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1、,消费者、生产者与市场效率 Consumers, Producers, and the Efficiency of Markets,第七章 Chapter 7,在本章中,我们要讨论福利经济学(welfare economics)这个主题,即研究资源配置如何影响经济福利。我们从考察买者和卖者从参与市场中得到的利益开始,然后考虑社会如何可以使这种利益尽量达到最大。,在前面几章中,我们说明了在市场经济中供给和需求的力量如何决定了物品的价格和销售量。那么,这种价格和销售对买者和卖者来说是不是最满意的?对我们整个社会来说是否是最佳的?,再看市场均衡 Revisiting the Market Equil
2、ibrium,市场均衡价格和数量使买者和卖者的总福利最大化吗 Do the equilibrium price and quantity maximize the total welfare of buyers and sellers? 市场均衡反映出市场配置稀缺资源的方式。 Market equilibrium reflects the way markets allocate scarce resources. 市场的资源配置是否令人满意,取决于福利经济学 Whether the market allocation is desirable is determined by welfare
3、 economics.,福利经济学 Welfare Economics,福利经济学研究资源配置如何影响经济福利。 Welfare economics is the study of how the allocation of resources affects economic well-being. 买者和卖者从参与市场中收益。 Buyers and sellers receive benefits from taking part in the market. 市场上供求均衡可以使买者和卖者的总福利最大化。 The equilibrium in a market maximizes the
4、 total welfare of buyers and sellers.,福利经济学 Welfare Economics,市场均衡导致收益最大化,因此导致消费者和生产者的总体福利的最大化。 Equilibrium in the market results in maximum benefits, and therefore maximum total welfare for both the consumers and the producers of the product.,Welfare Economics,消费者剩余衡量买方的经济福利。 Consumer surplus measu
5、res economic welfare from the buyers side. 生产者剩余衡量卖方的经济福利。 Producer surplus measures economic welfare from the sellers side.,消费者剩余 Consumer Surplus,支付意愿是买者愿意且能够为某一物品支付的最高价格。 Willingness to pay is the maximum price that a buyer is willing and able to pay for a good. 它衡量买者对物品或服务的评价是多少 It measures how
6、much the buyer values the good or service.,消费者剩余 Consumer Surplus,消费者剩余是买者的支付意愿减买者的实际支付额。 Consumer surplus is the amount a buyer is willing to pay for a good minus the mount the buyer actually pays for it.,让我们来参加一场拍卖会,拍卖品:外星人的经原课本1本 拍卖的参加者:John, Paul, George and Ringo. 拍卖规则:买者由低到高出价,每次加价以10美元为最小单位。出
7、价最高者得到这个课本,并支付其报价。,谁得到课本,成交价是多少?,四个可能买者的支付意愿 Four Possible Buyers Willingness to Pay.,让我们来参加一场拍卖会,John 将得到课本,成交价为80(或90)美元。 John 得到的消费者剩余(也是市场的总消费者剩 余)为: 100-80=20 美元 假设有两本课本呢? John和Paul 将得到课本,成交价为70美元。 John得到100-70=30 美元的消费者剩余;Paul得到80-70=10 美元的消费者剩余。 市场的总消费者剩余为30+10=40 美元。,消费者剩余 Consumer Surplus,消
8、费者剩余与一种物品的需求曲线密切相关。 Consumer surplus is closely related to the demand curve for a product. 市场需求曲线画出了在不同的价格下,买者愿意和能够购买的数量。 The market demand curve depicts the various quantities that buyers would be willing and able to purchase at different prices.,四个可能买者的支付意愿 Four Possible Buyers Willingness to Pay.
