经济学基础ppt课件

,12SHORT-RUNECONOMICFLUCTUATIONS,33,Part1:IS-LMModelandAD-ASModel,TheoriginofIS-LMmodel,IS-LMmodelisaboutthesimultaneouslyequilibriumsofgoods(services)marketsandassetmarket.I:Investment;S:Saving;L:Moneydemanded;M:Moneysupplied.TheIS-LMmodelwasdevelopedin1937byNobellaureateJohnHicks,whointendeditasagraphicalrepresentationoftheideasofKeynes.Theimportantassumption:theeconomyisclosed.,TheIScurve:equilibriuminthegoodsandservicesmarket,Figure1DerivingtheIScurve:,Realinterestrate,r,Realinterestrate,r,Saving,S;Investment,I,Output,Y,S1:Y=4000,S2:Y=5000,I,D,D,F,F,7%,7%,5%,5%,4000,5000,IS,TheIScurve:equilibriuminthegoodsandservicesmarket,Intheleft-handside,itisadeterminedprocessofrealinterestrateandmoneydemanded.Inthisprocess,achangeofoutputYbringsacorrespondingshiftofsavingcurve,whichthenresultinanewequilibrium.,TheIScurve:equilibriuminthegoodsandservicesmarket,TheimplicationofIScurve:IScurveshowstherealinterestrate,r,forwhichthegoodsmarketisinequilibrium;so,atallpointsontheIScurvedesiredinvestmentequalsdesirednationalsaving.Ingeneral,becauseariseinoutputincreasesdesirednationalsaving,therebyreducingtherealinterestratethatclearsthegoodsmarket,theIScurveslopesdownward.,FactorsthatshifttheIScurve:,TheIScurve:equilibriuminthegoodsandservicesmarket,Anincreasein,ShiftstheIScurve,Reason,Expectedfutureoutput,Up,S(C),r,Wealth,Up,S(C),r,Governmentpurchases,G,Up,S(demandforgoods),r,Taxes,T,Nochangeordown,Nochange:RicardianequivalenceDown:noR.E.，C,S,r,MPK,？,Expectedtaxrateoncapital,？,TheIScurve:equilibriuminthegoodsandservicesmarket,Figure2EffectontheIScurveofatemporaryincreaseingovernmentpurchases:,Realinterestrate,r,Realinterestrate,r,Output,Y,S2,S1,I,F,F,E,E,7%,6%,4500,IS1,Saving,S;Investment,I,IS2,IncreaseinG,TheIScurve:equilibriuminthegoodsandservicesmarket,Insummary,forconstantoutput,anychangeintheeconomythatreducesdesirednationalsavingrelativetodesiredinvestmentwillincreasetherealinterestratethatclearsthegoodsmarketandthusshifttheIScurveup.,TheLMcurve:Assetmarketequilibrium,Figure3DerivingtheLMcurve:assumption-Pconstant,Realinterestrate,r,Realinterestrate,r,Output,Y,A,A,7%,5%,4000,5000,IS,B,C,C,Realmoneysupply,MS,Realmoneydemand,MD(Y=5000),MD(Y=4000),LM,Realmoneysupply,M/P,RealmoneydemandMd/P,TheLMcurve:Assetmarketequilibrium,TheimplicationofLMcurve:LMcurveshowstherealinterestrate,r,forwhichtheassetmarketisinequilibrium;so,atallpointsontheLMcurvedesiredmoneydemandequalsdesiredmoneysupply.Ingeneral,becauseariseinoutputincreasesdesiredmoneydemand,therebyincreasingtherealinterestratethatclearstheassetmarket,theLMcurveslopesupward.,TheLMcurve:Assetmarketequilibrium,Themoneydemandfunction:Md=P*L(Y,r+e):NominaldemandorMd/P=L(Y,r+e):Realdemand.,TheLMcurve:Assetmarketequilibrium,Adjustprocess:ABCThepriceofanonmonetaryassetanditsnominalinterestrate(andthenrealinterestrate)arenegativelyrelated