宏观经济学ppt课件.ppt

Inthischapteryouwilllearn theIScurve anditsrelationtotheKeynesianCrosstheLoanableFundsmodeltheLMcurve anditsrelationtotheTheoryofLiquidityPreferencehowtheIS LMmodeldeterminesincomeandtheinterestrateintheshortrunwhenPisfixed slide1 Context Chapter9introducedthemodelofaggregatedemandandaggregatesupply Longrunpricesflexibleoutputdeterminedbyfactorsofproduction technologyunemploymentequalsitsnaturalrateShortrunpricesfixedoutputdeterminedbyaggregatedemandunemploymentisnegativelyrelatedtooutput slide2 Context ThischapterdevelopstheIS LMmodel thetheorythatyieldstheaggregatedemandcurve Wefocusontheshortrunandassumethepricelevelisfixed slide3 TheKeynesianCross Asimpleclosedeconomymodelinwhichincomeisdeterminedbyexpenditure duetoJ M Keynes Notation I plannedinvestmentE C I G plannedexpenditureY realGDP actualexpenditureDifferencebetweenactual plannedexpenditure unplannedinventoryinvestment slide4 ElementsoftheKeynesianCross consumptionfunction fornow investmentisexogenous plannedexpenditure Equilibriumcondition govtpolicyvariables slide5 Graphingplannedexpenditure income output Y Eplannedexpenditure slide6 Graphingtheequilibriumcondition income output Y Eplannedexpenditure 45 slide7 Theequilibriumvalueofincome income output Y Eplannedexpenditure E Y E C I G slide8 Anincreaseingovernmentpurchases E Y sofirmsincreaseoutput andincomerisestowardanewequilibrium slide9 Solvingfor Y equilibriumcondition inchanges becauseIexogenous because C MPC Y Collecttermswith Yontheleftsideoftheequalssign slide10 Thegovernmentpurchasesmultiplier Example MPC 0 8 TheincreaseinGcausesincometoincreaseby5timesasmuch slide11 Thegovernmentpurchasesmultiplier IntheexamplewithMPC 0 8 Definition theincreaseinincomeresultingfroma 1increaseinG Inthismodel theGmultiplierequals slide12 Whythemultiplierisgreaterthan1 Initially theincreaseinGcausesanequalincreaseinY Y G But Y C further Y further C further YSothefinalimpactonincomeismuchbiggerthantheinitial G slide13 Anincreaseintaxes sofirmsreduceoutput andincomefallstowardanewequilibrium Initially thetaxincreasereducesconsumption andthereforeE slide14 Solvingfor Y eq mconditioninchanges IandGexogenous Solvingfor Y Finalresult slide15 TheTaxMultiplier def thechangeinincomeresultingfroma 1increaseinT IfMPC 0 8 thenthetaxmultiplierequals slide16 TheTaxMultiplier isnegative Ataxhikereducesconsumerspending whichreducesincome isgreaterthanone inabsolutevalue Achangeintaxeshasamultipliereffectonincome issmallerthanthegovtspendingmultiplier Consumerssavethefraction 1 MPC ofataxcut sotheinitialboostinspendingfromataxcutissmallerthanfromanequalincreaseinG slide17 TheTaxMultiplier isnegative Anincreaseintaxesreducesconsumerspending whichreducesequilibriumincome isgreaterthanone inabsolutevalue Achangeintaxeshasamultipliereffectonincome issmallerthanthegovtspendingmultiplier Consumerssavethefraction 1 MPC ofataxcut sotheinitialboostinspendingfromataxcutissmallerthanfromanequalincreaseinG slide18 Exercise UseagraphoftheKeynesianCrosstoshowtheimpactofanincreaseininvestmentontheequilibriumlevelofincome output slide19 TheIScurve def agraphofallcombinationsofrandYthatresultingoodsmarketequilibrium i e actualexpenditure output plannedexpenditureTheequationfortheIScurveis slide20 Y2 Y1 Y2 Y1 DerivingtheIScurve r I E C I r1 G E C I r2 G r1 r2 E Y IS E Y slide21 