7consumers_producers 曼昆 微观经济学课件

,3SUPPLYANDDEMANDII:MARKETSANDWELFARE,7,Consumers,Producers,andtheEfficiencyofMarkets,REVISITINGTHEMARKETEQUILIBRIUM,Dotheequilibriumpriceandquantitymaximizethetotalwelfareofbuyersandsellers?Marketequilibriumreflectsthewaymarketsallocatescarceresources.Whetherthemarketallocationisdesirablecanbeaddressedbywelfareeconomics.,WelfareEconomics,Welfareeconomicsisthestudyofhowtheallocationofresourcesaffectseconomicwell-being.Buyersandsellersreceivebenefitsfromtakingpartinthemarket.Theequilibriuminamarketmaximizesthetotalwelfareofbuyersandsellers.,WelfareEconomics,Equilibriuminthemarketresultsinmaximumbenefits,andthereforemaximumtotalwelfareforboththeconsumersandtheproducersoftheproduct.,WelfareEconomics,Consumersurplusmeasureseconomicwelfarefromthebuyersside.Producersurplusmeasureseconomicwelfarefromthesellersside.,CONSUMERSURPLUS,Willingnesstopayisthemaximumamountthatabuyerwillpayforagood.Itmeasureshowmuchthebuyervaluesthegoodorservice.,CONSUMERSURPLUS,Consumersurplusisthebuyerswillingnesstopayforagoodminustheamountthebuyeractuallypaysforit.,Table1FourPossibleBuyersWillingnesstoPay,Copyright2004South-Western,CONSUMERSURPLUS,Themarketdemandcurvedepictsthevariousquantitiesthatbuyerswouldbewillingandabletopurchaseatdifferentprices.,TheDemandScheduleandtheDemandCurve,Figure1TheDemandScheduleandtheDemandCurve,Copyright2003Southwestern/ThomsonLearning,Priceof,Album,0,Quantityof,Albums,1,2,3,4,Figure2MeasuringConsumerSurpluswiththeDemandCurve,Copyright2003Southwestern/ThomsonLearning,(a)Price=$80,Priceof,Album,50,70,80,0,$100,1,2,3,4,Quantityof,Albums,Figure2MeasuringConsumerSurpluswiththeDemandCurve,Copyright2003Southwestern/ThomsonLearning,(b)Price=$70,Priceof,Album,50,70,80,0,$100,1,2,3,4,Quantityof,Albums,UsingtheDemandCurvetoMeasureConsumerSurplus,Theareabelowthedemandcurveandabovethepricemeasurestheconsumersurplusinthemarket.,Figure3HowthePriceAffectsConsumerSurplus,Copyright2003Southwestern/ThomsonLearning,Quantity,(a)ConsumerSurplusatPrice,P,Price,0,Figure3HowthePriceAffectsConsumerSurplus,Copyright2003Southwestern/ThomsonLearning,Quantity,(b)ConsumerSurplusatPrice,P,Price,0,WhatDoesConsumerSurplusMeasure?,Consumersurplus,theamountthatbuyersarewillingtopayforagoodminustheamounttheyactuallypayforit,measuresthebenefitthatbuyersreceivefromagoodasthebuyersthemselvesperceiveit.,PRODUCERSURPLUS,Producersurplusistheamountasellerispaidforagoodminusthesellerscost.Itmeasuresthebenefittosellersparticipatinginamarket.,Table2TheCostsofFourPossibleSellers,Copyright2004South-Western,UsingtheSupplyCurvetoMeasureProducerSurplus,Justasconsumersurplusisrelatedtothedemandcurve,producersurplusiscloselyrelatedtothesupplycurve.,TheSupplyScheduleandtheSupplyCurve,Figure4TheSupplyScheduleandtheSupplyCurve,UsingtheSupplyCurvetoMeasureProducerSurplus,Theareabelowthepriceandabovethesupplycurvemeasurestheproducersurplusinamarket.,Figure5MeasuringProducerSurpluswiththeSupplyCurve,Copyright2003Southwestern/ThomsonLearning,Quantityof,HousesPainted,Priceof,House,Painting,500,800,$900,0,600,1,2,3,4,(a)Price=$600,Figure5MeasuringProducerSurpluswiththeSupplyCurve,Copyright2003Southwestern/ThomsonLearning,Quantityof,HousesPainted,Priceof,House,Painting,500,800,$900,0,600,1,2,3,4,(b)Price=$800,Figure6HowthePriceAffectsProducerSurplus,Copyright2003Southwestern/ThomsonLearning,Quantity,(a)ProducerSurplusatPrice,P,Price,0,Figure6HowthePriceAffectsProducerSurplus,Copyright2003Southwestern/ThomsonLearning,Quantity,(b)ProducerSurplusatPrice,P,Price,0,P1,B,C,Supply,A,Initial,producer,surplus,Q1,MARKETEFFICIENCY,Consumersurplusandproducersurplusmaybeusedtoaddressthefollowingquestion:Istheallocationofresourcesdeterminedbyfreemarketsinanywaydesirable?,MARKETEFFICIENCY,ConsumerSurplus=ValuetobuyersAmountpaidbybuyersandProducerSurplus=AmountreceivedbysellersCosttosellers,MARKETEFFICIENCY,Totalsurplus=Consumersurplus+ProducersurplusorTotalsurplus=ValuetobuyersCosttosellers,MARKETEFFICIENCY,Efficiencyisthepropertyofaresourceallocationofmaximizingthetotalsurplusreceivedbyallmembersofsociety.,MARKETEFFICIENCY,Inadditiontomarketefficiency,asocialplannermightalsocareaboutequitythefairnessofthedistributionofwell-beingamongthevariousbuyersandsellers.,Figure7ConsumerandProducerSurplusintheMarketEquilibrium,Copyright2003Southwestern/ThomsonLearning,Price,0,Quantity,MARKETEFFICIENCY,ThreeInsightsConcerningMarketOutcomesFreemarketsallocatethesupplyofgoodstothebuyerswhovaluethemmosthighly,asmeasuredbytheirwillingnesstopay.Freemarketsallocatethedemandforgoodstothesellerswhocanproducethematleastcost.Freemarketsproducethequantityofgoodsthatmaximizesthesumofconsumerandproducersurplus.,Figure8TheEfficiencyoftheEquilibriumQuantity,Copyright2003Southwestern/ThomsonLearning,Quantity,Price,0,EvaluatingtheMarketEquilibrium,Becausetheequilibriumoutcomeisanefficientallocationofresources,thesocialplannercanleavethemarketoutcomeashe/shefindsit.ThispolicyofleavingwellenoughalonegoesbytheFrenchexpressionlaissezfaire.,EvaluatingtheMarketEquilibrium,MarketPowerIfamarketsystemisnotperfectlycompetitive,marketpowermayresult.Marketpoweristheabilitytoinfluenceprices.Marketpowercancausemarketstobeinefficientbecauseitkeepspriceandquantityfromtheequilibriumofsupplyanddemand.,EvaluatingtheMarketEquilibrium,Externalitiescreatedwhenamarketoutcomeaffectsindividualsotherthanbuyersandsellersinthatmarket.causewelfareinamarkettodependonmorethanjustthevaluetothebuyersandcosttothesellers.Whenbuyersandsellersdonottakeexternalitiesintoaccountwhendecidinghowmuchtoconsumeandproduce,theequilibriuminthemarketcanbeinefficient.,Summary,Consumersurplusequalsbuyerswillingnesstopayforagoodminustheamounttheyactuallypayforit.Consumersurplusmeasuresthebenefitbuyersgetfromparticipatinginamarket.Consumersurpluscanbecomputedbyfindingtheareabelowthedemandcurveandabovetheprice.,Summary,Producersurplusequalsth