经济学原理曼昆.ppt

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1、,4 THE ECONOMICS OF THE PUBLIC SECTOR公共部门经济学,Externalities 外部性,Chapter 10,Market Efficiency-Market Failures,Recall that:Adam Smiths“invisible hand”of the marketplace leads self-interested buyers and sellers in a market to maximize the total benefit that society can derive from a market.,But market f

2、ailures can still happen.,市场效率 和 市场失灵,回顾:亚当.斯密所说的市场中“看不见的手”引导着市场中自利的买者和卖者追求自己利益最大化的同时，使整个社会从市场中获得的总利益也达到最大化。,但是市场也会失灵,EXTERNALITIES AND MARKET INEFFICIENCY,An externality refers to the uncompensated impact of one persons actions on the well-being of a bystander.Externalities cause markets to be inef

3、ficient,and thus fail to maximize total surplus.,外部性与市场无效率,外部性一个人的行为对旁观者福利的影响，这种影响得不到补偿。外部性导致市场失灵，因此单靠市场力量不能使社会总剩余最大化。,An externality arises 外部性产生,.when a person engages in an activity that influences the well-being of a bystander and yet neither pays nor receives any compensation for that effect.当一

4、个人的行为影响到旁观者的福利时，若此人既不为此支付成本（给旁观者带来成本时）又不能得到补偿（给旁观者带来利益时），外部性就产生了。,EXTERNALITIES AND MARKET INEFFICIENCY 外部性与市场无效率,When the impact on the bystander is adverse,the externality is called a negative externality.给旁观者带来不利影响的外部性称为负外部性When the impact on the bystander is beneficial,the externality is called

5、a positive externality.给旁观者带来有利影响的外部性称为正外部性,Automobile exhaust 汽车尾气Cigarette smoking 吸烟Barking dogs(loud pets)狂叫的狗Loud stereos in an apartment building 在公寓楼里大声放立体声,Examples of Negative Externalities负外部性例子,Immunizations 免疫Restored historic buildings 修复历史古迹Research into new technologies新技术研究开发,Example

6、s of Positive Externalities正外部性例子,The Market for Aluminum 铝市场,数量Quantity ofAluminum,0,Demand(private value）需求（私人价值),Supply(private cost）供给（私人成本),The Market for Aluminum and Welfare Economics铝市场和福利经济学,The quantity produced and consumed in the market equilibrium is efficient in the sense that it maxim

7、izes the sum of producer and consumer surplus.“市场均衡时的生产量和消费量是有效率的”，这句话的意思是说生产者和消费者的总剩余最大。,The Market for Aluminum and Welfare Economics铝市场和福利经济学,If the aluminum factories emit pollution(a negative externality),then the cost to society of producing aluminum is larger than the cost to aluminum produce

8、rs.如果铝厂排放污染（负外部性），那么生产铝的社会成本就比铝生产者的私人成本高。,The Market for Aluminum and Welfare Economics铝市场和福利经济学,For each unit of aluminum produced,the social cost includes the private costs of the producers plus the cost to those bystanders adversely affected by the pollution.每生产一个单位量的铝，社会成本既包括铝生产者的私人成本，也包括污染给旁观者带

9、来的成本。,Pollution and the Social Optimum污染和社会最优,产量Quantity of,Aluminum,0,Demand,(private value）需求（私人价值),Supply,(private cost）供给（私人成本),Negative Externalities 负外部性,The intersection of the demand curve and the social-cost curve determines the optimal output level.需求曲线和社会 成本曲线的交点决定了社会最优产量。The socially opt

10、imal output level is less than the market equilibrium quantity.社会最优产量比市场均衡产量低。,Negative Externalities 负外部性,Internalizing an externality involves altering incentives so that people take into account the external effects of their actions.外部性的内在化通过改变激励，使人们考虑他们自己行为的外部效应。,Achieving the Socially Optimal O

