刘烨课件微观经济学chapter_9

1、,Chapter 9,The Analysis of Competitive Markets,Chapter 9,Slide 2,Topics to be Discussed,Evaluating the Gains and Losses from Government Policies-Consumer and Producer Surplus P315 Prices control(Prices ceiling)、Minimum Prices、Price Supports 、Production Quotas、 Incentive Plan、Import Quotas 、Tariffs、T

2、ax 、 Subsidy The Efficiency of a Competitive Market,Chapter 9,Slide 3,Evaluating the Gains and Losses from Government Policies-Consumer and Producer Surplus,Review Consumer surplus is the total benefit or value that consumers receive beyond what they pay for the good. Producer surplus is the total b

3、enefit or revenue that producers receive beyond what it cost to produce a good. Individual? Market?,一、Consumer and Producer Surplus P287,Quantity,0,Price,Chapter 9,Slide 5,To determine the welfare effect of a governmental policy we can measure the gain or loss in consumer and producer surplus.通过衡量生产

4、者剩余和消费者剩余的收益与损失来判断政府政策的福利效应 Welfare Effects 福利效应 Gains and losses caused by government intervention in the market.,Evaluating the Gains and Losses from Government Policies-Consumer and Producer Surplus,Chapter 9,Slide 6,Government intervention in these markets can increase efficiency.不是完全竞争市场时候 Mark

5、et Power、Externalities、Lack of Information Government intervention without a market failure creates inefficiency or deadweight loss.即没有市场失效时，即市场是完全竞争市场时 完全竞争市场条件及P292,The Efficiency of a Competitive Market,评价 Welfare Effects的三个基本问题： 1.谁受益？谁受损？（是否全部消费者或全部生产者） 2.损益有多大？（面积来衡量） 3.净损失有大？（整个社会无谓损失）衡量：两主体（

6、PS、CS）、三主体（CS、PS、财政）,Chapter 9,Slide 7,Chapter 9,Slide 8,二、 price ceiling （Price Controls） P289,Quantity,Price,区分实际量与意愿量,复习题1：为何称无谓损失 BC与A有何不同,Chapter 9,Slide 9,Observations: The total loss is equal to area B + C. The total change in surplus = (A - B) + (-A - C) = -B - C The deadweight loss is the i

7、nefficiency of the price controls or the loss of the producer surplus exceeds the gain from consumer surplus.,Change in Consumer and Producer Surplus from Price Controls,Chapter 9,Slide 10,Effect of Price Controls When Demand Is Inelastic P290,Quantity,Price,复习题3、2,典型的例子：1979年 的石油价格控制,Chapter 9,Slid

8、e 11,价格控制与天然气短缺 例子 （略）,1975 年的价格控制导致了天然气的短缺 价格控制导致的无谓损失是多少？,Chapter 9,Slide 12,Supply: QS = 14 + 2PG + 0.25PO Quantity supplied in trillion cubic feet (Tcf) Demand: QD = -5PG + 3.75PO Quantity demanded (Tcf) PG = price of natural gas in $/mcf and PO = price of oil in $/b.,Price Controls and Natural

9、Gas Shortages P290 略,Data for 1975,What was the deadweight loss?,Chapter 9,Slide 13,PO = $8/b Equilibrium PG = $2/mcf and Q = 20 Tcf Price ceiling set at $1 This information can be seen graphically:,Price Controls and Natural Gas Shortages,Data for 1975,Chapter 9,Slide 14,Quantity (Tcf),0,Price ($/m

10、cf),5,10,15,20,25,30,Price Controls and Natural Gas Shortages P290 略,Chapter 9,Slide 15,Measuring the Impact of Price Controls 1 Tcf = 1 billion mcf If QD = 18, then P = $2.40 18 = -5PG + 3.75(8) A = (18 billion mcf) x ($1/mcf) = $18 billion B = (1/2) x (2 b. mcf) x ($0.40/mcf) = $0.4 billion C = (1

