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1、Public Goods and Common Resources 公共品和共有资源,Chapter 11,思考一下：,为什么鲸鱼会面临灭绝而鲫鱼不会？ 为什么老虎会面临灭绝而狗却不会？ 为什么独裁者依靠一小支部队就能维持统治？,“The best things in life are free. . .”,Free goods provide a special challenge for economic analysis Most goods in our economy are allocated in markets for these goods, prices are the s
2、ignals that guide the decisions of buyers and sellers. When goods are available free of charge, the market forces that normally allocate resources in our economy are absent.,When a good does not have a price attached to it, private markets cannot ensure that the good is produced and consumed in the
3、proper amounts. In such cases, government policy can potentially remedy the market failure that results, and raise economic well-being.,“The best things in life are free. . .”,The Different Kinds of Goods,When thinking about the various goods in the economy, it is useful to group them according to t
4、wo characteristics: Is the good excludable? Is the good rival?,Excludability（排他性） People can be prevented from enjoying the good. Laws recognize and enforce private property rights. Rivalness（竞争性） One persons use of the good diminishes another persons enjoyment of it.,The Different Kinds of Goods,Fo
5、ur Types of Goods,Private Goods Are both excludable and rival. Public Goods Are neither excludable nor rival. Common Resources Are rival but not excludable. Natural Monopolies Are excludable but not rival.,Types of Goods,The Free-Rider Problem,A free-rider is a person who receives the benefit of a g
6、ood but avoids paying for it. Since people cannot be excluded from enjoying the benefits of a public good, individuals may withhold paying for the good hoping that others will pay for it. The free-rider problem prevents private markets from supplying public goods.,Solving the Free-rider Problem,The
7、government can decide to provide the public good if the total benefits exceed the costs. The government can make everyone better off by providing the public good and paying for it with tax revenue.,Some Important Public Goods,National Defense（国防） Basic Research（基础研究） Programs to Fight Poverty(扶贫),Ar
8、e Lighthouses Public Goods?,Cost-Benefit Analysis,In order to decide whether to provide a public good or not, the total benefits of all those who use the good must be compared to the costs of providing and maintaining the public good. Cost benefit analysis estimates the total costs and benefits of a
9、 good to society as a whole.,Cost-Benefit Analysis,A cost-benefit analysis would be used to estimate the total costs and benefits of the project to society as a whole. It is difficult to do because of the absence of prices needed to estimate social benefits and resource costs. The value of life, the
10、 consumers time, and aesthetics are difficult to assess.,Common Resources,Common resources, like public goods, are not excludable. They are available free of charge to anyone who wishes to use them. Common resources are rival goods because one persons use of the common resource reduces other peoples
11、 use.,Tragedy of the Commons,The Tragedy of the Commons is a story with a general lesson: When one person uses a common resource, he or she diminishes another persons enjoyment of it. Common resources tend to be used excessively when individuals are not charged for their usage. This creates a negati
12、ve externality.,Examples of Common Resources,Clean air and water Oil pools Congested roads Fish, whales, and other wildlife,公地悲剧：北京的道路,公地悲剧：野生动物,地球上曾经存在的种属中，只有0.02目前仍然存在。 大约在一万两千多年前，北美洲大多数量大的动物区系的灭绝与人类在此登陆有关。24种哺乳动物与22种鸟现已不复存在了。 对某一动物种属大量捕杀最好的例证是对蓝鲸的围捕，甚至在使用最为现代化的设备时，有时几乎重达100吨的巨大蓝鲸也是难以被捕杀的。但是密集的捕杀方
13、法逐渐将鲸鱼存量从大约30万到100万头减少到目前的600到3000头之间。 在1930年至1931年的冬季，差不多有3万头蓝鲸被捕捉。到了1945年至1946年，有不到10000头蓝鲸被捕捉；50年代末期，年捕获量下降到1500头。到了1964年至1965年，总数仅20头蓝鲸。 1966年国际捕鲸委员会宣布蓝鲸为禁捕的保护对象。国际捕鲸委员会1989年发表的统计报告说，根据在南半球经过8年的调查,蓝鲸现在只有200453头幸存者。,Why Isnt the Cow Extinct?,Private Ownership and the Profit Motive!,Solving the tr
14、agedy of Commons,Command-and-Control Tax License Property Privatization,Importance of Property Rights,The market fails to allocate resources efficiently when property rights are not well-established (i.e. some item of value does not have an owner with the legal authority to control it). When the abs
15、ence of property rights causes a market failure, the government can potentially solve the problem.,Summary,Goods differ in whether they are excludable and whether they are rival. A good is excludable if it is possible to prevent someone from using it. A good is rival if one persons enjoyment of the
16、good prevents other people from enjoying the same unit of the good.,Summary,Public goods are neither rival nor excludable. Because people are not charged for their use of public goods, they have an incentive to free ride when the good is provided privately. Governments provide public goods, making quantity decisions based upon cost-benefit analysis.,Summary,Common resources are rival but not excludable. Because people are not charged for their use of common reso
