ofEconomicGrowth宏观经济学加州大学詹姆斯·讲义课件

QuestionsWhataretheprincipaldeterminantsoflong-runeconomicgrowth?Whatequilibriumconditionisusefulinanalyzinglong-rungrowth?Howquicklydoesaneconomyheadforitssteady-stategrowthpath?1Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.QuestionsWhateffectdoesfasterpopulationgrowthhaveonlong-rungrowth?Whateffectdoesahighersavingsratehaveonlong-rungrowth?2Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Long-RunEconomic

Growth...isthemostimportantaspectofhowtheeconomyperformscanbeacceleratedbygoodeconomicpoliciescanberetardedbybadeconomicpolicies3Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Long-RunEconomicGrowthPoliciesandinitialconditionsaffectgrowththroughtwochannelstheirimpactontheleveloftechnologymultipliestheefficiencyoflabortheirimpactonthecapitalintensityoftheeconomythestockofmachines,equipment,andbuildingsthattheaverageworkerhasathisorherdisposal4Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Technologyleadstoahigherefficiencyoflaborskillsandeducationofthelaborforceabilityofthelaborforcetohandlemodernmachinestheefficiencywithwhichtheeconomy’sbusinessesandmarketsfunctionEconomistsaregoodatanalyzingtheconsequencesofbettertechnologyhavelesstosayaboutthesources5Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.CapitalIntensityThereisadirectrelationshipbetweencapital-intensityandproductivityTwoprincipaldeterminantsinvestmentefforttheshareoftotalproductionsavedandinvestedinordertoincreasethecapitalstockinvestmentrequirementshowmuchofnewinvestmentisusedtoequipnewworkerswiththestandardlevelofcapitalortoreplaceworn-outorobsoletecapital6Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelAlsocalledtheSolowmodelSteady-statebalanced-growthequilibriumthecapitalintensityoftheeconomyisstabletheeconomy’scapitalstockandlevelofrealGDParegrowingatthesameratetheeconomy’scapital-outputratioisconstant7Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelFirstcomponentistheproductionfunctiontellsushowtheproductiveresourcesoftheeconomycanbeusedtoproduceanddeterminethelevelofoutputCobb-Douglasproductionfunction8Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelParametersofthemodelEistheefficiencyoflaborahigherlevelofEmeansthatmoreoutputperworkercanbeproducedforeachpossiblevalueofthecapitalstockperworkermeasureshowfastdiminishingmarginalreturnstoinvestmentsetin9Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModel0<<1alevelofnearzeromeansthattheextraamountofoutputmadepossiblebyeachadditionalunitofcapitaldeclinesveryquicklyasthecapitalstockincreases10Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.1-TheCobb-DouglasProductionFunctionforParameterNearZero11Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModel0<<1alevelofnearonemeansthatthenextadditionalunitofcapitalmakespossiblealmostaslargeanincreaseinoutputasthelastunitofcapitalalevelofequaltoonemeansthatchangesinoutputareproportionaltochangesincapital12Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.2-TheCobb-DouglasProductionFunctionforParameterNear113Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.3-TheCobb-DouglasProductionFunctionisFlexible14Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelGrowthinlaborforce(L)assumethatLisgrowingataconstantrate(n)ifthisyear’slaborforceisequalto10millionandthegrowthrateis2%peryear,nextyear’slaborforcewillbe15Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.4-ConstantProportionalLabor-ForceGrowth(atRaten=2PercentperYear)16Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelGrowthintheefficiencyoflabor(E)assumethatEisgrowingataconstantproportionalrate(g)ifthisyear’sefficiencyoflaboris$10,000andthegrowthrateis1.5%peryear,nextyear’sefficiencyoflaborwillbe17Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.5-ConstantProportionalGrowth

intheEfficiencyofLabor

(atRateg=1.5PercentperYear)18Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelSavingandinvestmentassumethataconstantshareofrealGDPissavedandinvestedeachyear(s)capitalstockdoesnotgrowbyfullamountofgrossinvestmentrepresentsthefractionofthecapitalstockthatwearsoutorisscrappedeachyear19Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.6-ChangesintheCapitalStock20Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.StandardGrowthModelAnexampleofcapitalaccumulationcurrentrealGDP=$8trillioncurrentcapitalstock=$24trillionsavingsrate=20%depreciationrate=4%21Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.7-AdditionstoandSubtractionsfromtheCapitalStock22Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.SummaryofStandardGrowthModelThreeassumptionslaborforcegrowsatproportionalratenefficiencyoflaborgrowsatproportionalrategthereisaconstantproportionofrealGDPsavedandinvestedeachyear(s)ThecapitalstockchangesovertimeduetoinvestmentanddepreciationCobb-Douglasproductionfunction23Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.EquilibriuminStandardGrowthModelKeyeconomicvariablesinthegrowthmodelareneverconstantEquilibriumoccurswhenthevariablesaregrowingtogetheratthesameproportionalrateSteady-statebalancedgrowthoccurswhenthecapital-outputratioisconstantovertime24Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ThreeMathematicalRulesTheproportionalgrowthrateofaproduct(PQ)isthesumoftheproportionalgrowthratesofeachPandQTheproportionalgrowthrateofaquotient(E/Q)isthedifferenceoftheproportionalgrowthratesofthedividend(E)andthedivisor(Q)25Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ThreeMathematicalRulesTheproportionalgrowthrateofaquantityraisedtoanexponent(Qy)isequaltotheexponent(y)timesthegrowthratesofthequantity(Q)26Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapitalperWorkerTheproportionalgrowthrateofcapitalperworker[g(kt)]isSincethisisagrowthrateofaquotient,itwillbeequaltothegrowthrateofcapitalminusthegrowthrateoflabor(n)27Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.8-CalculatingtheProportionalGrowthRateoftheCapital-per-WorkerRatio28Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapitalperWorkerThegrowthrateofcapitalstockisNextyear’scapitalstockisMakingthesubstitution,weget29Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapitalperWorkerTheproportionalgrowthrateofcapitalperworkerisLetrepresentthecapital-outputratio(K/Y)30Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapitalperWorkerAllelseequal,therateofgrowthofcapitalperworkerwillbelowerthehighertherateoflaborforcegrowth(n)thehighertherateofdepreciation()thelowertherateofsaving(s)thehigherthecapital-outputratio()31Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.9-Capital-per-WorkerGrowthasaFunctionoftheCapital-OutputRatio32Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofOutputperWorkerWiththeCobb-Douglasproductionfunction,outputperworkerisThegrowthrateofoutputperworker[g(yt)]willbe33Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.10-CalculatingtheGrowthRateofOutputperWorker34Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofOutputperWorkerSinceg(kt)isequalto[(s/t)--n],wecansubstituteandsimplifytoget35Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapital-OutputRatioEquilibriumoccurswhenthecapital-outputratio(=K/Y)isconstantThegrowthrateofthecapital-outputratio[g(t)]isequaltothedifferenceinthegrowthrateofcapital[g(kt)]andthegrowthrateofoutput[g(yt)]36Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapital-OutputRatioWecanmakesubstitutionsfor[g(kt)]and[g(yt)]