11、utput实现社会最优产量,The government can internalize an externality by imposing a tax on the producer to reduce the equilibrium quantity to the socially desirable quantity.政府可以向生产者收税以降低市场均衡产量为社会所希望的产量，将 外部性内在化。,Positive Externalities 正外部性,When an externality benefits the bystanders,a positive externality ex

12、ists.当外部性有利于旁观者时，就存在正外部性。The social value of the good exceeds the private value.物品的社会价值大于私人价值。,Positive Externalities 正外部性,A technology spillover is a type of positive externality that exists when a firms innovation or design not only benefits the firm,but enters societys pool of technological knowl

13、edge and benefits society as a whole.一个企业的创新或设计不仅给本企业带来效益，还会增加社会的技术知识存量，给全社会带来效益，也就是说创新和设计存在着技术溢出效应，技术溢出效应是一种正外部性,Figure 3 Education and the Social Optimum,Copyright 2004 South-Western,Quantity of,Education,0,Price of,Education,图3.教育与社会最优,教育的数量,0,教育的价格,Positive Externalities,The intersection of the

14、supply curve and the social-value curve determines the optimal output level.The optimal output level is more than the equilibrium quantity.The market produces a smaller quantity than is socially desirable.The social value of the good exceeds the private value of the good.,正外部性,供给曲线和社会价值曲线的交点决定了社会最优产

15、量水平。社会最优产量比市场均衡产量多。市场生产的量比社会所希望的量少。物品的社会价值大于私人价值。,Positive Externalities,Internalizing Externalities:SubsidiesUsed as the primary method for attempting to internalize positive externalities.Industrial PolicyGovernment intervention in the economy that aims to promote technology-enhancing industriesPa

16、tent laws are a form of technology policy that give the individual(or firm)with patent protection a property right over its invention.The patent is then said to internalize the externality.,正外部性,外部性内在化：补贴作为首选的办法将正外部性内在化。技术政策政府旨在促进产业技术进步的经济干预专利保护是一种技术政策。专利法通过给予发明者在一定时期内排他性地使用自己的发明而保护了发明者的权益。专利制度将外部性内

17、在化,Internalizing Externalities外部性的内在化,Taxes are the primary tools used to internalize negative externalities.税收是将负外部性内在化的首选手段。Subsidies are the primary tools used to internalize positive externalities.补贴是将正外部性内在化的首选手段。,Private Solutions to Externalities外部性的私人解决方法,Government action is not always need

18、ed to solve the problem of externalities.并不总是需要政府行为来解决外部性问题,Types of Private Solutions to Externalities外部性的私下解决方式,Moral codes and social sanctions 道德规范和社会约束Charitable organizations 慈善组织Integrating different types of businesses 不同类型的企业一体化Contracting between parties 交易各方签订合同,The Coase Theorem,The Coas

19、e Theorem is a proposition that if private parties can bargain without cost over the allocation of resources,they can solve the problem of externalities on their own.Transactions CostsTransaction costs are the costs that parties incur in the process of agreeing to and following through on a bargain.

20、,科斯定理,科斯定理 一种观点，认为如果私人各方可以无成本地就资源配置进行协商，那么，他们就可以自己解决外部性问题。交易成本交易成本 各方在协商达成与遵守协议过程中所发生的成本。,Why Private Solutions Do Not Always Work为什么私下解决方式不能总是有效,Sometimes the private solution approach fails because transaction costs can be so high that private agreement is not possible.有时候，交易成本很高而不可能私下达成协议，因此私下方式不

21、能解决外部性问题,Public Policy Toward Externalities解决外部性的公共政策,When externalities are significant and private solutions are not found,government may attempt to solve the problem through.当外部性问题严重且找不到私人解决方式时，政府也许采用以下方式试图解决外部性问题：command-and-control policies.命令和控制政策。market-based policies.以市场为基础的政策。,Command-and-C

