最新平狄克微观经济学答案第17-18章
平狄克微观经济学答案第17－18章第十七章复习题1、当买方和卖方之间对商品存在着不对称信息时，即当不同质量的产品的购买者或出售者买卖时没有充分的信息来确定产品的质量，从而不同质量的产品以单一价格出售，逆淘汰问题就出现了，结果市场就有太多的低质量产品和太少的高质量产品出售，低质量产品把高质量的产品逐出了市场，导致市场失灵。
2、多。
3、保险市场的逆淘汰：由于信息的不对称，即使保险公司做身体检查，购买保险的人对他们总的健康情况也比任何保险公司所希望知道不健康的人在被保险人总数中的比例提高了。
这迫使价格上升，从而使那些较健康的人，由于知道自己的低风险，作出不投保决定，这进一步提高了不健康的人的比例，这又迫使保险价格上升，如此等等，直到几乎所有买保险的人都是不健康的人。
保险市场的道德风险：当被保险一方充分保险，而一家信息有限的保险公司又不能准确的监督他的话，被保险方可能采取会提高事故或受伤可能性的行动，当被保险方能影响导致赔偿的事件的可能性或程度时，道德风险就会发生。
4、保证和保证书、产品标准化、保证和保证书5、当不同质量的产品在购买者或出售者买卖时没有充分的住处来确定产品的真实质量，从而不同质量的产品以单一价格出售时，逆淘汰问题就出现了。
存在的根本原因是信息不对称，即买主对产品质量的住处知道的比卖主少的多，如果卖主能发出有关产品的信息，就会消除信息不对称，避免逆淘汰问题的发生，对高质量的产品而言当然是有利的。
保证和保证书有效地发出了产品质量信号，因为一项内容广泛的保证书对低质量的产品的生产者来说要比高质量产品的生产者成本更高（在保证书下，低质量产品更需要修理服务，而这都将由生产者支付）。
结果，出于他们的利益，低质量产品的生产者就不会提供内容广泛的保证书。
消费者就能因此而把一项社会主义少保证书看作是高质量的信号屏为提供保证书的商品支付较多的钱。
6、因为大多数企业业主并不能监督总经理所作的一切，总经理的住处比业主多的多，这种信息的不对称，产生委托——代理问题，即，经理可以追求他们的自己的目标，甚至不惜以获得较低利润为代价。
7、这属于公共企业的委托——代理问题，公共企业的经理们可能关心他的权利和额外的津贴，而这两者都可以通过他们的组织扩大到超过“有效率”水平来获得。
这常常有背于公共企业利润最大化的目标。
由于监督公共经理的成本也很高，因此没有什么能保证他们会生产有的产出。
8、由于代理人对自己的工作努力程度比委托人了解的多的多，加这监督成本太高，所有者无法直接衡量公认的努力程度，也不能确定同样的努力总会产生同样的利润水平，而代理人希望得到的是报酬减去所作努力的成本以后的最大化值。
所以支付固定工资时，代理人会降低努力的成本使净报酬最大化。
反之，如果代理人因生产努力而获得资金或利润分离，他就会增加努力程度，直到净报酬最大化。
当直接衡量努力不可能的时候，奖励高水平努力的结果的激励结构能够诱使代理人追求所有者设定的目标。
9、不发生偷懒的工资就是效率工资。
由于监督成本很高或根本不可能，厂商对于工人的生产率具有不完全的信息，因此厂商不能有效地监督工人的生产效率，从而工人就可能偷懒，这样就会影响到厂商的产出和利润。
如果厂商向工作提供高于市场出清的工资，工人就可能因偷懒而被解雇，再次就业的工人会面临市场出清这样一个较低的工资。
所有厂商都面临偷懒问题，这意味着所有厂商都提供高于市场出清的工资，这就导致失业，这就是说，被一家企业解雇的工人就面临一段时间的失业，工人被解雇的成本较高，偷懒所冒的风险越大。
为了避免失业，工人将会进行有效率的工作。
所以，支付效率工资对企业是有利的。
练习题1、品牌能提供有用的质量信号。
因为：第一，存在信息不对称问题时，创建品牌是解决问题的办法之一，品牌的取得通常靠以往产品的高质量所产生的声誉，是产品高质量的标志。
2、（A）加里作为一个买者，与卖者之间存在一个信息不对称的问题，他可以询问了解情况较多的已买车者，也可通过了解各种品牌的声誉来掌握更多的信息。
首先，他要决定是买一辆新车还是一辆二手车，如买二手车，还要决定是从专业的二手车市场购买还是从个人手里购买。
每种市场都有提供他们产品质量的特定信号。
（B）有用。
以往新毕业生融资买车所建立的声誉，是大学生偿贷能力和他们信誉的一个信号，信贷员可以通过所提供的信息来对加里进行判断。
3、不是一项好政策。
会产生类似保险市场的道德风险问题。
由于没有不及格的压力，一些学生会失去努力学习的动力，最后他们的水平可能低于应达到的平均水平。
4、不应当。
大学和教授之间存在委托——代理问题。
大学有教学和研究的双重目标，但教授是否努力教学容易衡量，而研究则住往需经过一段时间才能证实是否有成果，不易衡量。
可能通过激励机制来解决问题：如果教授可以不教学，但只能享有一个较低的工资水平，如果有重大的科研成果，可以获得资金。
7、答：（a）。
因为完全赔偿时，行为人所受损失能得到完全赔偿，会降低减少火灾发生的努力，从而产生道德风险。
而后两种方法，使行为人发生火灾后所得到的赔偿大于所受的损失，因此能避免道德风险的产生。
8、答：（a）不同意，这虽然会鼓励消费者投诉低质量产品，但需要政府对消费者协会提供资金。
（b）不同意，这是一项监督成本很高的办法，并且如果低质量的产品价格足够便宜，仍会有市场。
（c）同意，这是解决信息不对称的最好的办法，可使消费者辨别产品质量的高低而支付不同的价钱，这时低质量产品做出保证的成本是昂贵的，因此不会做出保证。
（d）不同意，因为如果所有产品都提供保证，则高质量产品所提供的保证便失去了意义。
9、答：（a）亨利车行提供一年期保证的盈利为：10000---500---8000=1500不提供保证的盈利为：8500---8000=5001500＞500，所以亨利车行会提供一年期的保证刘氏车行提供保证的盈利：8500---2000--5000=1500不提供保证的盈利为：7000—5000=2000，1500＜2000，因此，刘氏车行不会提供一年期的保证。
所以会产生可靠的质量信号（b）亨利车行提供两年期保证的盈利为：10000---500*2---8000=1000不提供保证的盈利为：8500---8000=5001000＞500，所以亨利车行会提供两年期的保证刘氏车行提供两年期保证的盈利：8500---2000*2--5000=--500不提供保证的盈利为：7000—5000=2000，--500＜2000，因此，刘氏车行不会提供两年期的保证。
会产生可靠的质量信号。
亨利车行提供三年期保证的盈利为：10000---500*3---8000=500不提供保证的盈利为：8500---8000=500500=500，所以亨利车行不会提供三年期的保证刘氏车行更不会提供三年期的保证。
（c ）如要产生可靠的质量信号，必须使亨利做出保证的期限恰好使刘氏无利可图，即：(8,500 - 5,000 - 2,000t) ≤ 7,000 – 5000即 3/4 ≤ t .所以我会建议亨利做出九个月的保证期限，这时亨利的盈利最大。
10、 设利润为L（1） L=R---W= (10)(1) - 12- 2 = $7。
W=2时，因为工人追求净工资最大化，所以固定工资下，他会选择最小的努力水平即：e=1，此时L=7（2） w e e e, e .e .=---10240522or 工人追求净工资最大化，求极值：则e=4，此时w=12，L=12。
因此，工人为了使净工资最大化，人提高工作努力程度，这将给厂商带来更大的利润。
（3）同上，得e=4.5 w=12.25 L= ((10)(4.5) - 4.52) - 12.25 =$12.25。
因此，在这种关系下，工人会更加努力工作，给厂商带来更大的利润。
第十八章1、（A ）因为产商在生产中排放的有害气体，损害了居民的身体健康，增加了社会成本，而这种成本又是不在市场中反映出来的，因此就存在厂商生产的负外在性。
（B）我认为私下讨价还价不能有效解决这一外在性问题。
因此就存在厂商的负外在性问题。
因为社区居民对西部的空气并不具有清洁权，而且这种外在性的影响又非常大。
没有产权明确确定的情况下，讨价还价是无效率的。
（C）社区可以就其受到的损失对产商提起诉讼，要求赔偿损失。
而产商根据近况作出减少污染设备安装的主张，从而使其利益最大化。
达到空气质量的有效水平。
2、我不同意编程人员的主张，我们可以通过外在性和无效率来解释。
如果我们不对软件进行保护，那么个人编写的创新程序就会产生正的外部性，既每个人都可以从中受益，于是就出了无效率。
这会打消其编写程序的积极性。
3、我们需要知道房屋的主人在河里游泳的价值，以及减污的边际成本。
政策工具的选择将取决于减污的边际成本和边际收益。
如果对商收取同样费率的排污费，厂商将会减低排污直到减污的边际成本等于排污费用的那一点。
如果这一污染减少还不足以在河中游泳，排污费还可以提高。
只有在决策对减污的边际收益和边际成本具有完全时，确定排污标准才会是有效率的。
而且，在新的过滤技术出现后，排污标准不会鼓励厂商进一步减低排放污水。
可转让废水许可制度仍要求决策者确定有效的废水标准。
一旦许可证颁发以后市场应付产生，具有较高减污成本的厂商向减污成本低的厂商购买许可证。
然而，除非一开始许可证就是出售的，否则政府将不会有收入。
4、答：（a）如果减低了所有香烟中的焦油和尼古丁，吸烟者从香烟中所得到的效用就会降低，而同时对空气的污染就会减少，对健康的负效用就会变小，即社会成本就会降低。
因此吸烟者不会受益，但社会作为一个整体是受益的。
（b）如果对出售的每包香烟征税，那么价格就会上涨。
这对吸烟者来说是不利的吸烟者的购买数量就会减少，从而污染也会减少，对健康的负效用也会变小。
而税收的征收足以抵消销售量的减少，社会因此而受益。
（c）吸烟许可证的分发，产生一个市场。
对那些愿意为吸烟付出较高成本的人将会从那些仅愿意付出较底价格的人那里买到许可证。
从而达到吸烟者内部利益最大化。
而社会为限制总的吸烟量也达到一个有效的空气清洁水平。
因此吸烟者受益。
而社会作为一个整体也从中受益。
5. (a) 利润在MC=MR时最大化。
在MR为20美元时，MC为10+2Q，Q=5。
即养蜂人将持有5箱蜂蜜。
(b) 如果蜜蜂不来，果园主人必须支付每亩10美来进行人工授粉。
由于果园主人愿意为每一额外箱的蜜蜂向养蜂人支付最高10美元，每一箱的边际成本，它大于20美元，R的边际私人收益，使边际社会收益与边际成本相等。
30=10+2Q，即经济上有效率的蜂箱数为10箱。
(c)导致j更有效的最激进变动就是让果园的业务与养蜂业务合并.这一合并将使蜜蜂授粉的外在效应内部化。
若没有合并，果园主人和养蜂人授粉服务签订一项合同。
平狄克《微观经济学》课后答案 18
CHAPTER 18EXTERNALITIES AND PUBLIC GOODSThis chapter extends the discussion of market failure begun in Chapter 17. To avoid over-emphasis on definitions, stress the main theme of the chapter: the characteristics of some goods lead to situations where price is not equal to marginal cost. Rely on the discussion of market power (Chapter 10) as an example of market failure. Also, point out with each case that government intervention might not be required if property rights can be defined and transaction costs are small (Section 18.3). The first four sections present positive and negative externalities and solutions to market failure. The last two sections discuss public goods and public choice.The consumption of many goods involves the creation of externalities. Stress the divergence between social and private costs. Exercise (5) presents the classic beekeeper/apple-orchard problem, originally popularized in Meade, “External Economies and Diseconomies in a Competitive Situation,” Economic Journal (March 1952). Empirical research on this example has shown that beekeepers and orchard owners have solved many of their problems: see Cheung, “The Fable of the Bees: An Economic Investigation,” Journal of Law and Economics (April 1973).Solutions to the problems of externalities are presented in Sections 18.2 and 18.3. Section 18.2, in particular, discusses emission standards, fees, and transferable permits. Example 18.1 and Exercise (3) are simple applications of these concepts.One of the main themes of the law and economics literature since 1969 is the application of Coase’s insight on the assignment of property rights. The original article is clear and can be understood by students. Stress the problems posed by transactions costs. For a lively debate, ask students whether non-smokers should be granted the right to smokeless air in public places (see Exercise (4)). For an extended discussion of the Coase Theorem at the undergraduate level, see Polinsky, Chapters 3-6, An Introduction to Law & Economics (Little, Brown & Co., 1983).The section on common property resources emphasizes the distinction between private and social marginal costs. Example 18.5 calculates the social cost of unlimited access to common property, and the information provided is used in Exercise (7). Exercise (8) provides an extended example of managing common property.The last two sections focus on public goods and private choice. Point out the similarities and differences between public goods and other activities with externalities. Since students confuse nonrival and nonexclusive goods, create a table similar to the following and give examples to fill in the cells:The next stumbling block for students is achieving an understanding of why we add individual demand curves vertically rather than horizontally. Exercise (6) compares vertical and horizontal summation of individual demand.The presentation of public choice is a limited introduction to the subject, but you can easily expand on this material. A logical extension of this chapter is an introduction to cost-benefit analysis. For applications of this analysis, see Part III, “Empirical Analysis of Policies and Programs,” in Haveman and Margolis (eds.), Public Expenditure and Policy Analysis (Houghton Mifflin, 1983).1. Which of the following describes an externality and which does not? Explain the difference.a. A policy of restricted coffee exports in Brazil causes the U.S. price of coffee to rise,which in turn also causes the price of tea to increase.Externalities cause market inefficiencies by preventing prices from conveying accurateinformation. A policy of restricting coffee exports in Brazil causes the U.S. price ofcoffee to rise, because supply is reduced. As the price of coffee rises, consumers switchto