LikeanEconomist宏观经济学-加州大学-詹姆斯·布

LikeanEconomist(宏观经济学-加州大学-詹姆斯·布LikeanEconomist(宏观经济学-加州大学-詹姆斯LikeanEconomist(宏观经济学-加州大学-詹姆斯·布LikeanEconomist(宏观经济学-加州大学-詹姆斯·布TheImportanceofExpectations:AnExampleThestockmarketcrashof1929changedwhatAmericansexpectedaboutthefutureoftheeconomyExpectationsthatfutureincomewouldbelowerbecamerealizedspendingproductionlayoffsincome4Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.TheImportanceofExpectationsFigure3.1-TheStockMarket,1928-19325Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.1-TheStockMarket,Economicsisaquantitativescienceusesarithmetictomeasureeconomicvariablesofinterestusesmathematicalmodelstorelateeconomicvariablesofinterestinvolvesaparticularwayofthinkingabouttheworldusinguniquetechnicallanguageaspecificsetofdata6Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.EconomicsisaquantitativesciEconomistsuseaspecialsetofanalogiesandmetaphorstodescribethefunctioningofthemacroeconomycurves“shift”moneyhasa“velocity”thecentralbank“pushestheeconomyupthePhillipscurve”7Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.EconomistsuseaspecialsetofFigure3.2-PushingtheEconomyUpthePhillipsCurve8Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.2-PushingtheEconoDominantConceptstheimageofthe“circularflowofeconomicactivity”theuseoftheword“market”theideaof“equilibrium”useofgraphsanddiagramsequationsdepictedbygeometriccurvessituationsofequilibriumoccurwherecurvescrosschangesineconomydemonstratedbyshiftsinthecurves9Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.DominantConceptstheimageofTheCircularFlowpatternsofspending,income,andproductionflowingthroughtheeconomyflowofpurchasingpower10Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.TheCircularFlowpatternsofsTheCircularFlow“incomeside”firmsbuythefactorsofproductionfromhouseholdsmoneypaymentsflowfromfirmstohouseholds“expenditureside”householdsbuygoodsandservicesfromfirmsmoneypaymentsflowfromhouseholdstofirms11Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.TheCircularFlow“incomeside”Figure3.3-TheCircularFlowDiagram12Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.3-TheCircularFlowCircularFlowcanbemadetobemorerealisticbyaddingthegovernmentfinancialmarketsinternationaltradeandfinance13Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.CircularFlowcanbemadetobeFigure3.4-TheCircularFlowof

