经济学原理曼昆.ppt

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-Control 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 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 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 that 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 T