tea, thereby increasing the demand for tea, and hence, increasing the price of tea.These are market effects, not externalities.b. An advertising blimp distracts a motorist who then hits a telephone pole.An advertising blimp is producing information by announcing the availability of somegood or service. However, its method of supplying this information can be distractingfor some consumers, especially those consumers who happen to be driving neartelephone poles. The blimp is creating a negative externality that influences thedrivers’ safety. Since the price charged by the advertising firm does not incorporate theexternality of distracting drivers, too much of this type of advertising is produced fromthe point of view of society as a whole.2. Compare and contrast the following three mechanisms for treating pollution externalities when the costs and benefits of abatement are uncertain: (a) an emissions fee, (b) an emissions standard, and (c) a system of transferable emissions permits.Since pollution is not reflected in the marginal cost of production, its emission createsan externality. Three policy tools can be used to reduce pollution: an emissions fee, anemissions standard, and a system of transferable permits. The choice between a feeand a standard will depend on the marginal cost and marginal benefit of reducingpollution. If small changes in abatement yield large benefits while adding little to cost,the cost of not reducing emissions is high. Thus, standards should be used. However, ifsmall changes in abatement yield little benefit while adding greatly to cost, the cost ofreducing emissions is high. Thus, fees should be used.A system of transferable emissions permits combines the features of fees and standardsto reduce pollution. Under this system, a standard is set and fees are used to transferpermits to the firm that values them the most (i.e., a firm with high abatement costs).However, the total number of permits can be incorrectly chosen. Too few permits willcreate excess demand, increasing price and inefficiently diverting resources to ownersof the permits. Typically, pollution control agencies implement one of threemechanisms, measure the results, reassess the success of their choice, then reset newlevels of fees or standards or select a new policy tool.3. When do externalities require government intervention, and when is such intervention unlikely to be necessary?Economic efficiency can be achieved without government intervention when theexternality affects a small number of people and when property rights are wellspecified. When the number of parties is small, the cost of negotiating an agreementamong the parties is small. Further, the amount of required information (i.e., the costsof and benefits to each party) is small. When property rights are not well specified,uncertainty regarding costs and benefits increases and efficient choices might not bemade. The costs of coming to an agreement, including the cost of delaying such anagreement, could be greater than the cost of government intervention, including theexpected cost of choosing the wrong policy instrument.4. An emissions fee is paid to the government, whereas an injurer who is sued and is held liable pays damages directly to the party harmed by an externality. What differences in the behavior of victims might you expect to arise under these two arrangements?When the price of an activity that generates an externality reflects social costs, anefficient level of the activity is maintained. The producer of the externality reduces (fornegative externalities) or increases (for positive externalities) activity away from(towards) efficient levels. If those who suffer from the externality are not compensated,they find that their marginal cost is higher (for negative externalities) or lower (forpositive externalities), in contrast to the situation in which they would be compensated.5. Why does free access to a common property resource generate an inefficient outcome?Free access to a resource means that the marginal cost to the user is less than the socialcost. The use of a common property resource by a person or firm excludes others fromusing it. For example, the use of water by one consumer restricts its use by another.Because private marginal cost is below social marginal cost, too much of the resource isconsumed by the individual user, creating an inefficient outcome.6. Public goods are both nonrival and nonexclusive. Explain each of these terms and state clearly how they differ from each other.A good is nonrival if, for any level of production, the marginal cost of providing the goodto an additional consumer is zero (although the production cost of an additional unitcould be greater than zero). A good is nonexclusive if it is impossible or very expensiveto exclude individuals from consuming it. Public goods are nonrival and nonexclusive.Commodities can be (1) exclusive and rival, (2) exclusive and nonrival, (3) nonexclusiveand rival, or (4) nonexclusive and nonrival. Most of the commodities discussed in thetext to this point have been of the first type. In this chapter, we focus on commodities ofthe last type.Nonrival refers to the production of a good or service for one more customer. It usuallyinvolves a production process with high fixed costs, such as the cost of building ahighway or lighthouse. (Remember that fixed cost depends on the period underconsideration: the cost of lighting the lamp at the lighthouse can vary over time, butdoes not vary with the number of consumers.) Nonexclusive refers to exchange, wherethe cost of charging consumers is prohibitive. Incurring the cost of identifyingconsumers and collecting from them would result in losses. Some economists focus onthe nonexclusion property of public goods because it is this characteristic that poses themost significant problems for efficient provision.7. Public television is funded in part by private donations, even though anyone with a television set can watch for free. Can you explain this phenomenon in light of the free rider problem?The free-rider problem refers to the difficulty of excluding persons from consuming anonexclusive commodity. Non-paying consumers can “free-ride” on commoditiesprovided by paying customers. Public television is funded in part by contributions.Some viewers contribute, but most watch without paying, hoping that someone else willpay so they will not. To combat this problem these stations (1) ask consumers to assesstheir true willingness to pay, then (2) ask consumers to contribute up to this amount,and (3) attempt to make everyone else feel guilty for free-riding.8. Explain why the median voter outcome need not be efficient when majority rule voting determines the level of public spending.The median voter is the citizen with the middle preference: half the voting population ismore strongly in favor of the issue and half is more strongly opposed to the issue.Under majority-rule voting, where each citizen’s vote is weighted equally, the preferredspending level on public-goods provision of the median voter will win an electionagainst any other alternative.However, majority rule is not necessarily efficient, because it weights each citizen’spreferences equally. For an efficient outcome, we would need a system that measuresand aggregates the willingness to pay of those citizens consuming the public good.Majority rule is not this system. However, as we have seen in previous chapters,majority rule is equitable in the sense that all citizens are treated equally. Thus, weagain find a trade-off between equity and efficiency.1. A number of firms located in the western portion of a town after single-family residences took up the eastern portion. Each firm produces the same product and, in the process, emits noxious fumes that adversely affect the residents of the community.a. Why is there an externality created by the firms?Noxious fumes created by firms enter the utility function of residents. We can assumethat the fumes decrease the utility of the residents (i.e., they are a negative externality)and lower property values.b. Do you think that private bargaining can resolve the problem with the externality?Explain.If the residents anticipated the location of the firms, housing prices should reflect thedisutility of the fumes; the externality would