(英文版)120CHAPTER12COSTSIn this chapter we illustrate the costs that a firm incurs in its productive activities. In Chap-ter 13, we will be able to use this information and information about revenues to show howmuch the firm will choose to produce. Here we will be concerned only with que
2、stions about thecosts associated with hiring the inputs that the firm chooses to employ.298Part IVProduction and SupplyDefinitions of CostsBefore we can discuss the theory of costs, some difficulties about the proper defi-nition of “costs” must be cleaned up. Specifically, we must differentiate betw
3、een (1) accounting cost and (2) economic cost. The accountants 6view of cost stressesout-of-pocket expenses, historical costs, depreciation, and other bookkeeping en-tries. The economists definition of cost (which in obvious ways draws on the fun-damental opportunity-cost notion) is that the cost of
4、 any input is given by the sizeof the payment necessary to keep the resource in its present employment. Alterna-tively, the economic cost of using an input is what that input would be paid in itsnext best use. One way to distinguish between these two views is to consider how thecosts of various inpu
5、ts (labor, capital, and entrepreneurial services) are defined un-der each system.Labor CostsEconomists and accountants regard labor costs in much the same way. To account-ants, expenditures on labor are current expenses and hence costs of production.For economists, labor is an explicitcost. Labor se
6、rvices (labor-hours) are contractedat some hourly wage rate (w), and it is usually assumed that this is also what the la-bor services would earn in their best alternative employment.Capital CostsIn the case of capital services (machine-hours), the two concepts of cost differgreatly. In calculating c
7、apital costs, accountants use the historical price of the par-ticular machine under investigation and apply some more-or-less arbitrary depreci-ation rule to determine how much of that machines original price to charge tocurrent costs. Economists regard the historical price of a machine as a “sunk c
8、ost,”which is irrelevant to output decisions. They instead regard the implicitcost of themachine to be what someone else would be willing to pay for its use. Thus the costof one machine-hour is the rental ratefor that machine in its best alternative use. Bycontinuing to use the machine itself, the f
9、irm is implicitly foregoing what someoneelse would be willing to pay to use it. This rental rate for one machine-hour will be1denoted by v.Costs of Entrepreneurial ServicesThe owner of a firm is a residual claimant who is entitled to whatever extra revenuesor losses are left after paying all input c
10、osts. To an accountant, these would be calledprofits(which might be either positive or negative). Economists, however, askwhether owners (or entrepreneurs) also encounter opportunity costs by working ata particular firm or devoting some of their funds to its operation. If so, these serv-1Sometimes t
11、he symbol ris chosen to represent the rental rate on capital. Because this variable is oftenconfused with the related though distinct concept of the market interest rate, an alternative symbol waschosen here. The exact relationship between vand the interest rate is examined in Chapter 23.Chapter 12C
12、osts299ices should be considered an input and some cost should be imputed to them. Forexample, suppose a highly skilled computer programmer starts a software firm withthe idea of keeping any (accounting) profits that might be generated. The programmers time is clearly an input to the firm, and a cos
13、t should be inputed forit. Perhaps the wage that the programmer might command if he or she worked forsomeone else could be used for that purpose. Hence some part of the accountingprofits generated by the firm would be categorized as entrepreneurial costs byeconomists. Economic profits would be small
14、er than accounting profits and mightbe negative if the programmers opportunity costs exceeded the accounting profitsbeing earned by the business.Economic CostsIn this book, not surprisingly, we shall use economists definition of cost:DEFINITIONEconomic costThe economic costof any input is the paymen
15、t required to keep that input in its present employment. Equivalently, the economic cost ofan input is the remuneration the input would receive in its best alternative employment.Use of this definition is not meant to imply that accountants concepts are irrele-vant to economic behavior. Indeed, acco
16、unting procedures are integrally importantto any managers decision-making process because they can greatly affect the rateof taxation to be applied against profits. Accounting data are also readily available,whereas data on economic costs must often be developed separately. Economistsdefinitions, however, do have the desirable features of being broadly applicable toall firms and of forming a conceptually consistent system. They therefore are bestsuited for a ge