22、ontrol Policies命令和控制政策,Usually take the form of regulations:经常采用管制形式：Forbid certain behaviors 禁止某些行为Require certain behaviors 要求采取某些行为Examples 例子:Requirements that all students be immunized.要求所有学生注射疫苗。Stipulations on pollution emission levels set by the Environmental Protection Agency(EPA).由环保局制订和实施

23、污染排放标准。,Market-Based Policies以市场为基础的政策,Government uses taxes and subsidies to align private incentives with social efficiency.政府利用税收和补贴手段给私人部门以激励，实现社会效率。Pigovian taxes are taxes enacted to correct the effects of a negative externality.庇古税用于纠正负外部性影响的税收。,Examples of Regulation versus Pigovian tax,If t

24、he EPA decides it wants to reduce the amount of pollution coming from a specific plant.The EPA couldtell the firm to reduce its pollution by a specific amount(i.e.regulation).levy a tax of a given amount for each unit of pollution the firm emits(i.e.Pigovian tax).,管制的例子和庇古税,如果环保局决定想减少某个工厂的污染排放量，环保局可

25、以命令工厂减少一定量的污染（即管制）按工厂的排污量收税（即庇古税）,Market-Based Policies,Tradable pollution permits allow the voluntary transfer of the right to pollute from one firm to another.A market for these permits will eventually develop.A firm that can reduce pollution at a low cost may prefer to sell its permit to a firm t

26、hat can reduce pollution only at a high cost.,以市场为基础的政策,可交易的污染许可证 允许排污权在企业之间自愿进行转移。交易这种许可证的市场将最终形成。以低成本可以减少污染的企业愿意将污染许可证出卖给只有以高成本才能减少污染的企业。污染量没有增加，但污染许可证这一稀缺资源重新配置给对其评价更高的企业。,The Equivalence of Pigovian Taxes and Pollution Permits,Quantity of,Pollution,0,Price of,Pollution,P,Q,Demand for,pollution r

27、ights,Pigovian,tax,(a)Pigovian Tax,2.which,togetherwith the demand curve,determines the quantityof pollution.,1.A Pigoviantax sets theprice ofpollution.,Quantity of,Pollution,0,Q,Demand for,pollution rights,Supply of,pollution permits,(b)Pollution Permits,Price of,Pollution,P,2.which,togetherwith th

28、e demand curve,determines the priceof pollution.,1.Pollutionpermits setthe quantityof pollution.,庇古税和排污许可证的等效性,污染量,0,污染的价格,P,Q,对排污权的需求,庇古税,(a)庇古税,2.庇古税和需求曲线决定污染量,1.庇古税决定污染价格,污染量,0,Q,对排污权的需求,排污许可证的供给,(b)污染许可证,污染的价格,P,2.许可证和需求曲线决定污染的价格.,1.污染许可证确定了污染量.,Summary,When a transaction between a buyer and a s

29、eller directly affects a third party,the effect is called an externality.Negative externalities cause the socially optimal quantity in a market to be less than the equilibrium quantity.Positive externalities cause the socially optimal quantity in a market to be greater than the equilibrium quantity.

30、,小结,当一个买者和一个卖者之间的交易影响到第三方时，这种影响被称为外部性。负外部性导致一个市场中的社会最优产量比市场均衡产量低。正外部性导致一个市场中的社会最优产量比市场均衡产量高。,Summary,Those affected by externalities can sometimes solve the problem privately.The Coase theorem states that if people can bargain without a cost,then they can always reach an agreement in which resources

31、 are allocated efficiently.,小结,受外部性影响的各方有时可以私下解决外部性问题。科斯定理认为，如果私人各方可以无成本地进行协商谈判，那么，他们就可以自己达成能使资源有效配置的协议，解决外部性问题。,Summary 小结,When private parties cannot adequately deal with externalities,then the government steps in.当私人各方不能适当地解决外部性问题时，政府就介入了。The government can either regulate behavior or internalize the externality by using Pigovian taxes.政府既可以通过管制行为也可以通过庇古税使外部性内在化，解决外部性问题。,