UnderstandingtheIScurve sslope TheIScurveisnegativelysloped Intuition Afallintheinterestratemotivatesfirmstoincreaseinvestmentspending whichdrivesuptotalplannedspending E Torestoreequilibriuminthegoodsmarket output a k a actualexpenditure Y mustincrease slide22 TheIScurveandtheLoanableFundsmodel r1 r2 r1 r2 a TheL F model b TheIScurve IS slide23 FiscalPolicyandtheIScurve WecanusetheIS LMmodeltoseehowfiscalpolicy GandT canaffectaggregatedemandandoutput Let sstartbyusingtheKeynesianCrosstoseehowfiscalpolicyshiftstheIScurve slide24 Y2 Y1 Y2 Y1 ShiftingtheIScurve G Atanyvalueofr G E Y E C I r1 G1 E C I r1 G2 r1 E Y IS1 ThehorizontaldistanceoftheISshiftequals IS2 sotheIScurveshiftstotheright slide25 Exercise ShiftingtheIScurve UsethediagramoftheKeynesianCrossorLoanableFundsmodeltoshowhowanincreaseintaxesshiftstheIScurve slide26 TheTheoryofLiquidityPreference duetoJohnMaynardKeynes Asimpletheoryinwhichtheinterestrateisdeterminedbymoneysupplyandmoneydemand slide27 MoneySupply Thesupplyofrealmoneybalancesisfixed M Prealmoneybalances rinterestrate slide28 MoneyDemand Demandforrealmoneybalances M Prealmoneybalances rinterestrate L r slide29 Equilibrium Theinterestrateadjuststoequatethesupplyanddemandformoney M Prealmoneybalances rinterestrate L r r1 slide30 HowtheFedraisestheinterestrate Toincreaser FedreducesM M Prealmoneybalances rinterestrate L r r1 r2 slide31 CASESTUDYVolcker sMonetaryTightening Late1970s 10 Oct1979 FedChairmanPaulVolckerannouncedthatmonetarypolicywouldaimtoreduceinflation Aug1979 April1980 FedreducesM P8 0 Jan1983 3 7 Howdoyouthinkthispolicychangewouldaffectinterestrates slide32 Volcker sMonetaryTightening cont i 0 i 0 1 1983 i 8 2 8 1979 i 10 4 4 1980 i 15 8 flexible sticky QuantityTheory FisherEffect Classical LiquidityPreference Keynesian slide33 TheLMcurve Nowlet sputYbackintothemoneydemandfunction TheLMcurveisagraphofallcombinationsofrandYthatequatethesupplyanddemandforrealmoneybalances TheequationfortheLMcurveis slide34 DerivingtheLMcurve r1 r2 r1 r2 a Themarketforrealmoneybalances b TheLMcurve slide35 UnderstandingtheLMcurve sslope TheLMcurveispositivelysloped Intuition Anincreaseinincomeraisesmoneydemand Sincethesupplyofrealbalancesisfixed thereisnowexcessdemandinthemoneymarketattheinitialinterestrate Theinterestratemustrisetorestoreequilibriuminthemoneymarket slide36 How MshiftstheLMcurve r1 r2 r1 r2 a Themarketforrealmoneybalances b TheLMcurve slide37 Exercise ShiftingtheLMcurve Supposeawaveofcreditcardfraudcausesconsumerstousecashmorefrequentlyintransactions UsetheLiquidityPreferencemodeltoshowhowtheseeventsshifttheLMcurve slide38 Theshort runequilibrium Theshort runequilibriumisthecombinationofrandYthatsimultaneouslysatisfiestheequilibriumconditionsinthegoods moneymarkets Equilibriuminterestrate Equilibriumlevelofincome slide39 TheBigPicture KeynesianCross TheoryofLiquidityPreference IScurve LMcurve IS LMmodel Agg demandcurve Agg supplycurve ModelofAgg DemandandAgg Supply Explanationofshort runfluctuations slide40 Chaptersummary KeynesianCrossbasicmodelofincomedeterminationtakesfiscalpolicy investmentasexogenousfiscalpolicyhasamultipliedimpactonincome IScurvecomesfromKeynesianCrosswhenplannedinvestmentdependsnegativelyoninterestrateshowsallcombinationsofrandYthatequateplannedexpenditurewithactualexpenditureongoods services slide41 Ch