9、,用需求曲线衡量消费者剩余 Measuring Consumer Surplus with the Demand Curve.,P,50,70,80,0,$100,1,2,3,4,Q,用需求曲线衡量消费者剩余 Measuring Consumer Surplus with the Demand Curve.,在任何一种数量下,需求曲线给出的价格(需求曲线的高度)表示边际买者的支付意愿;边际买者是如果价格再高一点,就首先离开的买者。 At any quantity, the price given by the demand curve shows the willingness to pay
10、of the marginal buyer, the buyer who would leave the market first if the price were any higher. 由于需求曲线反应了买者的支付意愿,我们可以用它衡量消费者剩余。 Because the demand curve reflects buyers Willingness to pay, we can also use it to measure consumer surplus.,Price of Album,50,70,80,0,$100,1,2,3,4,Quantity of Albums,Deman
11、d,Price = $80,用需求曲线衡量消费者剩余 Measuring Consumer Surplus with the Demand Curve.,Price of Album,50,70,80,0,$100,1,2,3,4,Quantity of Albums,Demand,Price = $70,用需求曲线衡量消费者剩余 Measuring Consumer Surplus with the Demand Curve.,用需求曲线衡量消费者剩余Measuring Consumer Surplus with the Demand Curve,需求曲线以下和价格以上的面积衡量市场的消费者
12、剩余。 The area below the demand curve and above the price measures the consumer surplus in the market.,Quantity,Price,0,Demand,原来的 消费者剩余,价格如何影响消费者剩余 How the Price Affects Consumer Surplus,消费者剩余与经济福利 Consumer Surplus and Economic Well-Being,消费者剩余,即买者愿意为一种物品支付的金额减他们实际支付的金额,衡量了消费者从一种物品中得到的买者自己感觉到的收益。 Con
13、sumer surplus, the amount that buyers are willing to pay for a good minus the amount they actually pay for it, measures the benefit that buyers receive from a good as the buyers themselves perceive it.,生产者剩余 Producer Surplus,生产者剩余:卖者出售一种物品得到的金额减去卖者的成本。 Producer surplus is the amount a seller is paid
14、 minus the cost of production. 它衡量了卖者参与市场得到的收益。 It measures the benefit to sellers participating in a market.,四个可能卖者的成本 The Costs of Four Possible Sellers.,生产者剩余与供给曲线 Producer Surplus and the Supply Curve,正如消费者剩余与需求曲线密切相关,生产者剩余也与供给曲线密切相关。 Just as consumer surplus is related to the demand curve, prod
15、ucer surplus is closely related to the supply curve. 在任何一种数量上,供给曲线给出的价格表示边际卖者的成本,这个边际卖者是如果价格再略低一点就首先离开市场的卖者。 At any quantity, the price given by the supply curve shows the cost of the marginal seller, the seller who would leave the market first if the price were any lower.,四个卖者的供给量 Supply Schedule f
16、or the Four Possible Sellers,生产者剩余和供给曲线 Producer Surplus and the Supply Curve.,Quantity of Houses Painted,Price of House Painting,500,800,$900,0,600,1,2,3,4,Supply,供给曲线以上和价格以下的面积衡量市场的生产者剩余。 The area below the price and above the supply curve measures the producer surplus in a market.,生产者剩余与供给曲线 Prod
17、ucer Surplus and the Supply Curve,用供给曲线衡量生产者剩余 Measuring Producer Surplus with the Supply Curve.,Quantity of Houses Painted,Price of House Painting,500,800,$900,0,600,1,2,3,4,Supply,Price = $600,用供给曲线衡量生产者剩余 Measuring Producer Surplus with the Supply Curve.,Quantity of Houses Painted,Price of House
18、Painting,500,800,$900,0,600,1,2,3,4,Supply,Price = $800,Quantity,Price,0,Supply,原先的生产者剩余,价格如何影响生产者剩余 How Price Affects Producer Surplus.,市场均衡的评价 Evaluating the Market Equilibrium,Price,均衡价格 Equilibrium price,0,Quantity,均衡数量 Equilibrium quantity,A,Supply,C,B,Demand,D,E,市场均衡时的消费者与生产者剩余 Consumer and Pr
19、oducer Surplus in the Market Equilibrium,Price,均衡价格,0,Quantity,均衡数量,A,Supply,C,B,Demand,D,E,生产者剩余,消费者剩余,市场效率 Market Efficiency,消费者剩余和生产者剩余可以用来回答下列问题:由自由市场决定的资源配置从某种意义上来说是令人满意的配置吗? Consumer surplus and producer surplus may be used to address the following question: Is the allocation of resources dete
20、rmined by free markets in any way desirable?,经济福利与总剩余 Economic Well-Being and Total Surplus,and,经济福利与总剩余 Economic Well-Being and Total Surplus,or,效率 Efficiency,当资源配置使总剩余最大化时,我们说,这种配置达到效率。 Efficiency is achieved when the allocation of resources maximizes total surplus.,如果你是一个仁慈的社会计划者, 你将进行怎样的配置以达到效率?