EconomicActivity14Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.4-TheCircularFlowDifferentMeasuresoftheCircularFlow“expenditureside”measureconsumptioninvestmentgovernmentpurchasesnetexports“incomeside”measurepurchasesoflabor,capital,andnaturalresourcesowneddirectlyorindirectlybyhouseholds15Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.DifferentMeasuresoftheCircDifferentMeasuresoftheCircularFlow“usesofincome”measurewherehouseholdsdecidetousetheirincomesavingtaxesconsumption16Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.DifferentMeasuresoftheCircMarketsareusedasametaphorforthecomplexprocessesofmatchingandexchangethattakeplaceintheeconomyeconomistsassumethatbuyersandsellersarewell-informedaboutprevailingpricesandquantities17Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.MarketsareusedasametaphorEquilibriumisapoint(orpoints)ofbalanceatwhichsomeeconomicquantityisneitherrisingnorfallingonceequilibriumisidentified,economistscandeterminehowfasteconomicforceswillpushtheeconomytothepointsofequilibrium18Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Equilibriumisapoint(orpoinGraphsandEquationsanalgebraicequationrelatingtwovariablescanalsoberepresentedasacurvedrawnonagraphthesolutiontoasetoftwoequationsisthepointonagraphwherethetwocurvesthatrepresenttheequationsintersect19Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GraphsandEquationsanalgebraFigure3.5-TwoFormsoftheProductionFunction20Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.5-TwoFormsoftheUsingGraphsInsteadofEquationsbehavioralrelationshipsbecomecurvesthatshiftaroundonagraphconditionsofeconomicequilibriumcanberepresentedbythepointswherethecurvesdescribingbehavioralrelationshipsintersect21Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.UsingGraphsInsteadofEquatiUsingGraphsInsteadofEquationschangesinthestateoftheeconomycanbeshownasmovementsintheintersectionofthecurves22Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.UsingGraphsInsteadofEquatiBuildingModelsrestricttheproblemtoonlyafewbehavioralrelationshipsandequilibriumconditionscapturetheserelationshipsandequilibriumconditionsinsimplealgebraicequationsusediagramstorepresenttheequationsapplythemodeltotherealworld23Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingModelsrestricttheprImportantConceptsinMacroeonomicModelsrepresentativeagentsassumethatallparticipantsintheeconomyarethesameexaminethedecision-makingofoneindividualandthengeneralizetotheeconomyasawhole24Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ImportantConceptsinMacroeonImportantConceptsinMacroeonomicModelsopportunitycostsoccurwhenanydecisionismademeasuredbythevalueofthebestalternativeforegone25Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ImportantConceptsinMacroeonImportantConceptsinMacroeonomicModelsexpectationformationmacroeconomicmodelsmustexplaintheamountoftimepeoplespendthinkingaboutthefuturetheinformationthatpeoplehaveavailabletherulesofthumbusedtoturninformationintoexpectations26Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ImportantConceptsinMacroeonImportantConceptsinMacroeonomicModelsexpectationformationstaticexpectationsdecisionmakersdonotthinkaboutthefutureadaptiveexpectationsdecisionmakersassumethatthefutureisgoingtobeliketherecentpast27Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ImportantConceptsinMacroeonImportantConceptsinMacroeonomicModelsexpectationformationrationalexpectationsdecisionmakersspendasmuchtimeastheycanthinkingaboutthefutureandknowasmuchaboutthestructureandbehavioroftheeconomyasthemodelbuilderdoes28Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ImportantConceptsinMacroeonBuildingandSolvinganEconomicModelwriteequationsthatrepresentbehavioralrelationshipsstatehowthe“effects”arerelatedtothe“causes”drawadiagramtohelpvisualizetherelationshipconsiderequilibriumconditionscanbeshownasintersectionsondiagram29Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleTheproductionfunctionrelatestheeconomy’scapital-laborratio(K/L)theleveloftechnologyorefficiencyofthelaborforce(E)thelevelofrealGDPperworker(Y/L)Cobb-Douglasproductionfunction30Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleEquilibriumconditionforbalancedgrowththeratiooftheeconomy’scapitalstock(K)toitslevelofoutput(Y)mustbeconstant31Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleEquilibriumconditionforbalancedgrowths=shareoftotalincomeintheeconomysavedandinvestedn=proportionalgrowthrateofthelaborforceg=proportionalgrowthrateoftheefficiencyofthelaborforce=thedepreciationrate32Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExamplearithmeticcanbeusedtodeterminethesteady-stateoutputperworkerLetE=$10,000,=1/2,s=25%,n=1%,g=1%,and=3%.33Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExamplesinceK/Y=5,thismustimplythatK/L=5Y/LsubstitutingforandEtintheCobb-Douglasproductionfunction34Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleinequilibrium,bothconditionsmusthold35Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExamplealgebracanbeusedtodeterminethesteady-stateoutputperworker36Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleputtinginthebalanced-growthcondition37Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExampleLetE=$10,000,=1/2,s=25%,n=1%,g=1%,and=3%38Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomBuildingandSolvinganEconomicModel:AnExamplegraphscanalsobeusedtoshowthesteady-stateoutputperworkertheproductionfunctioncanbedrawnwithoutputperworker(Y/L)ontheverticalaxisandcapitalperworker(K/L)onthehorizontalaxistheequilibriumconditionforbalancedgrowthcanalsobeshownK/L=s/(n+g+)

39Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.BuildingandSolvinganEconomFigure3.6-EquilibriumOutputperWorker40Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.6-EquilibriumOutpuTheAdvantagesofUsingAlgebrabestwaytosummarizecause-and-effectbehavioralrelationshipsallowsustoconsiderdifferentpossiblesystematicrelationshipsbychangingthevalueofparameters41Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.TheAdvantagesofUsingAlgebrFigure3.7-ASingleEquation,aHost

ofRelationships42Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.7-ASingleEquationFigure3.8-ChangingParameterValuesandtheShapeoftheCobb-DouglasProductionFunction43Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure3.8-ChangingParameteFigure3.9-TheEffectofChangesintheEfficiencyofLaborontheShapeoftheProductionFunction44Copyright©2002byTheMcGraw-Hill