have been internalized by the housingmarket in housing prices. If the noxious fumes were not anticipated, privatebargaining could resolve the problem of the externality only if there are a relativelysmall number of parties (both firms and families) and property rights are well specified.Private bargaining would rely on each family’s willingness to pay for air quality, buttruthful revelation might not be possible. All this will be complicated by theadaptability of the production technology known to the firms and the employmentrelations between the firms and families. It is unlikely that private bargaining willresolve the problem.c. How might the community determine the efficient level of air quality?The community could determine the economically efficient level of air quality byaggregating the families’ willingne ss to pay and equating it with the marginal cost ofpollution reduction. Both steps involve the acquisition of truthful information.2. A computer programmer lobbies against copyrighting software. He argues that everyone should benefit from innovative programs written for personal computers and that exposure to a wide variety of computer programs will inspire young programmers to create even more innovative programs. Considering the marginal social benefits possibly gained by his proposal, do you agree with the programmer’s position?Computer software as information is a classic example of a public good. Since it can becostlessly copied, the marginal cost of providing software to an additional user is nearzero. Therefore, software is nonrival. (The fixed costs of creating software are high, butthe variable costs are low.) Furthermore, it is expensive to exclude consumers fromcopying and using software because copy protection schemes are available only at highcost or high inconvenience to users. Therefore, software is also nonexclusive. As bothnonrival and nonexclusive, computer software suffers the problems of public goodsprovision: the presence of free-riders makes it difficult or impossible for markets toprovide the efficient level of software. Rather than regulating this market directly, thelegal system guarantees property rights to the creators of software. If copyrightprotection were not enforced, it is likely that the software market would collapse.Therefore, we do not agree with the computer programmer.3. Four firms located at different points on a river dump various quantities of effluent into it. The effluent adversely affects the quality of swimming for homeowners who live downstream. These people can build swimming pools to avoid swimming in the river, and firms can purchase filters that eliminate harmful chemicals in the material that is dumped in the river. As a policy advisor for a regional planning organization, how would you compare and contrast the following options for dealing with the harmful effect of the effluent:a. An equal-rate effluent fee on firms located on the river.First, one needs to know the value to homeowners of swimming in the river. Thisinformation can be difficult to obtain, because homeowners will have an incentive tooverstate this value. As an upper boundary, if there are no considerations other thanswimming, one could use the cost of building swimming pools, either a pool for eachhomeowner or a public pool for all homeowners. Next, one needs to know the marginalcost of abatement. If the abatement technology is well understood, this informationshould be readily obtainable. If the abatement technology is not understood, anestimate based on the firms’ knowledge must be used.The choice of a policy tool will depend on the marginal benefits and costs of abatement.If firms are charged an equal-rate effluent fee, the firms will reduce effluents to thepoint where the marginal cost of abatement is equal to the fee. If this reduction is nothigh enough to permit swimming, the fee could be increased. Alternatively, revenuefrom the fees could be to provide swimming facilities, reducing the need for effluentreduction.b. An equal standard per firm on the level of effluent each firm can dump.Standards will be efficient only if the policy maker has complete information regardingthe marginal costs and benefits of abatement. Moreover, the standard will notencourage firms to reduce effluents further when new filtering technologies becomeavailable.c. A transferable effluent permit system, in which the aggregate level of effluent isfixed and all firms receive identical permits.A transferable effluent permit system requires the policy maker to determine theefficient effluent standard. Once the permits are distributed and a market develops,firms with a higher cost of abatement will purchase permits from firms with lowerabatement costs. However, unless permits are sold initially, rather than merelydistributed, no revenue will be generated for the regional organization.4. Recent social trends point to growing intolerance of smoking in public areas. Many people point out the negative effects of “second hand” smoke. If you are a smoker and you wish to continue smoking despite tougher anti smoking laws, describe the effect of the following legislative proposals on your behavior. As a result of these programs, do you, the individual smoker, benefit? Does society benefit as a whole?Since smoking in public areas is similar to polluting the air, the programs proposedhere are similar to those examined for air pollution. A bill to lower tar and nicotinelevels is similar to an emissions standard, and a tax on cigarettes is similar to anemissions fee. Requiring a smoking permit is similar to a system of emissions permits,assuming that the permits would not be transferable. The individual smoker in all ofthese programs is being forced to internalize the externality of “second-hand” smokeand will be worse off. Society will be better off if the benefits of a particular proposaloutweigh the cost of implementing that proposal. Unfortunately, the benefits ofreducing second-hand smoke are uncertain, and assessing those benefits is costly.a. A bill is proposed that would lower tar and nicotine levels in all cigarettes.The smoker will most likely try to maintain a constant level of consumption of nicotine,and will increase his or her consumption of cigarettes. Society may not benefit fromthis plan if the total amount of tar and nicotine released into the air is the same.b. A tax is levied on each pack of cigarettes sold.Smokers might turn to cigars, pipes, or might start rolling their own cigarettes. Theextent of the effect of a tax on cigarette consumption depends on the elasticity ofdemand for cigarettes. Again, it is questionable whether society will benefit.c. Smokers would be required to carry smoking permits at all times. These permitswould be sold by the government.Smoking permits would effectively transfer property rights to clean air from smokers tonon-smokers. The main obstacle to society benefiting from such a proposal would bethe high cost of enforcing a smoking permits system.5. A beekeeper lives adjacent to an apple orchard. The orchard owner benefits from thebees because each hive pollinates about one acre of apple trees. The orchard owner pays nothing for this service, however, because the bees come to the orchard without his having to do anything. There are not enough bees to pollinate the entire orchard, and the orchard owner must complete the pollination by artificial means, at a cost of $10 per acre of trees.Beekeeping has a marginal cost of MC = 10 + 2Q, where Q is the number of beehives.Each hive yields $20 worth of honey.a. How many beehives will the beekeeper maintain?The beekeeper maintains the number of hives that maximizes profits, when marginalrevenue is equal to marginal cost. With a constant marginal revenue of $20 (there is noinformation that would lead us to believe that the beekeeper has any market power)and a marginal cost of 10 + 2Q:20 = 10 + 2Q, or Q = 5.b. Is this the economically efficient number of hives?If there are too few bees to pollinate the orchard, the farmer must pay $10 per acre forartificial pollination. Thus, the farmer would be willing to pay up to $10 to thebeekeeper to maintain each additional hive. So, the marginal social benefit, MSB, ofeach additional hive is $30, which is greater than the marginal private benefit of $20.Assuming that