andsimplifytoget37Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.GrowthofCapital-OutputRatioThegrowthrateofthecapital-outputratiodependsonthebalancebetweeninvestmentrequirements(n+g+)investmenteffort(s)Allelseequal,ahigherinvestmentrequirementwillmeanalowergrowthrateofthecapital-outputratio38Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.11-Growthofthe

Capital-OutputRatio39Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthEquilibriumoccurswhenthecapital-outputratioisconstantIft>[s/(n+g+)]thecapital-outputratiowillbeshrinkingIft<[s/(n+g+)]thecapital-outputratiowillbegrowing40Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.12-GrowthoftheCapital-OutputRatioasaFunctionoftheLeveloftheCapital-OutputRatio41Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthEquilibriumIft=[s/(n+g+)]thegrowthrateofthecapital-outputratiowillbezerothecapital-outputratiowillbestable(neithershrinkingnorgrowing)*=[s/(n+g+)]istheequilibriumlevelofthecapital-outputratio42Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.13-ConvergenceoftheCapital-OutputRatiotoItsSteady-StateValue43Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthEquilibriumWhenthecapital-outputratio(t)isatitssteadystatevalue(*)outputperworker[g(yt)]isgrowingatproportionalrategcapitalstockperworkerisgrowingatthesameproportionalrategtheeconomywidecapitalstockisgrowingattheproportionalraten+grealGDPisalsogrowingatproportionalraten+g44Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthPathWhenthecapital-outputratioisatitsequilibriumvalue(*),theeconomyisonitssteady-stategrowthpathFromChapter3,weknowthataslongasweareonthesteady-stategrowthpath45Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.14-CalculatingSteady-State

OutputperWorkeralongthe

Steady-StateGrowthPath46Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthPathAnincreaseinthecapital-outputratioincreasesthecapitalstockdirectlyandindirectlyextraoutputgeneratedbynewcapitalissourceforadditionalsavingandinvestmentThisleadstoamultipliereffectofanythingthatraises*47Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.16-TheGrowthMultiplier:TheEffectofIncreasingtheCapital-OutputRatioontheSteady-StateOutputperWorker48Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthPathLetthegrowthmultiplier()equal[/1-]Outputperworkeralongthesteady-stategrowthpathwillbe49Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Steady-StateGrowthPathTocalculateoutputperworkerwhentheeconomyisonitssteady-stategrowthpathcalculatethesteady-statecapital-outputratio[*=s/(n+g+)]amplifythesteady-statecapital-outputratio(*)bythegrowthmultiplier[=/(1-)]multiplybythecurrentvalueoftheefficiencyoflabor(Et)50Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.15-OutputperWorkerontheSteady-StateGrowthPath51Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ReachingtheSteady-StateGrowthPathHowlongdoesittakeforthecapital-outputratiotoadjusttoitssteady-statevalue(*)?aneconomythatisnotonitssteady-stategrowthpathwillcloseafraction[(1-)(n+g+)]ofthegapbetweenthesteadystatevalue(*)anditscurrentvalue(t)inayear52Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.17-WestGermanConvergencetoItsSteady-StateGrowthPath53Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.LaborForceGrowthThefasterthegrowthofthelaborforce,thelowerwillbetheeconomy’ssteady-statecapital-outputratiothelargertheshareofcurrentinvestmentthatmustgotoequipnewworkerswiththecapitaltheyneedAsudden,permanentincreaseinlaborforcegrowthwillloweroutputperworkeronthesteady-stategrowthpath54Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.18-LaborForceGrowthand

GDP-per-WorkerLevels55Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.Figure4.19-EffectsofaRiseinPopulationGrowthontheEconomy’sGrowthPath56Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.IncreasesintheDepreciationRateThehigherthedepreciationrate,thelowerwillbetheeconomy’ssteady-statecapital-outputratioexistingcapitalstockwearsoutandmustbereplacedmorequicklyAnincreaseinthedepreciationratewillloweroutputperworkeronthesteady-stategrowthpath57Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ProductivityGrowthThefasterthegrowthrateofproductivity,thelowerwillbetheeconomy’ssteady-statecapital-outputratiopastinvestmentwillbesmallrelativetocurrentoutputAnincreaseinproductivitygrowthwillraiseoutputperworkeralongthesteady-stategrowthpath58Copyri