11、/2) x (2 b. mcf) x ($1/mcf) = $1 billion,Price Controls and Natural Gas Shortages,Chapter 9,Slide 16,Measuring the Impact of Price Controls 1975 Change in consumer surplus = A - B = 18 - 0.04 = $17.6 billion Change in producer surplus = -A - C = -18-1 = -$19.0 billion 1975 dollars, deadweight loss =

12、 -B - C = -0.4 - 1 = -$1.4 billion In 2000 dollars, the deadweight loss is more than $4 billion per year.,Price Controls and Natural Gas Shortages,Chapter 9,Slide 17,三、Welfare Loss When Price Is Held Below Market-Clearing Level,Quantity,Price,Chapter 9,Slide 18,三、最低价格Minimum Prices P293图,Quantity,Pr

13、ice,超量生产原因？,Chapter 9,Slide 19,超量生产下的损失 P296图9-7,Quantity,Price,Chapter 9,Slide 20,A,W最低,L1,L2,失业,政府规定工资不得低于 w最低， 这将导致L2-L1的失业水平。,图9.8 最低工资 P297,劳动力,工资,Chapter 9,Slide 21,Airline Regulation P297 航空管制案例,During 1976-1981 the airline industry in the U.S. changed dramatically. Deregulation lead to major

14、 changes in the industry. Some airlines merged or went out of business as new airlines entered the industry.,Chapter 9,Slide 22,Effect of Airline Regulation by the Civil Aeronautics Board,Quantity,Price,Chapter 9,Slide 23,四、Price Supports P299,Much of agricultural policy is based on a system of pric

15、e supports.许多农业政策是建立在价格支持（price supports）制度这一基础上的。 This is support price is set above the equilibrium price and the government buys the surplus.在这一制度下，政府规定的价格高于均衡价格，并且，政府买进维持高价所需的全部产出。,Chapter 9,Slide 24,Price Supports P300,Quantity,Price,Chapter 9,Slide 25,B,A,Price Supports,Quantity,Price,S,D,P0,Q

16、0,Ps,Q2,Q1,The cost to the government is the speckled rectangle Ps(Q2-Q1),D,Total Welfare Loss,Total welfare loss D-(Q2-Q1)ps,Chapter 9,Slide 26,Price Supports,Question: Is there a more efficient way to increase farmers income by A + B + D? YES 直接发钱！ 为何不用？P300翻译有误,Chapter 9,Slide 27,P301302实际上包括了生产配

17、额与激励机制两种政策 Production Quotas 产量限制 The government can also cause the price of a good to rise by reducing supply. 政府也可以通过削减产量的方法推动商品的价格上涨,五、Production Quotas P301,Chapter 9,Slide 28,What is the impact of: 1) Controlling entry into the taxicab market? 2) Controlling the number of liquor licenses? 生产配额的

18、两种情形：1) 限制发放出租车营业执照来限制总供给。2) 政府控制售酒许可证。,Price Supports and Production Quotas,Chapter 9,Slide 29,Supply Restrictions P301 cause the price of a good to rise by reducing supply,Quantity,Price,Chapter 9,Slide 30,B,A,C,D,六、限耕方案（激励计划）P302,Quantity,Price,但在农产品生产上，只能采取激励办法来限产,Chapter 9,Slide 31,Supply Restr

19、ictions,= A - C + B + C + D = A + B + D. The change in consumer and producer surplus is the same as with price supports. = -A - B + A + B + D - B - C - D = -B - C.,Chapter 9,Slide 32,Supply Restrictions,Questions: 需要给农民多少钱的奖励? Which is more costly: supports or acreage limitations? 复习题6，几种方案的比较（P302）