the private marginal cost is equal to the social marginal cost, we setMSB = MC to determine the efficient number of hives:30 = 10 + 2Q, or Q = 10.Therefore, the beekeeper’s private choice of Q = 5 is not the socially efficient number ofhives.c. What changes would lead to the more efficient operation?The most radical change that would lead to more efficient operations would be themerger of the farmer’s business with the beekeeper’s business. This merger wouldinternalize the positive externality of bee pollination. Short of a merger, the farmerand beekeeper should enter into a contract for pollination services.7. Reconsider the common resource problem as given by Example 18.5. Suppose that crawfish popularity continues to increase, and that the demand curve shifts from C = 0.401 - 0.0064F to C = 0.50 - 0.0064F. How does this shift in demand affect the actual crawfish catch, the efficient catch, and the social cost of common access? (Hint: Use the marginal social cost and private cost curves given in the example.)The relevant information is now the following:Demand: C = 0.50 - 0.0064FMSC: C = -5.645 + 0.6509F.With an increase in demand, the demand curve for crawfish shifts upward, intersectingthe price axis at $0.50. The private cost curve has a positive slope, so additional effortmust be made to increase the catch. Since the social cost curve has a positive slope, thesocially efficient catch also increases. We may determine the socially efficient catch bysolving the following two equations simultaneously:0.50 - 0.0064F = -5.645 + 0.6509F, or F* = 9.35.To determine the price that consumers are willing to pay for this quantity, substituteF* into the equation for marginal social cost and solve for C:C = -5.645 + (0.6509)(9.35), or C = $0.44.Next, find the actual level of production by solving these equations simultaneously:Demand: C = 0.50 - 0.0064FMPC: C = -0.357 + 0.0573F0.50 - 0.0064F = -0.357 + 0.0573F, or F** = 13.45.To determine the price that consumers are willing to pay for this quantity, substituteF** into the equation for marginal private cost and solve for C:C = -0.357 + (0.0573)(13.45), or C = $0.41.Notice that the marginal social cost of producing 13.45 units isMSC = -5.645 +(0.6509)(13.45) = $3.11.With the increase in demand, the social cost is the area of a triangle with a base of 4.1million pounds (13.45 - 9.35) and a height of $2.70 ($3.11 - 0.41), or $5,535,000 morethan the social cost of the original demand.8. The Georges Bank, a highly productive fishing area off New England, can be divided into two zones in terms of fish population. Zone 1 has the higher population per square mile but is subject to severe diminishing returns to fishing effort. The daily fish catch (in tons) in Zone 1 isF 1 = 200(X1) - 2(X1) 2where X1is the number of boats fishing there. Zone 2 has fewer fish per mile but is larger, and diminishing returns are less of a problem. Its daily fish catch isF 2 = 100(X2) - (X2) 2where X2is the number of boats fishing in Zone 2. The marginal fish catch MFC in each zone can be represented asMFC1 = 200 - 4(X1) MFC2= 100 - 2(X2).There are 100 boats now licensed by the U.S. government to fish in these two zones. The fish are sold at $100 per ton. The total cost (capital and operating) per boat is constant at $1,000 per day. Answer the following questions about this situation.a. If the boats are allowed to fish where they want, with no government restriction,how many will fish in each zone? What will be the gross value of the catch?Without restrictions, the boats will divide themselves so that the average catch (AF 1and AF 2) for each boat is equal in each zone. (If the average catch in one zone is greaterthan in the other, boats will leave the zone with the lower catch for the zone with thehigher catch.) We solve the following set of equations:AF 1 = AF 2 and X 1 + X 2 = 100 where 11121120022002AF X X X X =-=- and 222222100100AF X X X X =-=-. Therefore, AF 1 = AF 2 implies200 - 2X 1 = 100 - X 2,200 - 2(100 - X 2) = 100 - X 2, or X 21003= and 320031001001=⎪⎭⎫ ⎝⎛-=X . Find the gross catch by substituting the value of X 1 and X 2 into the catch equations:()(),,,,F 444488983331332002320020021=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= and ().,,,F 2222111133333100310010022=-=⎪⎭⎫ ⎝⎛-⎪⎭⎫ ⎝⎛= The total catch is F 1 + F 2 = 6,666. At the price of $100 per ton, the value of the catch is$666,600. The average catch for each of the 100 boats in the fishing fleet is 66.66 tons.To determine the profit per boat, subtract total cost from total revenue:π = (100)(66.66) - 1,000, or π = $5,666.Total profit for the fleet is $566,000.b. If the U.S. government can restrict the boats, how many should be allocated to eachzone? What will the gross value of the catch be? Assume the total number of boats remains at 100.Assume that the government wishes to maximize the net social value of the fish catch,i.e., the difference between the total social benefit and the total social cost. Thegovernment equates the marginal fish catch in both zones, subject to the restrictionthat the number of boats equals 100:MFC 1 = MFC 2 and X 1 + X 2 = 100,MFC 1 = 200 - 4X 1 and MFC 2 = 100 - 2X 2.Setting MFC 1 = MFC 2 implies:200 - 4X 1 = 100 - 2X 2, or 200 - 4(100 - X 2) = 100 - 2X 2, or X 2 = 50 andX 1 = 100 - 50 = 50.Find the gross catch by substituting X 1 and X 2 into the catch equations:F 1 = (200)(50) - (2)(502) = 10,000 - 5,000 = 5,000 andChapter 18: Externalities and Public Goods242 F 2 = (100)(50) - 502 = 5,000 - 2,500 = 2,500.The total catch is equal to F 1 + F 2 = 7,500. At the market price of $100 per ton, thevalue of the catch is $750,000. Total profit is $650,000. Notice that the profits are notevenly divided between boats in the two zones. The average catch in Zone A is 100 tonsper boat, while the average catch in Zone B is 50 tons per boat. Therefore, fishing inZone A yields a higher profit for the individual owner of the boat.c. If additional fishermen want to buy boats and join the fishing fleet, should agovernment wishing to maximize the net value of the fish catch grant them licenses to do so? Why or why not?To answer this question, first determine the profit-maximizing number of boats in eachzone. Profits in Zone A areππA A X X X X X =--=-1002002100019000200112112b g e j,,, or . To determine the change in profit with a change in X 1 take the first derivative of theprofit function with respect to X 1:d dX X A π1119000400=-,. To determine the profit-maximizing level of output, setd dX A π1equal to zero and solve for X 1:19,000 - 400X 1 = 0, or X 1 = 47.5.Substituting X 1 into the profit equation for Zone A gives: ()()()()()()()()250,451$5.47000,15.4725.472001002=--=A π.For Zone B follow a similar procedure. Profits in Zone B areππB B X X X X X =--=-100100100090002002222222b g e j,,, or . Taking the derivative of the profit function with respect to X 2 givesd X B π229000200=-,. Setting d B π2equal to zero to find the profit-maximizing level of output gives 9,000 - 200X 2 = 0, or X 2 = 45.Substituting X 2 into the profit equation for Zone B gives:πB = (100)((100)(45) - 452) - (1,000)(45) = $202,500.Total profit from both zones is $653,750, with 47.5 boats in Zone A and 45 boats in ZoneB. Because each additional boat above 92.5 decreases total profit, the governmentshould not grant any more licenses.。
平狄克《微观经济学》第9版笔记和课后习题详解(外部性与公共物品)【圣才出品】
平狄克《微观经济学》第9版笔记和课后习题详解第18章外部性与公共物品18.1复习笔记【知识框架】【考点难点归纳】考点一：外部性★★★外部性是指一个经济主体的经济活动对他人和社会造成的非市场化影响，这种影响既可以是正向也可以是负向。
当某个经济主体的行为使他人或社会受益，而受益者无须付出任何代价时，称之为正的外部性；当某个经济主体的行为使他人或社会受损，而行为主体却无须为此承担成本时，称之为负的外部性。
由于外部性并不反应在市场价格中，因此可能会导致经济无效率和市场失灵。
1．负的外部性和无效率当存在负的外部性时，边际社会成本（MSC）大于边际私人成本（MC），差额就是边际外部成本（MEC）。
从社会的角度看，由于厂商未能将与负外部性伴随的成本纳入考虑，导致生产过剩。
有效产出水平应当是价格等于生产的边际社会成本。
外部性既导致短期也导致长期的无效率。
厂商通过对比产品价格和生产的平均成本来决定是否进入行业：价格高于成本，厂商就进入；价格低于成本，厂商就退出。
在长期均衡中，价格等于（长期）平均成本。
当存在负的外部性时，平均私人生产成本低于平均社会成本，厂商判断产品价格高于其生产的成本即平均私人成本，选择留在产业内，但对社会而言是无效率的。
2．正的外部性和无效率当存在正的外部性时，边际社会收益（MSB）大于边际私人收益（D），差额就是边际外部收益（MEB），即MSB＝D＋MEB。
有效产出水平处于MSB和MC曲线的相交处。
正的外部性也会导致无效率。
一个正的外部性导致无效率的例子就是厂商在研究与开发上所花费的钱，研究带来的创新常常难以受到保护而被别的厂商得到，研发投资得不到回报就无法再获得资金支持。
考点二：纠正市场失灵的办法★★★污染是外部性导致市场失灵的一般例子，可以通过排污标准、排污费、可转让排污许可证或者通过鼓励再生利用得到纠正。
在成本和收益都存在不确定性时，这些机制的选择，取决于边际社会成本和边际收益曲线的形状。
平狄克《微观经济学》配套题库【课后习题】第16章~第18章【圣才出品】
第4篇信息、市场失灵以及政府的角色第16章一般均衡与经济效率16.1课后复习题详解1．为什么反馈效应能使一般均衡分析与局部均衡分析发生很大的差异？答：（1）局部均衡分析主要研究的是一个市场上供给和需求的相互影响，它忽略了其他市场如替代品、互补品、要素投入市场对单一产品市场的供给和需求的影响。
