7消费者生产者与生产效率英文版课件

,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,*, 2015 CUFE,C H A P T E R,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,Consumers, Producers, and the Efficiency of Markets,7,消费者、生产者与市场效率,In this chapter, look for the answers to these questions:,What is consumer surplus (,消费者剩余,)? How is it related to the demand curve?,What is producer surplus,（生产者剩余）,? How is it related to the supply curve?,Do markets produce a desirable allocation of resources,（市场配置资源的合意配置）,? Or could the market outcome be improved upon?,1,Some normative questions,The consumers hope for a lower price all the time, and the producers hope for a higher price. Should the price be lower or higher? What is the “good” price?,What is the proper way to use the resource? Who should consume more goods? Is clearance,（出清）,the best result of market?,What is the value of the market?,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,2,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,3,Is market economy good?,The,allocation of resources,（资源配置）,refers to:,how much of each good is produced,which producers produce it,which consumers consume it,In market economies, the forces of supply and demand determine the prices of goods and services and the quantities sold.,The market could clear by itself, but is it a good result?,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,4,Welfare Economics,福利经济学,Welfare economics,studies,how,the allocation of resources affects economic well-being,（经济福利）,.,What benefits do the buyers and sellers get from taking part in a market?,What are the total benefits of the market?,How society can make these benefits as large as possible?,A profound conclusion: The equilibrium of supply and demand in a market maximizes the total benefits received by buyers and sellers.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,5,Willingness to Pay and Value,买者的支付意愿和价值,A buyers,willingness to pay (WTP),for a good is the maximum amount the buyer will pay for that good.,WTP measures how much the buyer values the good.,name,WTP,Anthony,安东尼,$250,Chad,查德,175,Flea,300,John,125,Example: 4 buyers WTP for an iPod,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,6,WTP and the Demand Curve,Q:,If price of iPod is $200, who will buy an iPod, and what is quantity demanded?,A:,Anthony & Flea will buy an iPod, Chad & John will not.,Hence,Q,d,= 2 when,P,= $200.,name,WTP,Anthony,$250,Chad,175,Flea,300,John,125,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,7,WTP and the Demand Curve,Derive the demand schedule:,4,John, Chad, Anthony, Flea,0 125,3,Chad, Anthony, Flea,126 175,2,Anthony, Flea,176 250,1,Flea,251 300,0,nobody,$301 & up,Q,d,who buys,P,(price of iPod),name,WTP,Anthony,$250,Chad,175,Flea,300,John,125,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,8,WTP and the Demand Curve,P,Q,d,$301 & up,0,251 300,1,176 250,2,126 175,3,0 125,4,P,Q,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,9,About the Staircase Shape,This,D,curve looks like a staircase with 4 steps one per buyer.,P,Q,If there were a huge # of buyers, as in a competitive market,there would be a huge # of very tiny steps,and it would look more like a smooth curve.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,10,WTP and the Demand Curve,At any,Q, the height of the,D,curve is the WTP of the,marginal buyer,边际购买者,the buyer who would leave the market if,P,were any higher.,P,Q,Fleas WTP,Anthonys WTP,Chads WTP,Johns WTP,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,11,Consumer Surplus (CS),消费者剩余,Consumer surplus,is the amount a buyer is willing to pay minus the amount the buyer actually pays:,CS = WTP ,P,name,WTP,Anthony,$250,Chad,175,Flea,300,John,125,Suppose,P,= $260.,Fleas CS = $300 260 = $40.,The others get no CS because they do not buy an iPod at this price.,Total CS = $40.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,12,CS and the Demand Curve,P,Q,Fleas WTP,P,= $260,Fleas CS = $300 260 =,$40,Total CS =,$40,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,13,CS and the Demand Curve,P,Q,Fleas WTP,Anthonys WTP,Instead, suppose,P,= $220,Fleas CS = $300 220 =,$80,Anthonys CS =$250 220 =,$30,Total CS =,$110,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,14,CS and the Demand Curve,P,Q,The lesson:,Total CS equals the area under the demand curve above the price, from 0 to,Q,.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,15,P,Q,$,CS with Lots of Buyers & a Smooth D Curve,The demand for shoes,D,1000s of pairs of shoes,Price per pair,At,Q,= 5(thousand), the marginal buyer is willing to pay $50 for pair of shoes.,Suppose,P,= $30.,Then his consumer surplus = $20.