發(fā)展經(jīng)濟(jì)學(xué)developmenteconomics

1、進(jìn)展經(jīng)濟(jì)學(xué)developmenteconomics本課程的結(jié)構(gòu)進(jìn)展經(jīng)濟(jì)學(xué)研究范疇、方法和歷史演變研究范疇進(jìn)展的測(cè)度研究方法歷史演變進(jìn)展與增長(zhǎng)理論增長(zhǎng)與進(jìn)展的差異增長(zhǎng)理論：Harrod-Dmarmodel;Solowmodel;convergence:unconditionalandconditional.新增長(zhǎng)理論人口增長(zhǎng)與經(jīng)濟(jì)進(jìn)展經(jīng)濟(jì)進(jìn)展與人類(lèi)進(jìn)展cs(1)進(jìn)展與收入分配收入分配的現(xiàn)實(shí)與理論收入決定機(jī)制與因素分析經(jīng)濟(jì)進(jìn)展與收入差距經(jīng)濟(jì)增長(zhǎng)與收入分配中國(guó)收入分配的變化趨勢(shì)進(jìn)展中國(guó)家中的貧困咨詢題絕對(duì)貧困與相對(duì)貧困貧困線的設(shè)定貧困標(biāo)準(zhǔn)的選擇：收入依舊消費(fèi)貧困的度量：貧困發(fā)生率、貧困距和加權(quán)貧困距

2、中國(guó)的貧困狀態(tài)進(jìn)展中國(guó)家的勞動(dòng)力市場(chǎng)與人力資本勞動(dòng)剩余與兩部門(mén)模型勞動(dòng)力市場(chǎng)中工資決定機(jī)制勞動(dòng)力市場(chǎng)中鄙視咨詢題中國(guó)農(nóng)民工的工資與鄙視狀態(tài)的研究勞動(dòng)力流淌與城鄉(xiāng)差距教育、健康與經(jīng)濟(jì)進(jìn)展土地與經(jīng)濟(jì)進(jìn)展土地產(chǎn)權(quán)與租賃制度土地租賃合同理論土地產(chǎn)權(quán)制度理論資本市場(chǎng)與經(jīng)濟(jì)進(jìn)展信貸市場(chǎng)的不完善性農(nóng)村信貸市場(chǎng)的功能與進(jìn)展非正規(guī)信貸市場(chǎng)資本市場(chǎng)的制度與信貸市場(chǎng)的進(jìn)展保險(xiǎn)與進(jìn)展保險(xiǎn)的功能完善的保險(xiǎn)模型保險(xiǎn)的局限性：信息的不對(duì)稱(chēng)性保險(xiǎn)的執(zhí)行困難國(guó)際貿(mào)易與經(jīng)濟(jì)進(jìn)展國(guó)際貿(mào)易的差不多理論比較優(yōu)勢(shì)理論世界貿(mào)易格局貿(mào)易政策和進(jìn)展戰(zhàn)略制度與經(jīng)濟(jì)進(jìn)展新制度經(jīng)濟(jì)學(xué)對(duì)經(jīng)濟(jì)進(jìn)展的啟發(fā)政府與市場(chǎng)的作用經(jīng)濟(jì)改革與經(jīng)濟(jì)進(jìn)展進(jìn)展經(jīng)濟(jì)學(xué)的以后

3、方向理論依舊體會(huì)研究？中國(guó)經(jīng)濟(jì)進(jìn)展的體會(huì)如何上升到一樣的經(jīng)濟(jì)進(jìn)展理論進(jìn)展經(jīng)濟(jì)學(xué)研究范疇、方法和歷史演變研究對(duì)象(DE是什么)Whatiseconomicdevelopment?Economicdevelopmentisthedevelopmentofeconomicwealthofcountriesorregionsforthewell-beingoftheirinhabitants.Theprocesswherebytherealpercapitaincomeofacountryincreasesoveralongperiodoftime,subjecttothestipulationsth

4、atthenumberofpeoplebelowanabsolutepovertylinedoesnotincreaseandthatthedistributionofincomedoesnotbecomemoreunequal.Economicdevelopmentisameanstomakemasspeopleoutofpoverty.Whatdevelopmenteconomicsstudies?DEstudiestheeconomicstructureandbehaviorofthepoor(lessdeveloped)countries(Lewis,1984).Development