一般均衡分析则是考虑反馈效应，同时决定所有市场的价格和数量。
反馈效应是指某一个市场的价格和数量调整所导致的相关市场的价格或数量调整。
（2）忽略反馈效应可能导致对单一市场上的变动的预测不准确。
需求在单一市场上的移动可能导致其他相关市场上的需求移动，最终又导致原市场上需求的再次移动。
局部均衡分析停留在初始移动，而一般均衡分析则根据反馈效应继续分析相关市场的需求变动情况，并最终反馈到原市场，对初始的需求曲线发生影响。
由此可知，反馈效应能使得一般均衡分析与局部分析发生很大的差异。
（3）考察录像带租赁和影剧院门票这两个竞争市场。
这两个市场有紧密的联系，现在假定政府对购买每一张电影票征收1美元的税。
这一税收的局部均衡效应就是使对电影的需求曲线向上提高1美元。
因为电影和录像是替代品，一般均衡分析则认为电影税会提高录像的需求，录像市场受到影响后，又通过反馈效应进一步影响电影票价格，结果必然同时决定电影和录像两者的均衡价格和均衡数量，与局部均衡分析的结果存在很大差异。
2．解释埃奇沃思盒形图中的一点是如何同时代表两个消费者所拥有的商品配置的。
答：假定两种产品分别为和，其既定数量为和，两个消费者分别为A和B，如图16－1所示的埃奇沃思盒形图，盒子的水平长度表示整个经济中的第一种产品的消费量，盒子的垂直长度表示第二种产品的数量，表示第一个消费者A的原点，表示第二个消费者B的原点，从水平向右测量消费者A对第一种商品的消费量，垂直向上测量它对第二种商品的消费量；从水平向左测量消费者B对第一种商品的消费量，垂直向下测量消费者B对第二种商品的消费量。
平狄克《微观经济学》课后答案 17
CHAPTER 17MARKETS WITH ASYMMETRIC INFORMATIONLike Chapter 15, this chapter follows a “hub-and-spoke” pattern. The hub, found in the introduction to the chapter, defines asymmetric information. The spokes include Sections 17.1 and 17.3 on adverse selection and moral hazard Section 17.2 on signaling the principal-agent problem in Sections 17.4 and 17.5 and the efficiency wage model in Section 17.6. Although much of the discussion of these topics is conceptual, an algebraic or geometric model is presented in each section and the exercises focus on the intuition behind the models.It is best to introduce asymmetric information by reviewing where microeconomics has assumed perfect information. For example, except for Chapter 5 and sections of Chapter 15, we have assumed perfect knowledge of the future (no uncertainty). In models of uncertainty, consumers and producers play “games against nature.” In models of asymmetric information, they are playing games with each other.Many of your students are likely to have bought or sold a used car and will, therefore, find the lemons model interesting. Start your presentation by asking the sellers of used cars how they determined their asking price. Emphasize the intuition of the model before presenting Figure 17.1. If they have understood the model, they should ask a high price to give the impression to buyers that the car they are selling is of high quality. Class discussion could consider whether the government should pass laws requiring warranties in the sale of used cars.The market for insurance is also one with which most students are familiar. Although car insurance is required in many states, liability limits may vary from policy to policy. Discuss how risk-averse individuals will want to purchase policies with higher limits and how insurance companies determine the riskiness of the insurance (see Review Question (3)). If you have used the example of buying a house in Chapter 15, you may extend it here by considering how bankers determine whether borrowers will default on their home loans (see Exercise (2)).When discussing market signaling, point out the dual function of education (as training and as a signal of higher productivity). The “Simple Model of Job Market Signaling,” which is presented in Section 17.2, might confuse students unfamiliar with discontinuous functions (see Figure 17.2). Explain how educational degrees lead to discontinuities, and stress the relationship between degrees, guarantees, and warranties of educational quality. See Exercises (1) and (2) for a discussion of these issues.Moral hazard is an easy concept to illustrate with examples, but it is important to draw a clear distinction between adverse selection and moral hazard. Exercise (5) combines discussions of the lemons market, signaling, and moral hazard. Exercise (7) combines discussions of moral hazard and warranties.The principal-agent problem is presented in the context of the relationship between employer and employee. It can be generalized to the relationship between a regulator and a regulated firm and to the relationship between voters and elected officials. In discussing the problems of monitoring agents, you can reintroduce the concept of transactions costs (from Section 16.2). Monitoring costs are discussed in Review Questions (6) and (7). The most interesting topic of this section is how to design contracts to provide the proper incentives for agents to perform in the interest of the principal. The starred Section 17.5 extends this topic to managerial incentives in an integrated firm. The model can be applied to government contracts, i.e., defense contracts, for a discussion of cost-plus contracting.The shirking model of efficiency wages is conceptually difficult. After discussing efficiency in Chapter 16, students might wonder what is so efficient about paying workers a wage that is greater than the value of their marginal product. Stress the role of asymmetric information here: firms have imperfect information about individual worker productivity. If you present this model, first read the references in Footnote 17. While Yellen’s article is concise, Stiglitz’s is more general, discussing shirking on page 20 and the relationship between efficiency wage theory and unemployment on pages 33-37.1. Why can asymmetric information between buyers and sellers lead to a market failure when a market is otherwise perfectly competitive?Asymmetric information leads to market failure because the transaction price does notreflect either the marginal benefit to the buyer or the marginal cost of the seller. Thecompetitive market fails to achieve an output with a price equal to marginal cost. Insome extreme cases, if there is no mechanism to reduce the problem of asymmetricinformation, the market collapses completely.2. If the used car market is a “lemons” market, how would you expect the repair record of used cars that are sold to compare with the repair record of those not sold?In the market for used cars, the seller has a better idea of the quality of the used carthan does the buyer. The repair record of the used car is one indicator of quality. Onewould expect that, at the margin, cars with good repair records would be kept whilecars with poor repair records would be sold. Thus, one would expect the repair recordsof used cars that are to be sold to be worse than those of used cars not sold.3. Explain the difference between adverse selection and moral hazard in insurance markets. Can one exist without the other?In insurance markets, both adverse selection and moral hazard exist. Adverse selectionrefers to the self-selection of individuals who purchase insurance policies. In otherwords, people who are less risky than the insured population will, at the margin, choosenot to insure, while people more risky than the population will choose to insure. As aresult, the insurance company is left with a riskier pool of policy holders. The problemof moral hazard occurs after the insurance is purchased. Once insurance is purchased,less risky individuals might engage in behavior characteristic of more risky individuals.If policy holders are fully insured, they have little incentive to avoid risky situations.An insurance firm may reduce adverse selection, without reducing moral hazard, andvice versa. Researching to determine the riskiness of a potential customer helpsinsurance companies reduce adverse selection. Furthermore, insurance companiesreevaluate the premium (sometimes canceling the policy) when claims are madeagainst the policy, thereby reducing moral hazard. Copayments also reduce moralhazard by creating a disincentive for policy holders to engage in risky behavior.4. Describe several ways in which sellers can convince buyers that their products are of high quality. Which methods apply in the following products: Maytag washing machines, Burger King hamburgers, large diamonds?Some signal the quality of their products to buyers through (1) investment in a goodreputation, (2) the standardization of products, (3) certification (i.e., the use ofeducational degrees in the labor market), (4) guarantees, and (5) warranties. Maytagsignals the high quality of its washing machines by offering one of the best warrantiesin the market. (See Consumer Reports, February 1988, p. 82.) Burger King relies onthe standardization of its hamburgers, e.g., the Whopper. The sale of a large diamondis accompanied by a certificate that verifies the weight and shape of the stone anddiscloses any flaws.5. Why might a seller find it advantageous to signal the quality