第三章经济增长理论ppt-TheoriesofDev

TheoriesofDevelopment:AComparativeAnalysisChapter3LeadingTheoriesofEconomicDevelopment:FiveApproachesClassicalScenario古典经济增长理论Linear-stages-of-growthmodel线性增长模型Neoclassicalmodels新古典增长模型Endogenousgrowth内生经济增长模型亚当·斯密与报酬递增产出、生活水平提高→资本积累→利润的储蓄→工业和农业的专业化劳动分工劳动分工决定了劳动生产率。劳动分工提高劳动生产率有三种途径：1、工人工作技能的提升，即边干边学。2、分工的细化节省了在不同工作间转移的时间。3、机器的发明使同一个劳动者可以从事多种工作。劳动分工受到市场规模的限制。1、如机器的使用只有在市场规模较大情况下才有经济性，否则就会出现剩余产品。2、自由贸易对市场规模的扩大有着积极的意义。斯密的报酬递增观点是新内生经济增长理论的核心思想古典悲观主义TP*TPOWsubsistencewagelinePE2W2W1E1N1N2LaborTotalproductionOriginalcondition:Labor:ON1Production:OPWage:N1W1Surplus:E1W1DemandforlaborincreaseWagesincreasetoE1N1N1W1AccordingtoMalthusiantheoryofpopulation,populationwillincreasetoON2;SurplusappearagainE2W2Equilibriumpoint:ETechnologydevelopment:E*,thedayofdoomcannotbeeliminatedEE*LimitationsoftheclassicalmodelTheroleoftechnologydevelopmenthasbeengrosslyunderestimatedTheMalthusiantheoryofpopulationgrowthhasbeenprovedtobemisleading:wheneverwagesareabovelevelofsubsistence,populationwillincrease??TooaggregatedanddidnotaccountforthediversitieswithlaborandcapitalinputTheLinear-StagesTheoryRostow’sstagesofgrowthTheHarrod-DomargrowthmodelObstaclesandconstraintsSomecriticismsofthestagesmodelRostow’sstagesofgrowthTheTransitionfromunderdevelopmenttodevelopmentcanbedescriedintermsofaseriesofstepsorstagesthroughwhichallcountriesmustproceedthetraditionalsocietythepre-conditionsfortake-offintoself-sustaininggrowththetake-offthedrivetomaturitytheageofhighmass-consumption三种不同的增长率：实际增长率g;有保证的增长率gw;自然增长率gn实际增长率TheHarrod-DomarModel增量资本产出比率储蓄率//)//()/(/I/Δ/ΔK/ΔYcYSscsYIYSYYg)(潜在投资供给）计划储蓄sYSKI投资需求(3.1)(3.2)YvK(3.3)IS动态均衡(3.4)v:capital-outputratio;S:savingratio;S:totalsaving;Y:totaloutput;K:capitalstock;I:totalinvestment有保证的增长率：这样一种增长率将引诱投资刚好等于计划的储蓄，保持资本完全被就业，从而制造商愿意在未来以过去相同的比例进行投资TheHarrod-DomarModelIKYvsYS(3.5)YvsY(3.6)wgvsYY(3.7)Harrod-DomartheoryofeconomicgrowthTherateofgrowthofeconomicoutputIsdeterminedjointlybythenationalsavingratioSandnationalcapital-outputratioKThemainobstacleondevelopmentistherelativelylowlevelofnewcapitalformationinmostpoorcountriesJustifyingmassivetransfersofcapitalandtechnicalassistancefromdevelopedtolessdevelopednationsSavingandinvestmentisthenecessaryconditionforeconomicgrowthbutnotthesufficientconditionHowabouttheabilityofconvertingnewcapitaleffectivelyintohighlevelsofoutputmanagerialcompetence;skilledlabor;well-integratedcommodityandmoneymarket;institutionalsettings;infrastructuresCriticismofHarrod-DomarmodelStabilityofeconomicgrowth-Harrodianknife-edge保证均衡增长：g=gw一旦偏离均衡，即实际增长率与有保证增长率出现偏差，则这种偏离不会自行矫正，反而会加重如实际增长率低于有保证的增长率，在初期储蓄率相同情况下，实际的资本产出比大于有保证的资本产出比，将出现资本品过剩，投资受到抑制，储蓄率进一步下降，投资受到抑制，使实际增长率更低于均衡增长率如实际增长率高于有保证的增长率，则实际的资本产出率低于有保证的资本产出率，资本品不足会刺激投资，导致实际增长率进一步增大，更加偏离有保证的增长率，使得资本品更加不足Stabilityofeconomicgrowth-Harrodianknife-edgeStabilityofeconomicgrowth-Harrodianknife-edge黄金时代定理:actualgrowthrate=warrantedgrowthrate=naturalgrowthrateofthelaborforce.Thusn=s/visthenecessaryconditionforeconomicgrowth.（JoanRobinson：GoldenAgerule，CambridgeUniversity）自然增长率-取决于劳动力的增长速率和劳动生产率的增长速率)//()/(//)/log(loglog)/(LYLYLLYYLYLYLYLYButs,vandnaredeterminedindependentlyandthereisnothingthatguaranteesthats/vwillbeequalton.thusthegoldenruleisveryhardtoachieve.Itisaknife-edgegrowthrate(veryunstablesystem,withnomechanismtobringtheeconomybacktotheequilibriumgrowthrate).Whentheeconomyisgrowingfast,itcontinuestogrowevenfasterandgoesbeyondfullemployment(i.e.highinflation),butwhengrowthisslow,itcontinuestogrowevenslower(i.e.highunemployment).发展中国家的情况自然增长率高于有保证的增长率意味着有效劳动力增长高于资本积累速度，导致失业日益增长意味着计划投资高于计划储蓄，产生通货膨胀压力要使自然增长率趋近有保证的增长率1、控制人口规模2、控制劳动生产率增长幅度：效率与就业的冲突3、提高储蓄率4、使用劳动密集型技术降低所要求的资本－产出比NeoclassicalgrowthmodelIntheHarrod-Domargrowthmodel,steady-stategrowthwasunstable.Inthepopulartermoftheday,itwasaknife-edgeinthesensethatanydeviationfromthatpathwouldresultinafurthermoveawayfromthatpathRobertM.Solow(1956),TrevorSwan(1956)andJamesE.Meade(1961)contestedthisconclusion.Theyclaimedthatthecapital-outputratiooftheHarrod-Domarmodelshouldnotberegardedasexogenous.Neoclassicalmodel:thecapital-outputratio,v,waspreciselytheadjustingvariablethatwouldleadasystembacktoitssteady-stategrowthpath,i.e.thatvwouldmovetobrings/vintoequalitywiththenaturalrateofgrowth(n).TheresultingmodelhasbecomefamouslyknownastheSolow-SwanorsimplytheNeoclassicalgrowthmodel.新古典增长理论的三个基本命题在长期稳定状态，产出的增长来自于有效的劳动力增长率（即劳动力的增长率加上劳动生产率的增长率），与储蓄率无关，更高的储蓄或投资比率被更高的资本－产出比抵消。人均收入水平取决于储蓄率或投资－GDP比率，与人口增长率呈反比。资本－劳动比和资本生产率的反向关系使得发展中国家在人均资本数量较少的情况下拥有更高的短期经济增长速率，各国的人均收入和生活水平应该趋同。索罗模型1956年，开创性贡献《对经济增长理论的一个贡献》1987年，索罗获得诺贝尔经济学奖索罗模型的三个基本假定：1、世界上每一个国家只生产和消费相同商品；2、国家与国家之间不存在贸易关系；3、技术是外生的：公司可利用的技术游离于公司之外，不受公司行为的影响。索罗模型的三个技术假定1、劳动力以外生的不变速率增长2、产出是劳动和资本的函数，生产函数规模报酬不变，单个生产要素符合报酬递减规律。3、所有储蓄都用于投资。KYKFLYKLLFLKLKFLKLKFY///)1()1(/),(P),(1本租金率直到其边际产出等于资资本使用量持续增加，＝其边际产出等于工资劳动力持续增加，直到利润最大化条件：＝利润函数资本租金资本价格：工人工资劳动力价格：一、生产函数索罗模型两个重要函数递减的均资本该函数说明：则有：新表述：和人均资本使用量来重将生产函数用人均产出增加是所带带来的产出，人每增加一个单位劳动力报酬是递减的：劳动力人均资本的规模/;/