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,16,P,Q,CS with Lots of Buyers & a Smooth D Curve,The demand for shoes,D,CS is the area b/w,P,and the,D,curve, from 0 to,Q,.,Recall: area of a triangle equals x base x height,Height =$60 30 =,$30,.,So, CS = x 15 x $30 =,$225,.,h,$,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,17,P,Q,How a Higher Price Reduces CS,D,If,P,rises to $40,CS = x 10 x $20 = $100.,Two reasons for the fall in CS.,1. Fall in CS due to buyers leaving market,2. Fall in CS due to remaining buyers paying higher,P,Some notes on CS,The CS equals to WTP minus the actual pay. it measures the benefit that buyers receive from a good as the buyers themselves perceive it.,消费者剩余，,即买者愿意为一种物品支付的量减他们实际支付的量，衡量了消费者从一种物品中得到的买者自己感觉到的利益。,CS is a good measure if preferences of buyers should be respected all the time.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,18,But, sometimes, the WTP (perceived value,感知 价值,) may be different from the real value. The CS is not a good measure in this case.,In most case, especially under the rational assumption, CS works quite well.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,19,20,P,Q,demand curve,A.,Find marginal buyers WTP at,Q,= 10.,B.,Find CS for,P,= $30.,Suppose,P,falls to $20.How much will CS increase due to,C.,buyers entering the market,D.,existing buyers paying lower price,$,A C T I V E L E A R N I N G,1,Consumer surplus,A C T I V E L E A R N I N G,1,Answers,21,P,$,Q,demand curve,A.,At,Q,= 10, marginal buyers WTP is,$30,.,B.,CS = x 10 x $10 =,$50,P,falls to $20.,C.,CS for the additional buyers = x 10 x $10 =,$50,D.,Increase in CS on initial 10 units= 10 x $10 =,$100,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,22,Cost and the Supply Curve,name,cost,Jack,杰克,$10,Janet,珍妮特,20,Chrissy,克丽希,35,A seller will produce and sell the good/service only if the price exceeds his or her cost.,Hence, cost is a measure of willingness to sell.,Cost,is the value of everything a seller must give up to produce a good (,i.e., opportunity cost).,Includes cost of all resources used to produce good, including value of the sellers time.,Example: Costs of 3 sellers in the lawn-cutting,（修草）,business.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,23,Cost and the Supply Curve,3,35 & up,2,20 34,1,10 19,0,$0 9,Q,s,P,Derive the supply schedule from the cost data:,name,cost,Jack,$10,Janet,20,Chrissy,35,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,24,Cost and the Supply Curve,P,Q,P,Q,s,$0 9,0,10 19,1,20 34,2,35 & up,3,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,25,Cost and the Supply Curve,P,Q,At each,Q, the height of the,S,curve is the cost of the,marginal seller,（边际卖家）, the seller who would leave the market if the price were any lower.,Chrissys cost,Janets cost,Jacks cost,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,26,Producer Surplus,生产者剩余,P,Q,Producer surplus,(PS): the amount a seller is paid for a good minus the sellers cost,生产者剩余,卖者得到的量减去卖者的成本。,PS =,P, cost,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,27,Producer Surplus and the S Curve,P,Q,Suppose,P,= $25.,Jacks PS = $15,Janets PS = $5,Chrissys PS = $0,Total PS = $20,Janets,珍妮特,cost,Jacks,杰克,cost,Total PS equals the area above the supply curve under the price, from 0 to,Q,.,Chrissys,克丽希,cost,PS =,P, cost,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,28,P,Q,PS with Lots of Sellers & a Smooth S Curve,The supply of shoes,S,1000s of pairs of shoes,Price per pair,Suppose,P,= $40.,At,Q,= 15(thousand), the marginal sellers cost is $30,and her producer surplus is $10.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,29,P,Q,PS with Lots of Sellers & a Smooth S Curve,The supply of shoes,S,PS is the area b/w,P,and the,S,curve, from 0 to,Q,.,The height of this triangle is $40 15 = $25.,So, PS = x,b,x,h,= x 25 x $25 =,$312.50,h,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,30,P,Q,How a Lower Price Reduces PS,If,P,falls to $30,PS = x 15 x $15 =,$112.50,Two reasons for the fall in PS.,S,1. Fall in PS due to sellers leaving market,2. Fall in PS due to remaining sellersgetting lower,P,P,Q,supply curve,A.,Find marginal sellers cost at,Q,= 10.,B.,Find total PS for,P,= $20.,Suppose,P,rises to $30.Find the increase in PS due to,C.,selling 5 additional units,D.,getting a higher price on the initial 10 units,31,A C T I V E L E A R N I N G,2,Producer surplus,A C T I V E L E A R N I N G,2,Answers,P,Q,supply curve,A.,At,Q,= 10,marginal cost =,$20,B.,PS = x 10 x $20 =,$100,P,rises to $30.,C.,PS on additional units= x 5 x $10 =,$25,D.,Increase in PS on initial 10 units= 10 x $10 =,$100,32,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,33,CS, PS, and Total Surplus,消费者剩余，生产者剩余，总剩余,CS = (value to buyers) (amount paid by buyers),= buyers gains from participating in