,why?InpointB,thereareexcessdemandformoney,peoplewilltrytosellaportionoftheirnonmonetaryassetsformoney,whichwillleadthepricesoftheseassetstofall,andthentherealinterestratesontheseassetstorise.,TheLMcurve:Assetmarketequilibrium,FactorsthatshifttheLMcurve:,Anincreasein,ShiftstheLMcurve,Reason,NominalmoneySupply,M,Down,M/P,r,Pricelevel,P,Up,M/P,r,Expectedinflation,e,Down,Md/P,r,Nominalinterestrateonmoney,im,Up,Md/P,r,Wealth,？,Theefficiencyofpaymenttechnologies,？,Theliquidityofalternativeassets,？,TheLMcurve:Assetmarketequilibrium,Figure4AnincreaseintherealmoneysupplyshiftstheLMcurvedown,Realinterestrate,r,Realinterestrate,r,Output,Y,A,A,3%,2%,4000,IS,D,D,MS1,MD(Y=4000),LM(M/P=1200),Realmoneysupply,M/P,RealmoneydemandMd/P,LM(M/P=1000),Realmoneysupplyincreases,MS2,3%,2%,Realmoneysupplyincreases,TheLMcurve:Assetmarketequilibrium,Figure5AnincreaseinrealmoneydemandshiftstheLMcurveup,Realinterestrate,r,Realinterestrate,r,Output,Y,A,A,6%,3%,4000,IS,G,G,MS,MD1,LM1,Realmoneysupply,M/P,RealmoneydemandMd/P,IS,LM2,Realmoneydemandincreases,Realmoneydemandincreases,MD2,6%,3%,GeneralequilibriuminthecompleteIS-LMmodel,Figure6IS-LMmodel:,Realinterestrate,r,Output,Y,LMcurve,IScurve,Y0,r0,GeneralequilibriuminthecompleteIS-LMmodel,r0istherealinterestratewhichmakesgoodsmarketandassetmarkettobesimultaneouslyinequilibrium.r0isnotdeterminatedbyISandLM.,FromIS-LMtoAggregateDemand,Theaggregatedemandcurveshowstherelationbetweentheaggregatequantityofgoodsdemanded,C+I+G,andpricelevel,P.Theaggregatedemandcurveslopesdownward,asdoesthedemandcurveforasingleproduct.,FromIS-LMtoAggregateDemand,Figure7Derivationoftheaggregatedemandcurve,LM1(P=P1),LM2(P=P2),IS,F,E,E,F,P1,P2,r2,r1,Y1,Y1,Y2,Y2,AD,Realinterestrate,r,Pricelevel,P,Output,Y,Output,Y,FromIS-LMtoAggregateDemand,Figure8Theeffectofanincreaseingovernmentpurchasesontheaggregatedemandcurve.,LM,IS1,F,E,E,F,P1,r2,r1,Y1,Y1,Y2,Y2,AD1,Realinterestrate,r,Pricelevel,P,Output,Y,Output,Y,IS2,Governmentpurchasesincrease,AD2,FromIS-LMtoAggregateDemand,FactorsThatShifttheADCurveForaconstantpricelevel,anyfactorthatshiftstheintersectionoftheISandLMcurvestotherightincreasesaggregateoutputdemandedandshiftstheADcurvetotheright,include:Anincreaseinexpectedfutureoutput;Anincreaseinwealth;Anincreaseingovernmentpurchases,G;Areductionintaxes,T(assumingnoRicardianequivalencesothatconsumersrespondbyraisingdesiredconsumption);AnincreaseintheexpectedfutureMPK;andAreductionintheeffectivetaxrateoncapital.,FromIS-LMtoAggregateDemand,FactorsThatShifttheADCurveFactorsthatshifttheLMcurvedownandtotheright,andthusshifttheADcurvetotheright,include:Anincreaseinthenominalmoneysupply,M;Ariseinexpectedinflation,e;Adecreaseinthenominalinterestrateonmoney,im;andAnyotherchangethatreducestherealdemandformoney.,IS-LMModel:Keynesianvs.ClassicalMacroeconomics,TheimportantassumptionofKeynesianmacroeconomicsistha