王则柯微观经济学

IntermediateMicroeconomicsIntroductionContentsInstructorandTAsRequirementsCourseoutlineAnexample:marketforapartmentsTextbookIntermediateMicroeconomics:AModernApproach(SixthEdition)byHalR.VarianW.W.Norton，2003TheTheoryofEconomicsdoesnotfurnishabodyofsettledconclusionsimmediatelyapplicabletopolicy.Itisamethodratherthanadoctrine,anapparatusofthemind,atechniqueofthinkingwhichhelpsitspossessortodrawcorrectconclusions---JohnMaynardKeynesIsEconomicsUseful?AthinkingmachineChangesthewayyouviewlifeandunderstandproblemsAnallroundmajorEconomicsGraduatesTypeofEmployerPercentofGraduatesTraditionalBusiness23.3Government18.4FinancialBusiness17.7GraduateSchool13.7ConsultingServices4.4Private/publicSchool3.9LawFirm3.5Other9.8JobsforEconomistsBusinesseconomistsGovernmenteconomistsAcademiceconomistsMicroeconomicsTheoryApplications–Laboreconomics–Economicsofeducation–Agriculturaleconomics–Industrialorganizations–Healtheconomics–……CourseOutlineConsumertheory(1-15)Producertheory(18-27)Marketequilibrium(16-17,30-32)SpecialtopicsonequilibriumEconomicModelingWhatcauseswhatineconomicsystems?Atwhatlevelofdetailshallwemodelaneconomicphenomenon?Whichvariablesaredeterminedoutsidethemodel(exogenous)andwhicharetobedeterminedbythemodel(endogenous)?ModelingtheApartmentMarketHowareapartmentrentsdetermined?Suppose–apartmentsarecloseordistant,butotherwiseidentical–distantapartmentsrentsareexogenousandknown–manypotentialrentersandlandlordsModelingtheApartmentMarketWhowillrentcloseapartments?Atwhatprice?Willtheallocationofapartmentsbedesirableinanysense?Howcanweconstructaninsightfulmodeltoanswerthesequestions?TwoPrinciplesinEconomicsOptimization:Eachpersontriestochoosethebestalternativeavailabletohimorher.Equilibrium:Marketpriceadjustsuntilquantitydemandedequalsquantitysupplied.ModelingApartmentDemandDemand:Supposethemostanyonepersoniswillingtopaytorentacloseapartmentis$500/month.Thenp=$500QD=1.Supposethepricehastodropto$490beforea2ndpersonwouldrent.Thenp=$490QD=2.ModelingApartmentDemandTheloweristherentalratep,thelargeristhequantityofcloseapartmentsdemandedpQD.Thequantitydemandedvs.pricegraphisthemarketdemandcurveforcloseapartments.MarketDemandCurveforApartmentspQDModelingApartmentSupplySupply:Ittakestimetobuildmorecloseapartmentssointhisshort-runthequantityavailableisfixed(atsay100).MarketSupplyCurveforApartmentspQS100CompetitiveMarketEquilibrium“low”rentalpricequantitydemandedofcloseapartmentsexceedsquantityavailablepricewillrise.“high”rentalpricequantitydemandedlessthanquantityavailablepricewillfall.CompetitiveMarketEquilibriumQuantitydemanded=quantityavailablepricewillneitherrisenorfallsothemarketisatacompetitiveequilibrium.CompetitiveMarketEquilibriumpQD,QS100CompetitiveMarketEquilibriumpQD,QSpe100CompetitiveMarketEquilibriumpQD,QSpe100Peoplewillingtopaypeforcloseapartmentsgetcloseapartments.CompetitiveMarketEquilibriumpQD,QSpe100Peoplewillingtopaypeforcloseapartmentsgetcloseapartments.Peoplenotwillingtopaypeforcloseapartmentsgetdistantapartments.CompetitiveMarketEquilibriumQ:Whorentsthecloseapartments?A:Thosemostwillingtopay.Q:Whorentsthedistantapartments?A:Thoseleastwillingtopay.Sothecompetitivemarketallocationisby“willingness-to-pay”.ComparativeStaticsWhatisexogenousinthemodel?–priceofdistantapartments–quantityofcloseapartments–incomesofpotentialrenters.Whathappensiftheseexogenousvariableschange?ComparativeStaticsSupposethepriceofdistantapartmentrises.Demandforcloseapartmentsincreases(rightwardshift),causingahigherpriceforcloseapartments.MarketEquilibriumpQD,QSpe100MarketEquilibriumpQD,QSpe100HigherdemandMarketEquilibriumpQD,QSpe100Higherdemandcauseshighermarketprice;samequantitytraded.ComparativeStaticsSupposethereweremorecloseapartments.Supplyisgreater,sothepriceforcloseapartmentsfalls.MarketEquilibriumpQD,QSpe100MarketEquilibriumpQD,QS100HighersupplypeMarketEquilibriumpQD,QSpe100Highersupplycausesalowermarketpriceandalargerquantitytraded.ComparativeStaticsSupposepotentialrenters’incomesrise,increasingtheirwillingness-to-payforcloseapartments.Demandrises(upwardshift),causinghigherpriceforcloseapartments.MarketEquilibriumpQD,QSpe100MarketEquilibriumpQD,QSpe100Higherincomescausehigherwillingness-to-payMarketEquilibriumpQD,QSpe100Higherincomescausehigherwillingness-to-pay,highermarketprice,andthesamequantitytraded.TaxationPolicyAnalysisLocalgovernmenttaxesapartmentowners.Whathappensto–price–quantityofcloseapartmentsrented?Isanyofthetax“passed”torenters?TaxationPolicyAnalysisMarketsupplyisunaffected.Marketdemandisunaffected.Sothecompetitivemarketequilibriumisunaffectedbythetax.Priceandthequantityofcloseapartmentsrentedarenotchanged.Landlordspayallofthetax.ImperfectlyCompetitiveMarketsAmongstmanypossibilitiesare:–amonopolisticlandlord–aperfectlydiscriminatorymonopolisticlandlord–acompetitivemarketsubjecttorentcontrol.AMonopolisticLandlordWhenthelandlordsetsarentalpricepherentsD(p)apartments.Revenue=pD(p).Revenueislowifp0RevenueislowifpissohighthatD(p)0.Anintermedi