the market,PS = (amount received by sellers) (cost to sellers),= sellers gains from participating in the market,Total surplus,= CS + PS,= total gains from trade in a market,= (value to buyers) (cost to sellers),CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,34,P,Q,$,D,S,CS of single buyer,PS of single seller,CS of all buyers,PS of all sellers,Surplus of the market,CS, PS, and Total Surplus,消费者剩余，生产者剩余，总剩余,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,35,The Markets Allocation of Resources,In a market economy, the allocation of resources is decentralized,（,权力下放,）, determined by the interactions of many self-interested buyers and sellers.,Is the markets allocation of resources desirable,（合意）,? Or would a different allocation of resources make society better off?,To answer this, we use total surplus as a measure of societys well-being, and we consider whether the markets allocation is,efficient,.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,36,The Benevolent Social Planner,好心的社会管理者,The benevolent social planner is an all-knowing,（全知）, all-powerful,（全能）, well-intentioned dictator,（目标明确的独裁者）,. The planner wants to maximize the economic well-being of everyone in society.,To achieve the aim, the planner must first decide how to measure the economic well-being of a society.,One possible measure is the sum of consumer and producer surplus, which we call total surplus.,the social planner might also care about,equality, though the focus here is on,efficiency.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,37,Efficiency,An allocation of resources is,efficient,if it maximizes total surplus. Efficiency means:,The goods are consumed by the buyers who value them most highly.,The goods are produced by the producers with the lowest costs.,Raising or lowering the quantity of a good would not increase total surplus.,= (value to buyers) (cost to sellers),Total surplus,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,38,Evaluating the Market Equilibrium,Market eqm:,P,= $30,Q,= 15,000,Total surplus = CS + PS,Is the market eqm efficient?,P,Q,S,D,CS,PS,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,39,Which Buyers Consume the Good?,P,Q,S,D,Every buyer whose WTP is $30 will buy.,Every buyer whose WTP is $30 will not.,So,the sellers with the lowest cost produce the good.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,41,Does Eqm,Q,Maximize Total Surplus?,P,Q,S,D,At,Q,= 20, cost of producing the marginal unit is $35,value to consumers of the marginal unit is only $20,Hence, can increase total surplus by reducing,Q,.,This is true at any,Q,greater than 15.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,42,Does Eqm,Q,Maximize Total Surplus?,P,Q,S,D,At,Q,= 10, cost of producing the marginal unit is $25,value to consumers of the marginal unit is $40,Hence, can increase total surplus by increasing,Q,.,This is true at any,Q,less than 15.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,43,Does Eqm,Q,Maximize Total Surplus?,P,Q,S,D,The market eqm quantity maximizes total surplus:At any other quantity, can increase total surplus by moving toward the market eqm quantity.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,44,Price,0,Quantity,Equilibrium,quantity,Supply,Demand,Cost to sellers,Value to buyers,Value to buyers,Cost to sellers,Value to buyers is greater than cost to sellers.,Value to buyers is less than cost to sellers.,The Efficiency of the Equilibrium Quantity,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,45,Adam Smith and the Invisible Hand,“Man has almost constant occasion for the help of his brethren, and it is vain for him to expect it from their benevolence only.,Adam Smith, 1723-1790,Passages from,The Wealth of Nations, 1776,He will be more likely to prevail if he can interest their self-love in his favor, and show them that it is for their own advantage to do for him what he requires of them,It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,46,Adam Smith and the Invisible Hand,“Every individualneither intends to promote the public interest, nor knows how much he is promoting it.,Adam Smith, 1723-1790,Passages from,The Wealth of Nations, 1776,He intends only his own gain, and he is in this, as in many other cases, led by,an invisible hand,to promote an end which was no part of his intention.,Nor is it always the worse for the society that it was no part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it.”,an invisible hand,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,47,The Free Market vs. Govt Intervention,自由市场,Vs.,政府干预,The market equilibrium is efficient. No other outcome achieves higher total surplus.,Govt cannot raise total surplus by changing the markets allocation of resources.,Laissez faire,(French for “allow them to do”),自由主义,:,the notion that govt should not interfere with (,干预,) the market.