微观经济学：公共物品和公共资源讲解.ppt

* * Using the two characteristics on the preceding slide, we can classify most goods in one of the four categories on this slide. As each example displays, explain why it belongs to its category/classification. E.g., food is a private good because: 1) It is excludable: you cannot have any unless you buy it. 2) It is rival in consumption: if you eat that fish taco, I won’t be able to eat it. 准公共物品一般具有“拥挤性”的特点，即当消费者的数目增加到某一个值后，就会出现边际成本为正的情况，而不是像纯公共物品，增加一个人的消费，边际成本为零。 * This brief exercise gives students practice applying the definitions of rival and excludable and the four different types of goods. Suggestion: Tell students they have 1-2 minutes to formulate an answer, then another 2 minutes to compare their answer with that of one student sitting near them. Then ask for students to volunteer their responses. If you’re pressed for time, you can safely omit this exercise. Students can get this information from a careful reading of the chapter. * The textbook exposits these ideas using a simple example – a fireworks display in Smalltown, U.S.A. The Study Guide offers another example, in which the cost of installing a streetlight in a neighborhood is less than the collective benefits of the people who live on that street – yet, no one takes the initiative to provide it. * 鄂尔多斯羊绒衫与西北草地沙化，为什么牧民会做出这样的选择？“公地悲剧”也 * If you’re pressed for time, you can safely omit this exercise. Its contents will be covered in a subsequent slide, and students can learn this material from a careful reading of the chapter. This exercise has several objectives: 1) It gets students to anticipate the policy solutions to the common resource problem based on what they have just learned about the problem. 2) After giving students a big hint on the preceding slide, it tests to see whether they make the connection between the common resource problem and the policies to deal with negative externalities they learned in the preceding chapter. To get through this activity qui