5、Economics(DE)studiestheeconomictransformationofdevelopingcountries(DebrajRay,1998).ThemajortaskofDEistoexplorethepossibilitiesofemancipationfrompovertyfordevelopingeconomies(YujiroHayami,2001).DEisaboutthebigissues:howeconomiesandsocietiesgrowandchange(N.Stern,2001).Backward?underdevelopment?lessdev

6、elopedcountries?poorcountriesemergentcountries?developingeconomies.ntheworlds1970-20101。6Gm6Gm66666006666600。OOOOT TI IIIIIIIIIIIInjrslrNr*JnJInjrslrNr*JnJ1.4研究方法(1)理論研究與體會(huì)研究(theoreticalandempiricalapproach)(2)進(jìn)展微觀經(jīng)濟(jì)學(xué)與進(jìn)展宏觀經(jīng)濟(jì)學(xué)(developmentmicroeconomicsanddevelopmentmacroeconomics*1.2研究?jī)?nèi)容(研究什么)(1)懂得現(xiàn)在

7、世界各國(guó)進(jìn)展的不平穩(wěn)性。(2)懂得進(jìn)展中國(guó)家現(xiàn)在的咨詢題需要懂得發(fā)達(dá)國(guó)家的進(jìn)展體會(huì)，具有比較的意義。(3)對(duì)前人的進(jìn)展理論要加以研究。(4)進(jìn)展涉及到專(zhuān)門(mén)多層面,110L.3190-GDP80際比它在國(guó)較中的缺陷：進(jìn)展中國(guó)家GDP低估的咨詢題；PPP方法來(lái)修正GDP;?人類(lèi)進(jìn)展指數(shù)(HDI)的意義和應(yīng)用60-kChinarankofHDI小K KK KZK3COZK3CO6666ch666666ch66IIIITITIIIITITofdevelopment)orGDPpercapita是否是衡量進(jìn)展匕(3)純粹的經(jīng)濟(jì)分析依舊多學(xué)科研究1.5歷史演變古典經(jīng)濟(jì)學(xué)是當(dāng)時(shí)的進(jìn)展經(jīng)濟(jì)學(xué)在20世紀(jì)40年代

8、后期，現(xiàn)代進(jìn)展經(jīng)濟(jì)學(xué)形成。Capitalaccumulation,asthenecessaryrequirement,wasthecentralfocusofthemodels.TheHarrod-Domarequation,althoughoriginallyformulatedforconditionsoffullgrowthinanindustrialeconomy,wasappliedtoestimatecapitalrequirementsindevelopingcountries.Otherearlymodelsofdevelopmentstrategyalsofeaturedca

9、pitalaccumulation:Rostowsstagesofgrowth,TraditionalsocietyPreconditionsfortake-offTake-offDrivetomaturityAgeofHighmassconsumptionNurksesbalancedgrowth,Thetheoryhypothesesthatthegovernmentofanyunderdevelopedcountryneedstomakelargeinvestmentsinanumberofindustriessimultaneously.Thiswouldconsequentlyenl

10、argethemarketsizeandprovideanincentivefortheprivatesectortoinvest.Rosenstein-Rodansexternaleconomiesandbigpush,Thistheoryisaninvestmenttheorywhichstressestheconditionsoftake-off.Theargumentationisquitesimilartothebalancedgrowththeorybutemphasisisputontheneedforabigpush.Theinvestmentsshouldbeofarelat

11、ivelyhighminimuminordertoreapthebenefitsofexternaleconomies.Onlyinvestmentsinbigcomplexeswillresultinsocialbenefitsexceedingsocialcosts.Highpriorityisgiventoinfrastruc-turaldevelopmentandindustry,andthisemphasiswillleadtogovernmentaldevelopmentplanningandinfluence.Lewissunlimitedsupplyoflaboranddual