21、,效率 Efficiency,条件1:在给定的数量下,一种物品的分配使得它: 由最低成本的那些卖者来生产; 由最高评价(支付意愿)的那些买者来消费 条件2:给定上述的分配方案,该物品的数量是使得总剩余最大的数量。,有效率的配置 Efficient Allocation,评价/成本,0,Quantity,有效率数量,卖者成本曲线,买者评价曲线,卖者的成本,买者的评价,买者的评价,卖者的成本,买者的评价大于卖者的成本,买者的评价小于卖者的成本,有效率的配置 Efficient Allocation,市场均衡是有效率的 Market Equilibrium is Efficient,关于市场运行结果
22、的三大结论 Three Insights Concerning Market Outcomes,自由市场把物品的供给分配给对这些物品评价最高的买者。 Free markets allocate the supply of goods to the buyers who value them most highly. 自由市场把物品的需求分配给可以以最低成本生产这些物品的卖者。 Free markets allocate the demand for goods to the sellers who can produce them at least cost. 自由市场的总生产量使消费者和生产
23、者剩余最大化 Free markets produce the quantity of goods that maximizes the sum of consumer and producer surplus.,这三个关于市场结果的观点告诉我们,供求均衡使消费者与生产者剩余之和最大化。换句话说,均衡结果是资源的有效配置。 现在我们可以更好地评价我们在第1章中讨论的亚当斯密的市场这只看不见的手。看不见的手指导了使买者与卖者总剩余最大化的经济资源配置。这个结论解释了经济学家通常支持自由市场是组织经济活动的最好方法的原因。,无效率与贸易 Inefficiency and Trade,如果一种配置是
24、无效率的,那么,买者或卖者内部、买者和卖者之间的贸易好处就还没有完全实现。 If an allocation is not efficient, then some of the gains from trade among buyers and sellers are not being realized. 市场配置是有效率的,因为它实现了所有的贸易好处。,市场的有效率性 The Efficiency of the Market,因为市场均衡时的资源配置是有效率的,社会计划者可以让市场自己找出结果。 Because the equilibrium outcome is an efficien
25、t allocation of resources, the social planner can leave the market outcome as he/she finds it. 这种完全放开的政策可以用法语自由放任来表述。 This policy of leaving well enough alone goes by the French expression laissez faire. 亚当.斯密:市场是只看不见的手 原理之六:市场通常是组织经济活动的好方式,效率与平等 Efficiency and Equity,除了效率之外,社会计划者也会关心平等在不同的买者和卖者之间福利
26、分配的公平性。 In addition to market efficiency, a social planner might also care about equity the fairness of the distribution of well-being among the various buyers and sellers.,例子:倒卖门票 Example: Ticket Scalping,如果一个经济能有效地配置其稀缺资源,物品必须给与对此评价最高的那些消费者。倒卖门票是市场如何实现有效结果的一个例子 If an economy is to allocate its sca
27、rce resources efficiently, goods must get to those consumers who value them most highly. Ticket scalping is one example of how markets reach efficient outcomes.,例子:倒卖门票 Example: Ticket Scalping,倒票者购买戏剧、音乐会和运动会的门票,并以高出他们原来成本的价格卖出这些票。通过收取市场可以承受的最高价格,倒票者有助于保证对门票支付意愿最高的人实际上得到这些票。 Scalpers buy tickets to
28、 plays, concerts, and sports events and then sell the tickets at a price above their original cost. By charging the highest price the market will bear, scalpers help ensure that consumers with the greatest willingness to pay for the tickets actually do get them.,警告:假设的作用 Warning: Assumptions,为了得出市场有