of her product? How are guarantees and warranties a form of market signaling?Firms producing high-quality products would like to charge higher prices, but to do thissuccessfully, potential consumers must be made aware of the quality differences amongbrands. One method of providing product quality information is through guarantees(i.e., the promise to return what has been given in exchange if the product is defective)and warranties (i.e., the promise to repair or replace if defective). Since low-qualityproducers are unlikely to offer costly signaling devices, consumers can correctly view aguarantee or an extensive warranty as a signal of high quality, thus confirming theeffectiveness of these measures as signaling devices.6. Why might managers of firms be able to achieve objectives other than profit maximization, the goal of the firm’s shareholders?It is difficult and costly for shareholders to constantly monitor the actions of the firm’smanagers. The firm’s owners are in a better position to engage in monitoring, butmanagers’ behaviors still cannot be scrutinized one hundred percent of the time.Therefore, managers have some leeway to pursue their own objectives.7. How can the principal-agent model be used to explain why public enterprises, such as post offices, might pursue goals other than profit maximization?The problem of overseeing a public enterprise is one of asymmetric information. Themanager (agent) is more familiar with the cost structure of the enterprise and thebenefits to the customers than the principal, an elected or appointed official, who mustelicit cost information controlled by the manager. The costs of eliciting and verifyingthe information, as well as independently gathering information on the benefitsprovided by the public enterprise, can be more than the difference between the agency’spotential net returns (“profits”) and realized returns. This difference provides room forslack, which can be distributed to the management as personal benefits, to the agency’sworkers as greater-than-efficient job security, or to the agency’s customers in the formof greater-than-efficient provision of goods or services.8. Why are bonus and profit-sharing payment schemes likely to resolve principal-agent problems, whereas a fixed wage payment will not?With a fixed wage, the agent-employee has no incentive to maximize productivity. Ifthe agent-employee is hired at a fixed wage equal to the marginal revenue product ofthe average employee, there is no incentive to work harder than the least productiveworker. Bonus and profit-sharing schemes involve a lower fixed wage than fixed-wageschemes, but they include a bonus wage. The bonus can be tied to the profitability ofthe firm to the output of the individual employee, or to that of the group in which theemployee works. These schemes provide a greater incentive for agents to maximize theobjective function of the principal.9. What is an efficiency wage? Why is it profitable for the firm to pay an efficiency wage when workers have better information about their productivity than firms do?An efficiency wage, in the context of the shirking model, is the wage at which noshirking occurs. If employers cannot monitor employees’ productivity, then employeesmay shirk (work less productively), which will affect the firm’s output and profits. Ittherefore pays the firm to offer workers a higher-than-market wage, thus reducing theworkers’ incentive to shirk, because they know that if they are fired and end upworking for another firm, their wage will fall.1. Many consumers view a well-known brand name as a signal of quality and will pay more for a brand-name product (e.g., Bayer aspirin instead of generic aspirin, Birds Eye frozen vegetables instead of the supermarket’s own brand). Can a brand name provide a useful signal of quality? Why or why not?A brand name can provide a useful signal of quality for several reasons. First, wheninformation asymmetry is a problem, one solution is to create a “brand-name” product.Standardization of the product produces a reputation for a given level of quality that issignaled by the brand name. Second, if the development of a brand-name reputation iscostly (i.e., advertising, warranties, etc.), the brand name is a signal of higher quality.Finally, pioneer products, by virtue of their “first-mover” status, enjoy consumer loyaltyif the products are of acceptable quality. The uncertainty surrounding newer productsinhibits defection from the pioneering brand-name product.2. Gary is a recent college graduate. After six months at his new job, he has finally saved enough to buy his first car.a. Gary knows very little about the differences between makes and models of cars.How could he use market signals, reputation, or standardization to make comparisons?Gary’s problem is one of asymmetric information. As a buyer of a first car, he will benegotiating with sellers who know more about cars than he does. His first choice is todecide between a new or used car. If he buys a used car, he must choose between aprofessional used-car dealer and an individual seller. Each of these three types ofsellers (the new-car dealer, the used-car dealer, and the individual seller) uses differentmarket signals to convey quality information about their products.The new-car dealer, working with the manufacturer (and relying on the manufacturer’sreputation) can offer standard and extended warranties that guarantee the car willperform as advertised. Because few used cars carry a manufacturer’s warranty and theused-car dealer is not intimately familiar with the condition of the cars on his or her lot(because of their wide variety and disparate previous usage), it is not in his or her self-interest to offer extensive warranties. The used-car dealer, therefore, must rely onreputation, particularly on a reputation of offering “good values.” Since the individualseller neither offers warranties nor relies on reputation, purchasing from such a sellercould make it advisable to seek additional information from an independent mechanicor from reading the used-car recommendations in Consumer Reports. Given his lack ofexperience, Gary should gather as much information about these market signals,reputation, and standardization as he can afford.b. You are a loan officer in a bank. After selecting a car, Gary comes to you seeking aloan. Since he has only recently graduated, he does not have a long credit history.Despite this, the bank has a long history of financing cars of recent college graduates. Is this information useful in Gary’s case? If so, how?The bank’s problem in loaning money to Gary is also one of asymmetric information.Gary has a much better idea than the bank does about the quality of the car and hisability to pay back the loan. While the bank can learn about the car through thereputation of the manufacturer (if it is a new car) and through inspection (if it is a usedcar), the bank has little information on Gary’s ability to handle credit. Therefore, thebank must infer information about Gary’s credit-worthiness from easily availableinformation, such as his recent graduation from college, how much he might haveborrowed while in school, and the similarity of his educational and credit profile to thatof college graduates currently holding car loans from the bank. If recent graduateshave built a good reputation for paying off their loans, Gary can use this reputation tohis advantage, but poor repayment patterns by this group will lessen his chances ofobtaining a car loan from this bank.3. A major university bans the assignment of D or F grades. It defends its action by claiming that students tend to perform above average when they are free from the pressures of flunking out. The university states that it wants all its students to get As and Bs. If the goal is to raise overall grades to the B level or above, is this a good policy? Discuss with respect to the problem of moral hazard.By eliminating the lowest grades, the innovating university creates a moral hazardproblem similar to that which is found in insurance markets. Since they are protectedfrom receiving a below-average grade, some students will have little incentive to workat above-average levels. The policy only addresses the pressures facing below-averagestudents, i.e., those who flunk out. Average and above-average students do not face thepressure of failing. For these students, the destructive pressure of earning good grades(instead of learning a subject well) remains. Their problems are not addressed by thispolicy. Therefore, the policy creates a moral hazard problem primarily for the below-average students who are its intended beneficiaries.4. Professor Jones has just been hired by the economics department at a major private university. The president of the board of regents has stated that the university is committed to providing top-quality education for its undergraduates. Two months into the semester, Professor Jones fails to show up for his classes. It seems he is devoting all his time to economic research rather than to teaching. Professor Jones argues that his research will bring additional prestige to the department and the university. Should he be allowed to continue exclusively with research? Discuss with reference to the principal-agent problem.In the university context, the board of regents and its president are the principals,while the agents are the members of the faculty hired by the department with theapproval of the president and the board. The dual purpose of most universities isteaching students and producing research; thus, most faculty are hired to perform bothtasks. The problem is that teaching effort can be easily monitored (particularly if Jonesdoes not show up for class), while the benefits of establishing a prestigious researchreputation are uncertain and are realized only over time. While the quantity ofresearch is easy to calculate, determining research quality is more difficult. Theuniversity should not simply take Jones’ word regarding the benefits of his researchand allow him to continue exclusively with his research without altering his paymentscheme. One alternative would be to tell Jones that he does not have to teach if he iswilling to accept a lower salary. On the other hand, the university could offer Jones abonus if, due to his research reputation, he is able to bring a lucrative grant or otherdonations to the university5. Faced with a reputation for producing automobiles with poor repair records, a number of American automobile companies have offered extensive guarantees to car purchasers (i.e., a seven-year warranty on all parts and labor associated with mechanical problems). a. In light of your knowledge of the lemons market, why is this a reasonable policy?In the past, American companies enjoyed a reputation for producing high-quality cars.More recently, faced with competition from Japanese car manufacturers, their productsappeared to customers to be of lower quality. As this reputation spread, customerswere less willing to pay high prices for American cars. To reverse this trend, Americancompanies invested in quality control, improving the repair records of their products.Consumers, however, still considered American cars to be of lower quality (lemons, insome sense), and would not buy them, American companies were forced to signal theimproved quality of their products to their customers. One way of providing thisinformation is through improved warranties that directly address the issue of poorrepair records. This was a reasonable reaction to the “lemons” problem that they faced.b. Is the policy likely to create a moral hazard problem? Explain.Moral hazard occurs when the insured party (here, the owner of an Americanautomobile with an extensive warranty) can influence the probability of the event thattriggers payment (here, the repair of the automobile). The coverage of all parts andlabor associated with mechanical problems reduces the incentive to maintain theautomobile. Hence, a moral hazard problem is created by the offer of extensivewarranties. To avoid this problem, all routine maintenance could be performed as longas the car is under warranty.6. To promote competition and consumer welfare, the Federal Trade Commission requires firms to advertise truthfully. How does truth in advertising promote competition? Why would a market be less competitive if firms advertised deceptively?Truth-in-advertising promotes competition by providing the information necessary forconsumers to make optimal decisions. “Competitive forces” function properly only ifconsumers are aware of all prices (and qualities), so comparisons may be made. In theabsence of truthful advertising, buyers are unable to make these comparisons becausegoods priced identically can be of different quality. Hence, there will be a tendency forbuyers to “stick” with proven products, reducing competition between existing firmsand discouraging entry. Note that monopoly rents may result when consumers stickwith proven products.7. An insurance company is considering issuing three types of fire insurance policies: (i) complete insurance coverage, (ii) complete coverage above and beyond a $10,000 deductible, and (iii) 90 percent coverage of all losses. Which policy is more likely to create moral hazard problems?Moral hazard problems arise with fire insurance when the insured party can influencethe probability of a fire and the magnitude of a loss from a fire. The property owner canengage in behavior that reduces the probability of a fire, for example, by inspecting andreplacing faulty wiring. The magnitude of losses can be reduced by the installation ofwarning systems or the storage of valuables away from areas where fires are likely tostart.After purchasing complete insurance, the insured has little incentive to reduce eitherthe probability or the magnitude of the loss, and the moral hazard problem will besevere. In order to compare a $10,000 deductible and 90 percent coverage, we wouldneed information on the value of the potential loss. Both policies reduce the moralhazard problem of complete coverage. However, if the property is worth less (more)than $100,000, the total loss will be less (more) with 90 percent coverage than with the$10,000 deductible. As the value of the property increases above $100,000, the owner ismore likely to engage in fire prevention efforts under the policy that offers 90 percentcoverage than under the one that offers the $10,000 deductible.8. You have seen how asymmetric information can reduce the average quality of the products sold in a market as low-quality products drive out the high-quality ones. For those markets where asymmetric information is prevalent, would you agree or disagree with each of the following? Explain briefly:a. The government should subsidize Consumer Reports.Asymmetric information implies an unequal access to information by either buyers orsellers, a problem that leads to inefficient markets or market collapse.Although Consumer Reports provides evaluations for products ranging fromhamburgers to washing machines, it refuses to let its name be used as an endorsementof a product. While government support of Consumer Reports would be likely toincrease the ability of consumers to distinguish between high- and low-quality goods, itis probable that the Consumers Union, publisher of Consumer Reports,would rejectgovernment subsidization because such subsidization might taint the objectivity of theorganization. Note that the government has already provided an indirect subsidy to thepublication by granting the Consumers Union nonprofit status.b. The government should impose quality standards — e.g., firms should not be allowedto sell low-quality items.Option b involves a cost of monitoring. After imposing quality standards, thegovernment must either administratively monitor the quality of goods or adjudicatedisputes between the public and the manufacturers. Note, however, that low-qualitygoods may be preferred if they are sufficiently cheaper.c. The producer of a high-quality good will probably want to offer an extensivewarranty.This option provides the least-cost solution to the problems of asymmetric information.It allows the producer to distinguish products from low-quality goods because it is morecostly for the low-quality producer to offer an extensive warranty than for the high-quality producer to offer one.d. The government should require all firms to offer extensive warranties.By requiring all firms to offer extensive warranties, the government negates themarket signaling value of warranties offered by the producers of high-quality goods.9. Two used car dealerships compete side by side on a main road. The first, Harry’s Cars, sells high-quality cars that it carefully inspects and, if necessary, services. It costs Harry, on average, $8,000 to buy and service each car that it sells. The second dealership, Lew’s Motors, sells lower-quality cars. It costs Lew on average only $5,000 for each car that it sells. If consumers knew the quality of the used cars they were buying, they would gladly pay $10,000 on average for cars Harry sells, but only $7,000 on average for the cars Lew sells.Unfortunately, the dealerships are new and have not had time to establish reputations, so consumers don’t know the quality of each dealership’s cars. Consumers shopping at these dealerships figure that they have a 50-50 chance of ending up with a high-quality car, no matter which dealership they go to, and hence are willing to pay $8,500 on average for a car.Harry’s has an idea—it will offer a bumper-to-bumper warranty for all the cars it sells. He knows that a warranty lasting Y years will cost $500Y on average, and it also knows that if Lew’s tries to offer the same warranty, it will cost Lew’s $1000Y on average.