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,48,The Free Market vs. Central Planning,自由市场,Vs.,中央计划,Suppose resources were allocated not by the market, but by a central planner who cares about societys well-being.,To allocate resources efficiently and maximize total surplus, the planner would need to know every sellers cost and every buyers WTP for every good in the entire economy.,This is impossible, and why centrally-planned economies are never very efficient.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,49,Discuss:,Should There be a Market in Organs,（,器官,）,?,On April 12, 2001, the front page of the Boston Globe ran the headline “How a Mothers Love Helped Save Two Lives.”,A woman whose named Susan Stephens has a son who needs a kidney transplant. When the doctor learned that the mothers kidney was not compatible,（不相容）, he proposed a novel solution: If Stephens donated one of her kidneys to a stranger, her son would move to the top of the kidney waiting list. The mother accepted the deal, and soon two patients had the transplant they were waiting for.,If the mother could trade a kidney for a kidney, would the hospital allow her to trade a kidney for something else?,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,50,Case study,Strong Booze: Criminal Incentives,烈酒：犯罪激励,During 1920s Prohibition, the sell, manufacture, and transportation of alcohol were restricted or illegal.,Prohibition was supposed to lower crime and corruption, reduce social problems, lower taxes needed to support prisons and poorhouses, and improve health and hygiene,（卫生学）,in America.,But it turns out that alcohol became more dangerous to consume; organized crime blossomed,（涌现）,; courts and prisons systems became overloaded; and endemic corruption,（地区腐败）,of police and public officials occurred.,Why did the prohibition of the 1920s fail?,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,51,CONCLUSION,This chapter used welfare economics to demonstrate one of the Ten Principles:,Markets are usually a good way to organize economic activity.,Important note: We derived these lessons assuming perfectly competitive markets,（,完全竞争市场,）,.,In other conditions we will study in later chapters, the market may fail to allocate resources efficiently,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,52,CONCLUSION,Such market failures occur when:,A buyer or seller has,market power,（,市场势力,）, the ability to affect the market price.,Transactions have side effects, called,externalities,（外部性）, that affect bystanders. (example: pollution),One side of the traders doesnt have enough information about the goods,Well use welfare economics to see how public policy may improve on the market outcome in such cases.,Despite the possibility of market failure, the analysis in this chapter applies in many markets, and the invisible hand remains extremely important.,Exercise,1. If a buyers willingness to pay for a new Honda is $20,000 and she is able to actually buy it for $18,000, her consumer surplus is,a. $0.,b. $2,000.,c. $18,000.,d. $20,000.,e. $38,000.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,53,2. In general, if a benevolent social planner wanted to maximize the total benefits received by buyers and sellers in a market, the planner should,a. choose a price above the market equilibrium price.,b. choose a price below the market equilibrium price.,c. allow the market to seek equilibrium on its own.,d. choose any price the planner wants.,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,54,Exercise,3. Suppose that the price of a new bicycle is $300. Sue values a new bicycle at $400. It costs $200 for the seller to produce the new bicycle. What is the value of total surplus if Sue buys a new bike?,a. $100,b. $200,c. $300,d. $400,e. $500,CONSUMERS, PRODUCERS, AND THE EFFICIENCY OF MARKETS,55,Exercise,CHAPTER SUMMARY,The height of the,D,curve reflects the value of the good to buyerstheir,willingness to pay,for it.,Consumer surplus,is the difference between what buyers are willing to pay for a good and what they actually pay.,On the graph, consumer surplus is the area between,P,and the,D,curve.,56,CHAPTER SUMMARY,The height of the,S,curve is sellers,cost,of producing the good. Sellers are willing to sell if the price they get is at least as high as their cost.,Producer surplus,is the difference between what sellers receive for a good and their cost of producing it.,On the graph, producer surplus is the area between,P,and the,S,curve.,57,CHAPTER SUMMARY,To measure of societys well-being, we use,total surplus, the sum of consumer and p