lecture03市场福利分析

©2007ThomsonSouth-WesternLecturethreeMarketandWelfare©2007ThomsonSouth-Western消费者、生产者与市场效率©2007ThomsonSouth-WesternConsumers,ProducersandtheEfficiencyofMarkets•RevisitingtheMarketEquilibrium–Dotheequilibriumpriceandquantitymaximizethetotalwelfareofbuyersandsellers?–Marketequilibriumreflectsthewaymarketsallocatescarceresources.–Whetherthemarketallocationisdesirablecanbeaddressedbywelfareeconomics.©2007ThomsonSouth-Western消费者、生产者与市场效率•回顾市场均衡–市场均衡价格和数量能否使买者和卖者的总利益最大化？•市场均衡反映了市场配置稀缺资源的方式。•市场配置资源是否合意可以根据福利经济学理论判定。©2007ThomsonSouth-WesternConsumers,ProducersandtheEfficiencyofMarkets•WelfareEconomics–Welfareeconomicsisthestudyofhowtheallocationofresourcesaffectseconomicwell-being.–Buyersandsellersreceivebenefitsfromtakingpartinthemarket.–Theequilibriuminamarketmaximizesthetotalwelfareofbuyersandsellers.©2007ThomsonSouth-Western消费者、生产者与市场效率•福利经济学–福利经济学研究资源配置如何影响经济福利。–买者和卖者可以从参与市场活动中获得利益。–市场均衡可以使买者和卖者的总利益最大化。©2007ThomsonSouth-WesternConsumers,ProducersandtheEfficiencyofMarkets•WelfareEconomics–Equilibriuminthemarketresultsinmaximumbenefits,andthereforemaximumtotalwelfareforboththeconsumersandtheproducersoftheproduct.©2007ThomsonSouth-Western消费者、生产者与市场效率•福利经济学–市场均衡使利益最大化，即使产品的消费者和生产者的总利益最大化。©2007ThomsonSouth-WesternConsumers,ProducersandtheEfficiencyofMarkets•WelfareEconomics–Consumersurplusmeasureseconomicwelfarefromthebuyer’sside.–Producersurplusmeasureseconomicwelfarefromtheseller’sside.©2007ThomsonSouth-Western消费者、生产者与市场效率•福利经济学–消费者剩余从消费者角度衡量经济福利。–生产者剩余从生产者角度衡量经济福利。©2007ThomsonSouth-WesternCONSUMERSURPLUS•Willingnesstopayisthemaximumamountthatabuyerwillpayforagood.•Itmeasureshowmuchthebuyervaluesthegoodorservice.•Consumersurplusisthebuyer’swillingnesstopayforagoodminustheamountthebuyeractuallypaysforit.©2007ThomsonSouth-Western消费者剩余•支付意愿——买者为某种物品愿意和能够支付的最高价格。•它衡量买者对物品的评价是多少。•消费者剩余——买者支付意愿减去买者的实际支付量。©2007ThomsonSouth-WesternTable1:FourPossibleBuyers’WillingnesstoPay©2007ThomsonSouth-Western表1.四个可能买者的支付意愿买者支付意愿约翰100美元保罗80乔治70林格50©2007ThomsonSouth-WesternUsingtheDemandCurvetoMeasureConsumerSurplus•Themarketdemandcurvedepictsthevariousquantitiesthatbuyerswouldbewillingandabletopurchaseatdifferentprices.©2007ThomsonSouth-Western用需求曲线衡量消费者剩余•市场需求曲线表示在不同价格水平下买者愿意和能够购买的数量。TheDemandScheduleandtheDemandCurve需求表与需求曲线价格买者需求量大于100美元无080—100美元约翰170—80美元约翰、保罗250—70美元约翰、保罗、乔治350美元或以下约翰、保罗、乔治、林格4Figure1TheDemandScheduleandtheDemandCurvePriceofAlbum0QuantityofAlbumsDemand1234$100John’swillingnesstopay80Paul’swillingnesstopay70George’swillingnesstopay50Ringo’swillingnesstopay图1.