1、路漫漫其悠远路漫漫其悠远2022-8-9曼昆经济学原理英文版完整讲义丛externalities曼昆曼昆经济学原理经济学原理英英文版完整讲义丛文版完整讲义丛externalities路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalities10Externalities 路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalities Recall:Adam Smiths“invisible hand”of the marketplace leads self-interested buyers and sellers in a market to max
2、imize the total benefit that society can derive from a market.But market failures can still happen.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MARKET INEFFICIENCY An externality refers to the uncompensated impact of one persons actions on the well-being of a bystander.Externalities cau
3、se markets to be inefficient,and thus fail to maximize total surplus.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MARKET INEFFICIENCY An externality arises.when a person engages in an activity that influences the well-being of a bystander and yet neither pays nor receives any compensati
4、on for that effect.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MARKET INEFFICIENCY When the impact on the bystander is adverse,the externality is called a negative externality.When the impact on the bystander is beneficial,the externality is called a positive externality.路漫漫其悠远路漫漫其悠远曼昆
5、经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MARKET INEFFICIENCY Negative Externalities Automobile exhaust Cigarette smoking Barking dogs(loud pets)Loud stereos in an apartment building路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MARKET INEFFICIENCY Positive Externalities Immunizations R
6、estored historic buildings Research into new technologies曼昆经济学原理英文版完整讲义丛externalitiesFigure 1 The Market for AluminumCopyright 2004 South-WesternQuantity ofAluminum0Price ofAluminumEquilibriumDemand(private value)Supply(private cost)QMARKET路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesEXTERNALITIES AND MA
7、RKET INEFFICIENCY Negative externalities lead markets to produce a larger quantity than is socially desirable.Positive externalities lead markets to produce a larger quantity than is socially desirable.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesWelfare Economics:A Recap The Market for Aluminum The quan
8、tity produced and consumed in the market equilibrium is efficient in the sense that it maximizes the sum of producer and consumer surplus.If the aluminum factories emit pollution(a negative externality),then the cost to society of producing aluminum is larger than the cost to aluminum producers.路漫漫其
9、悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesWelfare Economics:A Recap The Market for Aluminum 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.曼昆经济学原理英文版完整讲义丛externalitiesFigure 2 Pollution an
10、d the Social OptimumCopyright 2004 South-WesternEquilibriumQuantity ofAluminum0Price ofAluminumDemand(private value)Supply(private cost)SocialcostQOPTIMUMOptimumCost ofpollutionQMARKET路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesNegative Externalities The intersection of the demand curve and the social-c
11、ost curve determines the optimal output level.The socially optimal output level is less than the market equilibrium quantity.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesNegative Externalities Internalizing an externality involves altering incentives so that people take account of the external effects of
12、 their actions.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesNegative Externalities Achieving the Socially Optimal Output The government can internalize an externality by imposing a tax on the producer to reduce the equilibrium quantity to the socially desirable quantity.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externa
13、litiesPositive Externalities When an externality benefits the bystanders,a positive externality exists.The social value of the good exceeds the private value.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPositive Externalities A technology spillover is a type of positive externality that exists when a fir
14、ms innovation or design not only benefits the firm,but enters societys pool of technological knowledge and benefits society as a whole.曼昆经济学原理英文版完整讲义丛externalitiesFigure 3 Education and the Social OptimumCopyright 2004 South-WesternQuantity ofEducation0Price ofEducationDemand(private value)Socialval
15、ueSupply(private cost)QMARKETQOPTIMUM路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPositive Externalities The intersection of the 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 quantit
16、y than is socially desirable.The social value of the good exceeds the private value of the good.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPositive Externalities Internalizing Externalities:Subsidies Used as the primary method for attempting to internalize positive externalities.Industrial Policy Gover
17、nment intervention in the economy that aims to promote technology-enhancing industries Patent 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.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版
18、完整讲义丛externalitiesPRIVATE SOLUTIONS TO EXTERNALITIES Government action is not always needed to solve the problem of externalities.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPRIVATE SOLUTIONS TO EXTERNALITIES Moral codes and social sanctions Charitable organizations Integrating different types of busine
19、sses Contracting between parties路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesThe Coase Theorem The Coase 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 Costs Transaction costs
20、 are the costs that parties incur in the process of agreeing to and following through on a bargain.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesWhy Private Solutions Do Not Always Work Sometimes the private solution approach fails because transaction costs can be so high that private agreement is not pos
21、sible.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPUBLIC POLICY TOWARD EXTERNALITIES When externalities are significant and private solutions are not found,government may attempt to solve the problem mand-and-control policies.market-based policies.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPUBLIC POLICY TO
22、WARD EXTERNALITIES Command-and-Control Policies Usually take the form of regulations:Forbid certain behaviors.Require certain behaviors.Examples:Requirements that all students be immunized.Stipulations on pollution emission levels set by the Environmental Protection Agency(EPA).路漫漫其悠远路漫漫其悠远曼昆经济学原理英文
23、版完整讲义丛externalitiesPUBLIC POLICY TOWARD EXTERNALITIES Market-Based Policies Government uses taxes and subsidies to align private incentives with social efficiency.Pigovian taxes are taxes enacted to correct the effects of a negative externality.路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPUBLIC POLICY T
24、OWARD EXTERNALITIES Examples of Regulation versus Pigovian Tax If the EPA decides it wants to reduce the amount of pollution coming from a specific plant.The EPA could tell 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 t
25、he firm emits(i.e.Pigovian tax).路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesPUBLIC POLICY TOWARD EXTERNALITIES 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
26、 reduce pollution at a low cost may prefer to sell its permit to a firm that can reduce pollution only at a high cost.曼昆经济学原理英文版完整讲义丛externalitiesFigure 4 The Equivalence of Pigovian Taxes and Pollution PermitsCopyright 2004 South-WesternQuantity ofPollution0Price ofPollutionDemand forpollution righ
27、tsPPigoviantax(a)Pigovian Tax2.which,togetherwith the demand curve,determines the quantityof pollution.1.A Pigoviantax sets theprice ofpollution.Q曼昆经济学原理英文版完整讲义丛externalitiesFigure 4 The Equivalence of Pigovian Taxes and Pollution PermitsCopyright 2004 South-WesternQuantity ofPollution0Demand forpol
28、lution rightsQSupply ofpollution permits(b)Pollution PermitsPrice ofPollution2.which,togetherwith the demand curve,determines the priceof pollution.1.Pollutionpermits setthe quantityof pollution.P路漫漫其悠远路漫漫其悠远曼昆经济学原理英文版完整讲义丛externalitiesSummary When a transaction between a buyer and a seller directly
29、 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.路漫漫其悠远路漫漫其悠远曼昆
30、经济学原理英文版完整讲义丛externalitiesSummary 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 are allocated efficiently.路漫漫其悠远路漫漫其悠远2022-8-9曼昆经济学原理英文版完整讲义丛externalities
