宏观经济学-增长 45页

IntroductiontoEconomicGrowthChapter31MacroeconomicsChapter3\nEconomicGrowthandStandardofLiving2MacroeconomicsChapter3\nWorldDistributionofRealGDPWorldDistributionofPerCapitaincomein2000WorldDistributionofPerCapitaIncomein1960GrowthRateinPercapitaIncome1960-2000.IncomeInequality.3MacroeconomicsChapter3\n4MacroeconomicsChapter3\n5MacroeconomicsChapter3\n6MacroeconomicsChapter3\n7MacroeconomicsChapter3\n8MacroeconomicsChapter3\nLongTermEconomicGrowthinOECDCountries9MacroeconomicsChapter3\nProductivitySlowdownThedeclineinthegrowthrateofrealGDPperpersonfrom3.1%peryearfor1960–1980to1.8%peryearfor1980–2000issometimescalledtheproductivityslowdown.10MacroeconomicsChapter3\nGrowthQuestionsWhatfactorscausedsomecountriestogrowfastandotherstogrowslowoverperiodssuchas1960to2000?Inparticular,whydidtheEastAsiancountriesdosomuchbetterthanthesub-SaharanAfricancountries?11MacroeconomicsChapter3\nGrowthQuestionsHowdidcountriessuchastheUnitedStatesandotherOECDmemberssustaingrowthratesofrealGDPperpersonofaround2%peryearforacenturyormore?12MacroeconomicsChapter3\nGrowthQuestionsWhatcanpolicymakersdotoincreasegrowthratesofrealGDPperperson?13MacroeconomicsChapter3\nProductionFunctionY=A·F(K,L)ATechnologyLevelKCapitalStock–machinesandbuildingsusedbybusiness.LLaborForce–numberofworkers14MacroeconomicsChapter3\n15MacroeconomicsChapter3\n16MacroeconomicsChapter3\nProductionFunctionsMPL–MarginalProductofLaborDiminishingMarginalProductoflaborMPK–MarginalProductofCapitalDiminishingMarginalProductofCapital17MacroeconomicsChapter3\nConstantReturnstoScaleConstantReturnstoScaleDoubleKandLandYwillalsodoubleTherefore,ifwemultiplyKandLbythequantity1/LwealsomultiplyYby1/LtogetY/L=A·F(K/L,L/L)18MacroeconomicsChapter3\nPerWorkerProductionFunctiony=f(k)youtputperworkerkcapitalperworker19MacroeconomicsChapter3\n20MacroeconomicsChapter3\nAnexample:Cobb-DouglasProductionFunction21MacroeconomicsChapter3\nContributionstoGDPGrowthY=A·F(K,L)∆Y/Y=∆A/A+α·(∆K/K)+β·(∆L/L)ThegrowthrateofrealGDP,∆Y/Y,equalsthegrowthrateoftechnology,∆A/A,plusthecontributionsfromthegrowthofcapital,α·(∆K/K),andlabor,β·(∆L/L).Solowresidual22MacroeconomicsChapter3\nContributionstoGDPGrowthα+β=1Shareofcapitalincome(α)+shareoflaborincome(β)=1∆Y/Y=∆A/A+α·(∆K/K)+β·(∆L/L)0<α<10<β<123MacroeconomicsChapter3\nSolowGrowthModelModelignores:GovernmentNotaxes,publicexpenditures,debt,ormoneyInternationalTradeNotradeingoodsorfinancialassets24MacroeconomicsChapter3\nSolowGrowthModelLaborforce,L=(laborforce/population)·populationLabor-forceparticipationrateAssumelaborforceparticipationrateisconstant.Laborforcegrowthrateisthepopulationgrowthrate25MacroeconomicsChapter3\nSolowGrowthModelGrowthrateinpopulationWeassumethatpopulationgrowsataconstantrate,denotedbyn,wherenisapositivenumber(n>0).∆L/L=n26MacroeconomicsChapter3\nSolowGrowthModel27MacroeconomicsChapter3\nSolowGrowthModelAssume∆A/A=0∆Y/Y=α·(∆K/K)+(1−α)·(∆L/L)ThegrowthrateofrealGDPisaweightedaverageofthegrowthratesofcapitalandlabor.28MacroeconomicsChapter3\nSolowGrowthModelFromtheperworkerproductionfunction∆y/y=∆Y/Y−∆L/L∆k/k=∆K/K−∆L/L29MacroeconomicsChapter3\nSolowGrowthModel∆Y/Y=α·(∆K/K)+(1−α)·(∆L/L)∆Y/Y=α·(∆K/K)−α·(∆L/L)+∆L/L∆Y/Y−∆L/L=α·(∆K/K−∆L/L)∆y/y=α·(∆k/k)30MacroeconomicsChapter3\nSolowGrowthModelEachhouseholddividesupitsrealincomeinafixedproportionstosavingand1−stoconsumption(C).CapitaldepreciateatthesameconstantrateδδKistheamountofcapitalthatdepreciateseachyear31MacroeconomicsChapter3\nSolowGrowthModelRealsaving=s·(Y−δK)Realsaving=(savingrate)·(realincome)(net)savingrate≡realsaving/realincomeSomeotherbooksuse“grosssavingrate”,grosssaving≡s·Y=netrealsaving+δK32MacroeconomicsChapter3\nSolowGrowthModelY−δK=C+s·(Y−δK)Realincome=consumption+realsaving33MacroeconomicsChapter3\nSolowGrowthModelY=C+IRealGDP=consumption+grossinvestmentY−δK=C+(I−δK)RealNDP=consumption+netinvestment34MacroeconomicsChapter3\nSolowGrowthModelC+s·(Y−δK)=C+I−δKors·(Y−δK)=I−δKRealsaving=netinvestment35MacroeconomicsChapter3\nSolowGrowthModel∆K=I−δKChangeincapitalstock=grossinvestment−depreciation,orChangeincapitalstock=netinvestment∆K=s·(Y−δK)Changeincapitalstock=realsaving36MacroeconomicsChapter3\nSolowGrowthModelDividebothsidesbyK∆K/K=s·Y/K−sδ37MacroeconomicsChapter3\nSolowGrowthModel∆k/k=∆K/K−∆L/L∆k/k=s·(Y/K)−sδ−n38MacroeconomicsChapter3\nSolowGrowthModelY/K=(Y/L)/(K/L)Y/K=y/k39MacroeconomicsChapter3\nSolowGrowthModel∆k/k=s·(y/k)−sδ−n∆y/y=α·(∆k/k)∆y/y=α·[s·(y/k)−sδ−n]40MacroeconomicsChapter3\nSolowGrowthModel41MacroeconomicsChapter3\nSolowGrowthModel42MacroeconomicsChapter3\nSolowGrowthModelsteadystate.Whenk=k∗,∆k/kequalszero.∆k/k=0,kstaysfixedatthevaluek∗.y*=f(k*)43MacroeconomicsChapter3\nSolowGrowthModel44MacroeconomicsChapter3\nSolowGrowthModelInthesteadystate,∆k/kequalszero.s·(y*/k*)−sδ−n=0s·(y*−δk*)=nk*Steady-statesavingperworker=steady-statecapitalprovidedforeachnewworker作业一45MacroeconomicsChapter3