需求表与需求曲线专辑的价格5070800$1001234专辑的数量约翰的支付意愿保罗的支付意愿乔治的支付意愿林格的支付意愿需求Figure2MeasuringConsumerSurpluswiththeDemandCurve(a)Price=$80PriceofAlbum5070800$100Demand1234QuantityofAlbumsJohn’sconsumersurplus($20)表2.用需求曲线衡量消费者剩余专辑的价格5070800$1001234专辑的数量需求约翰的消费者剩余（20美元）（a）价格=80美元Figure2MeasuringConsumerSurpluswiththeDemandCurve(b)Price=$70PriceofAlbum5070800$100Demand1234Totalconsumersurplus($40)QuantityofAlbumsJohn’sconsumersurplus($30)Paul’sconsumersurplus($10)图2.用需求曲线衡量消费者剩余(b)价格=70美元专辑的价格5070800$100需求1234总消费者剩余(40美元)专辑的数量约翰的消费者剩余(30美元)’保罗的消费者剩余(10美元)’©2007ThomsonSouth-WesternUsingtheDemandCurvetoMeasureConsumerSurplus•Theareabelowthedemandcurveandabovethepricemeasurestheconsumersurplusinthemarket.©2007ThomsonSouth-Western用需求曲线衡量消费者剩余•需求曲线以下和价格以上的面积衡量市场的消费者剩余。Figure3HowthePriceAffectsConsumerSurplusConsumersurplusQuantity(a)ConsumerSurplusatPricePPrice0DemandP1Q1BAC图3.价格如何影响消费者剩余消费者剩余数量(a)价格在P价格0需求P1Q1BAC时的消费者剩余Figure3HowthePriceAffectsConsumerSurplusInitialconsumersurplusQuantity(b)ConsumerSurplusatPricePPrice0DemandABCDEFP1Q1P2Q2ConsumersurplustonewconsumersAdditionalconsumersurplustoinitialconsumersQ2P2图3.价格如何影响消费者剩余数量价格0需求原来的消费者剩余原来消费者新增的消费者剩余新消费者的消费者剩余Q1P1DEFBCA（b）价格在P2时的消费者剩余©2007ThomsonSouth-WesternWhatDoesConsumerSurplusMeasure?•Consumersurplus,theamountthatbuyersarewillingtopayforagoodminustheamounttheyactuallypayforit,measuresthebenefitthatbuyersreceivefromagoodasthebuyersthemselvesperceiveit.©2007ThomsonSouth-Western消费者剩余衡量了什么？•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。©2007ThomsonSouth-WesternPRODUCERSURPLUS•Producersurplusistheamountasellerispaidforagoodminustheseller’scost.•Itmeasuresthebenefittosellersparticipatinginamarket.©2007ThomsonSouth-Western生产者剩余•生产者剩余——卖者得到的量减去卖者的成本。•它衡量了卖者从参与市场中得到的利益。©2007ThomsonSouth-WesternTable2:TheCostsofFourPossibleSellers©2007ThomsonSouth-Western表2.四个可能卖者的成本买者成本玛丽900美元弗瑞达800乔治亚600格拉玛500©2007ThomsonSouth-WesternUsingtheSupplyCurvetoMeasureProducerSurplus•Justasconsumersurplusisrelatedtothedemandcurve,producersurplusiscloselyrelatedtothesupplycurve.©2007ThomsonSouth-Western利用供给曲线衡量生产者剩余•正如消费者剩余与需求曲线密切相关一样，生产者剩余也与供给曲线紧密相关。TheSupplyScheduleandtheSupplyCurve供给表和供给曲线价格卖者供給量900美元或以上玛丽、弗瑞达、乔治亚、格拉玛4800—900美元弗瑞达、乔治亚、格拉玛3600—800美元乔治亚、格拉玛2500—600美元格拉玛1500美元以下无0Figure4TheSupplyScheduleandtheSupplyCurve图4.供给表和供给曲线要油漆的房子数量油漆房子的价格500800$90006001234格拉玛的成本乔治亚的成本弗瑞达的成本玛丽的成本供给©2007ThomsonSouth-WesternUsingtheSupplyCurvetoMeasureProducerSurplus•Theareabelowthepriceandabovethesupplycurvemeasurestheproducersurplusinamarket.©2007Tho