12、-sectormodelTheprocessofeconomicgrowthisinextricablylinkedtothegrowthofcapitalistsurplus,thatisaslongasthethecapitalistsurplusincreases,thenationalincomealsoincreasesraisingthegrowthoftheeconomy.Theincreaseincapitalistsurplusislinkedtotheuseofmoreandmorelaborwhichisassumedtobeinsurplusincaseofthismo

13、del.Thisprocessofcapitalaccumulationdoescometoanendatsomepoint.Thispointiswherecapitalaccumulationcatchesupwithpopulationsothatthereisnolongeranysurpluslaborleft.Prebisch-Myrdal-SingerhypothesesabouttermsoftradeandimportsubstitutionThethesispostulatesthattermsoftrade,betweenprimaryproductsandmanufac

14、turedgoods,deteriorateintime.Countriesthatexportcommodities(developingcountries)intimewouldimportfewermanufacturedgoodsrelativetoagivenlevelofexports.Leibensteinscriticalminimumeffortthesis,Criticalminimumefforttheoryisoneofthebalancedgrowththeories.Ittalksabouthowaminimumamountofpushisrequiredbyane

15、conomyforittobesetonthepathofdevelopment.Thispushcanbeintheformofinvestments.Theminimumamountofeffortthatisrequirediscriticalfortheeconomytomovetowardsdevelopmenthencethistheoryiscalledcriticalminimumeffort.Becauseofthehighpopulationinunderdevelopedcountriesthecapitalaccumulationandlaboursupplyareno

16、tsufficienttoincreasethepercapitaincome.Chenerystwo-gapmodel.Two-gapmodel(Two-gapModel),isthedevelopingcountriestoachievethesavingsgapandforeignexchangegapsinthetheoryoftheequilibriummodel.Themodelisthroughtheuseofexternalresourcesindevelopingcountries,toplaytheroleofgovernmentinthesametime,adjustme

17、ntofdomesticeconomicstructuretoadapttotheintroductionofexternalresources.Itreflectstheintroductionofexternalresourcesindevelopingcountries,foreasingthescarcityofdomesticresourcesisimportant.Two-gapmodelofthebasicequation:I-S=M-XI-Sisthedifferencebetweeninvestmentandsavings,knownasthesavingsgapM-Xist

18、hedifferencebetweenimportsandexports,knownastheforeignexchangegapadjustedforthepurposeofeachvariableistobalancetheequation.Hirschman,StrategyofEconomicDevelopment(1958).UnbalancedgrowthContrarytothetheoryofbalancedgrowth,inHirschmansopinion,therealbottleneckisnottheshortageofcapital,butlackofentrepr

19、eneurialabilities.Potentialentrepreneursarehinderedintheirdecision-makingbyinstitutionalfactors:eithergroupconsiderationsplaya-greatroleandhinderthepotentialentrepreneur,orentrepreneursaimatpersonalgainsatthecostofothersandarethusequallydetrimentaltodevelopment.Inviewofthelackofenterpreneurialabilit

20、iesthereisaneedforamechanismofincentiveandpressurewhichwillautomaticallyresultintherequireddecisions.AccordingtoHirschman,notabalancedgrowthshouldbeaimedat,butratherexistingimbalanceswhosesymptomsareprofitandlosses-mustbemaintained.Investmentsshouldnotbespreadevenlybutconcentratedinsuchprojectsinwhi

21、chtheycauseadditionalinvestmentsbecauseoftheirbackwardandforwardlinkageswithoutbeingtoodemandingonentrepreneurialabilities.Manufacturingindustriesandimportsubstitutionsarerelevantexamples.Thesefirstinvestmentsinitiatefurtherinvestmentswhicharemadebylessqualifiedentrepreneurs.Thus,thestrategyovercome

22、sthebottleneckofentrepreneurialability.Thetheorygivesnohintsastohowtheattitudeofentrepreneursandtheirinstitutionalinfluencewillbechangedintime.P.Rosenstein-Roden,ProblemsofIndustrializationofEasternandSoutheasternEurope,EconomicJournal(June-September,1943).H.Leibenstein,Economicbackwardnessandeconom