(a) Suppose Harry’s offers a one-year warranty on all the cars it sells. Will this generatea credible signal of quality? Will Lew’s match the offer, or will it fail to match it sothat consumers can correctly assume that because of the warranty, Harry’s cars are high quality and hence worth $10,000 on average?If Harry were to offer a one-year warranty, the average cost to him of each car will risefrom $8,000 to $8,500. By offering the warranty, Harry will communicate the highquality of his cars and will be able to sell them for $10,000, which means that Harry’sprofit per car will increase from $500 to $1,500.Lew will not match Harry’s warranty. Without offering the warranty, Lew is able tomake $2,000 per car. If he were to offer the warranty, each car will now cost Lew$7,000, but as consumers will not be able to determine the quality of the cars Lew willmake $1,500 per car.(b) What if Harry offers a two-year warranty on his cars? Will this generate a crediblesignal of quality? What about a three-year warranty?If Harry offers a two-year warranty each car will cost him $9,000. He will earn $1,000per car as consumers will recognize the higher quality of his cars.With a three-year warranty Harry would be making $500 per car, the same that hewould have made had he not signaled the higher quality of his cars with a warranty.Therefore, Harry would not offer a three-year warranty.(c) If you were advising Harry, how long a warranty would you urge him to offer?Explain why.Harry will need to offer a warranty of sufficient length such that Lew will not find itprofitable to match the warranty. Let t denote the number of years of the warranty,then Lew will offer a warranty according to the following inequality:(8,500 - 5,000 - 2,000t) ≤ 7,000 - 5000, or 3/4 ≤t.Therefore, I would advise Harry to offer a nine-month warranty on his cars as Lew willnot find it profitable to match the warranty.。
平狄克微观经济学答案——第18章 外部性和公共产品
第十八章外部性和公共产品1．在居民住宅占据了城镇的东部之后，几家工厂设立在西部。
每家厂商生产相同的产品，并且在生产中排放有害气体，对社区的居民产生不利的影响。
（1）为什么厂商生产会产生外部性？工厂产生的有害气体会影响居民的效用函数，而且居民不能控制气体的量。
我们可以认为有害气体会减少居民的效用（即负的外部性），降低房地产的价值。
（2）你认为私下讨价还价会解决这一外部性问题吗？请解释。
如果居民预计到工厂的设立，那么房屋价格会反映出有害气体造成的效用低下；通过房屋市场的价格调节使外部性内部化。
如果预计到有害气体，只有当存在数量较少的团体（企业或家庭）且产权界定清晰时，私下的讨价还价才能解决外部性的问题。
私下的讨价还价取决于每个家庭为空气质量支付的意愿，但是真实的信息披露几乎不可能。
工厂已有的生产技术的转化以及工厂和家庭之间的雇佣关系都会使这个问题更加复杂。
私下的讨价还价不大可能解决这个问题。
（3）社区可能会怎样决定空气质量的有效水平?社区可以通过把家庭的支付意愿相加并使其等于减少污染的边际成本来求出空气质量的经济效率水平。
这两步都要求获得真实的信息。
2．一个电脑编程人员游说反对对软件进行版权保护。
他的论点是，每个人都应当从为个人电脑编写的创新程序中获益，，与各种各样电脑程序的接触甚至会鼓舞年轻的编程人员编出更多的创新程序。
考虑到由于它的建议而可能得到的边际社会收益，你同意该编程人员的主张吗？信息中给出的计算机软件是一个经典的公共产品的例子。
因为它可以无成本的复制，所以向一个额外的消费者提供软件的边际成本几乎为零。
所以软件是非竞争性的。
（编写软件的固定成本很高，但可变成本却很低。
）另外，防止消费者复制和使用软件的代价很高，因为只有付出很高的成本或给消费者带来很大不便才能保护版权。
所以，软件也是非排他性的。
由于具有非竞争性和非排他性，计算机软件面临着公共产品：免费搭车者的存在使得市场很难或不可能提供有效率的软件水平。
平狄克微观经济学第七版课件-第17章-信息不对称市场
MC
$1.00
MC’
$0.50
D = MB
0
50
100 140
Chapter 17
每周英里数 Slide 29
16.4 委托——代理问题
代理关系
当一个人的福利取决于另一个人的 行为时，就出现了代理关系
代理人——行为人 委托人——受行为影响的人
Chapter 17
若R = $10,000 或 $20,000,则w = 0 若R = $40,000; 则w = $24,000
预期收益= $30,000; 预期利润 = $18,000
工资=12000，净工资 = $2,000
Chapter 17
Slide 41
委托——代理问题
委托——代理框架中的激励 工资的决定方案
答案
厂商要使得消费者相信其提供的 商品是高质量的，即要建立声誉 。
Chapter 17
Slide 12
17.1 质量不确定性和“柠檬”市场
问题
当你去旅游的时候，你可能会去麦当劳餐 厅，即使你平常在家时从不吃汉堡。为什 么？
因为标准化使人们对于商品的质量有较为 准确的判断，减少了信息不对称的影响。
w = R - $18,000
问题
个人的信用史是否有助于使得信 贷市场的运作更有效率，减少贷 款的成本？
Chapter 17
Slide 10
声誉和标准化的重要性
信息不对称也存在于诸多的市 场： 零售市场 古董、字画及钱币市场 房屋修理 餐厅
Chapter 17
Slide 11
质量不确定性和“柠檬”市场
问题
当信息不对称导致逆淘汰使得低质 量商品驱逐高质量商品时，那些提 供高质量商品的厂商该如何吸引消 费者？
平狄克《微观经济学》(第7版)习题详解(第18章 外部性与公共品)
平狄克《微观经济学》（第7版）第18章外部性与公共品课后复习题详解跨考网独家整理最全经济学考研真题，经济学考研课后习题解析资料库，您可以在这里查阅历年经济学考研真题，经济学考研课后习题，经济学考研参考书等内容，更有跨考考研历年辅导的经济学学哥学姐的经济学考研经验，从前辈中获得的经验对初学者来说是宝贵的财富，这或许能帮你少走弯路，躲开一些陷阱。
以下内容为跨考网独家整理，如您还需更多考研资料，可选择经济学一对一在线咨询进行咨询。
1．下列哪个描述了外部性，哪个没有？解释它们的区别。
（1）巴西限制咖啡出口的政策导致美国咖啡的价格上升，它反过来又导致茶叶的价格上升。
（2）一则广告传单使一个驾驶汽车的人分心，结果使他撞上一根电线杆。
答：（1）巴西限制咖啡出口的政策没有外部性。
巴西限制咖啡出口的政策导致美国咖啡的价格上升，是因为美国所面临的咖啡的供给减少了。
因为咖啡的价格提高，所以消费者转向咖啡的替代品茶，从而使得茶的需求增加，因此导致茶叶价格的上升。
这是市场的作用，而不是外部性。
（2）广告传单有外部性。
广告传单通过宣传某些产品或服务而传达信息。
但是，它传达这些信息的方式可能会使驾驶汽车的人分心，对那些在电线杆附近的驾驶者就可能会造成事故。
因为广告公司索取的广告费中并不包含使驾驶者分心的外部性的成本，传单对驾驶者产生了危害他们安全的负的外部性。
两者的区别在于：巴西的这项政策对美国产生的影响并没有造成其私人成本和社会成本之间，或其私人收益和社会收益之间的不一致，所以没有外部性；而广告传单对它所处的经济环境产生负面影响，所以具有外部性。
2．在减污的成本和收益不确定时，比较和对照下列三种对付污染外部性的机制：（a）排污费；（b）排污标准；（c）可转让排污许可证制度。
答：（1）三种机制的含义排污费是对厂商每单位污染物的收费。
征收一定的排污费将产生有效率的行为。
排污标准是对厂商可以排放多少污染物的法定限制。
如果厂商超过限制，它就会面临经济惩罚甚至刑事惩罚。
平狄克微观经济学答案——第17章信息不对称的市场
第17章信息不对称的市场教学注解这一章探求了一部分人比另一部分人知道得更多时的不同情况，或者换言之，当存在不对称信息时会发生什么。
17.1节讨论了卖方比买方拥有更多信息的情况，17.2节讨论了市场信号机制处理不对称信息的问题。
17.3节讨论了当一方对自己的行为比另一方了解得更多时的道德风险。
17.4节讨论了委托——代理问题，17.5节扩展了一体化企业案例的分析。
两节都讲述了所有者与经理的目标不一致的问题。
17.6节检验了效率工资问题。
基本上有四个话题可由指导教师根据时间限制和大多数兴趣从中挑选。
介绍不对称信息最好通过复习微观经济学以完全信息为假定来展开。
例如，除了第5章和15章的几节，我们以对未来完全已知为假设（无不确定性）。
在不确定模型中，消费者和生产者与自然规律博弈。
在不对称信息模型中，他们互相博弈。
你的许多学生可能买卖或将要买卖旧车，因此，他们会觉得柠檬模型有趣。
通过询问旧车的卖者他们如何定价来开始你的讲解。
在展示图17.1前强调对于模型的直觉。
如果他们弄懂了这一模型，他们应当索要更高的价格，以变给买者留下他们的车质量高的印象。
课堂讨论可以考虑政府是否应通过立法，要求出售旧车时提供保证书。
保险市场也是大多数学生所熟悉的市场。
尽管许多州要求汽车保险，责任限制可能每个保险单都不同。
(liability limits may vary from policy to policy.)讨论风险规避者怎样想购买更高赔偿额度的保险单，以及保险公司怎样决定保险的风险。
如果你在15章用了购买房屋的案例，这里你可以通过考虑银行家怎样决定借款者是否违约将其扩展。
当讨论市场信号时，支出教育的双重作用（作为培训和更高生产率的信号）。
在17.2节展示的“工作市场信号的简单模型”，可能会使不熟悉不连续函数的学生困惑不解（见图17.2）。
解释教育程度怎样导致不连续性，强调教育质量的程度、保证和担保的关系。
（stress the relationship between degrees,guarantees,and warranties of educational quality.）道德风险是一个用例子容易解释的概念，但对逆向选择和道德风险的清晰的区别是重要的。
平狄克《微观经济学》(第7版)课后习题详解 第18章 外部性与公共品【圣才出品】
第18章外部性与公共品18.1课后复习题详解1．下列哪个描述了外部性，哪个没有？解释它们的区别。
（1）巴西限制咖啡出口的政策导致美国咖啡的价格上升，它反过来又导致茶叶的价格上升。
（2）一则广告传单使一个驾驶汽车的人分心，结果使他撞上一根电线杆。
答：（1）巴西限制咖啡出口的政策没有外部性。
巴西限制咖啡出口的政策导致美国咖啡的价格上升，是因为美国所面临的咖啡的供给减少了。
因为咖啡的价格提高，所以消费者转向咖啡的替代品茶，从而使得茶的需求增加，因此导致茶叶价格的上升。
这是市场的作用，而不是外部性。
（2）广告传单有外部性。
广告传单通过宣传某些产品或服务而传达信息。
但是，它传达这些信息的方式可能会使驾驶汽车的人分心，对那些在电线杆附近的驾驶者就可能会造成事故。
因为广告公司索取的广告费中并不包含使驾驶者分心的外部性的成本，传单对驾驶者产生了危害他们安全的负的外部性。
两者的区别在于：巴西的这项政策对美国产生的影响并没有造成其私人成本和社会成本之间，或其私人收益和社会收益之间的不一致，所以没有外部性；而广告传单对它所处的经济环境产生负面影响，所以具有外部性。
2．在减污的成本和收益不确定时，比较和对照下列三种对付污染外部性的机制：（a）排污费；（b）排污标准；（c）可转让排污许可证制度。
答：（1）三种机制的含义排污费是对厂商每单位污染物的收费。
征收一定的排污费将产生有效率的行为。
排污标准是对厂商可以排放多少污染物的法定限制。
如果厂商超过限制，它就会面临经济惩罚甚至刑事惩罚。
可转让排污许可证是一种可以产生数量一定且有限的污染的许可证，它分配在各个厂商之间并且可以在它们之间进行买卖。
（2）排污费和排污标准的比较①某一点的有效排放水平可以通过排污费或者排污标准来实现。
如图18-1所示，*E点的有效排污水平可以通过排污费或者排污标准来实现。
当面临每单位排放3美元的费时，厂商减少排放直至排污费等于边际收益那一点。
同样水平的排放削减可以用标准将排放限制在12单位来实现。
平狄克《微观经济学》(第8版)配套题库(下册)-名校考研真题-信息不对称的市场【圣才出品】
第17章信息不对称的市场一、名词解释1．逆淘汰（逆向选择）（中南财经政法大学2017研；东北大学2016研；东南大学2014研；山东大学2014研；北京理工大学2013研；中央财经大学2010研；对外经济贸易大学2009研；西安交通大学2008研）答：逆向选择是指在签订交易合约之前，进行交易的一方拥有另一方所不知道的信息，并且该信息有可能影响到另一方的利益，掌握信息的一方会做出对自己有利而对对方不利的选择。
因此，逆向选择有时也被称作隐藏信息问题。
美国经济学家阿克洛夫在论文《柠檬市场：质量的不确定与市场机制》中提出著名的旧车市场模型，开创了逆向选择理论的研究先河。
他考察了一个次品充斥的旧车市场。
假设有一批旧车，每辆车的好坏只有卖主知道，要让交易做成，最合理的办法是按平均质量水平定价。
这就意味着其中有些好车的价格被低估了，从而卖方就不愿按照平均定价出售，或者卖方“理性”的抽走好车，让买主在剩下的差车中任意挑选。
如果买方明白这一道理，就不会接受卖方的定价，而只愿出较低的价格。
接着这将可能导致另一回合的出价和杀价：卖主再从中抽走一些较好的车，买主则再次降低意愿价格。
最终的均衡可能使所有好车都卖不出去，显然，这是无效率的，因为最终成交量低于供求双方理想的成交量。
逆向选择在经济生活中经常会出现，并阻碍市场对资源的配置。
解决逆向选择问题的方法主要有：①政府介入市场进行行政干预，避免逆向选择的情况发生；②占有信息多的一方向另一方提供更多的信息，即发送信号，以减小信息不对称的程度。
2．道德风险（中南财经政法大学2017研；东南大学2014研；山东大学2014研；北京理工大学2013研；中央财大2010研）答：道德风险也被称作隐藏行动问题，是指交易双方在签订交易合约后，信息占优势的一方为了最大化自己的收益而损坏另一方，同时也不承担后果的一种行为，即是市场的一方不能查知另一方的行动这样一种情形。
道德风险是20世纪80年代经济学家提出的一个经济哲学范畴的概念，即“从事经济活动的人在最大限度地增进自身效用的同时做出不利于他人的行动。