ofCompetitiveMarkets(微观经济学-华侨大学,Jeff

Chapter9TheAnalysisofCompetitiveMarketsChapter9Slide2TopicstobeDiscussedEvaluatingtheGainsandLossesfromGovernmentPolicies--ConsumerandProducerSurplusTheEfficiencyofaCompetitiveMarketMinimumPricesChapter9Slide3TopicstobeDiscussedPriceSupportsandProductionQuotasImportQuotasandTariffsTheImpactofaTaxorSubsidyChapter9Slide4EvaluatingtheGainsandLossesfromGovernmentPolicies--ConsumerandProducerSurplusReviewConsumersurplusisthetotalbenefitorvaluethatconsumersreceivebeyondwhattheypayforthegood.Producersurplusisthetotalbenefitorrevenuethatproducersreceivebeyondwhatitcosttoproduceagood.ProducerSurplusBetween0andQ0producersreceiveanetgainfromsellingeachproduct--producersurplus.ConsumerSurplusConsumerandProducerSurplusQuantity0PriceSD5Q0ConsumerC107ConsumerBConsumerABetween0andQ0consumersAandBreceiveanetgainfrombuyingtheproduct--consumersurplusChapter9Slide6Todeterminethewelfareeffectofagovernmentalpolicywecanmeasurethegainorlossinconsumerandproducersurplus.WelfareEffectsGainsandlossescausedbygovernmentinterventioninthemarket.EvaluatingtheGainsandLossesfromGovernmentPolicies--ConsumerandProducerSurplusChapter9Slide7ThelosstoproducersisthesumofrectangleAandtriangleC.TriangleBandCtogethermeasurethedeadweightloss.BACThegaintoconsumersisthedifferencebetweentherectangleAandthetriangleB.DeadweightLossChangeinConsumerandProducerSurplusfromPriceControlsQuantityPriceSDP0Q0PmaxQ1Q2SupposethegovernmentimposesapriceceilingPmaxwhichisbelowthemarket-clearingpriceP0.Chapter9Slide8Observations:ThetotallossisequaltoareaB+C.Thetotalchangeinsurplus=(A-B)+(-A-C)=-B-CThedeadweightlossistheinefficiencyofthepricecontrolsorthelossoftheproducersurplusexceedsthegainfromconsumersurplus.ChangeinConsumerandProducerSurplusfromPriceControlsChapter9Slide9ObservationConsumerscanexperienceanetlossinconsumersurpluswhenthedemandissufficientlyinelasticChangeinConsumerandProducerSurplusfromPriceControlsChapter9Slide10BAPmaxCQ1Ifdemandissufficientlyinelastic,triangleBcanbelargerthanrectangleAandtheconsumersuffersanetlossfrompricecontrols.ExampleOilpricecontrolsandgasolineshortagesin1979SDEffectofPriceControlsWhenDemandIsInelasticQuantityPriceP0Q2Chapter9Slide11PriceControlsandNaturalGasShortages1975Pricecontrolscreatedashortageofnaturalgas.Whatwasthedeadweightloss?Chapter9Slide12Supply:QS=14+2PG+0.25POQuantitysuppliedintrillioncubicfeet(Tcf)Demand:QD=-5PG+3.75POQuantitydemanded(Tcf)PG=priceofnaturalgasin$/mcfandPO=priceofoilin$/b.PriceControlsandNaturalGasShortagesDatafor1975Chapter9Slide13PO=$8/bEquilibriumPG=$2/mcfandQ=20TcfPriceceilingsetat$1Thisinformationcanbeseengraphically:PriceControlsandNaturalGasShortagesDatafor1975Chapter9Slide14BA2.40CThegaintoconsumersisrectangleAminustriangleB,andthelosstoproducersisrectangleAplustriangleC.SD2.00Quantity(Tcf)0Price($/mcf)5101520253018(Pmax)1.00PriceControlsandNaturalGasShortagesChapter9Slide15MeasuringtheImpactofPriceControls1Tcf=1billionmcfIfQD=18,thenP=$2.40[18=-5PG+3.75(8)]A=(18billionmcf)x($1/mcf)=$18billionB=(1/2)x(2b.mcf)x($0.40/mcf)=$0.4billionC=(1/2)x(2b.mcf)x($1/mcf)=$1billionPriceControlsandNaturalGasShortagesChapter9Slide16MeasuringtheImpactofPriceControls1975Changeinconsumersurplus=A-B=18-0.04=$17.6billionChangeinproducersurplus=-A-C=-18-1=-$19.0billionPriceControlsandNaturalGasShortagesChapter9Slide17MeasuringtheImpactofPriceControls1975dollars,deadweightloss=-B-C=-0.4-1=-$1.4billionIn2000dollars,thedeadweightlossismorethan$4billionperyear.PriceControlsandNaturalGasShortagesChapter9Slide18TheEfficiencyofaCompetitiveMarketWhendocompetitivemarketsgenerateaninefficientallocationofresourcesormarketfailure?1)ExternalitiesCostsorbenefitsthatdonotshowupaspartofthemarketprice(e.g.pollution)Chapter9Slide19TheEfficiencyofaCompetitiveMarketWhendocompetitivemarketsgenerateaninefficientallocationofresourcesormarketfailure?2)LackofInformationImperfectinformationpreventsconsumersfrommakingutility-maximizingdecisions.Chapter9Slide20Governmentinterventioninthesemarketscanincreaseefficiency.Governmentinterventionwithoutamarketfailurecreatesinefficiencyordeadweightloss.TheEfficiencyofaCompetitiveMarketChapter9Slide21P1Q1ABCWhenpriceisregulatedtobenohigherthanP1,thedeadweightlossgivenbytrianglesBandCresults.WelfareLossWhenPriceIsHeldBelowMarket-ClearingLevelQuantityPriceSDP0Q0Chapter9Slide22P2Q3ABCQ2WhatwouldthedeadweightlossbeifQS=Q2?WhenpriceisregulatedtobenolowerthanP2onlyQ3willbedemanded.ThedeadweightlossisgivenbytrianglesBandCWelfareLossWhenPriceIsHeldAboveMarket-ClearingLevelQuantityPriceSDP0Q0Chapter9Slide23TheMarketforHumanKidneysThe1984NationalOrganTransplantationActprohibitsthesaleoforgansfortransplantation.AnalyzingtheImpactoftheActSupply:QS=8,000+0.2PIfP=$20,000,Q=12,000Demand:QD=16,000-0.2PChapter9Slide24DRectanglesAandDmeasurethetotalvalueofkidneyswhensupplyisconstrained.ACThelosstosuppliersisgivenbyrectangleAandtriangleC.TheMarketforKidneys,andEffectsofthe1984OrganTransplantationActQuantityPrice8,0004,0000$10,000$30,000$40,000S’The1984acteffective