29、效率的结论,我们作出了一些关于市场如何运行的假设。 当这些假设不成立的时候,关于市场均衡有效率的结论可能就不成立了。 两个重要的假设 市场是完全竞争的,即不存在市场势力。(Market power) 市场结果只与买者和卖者相关,即无外部性(externalities) 。 市场失灵(market failures) :自由的市场不能有效率地配置资源。,为什么关于市场有效率的模型 如此重要,尽管假设与现实会有距离,当这些假设成立的时候,关于市场均衡有效率的结论成立 即使在现实中这些假设不完全成立,它仍然为我们分析问题提供了一个基准或标尺(benchmark)或称参照系(reference) 有了
30、这一基准或标尺,我们对现实的进一步分析就有力量。 比如对市场势力和外部性情况的分析。,市场势力 Market Power,如果市场不完全竞争,市场势力便形成。 If a market system is not perfectly competitive, market power may result. 市场势力是影响价格的能力。 Market power is the ability to influence prices. 市场势力可以使市场无效率,因为它会使价格和数量偏离供求均衡点。 Market power can cause markets to be inefficient be
31、cause it keeps price and quantity from the equilibrium of supply and demand.,外部性 Externalities,当市场的结果影响了买者和卖者以外的人时,产生外部性 Externalities are created when a market outcome affects individuals other than buyers and sellers in that market. 外部性使市场福利还要取决于买者评价和卖者评价之外的其他因素。 Externalities cause welfare in a m
32、arket to depend on more than just the value to the buyers and cost to the sellers. 当买者和卖者在决定消费和生产时不考虑外部性的时候,市场均衡可能是无效率的。 When buyers and sellers do not take externalities into account when deciding how much to consume and produce the equilibrium in the market can be inefficient.,总结 Summary,消费者剩余衡量买者
33、参与市场的收益。 Consumer surplus measures the benefit buyers get from participating in a market. 消费者剩余可以通过找出需求曲线以下和价格以上的面积来计算。 Consumer surplus can be computed by finding the area below the demand curve and above the price.,总结 Summary,生产者剩余衡量卖者参与市场的收益。 Producer surplus measures the benefit sellers get from
34、 participating in a market. 生产者剩余可以通过找出价格以下和供给曲线以上的面积来计算。 Producer surplus can be computed by finding the area below the price and above the supply curve.,总结 Summary,使消费者与生产者剩余的总和最大化的资源配置被称为是有效率的资源配置。 An allocation of resources that maximizes the sum of consumer and producer surplus is said to be ef
35、ficient. 政策制定者通常关心经济的效率问题,但同时也关心平等问题。 Policymakers are often concerned with the efficiency, as well as the equity, of economic outcomes.,总结 Summary,供给与需求的均衡最大化消费者与生产者剩余之和 The equilibrium of demand and supply maximizes the sum of consumer and producer surplus. 就好象市场这只看不见的手在指引买者和卖者在有效率地配置资源。 This is as if the invisible hand of the marketplace leads buyers and sellers to allocate resources efficiently. 当有市场势力和外部性时,市场不能有效率地配置资源。 Markets do not allocate resources efficiently in the presence of market power or externalities.,案例解读七,运用消费者剩余理论学会杀价,精品课件资料分享,SL出品,
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