经济学原理双语PPT06

1、Supply, Demand and Government PoliciesChapter 6供给、需求与政府政策供给、需求与政府政策Supply, Demand, and GovernmentPolicies在自由的、无管制的市场中，市场的力量建立均衡价格，决定交换的数量In a free, unregulated market system, market forces establish equilibrium prices and exchange quantities.虽然均衡的状态是有效率的，但也许并非使每人都满意。While equilibrium conditions may

2、be efficient, it may be true that not everyone is satisfied.经济学家的作用之一是运用他们的理论帮助制定政府政策。One of the roles of economists is to use their theories to assist in the development of policies.价格控制Price Controls.实行价格控制通常是政府相信市场价格对买方或卖方不公平。Are usually enacted when policymakers believe the market price is unfai

3、r to buyers or sellers.两种价格控制：价格上限和价格下限Result in government-created price ceilings and floors.常常引发事与愿违的结果（效率和公平损失）经济分析的重要性：供给和需求工具价格上限与价格下限Price Ceilings & Price Floors价格上限（Price Ceiling ）法定最高价格A legally established maximum price at which agood can be sold.价格下限（Price Floor）法定最低价格A legally establishe

4、d minimum price at which agood can be sold.价格上限Price Ceilings 政府实行价格上限时有两种可能结果 Two outcomes are possible when the government imposes a price ceiling:当价格上限高于均衡价格时，价格上限没有限制性The price ceiling is not binding if set above the equilibrium price.当价格上限低于均衡价格时，价格上限有限制性 The price ceiling is binding if set bel

5、ow the equilibrium price, leading to a shortage.没有限制作用的价格上限A Price Ceiling That Is Not Binding.$43Quantity ofIce-CreamCones0Price ofIce-CreamConeDemandSupplyPriceceilingEquilibriumprice100EquilibriumquantityHarcourt, Inc. items and derived items copyright 2001 by Harcourt, Inc.有限制作用的价格上限A Price Ceil

6、ing That Is Binding.$3Quantity ofIce-CreamCones0Price ofIce-CreamCone2DemandSupplyEquilibriumpricePriceceilingShortage125Quantitydemanded75QuantitysuppliedHarcourt, Inc. items and derived items copyright 2001 by Harcourt, Inc.实行价格上限的结果(1)Effects of Price Ceilings有限制作用的价格上限导致短缺A binding price ceiling

7、 creates shortages因为需求量大于供给量because QD QS.举例： 70年代：食品 80年代：原材料（如钢铁） 90年代：发售原始股实行价格上限的结果(2)Effects of Price Ceilings有限制作用的价格上限导致配给A binding price ceiling creates rationing因为有短缺Because of shortage举例： 排队queuing 卖者对买者的歧视discrimination 发票凭证coupons “走后门going through a “back door”谁应该对排长队负责？谁应该对走后门负责？ 经济学认为

8、是政府的价格控制政策Economists blame government pricecontrols that limited the price the sellercould charge.Lines at the Gas PumpIn 1973 OPEC raised the price of crude oil in world markets. Because crude oil is the major input used to make gasoline, the higher oil prices reduced the supply of gasoline.What wa

9、s responsible for the long gas lines?Economists blame government regulations that limited the price oil companies could charge for gasoline.价格上限没有限制性The Price Ceiling on Gasoline Is Not Binding$4P1Quantity ofGasoline0Price ofGasolineQ1DemandSupplyPriceceiling1. Initially, the price ceiling is not bi

10、nding.价格上限变为有限制性The Price Ceiling on Gasoline Is BindingP1Quantity ofGasoline0Price ofGasolineQ1DemandS1PriceceilingS22. but when supply falls.P23. the price ceiling becomes binding.4. resulting in a shortage.房租控制Rent Control房租控制是指房主出租房屋时所收房租的上限。Rent controls are ceilings placed on the rentsthat lan

11、dlords may charge their tenants.房租控制的目的帮助穷人，使他们能负得起房租。The goal of rent control policy is to help thepoor by making housing more affordable.一名经济学家称房租控制是“除了炸弹外摧毁一座城市的最好的方法”One economist called rent control “the best way to destroy a city, other than bombing.”房租控制在短期内的结果Rent Control in the Short Run.Qu

12、antity ofApartments0Rental Price ofApartmentDemandSupplyControlled rentShortageSupply and demand for apartments are relatively inelastic房租控制在长期内的结果Rent Control in the Long Run.Quantity ofApartments0Rental Price ofApartmentDemandSupplyControlled rentShortageBecause the supply and demand for apartment

13、s are more elastic.rent control causes a large shortage价格下限Price Floors政府实行价格下限时有两种可能结果When the government imposes a price floor, two outcomes are possible.当价格下限低于均衡价格时，价格下限没有限制性。The price floor is not binding if set below the equilibrium price.当价格下限高于均衡价格时，价格下限有限制性导致过剩。The price floor is binding if

14、 set above the equilibriumprice, leading to a surplus.没有限制作用的价格下限A Price Floor That Is Not Binding.$3Quantity ofIce-CreamCones0Price ofIce-CreamCone100EquilibriumquantityEquilibriumpriceDemandSupplyPricefloor2有限制作用的价格下限A Price Floor That Is Binding.$3Quantity ofIce-CreamCones0Price ofIce-CreamConeEq