23、icgrowth(1957).R.Nelson,“Atheoryofthelow-levelequilibriumtrapinunderdevelopedeconomies,AER(Dec.1956).W.Rostow,Thestagesofeconomicgrowth(1960).R.Nurkse,Problemsofcapitalformationinunderdevelopedcountries(1953).Structuralistanalysis:rigidities,lags,shortageandsurpluses,lowelasticitiesofsupplyanddemand

24、.G.Myrdal.Economictheoryandunderdevelopedregions(1957).R.Prebisch,“TheeconomicdevelopmentofLatinAmericaandItsprincipalproblems”,EconomicBulletinforLatinAmerica7(1950).H.Singer,Gainsandlossesfromtradeandinvestmentinunderdevelopedcountries/,AER(may1950).在20世紀(jì)60年代后期至70年代初期，進(jìn)展經(jīng)濟(jì)學(xué)更加注重貧困和收入分配。增長(zhǎng)的不平穩(wěn)性，注重農(nóng)村

25、進(jìn)展；人力資本的形成，對(duì)人力資源的研究；適用技術(shù)，而是最新技術(shù)的引進(jìn)。Furthermore,inthe1960stheinitialconcentrationonphysicalcapitalaccumulationwasgivingwaytotheconceptofinvestmentinhumancapitalanditsimplicationsfordevelopment.Itwasincreasinglyrecognizedthatdevelopmentdependedonproductivehumanagentswho,throughtheiracquisitionofknowle

26、dge,betterhealthandnutrition,andincreaseinskills,couldraisetotalfactorproductivity.(4)70年代至80年代，新古典經(jīng)濟(jì)學(xué)的重新崛起：對(duì)政策導(dǎo)致的市場(chǎng)扭曲的批判，對(duì)非市場(chǎng)失靈的批判，對(duì)政府操縱的批判，from“getpricesright”to“getpoliciesright”,市場(chǎng)、價(jià)格、鼓舞成為主題。內(nèi)向型進(jìn)展戰(zhàn)略轉(zhuǎn)向外向型(出口導(dǎo)向性)戰(zhàn)略，價(jià)格穩(wěn)固和操縱通貨膨脹成為首選目標(biāo)，大力推進(jìn)國(guó)有企業(yè)的私有化。注意到進(jìn)展中國(guó)家之間的差異性，總體增長(zhǎng)模型被國(guó)別的微觀化模型所取代，國(guó)別的研究和體會(huì)研究受到越來(lái)越多的重

27、視，新古典經(jīng)濟(jì)學(xué)的差不多原理被應(yīng)用到進(jìn)展中國(guó)家的政策研究。 老進(jìn)展經(jīng)濟(jì)學(xué)家是不承認(rèn)新古典經(jīng)濟(jì)學(xué)能夠用于進(jìn)展中國(guó)家，而新進(jìn)展經(jīng)濟(jì)學(xué)家不僅認(rèn)為新古典經(jīng)濟(jì)學(xué)能夠用于進(jìn)展中國(guó)家，而且認(rèn)為進(jìn)展經(jīng)濟(jì)學(xué)不能成為一個(gè)專(zhuān)門(mén)的學(xué)科。Ifthefirstgenerationofdevelopmenteconomistswasvisionaryanddedicatedtograndtheoriesandgeneralstrategies,thesecondgenerationwasalmostmoralistic,dedicatedtoasomberrealismgroundedonfundamentalprinci

28、plesofneoclassicaleconomics.Harbergercouldsaytothegovernmentsofdevelopingcountries,Economicsisgoodforyou-andbyeconomics,hemeantneoclassicalanalysisasthebasisforpolicymaking(Harberger1993).Onceitisrecognizedthatindividualsrespondtoincentives,andthatmarketfailureistheresultofinappropriateincentivesrat

29、herthanofnonresponsiveness,theseparatenessofdevelopmenteconomicsasafieldlargelydisappears.Instead,itbecomesanappliedfield,inwhichthetoolsandinsightsoflaboreconomics,agriculturaleconomics,internationaleconomics,publicfinanceandotherfieldsareaddressedtothespecialquestionsandpolicyissuesthatariseinthec