20、,Chapter 9,Slide 33,七、Import Quotas 八、 Tariffs,Many countries use import quotas and tariffs to keep the domestic price of a product above world levels 许多国家利用进口配额和关税将商品的国内价格维持在高于世界价格水平之上 目的是什么？,Chapter 9,Slide 34,图9.14 使进口消失的进口关税或配额 P306,数量,价格,此图同时表明了 自由贸易的益处 即B+C,Chapter 9,Slide 35,Import Tariff or

21、Quota (general case) P307,Quantity,Price,一般情况下不可能完全取消进口。更为现实的是对进口给予一定的限制。通过关税或配额。 国内生产者的获益仍为A 消费者损失为 A + B + C + D。,T,Chapter 9,Slide 36,Import Tariff or Quota (general case),配额与关税损益的比较 P307 If a tariff is used the government gains D, so the net domestic product loss is B + C. If a quota is used ins

22、tead, rectangle D becomes part of the profits of foreign producers, and the net domestic loss is B + C + D. （复习题7），但为何有时仍用配额而非关税,Price,Chapter 9,Slide 37,Question: 既然取消或限制进口社会有净损失，为何政府还要实行？,Import Tariff or Quota (general case),Quantity,Price,Chapter 9,Slide 38,案例 The Sugar Quota,The world price of

23、sugar has been as low as 4 cents per pound, while in the U.S. the price has been 20-25 cents per pound.,Sugar Quota in 1997,Quantity (billions of pounds),Price (cents/lb.),5,10,15,20,25,0,4,8,11,16,20,30,C,D,B,QS = 4.0,QS = 15.6,Qd = 21.1,Qd = 24.2,A,Sugar Quota in 1997,Quantity (billions of pounds)

24、,Price (cents/lb.),5,10,15,20,25,0,4,8,11,16,20,30,Rectangle D was the gain to foreign producers who obtained quota allotments, or $600 million. Triangles B and C represent the deadweight loss of $800 million.,Chapter 9,Slide 41,八、The Impact of a Tax 九、Subsidy,书上关于税收的两个问题 （P309） The burden of a tax

25、(or the benefit of a subsidy) falls partly on the consumer and partly on the producer. We will consider a specific tax which is a tax of a certain amount of money per unit sold. 税收楔子；分摊程度；无谓损失,Chapter 9,Slide 42,图9.17 税收的影响 P310,数量,价格,Chapter 9,Slide 43,9.6 征税或补贴的影响,征税后必须满足四个条件(P311)： 1) 销售量和购买价格 Pb

26、位于需求曲线上:QD = QD(Pb) 销售量和销售价格PS 位于供给曲线上:QS = QS(PS) QD = QS Pb - PS = 税收 t 练习题 P316. 2,图9.18 供求弹性决定税收影响 P312,数量,数量,价格,价格,税收由消费者负担,税收由卖方负担,Chapter 9,Slide 45,P311 倒数第四行 Pass-through fraction （P311 转嫁因子，衡量由生产者转嫁给消费者的程度） ES/(ES - Ed) For example, when demand is perfectly inelastic (Ed = 0), the pass-thr

27、ough fraction is 1, and all the tax is borne by the consumer. P318 习题,The Impact of a Tax or Subsidy,Chapter 9,Slide 46,福利变化 P310,数量,价格,Chapter 9,Slide 47,The Effects of a Tax or Subsidy,A subsidy can be analyzed in much the same way as a tax. It can be treated as a negative tax. The sellers price e

28、xceeds the buyers price.,Chapter 9,Slide 48,Subsidy,Quantity,Price,1. 给卖者补贴还是给买者补贴，效果相同 2. 分享补贴 3. 弹性与分享程度,Chapter 9,Slide 49,Chapter 9,Slide 50,Subsidy,With a subsidy (s), the selling price Pb is below the subsidized price PS so that: s = PS - Pb,Chapter 9,Slide 51,Subsidy,The benefit of the subsidy depends upon Ed /ES. If the ratio is small, most of the benefit accrues to the consumer. If t