15、uilibriumpriceDemandSupplyPrice floor$4120Quantitysupplied80QuantitydemandedSurplusHarcourt, Inc. items and derived items copyright 2001 by Harcourt, Inc.实行价格下限的结果Effects of a Price Floor价格下限阻止供给和需求向均衡价格和数量移动A price floor prevents supply and demand from moving toward the equilibrium price and quanti

16、ty.市场价格最多降到价格下限When the market price hits the floor, it can fall no further, and the market price equals the floor price.实行价格下限的结果Effects of a Price Floor有限制作用的价格下限导致过剩因为供给量大于需求量。A binding price floor causes a surplus because QSQD.非价格的配给机制：使用歧视性标准配给物品nonprice rationing is an alternative mechanism fo

17、rrationing the good, using discrimination criteria.例子：最低工资、农产品保护价格Examples: The minimum wage Agricultural price supports最低工资The Minimum Wage价格下限的一个重要例子是最低工资An important example of a price floor is the minimum wage.最低工资法规定任何雇主必须支付受雇者的最低价格Minimum wage laws dictate the lowest price possible for labor t

18、hat any employer may pay.最低工资The Minimum WageQuantity ofLabor0WageEquilibriumwageLabor demandLabor supplyA Free Labor MarketEquilibriumemploymentMinimumwage最低工资The Minimum WageQuantity ofLabor0WageLabor demandLabor supplyQuantitysuppliedQuantitydemandedLabor surplus(unemployment)A Labor Market with

19、a Minimum Wage税收Taxes政府用征税方式来为公共项目筹款Governments levy taxes to raise revenue for public projects.税收Taxes税收归宿(负担)研究谁承受税收负担Tax incidence is the study of who bears the burden of a tax. 税收改变市场均衡Taxes result in a change in market equilibrium.不管向谁征税，税收总使得买者付出更多而卖者得到更少Buyers pay more and sellers receive les

20、s, regardless of whom the tax is levied on.向买者征税的结果Impact of a 50 Tax Levied on Buyers.3.00Quantity ofIce-Cream Cones0Price ofIce-CreamCone100D1Supply, S1A tax on buyersshifts the demandcurve downwardby the size ofthe tax ($0.50).D2Copyright 2001 by Harcourt, Inc. All rights reserved3.00Quantity ofI

21、ce-Cream Cones0Price ofIce-CreamCone10090$3.30PricebuyerspayD1D2Equilibriumwith taxSupply, S1Equilibrium without tax向买者征税的结果Impact of a 50 Tax Levied on Buyers.2.80PricesellersreceiveCopyright 2001 by Harcourt, Inc. All rights reservedPricewithouttax Tax ($0.50)税收的影响是什么？What was the impact of tax?税收

22、抑制市场活动Taxes discourage marketactivity.一个商品被征税，销售量减小When a good is taxed, thequantity sold is smaller.买卖双方都承担税收负担Buyers and sellers sharethe tax burden.3.00Quantity ofIce-Cream Cones0Price ofIce-CreamCone10090S1S2Demand, D1向卖者征税的结果Impact of a 50 Tax on Sellers.Price without tax2.80Price sellers recei

23、ve$3.30Price buyers payEquilibrium without taxCopyright 2001 by Harcourt, Inc. All rights reservedA tax on sellers shifts the supply curve upward by the amount of the tax ($0.50). Tax ($0.50)Equilibriumwith tax比较向买者征税和向卖者征税的结果Compare the effects of taxes onsellers with those on buyers?对买者征税和对卖者征税结果是

24、相同的！ 买者和卖者分摊税收负担 对买者征税和对卖者征税的唯一差别是谁把钱交给政府。A Payroll TaxQuantity ofLabor0WageWage without taxLabor demandLabor supplyTax wedgeWage firms payWage workers receive税收负担The Incidence of Tax税收负担在买者和卖者间是按何种比例划分的？In what proportions is the burden of the tax divided?答案取决于需求弹性和供给弹性The answers to these question

25、s depend on the elasticity of demand and the elasticity of supply.富有弹性的供给、缺乏弹性的需求Elastic Supply, Inelastic Demand.Quantity0PriceDemandSupplyTax1. When supply is moreelastic than demand.2. .theincidence of thetax falls moreheavily onconsumers.3. .than onproducers.Price without taxPrice buyers payPric

26、e sellers receive缺乏弹性的供给、富有弹性的需求Inelastic Supply, Elastic Demand.Quantity0PriceDemandSupplyPrice without taxTax1. When demand is moreelastic than supply.2. .theincidence of the tax falls more heavily on producers.3. .than on consumers.Price buyers payPrice sellers receive税收负担是如何划分的？So, how is the bu

27、rden of thetax divided?税收负担更多地落在缺乏弹性的市场一方The burden of a taxfalls more heavily onthe side of themarket that is lesselastic. 为什么？ Why?弹性是衡量当条件变得不利时，买者或卖者离开市场的意愿。当征税时，不能轻而易举离开市场的一方承担更多的税收负担。举例：工薪税与社会保障Payroll Tax and Social Security 工薪税在雇员和企业之间的税收负担的划分与法律规定的划分（比如平摊）无关。 因为劳动的供给远比劳动的需求缺乏弹性。 所以雇员而不是企业承担了大部分工薪税的负担。举例：谁支付奢侈品税？Who Pays Taxes on Luxury Goods?对奢侈品征税似乎是向富人征税的有效方式。 但是，因为对某一奢侈品的需求极富弹性，但供应在短期内缺乏弹性 所以，税收负担主要落在生产者（企业和工人）身上。 事与愿违：奢侈品税的负担落在中产阶级身上比富人身上要多。 总结 Summary价