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1、微观经济理论-基本模型和扩展(英文版)170CHAPTER17THE EFFICIENCY OF PERFECTCOMPETITIONAlthough most people recognize the equilibrium properties of the competitive price system (afterall, prices usually do not fluctuate widely from day to day), they see little overall pattern to theresulting allocation of resources. Th
2、e relationships described by the competitive model presentedin the previous chapter are so complex it is hard to believe that any desirable outcome willemerge from the chaos. This 6view provides an open-ended rationale to tinker with the systembecause the results of market forces are chaotic, surely
3、 human societies can do better throughcareful planning.456Part VPerfect CompetitionSmiths Invisible Hand HypothesisIt took the genius of Adam Smith to challenge this view, which was probably theprevalent one in the eighteenth century. To Smith, the competitive market systemrepresented the polar oppo
4、site from chaos. Rather, it provided 8a powerful “invisi-ble hand” that ensured resources would find their way to where they were most val-ued, thereby enhancing the “wealth” of the nation. In Smiths view, reliance on theeconomic self-interest of individuals and firms would result in a (perhaps surp
5、ris-ingly) desirable social outcome.Smiths initial insights gave rise to modern welfare economics. Specifically, hiswidely quoted “invisible hand” image provided the impetus for what is now calledthe “fundamental theorem” of welfare economicsthat there is a close correspon-dence between the efficien
6、t allocation of resources and the competitive pricing ofthese resources. In this chapter we will investigate this correspondence in some de-tail. We begin by defining economic efficiency in a variety of contexts. These defi-nitions, all of which draw on the work of the nineteenth-century economist V
7、ilfredPareto, have already been described briefly in earlier chapters; our goal here is todraw these discussions together and illustrate their underlying relationship to thecompetitive allocation of resources.Pareto EfficiencyWe begin with Paretos definition of economic efficiency.DEFINITIONPareto e
8、fficient allocationAn allocation of resources is Pareto efficientif it isnot possible (through further reallocations) to make one person better offwithout making someone else worse off.The Pareto definition then identifies particular allocations as being “inefficient” ifunambiguous improvements are
9、possible. Notice that the definition does not re-quire interperson comparisons of utility. “Improvements” are defined by individu-als themselves.Efficiency in ProductionAn economy is efficient in production if it is on its production possibility frontier.Formally, we can use Paretos terminology to d
10、efine productive efficiency as follows:DEFINITIONProductive efficiencyAn allocation of resources is efficient in production(or“technically efficient”) if no further reallocation would permit more of onegood to be produced without necessarily reducing the output of some othergood.Chapter 17The Effici
11、ency of Perfect Competition457As for Pareto efficiency itself, it is perhaps easiest to grasp this definition bystudying its conversean allocation would be inefficient if it were possible to moveexisting resources around a bit and get additional amounts of one good and no lessof anything else. With
12、technically efficient allocations, no such unambiguous im-provements are possible. The trade-offs among outputs necessitated by movementsalong the production possibility frontier reflect the technically efficient nature ofall of the allocations on the frontier.Technical efficiency is an obvious prec
13、ondition for overall Pareto efficiency. Sup-pose resources were allocated so that production was inefficient; that is, productionwas occurring at a point inside the production possibility frontier. It would then bepossible to produce more of at least one good and no less of anything else. This in-cr
14、eased output could be given to some lucky person making him or her better off(and no one else worse off). Hence, inefficiency in production is also Pareto inef-ficiency. As we shall see in the next section, however, technical efficiency does notguarantee Pareto efficiency. An economy can be efficien
15、t at producing the wronggoodsdevoting all available resources to producing left shoes would be a techni-cally efficient use of those resources, but surely some Pareto improvement could befound in which everyone would be better off.A discussion of efficiency in production and its relationship to the
16、productionpossibility frontier is somewhat more complex than our simple presentation inChapter 16 might imply. Because production is divided among many firms, we mustbe concerned not only with the ways in which a single firm uses its resources (as weessentially were in the previous chapter), but also with how resources are allocatedamong firms. To faci