30、ontextofdevelopment.(Krueger1986:62f)9Inaccordancewithneoclassicaleconomictheory,thesecondgenerationmovedfromhighlyaggregativemodelstodisaggregatedmicrostudiesinwhichtheunitsofanalysiswereproductionunitsandhouseholds.Forofferingpolicyadvice,grandtheoriescametobeviewedaslessusefulthanhighlyspecificap

31、plications.Microstudies,ratherthanthebroadervisionarymodelsoftheearlierperiod,couldprovidemoredirectpolicyimplicationsforspecificpoliciessuchasachangeintariffsoragriculturalsubsidies.Therewasamarkedchangefromafocusontheprocessofdevelopmenttoanemphasisonparticularfeaturesofunderdevelopment.Quantitati

32、veanalyticaltoolswereusedmoreextensively,especiallyforempiricalanalysisofmicrophenomenathatwerecountryspecific,sectorspecific,orprojectspecific.Thegreateravailabilityofmicrodatasetsallowedthemodelingofhouseholdbehaviorandofhumancapitalinvestmentsineducationandhealth.Thesecondgeneration,whichwasablet

33、oreflectontwoorthreedecadesofdevelopmentexperience,recognizedtheincreasingheterogeneityofdevelopingcountriesandgavemoreattentiontoanexplanationofdifferentialratesofcountryperformance.Cross-countryeconometricstudiesofthedeterminantsofeconomicgrowthmultiplied.Acomparativeapproachwasadoptedinanattemptt

34、ounderstandwhycertainpolicieswereeffectiveinagivencountrywhileotherswerenot,andwhythesametypeofpolicywaseffectiveinonecountrybutnotinanother.Forexample:Inearlierconceptsoftheaggregateproductionfunction,theresidualwasthoughtofasacoefficientoftechnicaladvance.Thesecondgeneration,however,lookedatthegro

35、wthprocessinamoremicroeconomicfashion.Theresidualwasrecognizedtobeacompositeoftheeffectsofmanydifferentforces:(i)improvementsinthequalityoflaborthrougheducation,experienceandon-the-jobtraining;(ii)reallocationofresourcesfromlow-productivitytohigher-productivityuses,eitherthroughnormalmarketforces,or

36、throughthereductionofbarriersordistortions;(iii)exploitationofeconomiesofscale;(iv)improvedwaysofcombiningresourcestoproducegoodsandservices,notjustatthelevelofnewmachinesorprocesses,butalsobyrelativelyadjustmentsatthelevelofthefactoryorthefarmFigure1.EvolutionofdevelopmentthoughtGoalsofdevelopmentG

37、DP?GDPpercapita?HDI?Mitigationofpoverty?Entitlementsandcapabilities?FreedomSustainableDGrowththeoryHarrod-Domarmodel?Solowsourcesofgrowth?NewgrowththeoryCapitalaccumulationPhysicalcapital?H.C.?KnowledgeC?SocialC.StateandmarketMarketfailures?Nonmarketfailures?Newmarketfailures?InstitutionalfailuresGo

38、vernmentinterventionsProgrammingandplanning?minimalistgovernment?complementarityofgovernmentandmarketPolicyreformPoorbecausepoor?poorbecausepoorpolices(getpricesright)?getpoliciesright?getinstitutionsright進(jìn)展與增長(zhǎng)理論增長(zhǎng)與進(jìn)展的差異Developmentistakentomeangrowthpluschange.”“Improvementofthefactorsofproduction,v

39、elopmentofinstitutionsandaimprovedtechnologyofproduction;thedechangeinattitudesandvalues.owlem加Upward80000.00080000.000movementoftheentiresocialsystem”GunnarMyrdal.區(qū)A%seinproductivity,socialandeconomicequalization,modernknsooooooog西oimptro、.000.000venstitutionsandattitudesandrationallycoordinatedsys

40、tlIllIIJi快omeasuresC.E.Black.10000.00010000.0000,0000,000UiUUUnirWGrowth,equalityandvalLi 匚q q_ _DifferencesineconomicationI吊萬(wàn)甫LLlevelofoutput.至qe3二 ECDBms 五andgrowthCountrysGNPpercapitain2010仁S5S5一三冷一S Sslesle1-1-r r田二衛(wèi).二區(qū)一聲討u,U一 RI-I-C Cl l-.-.fj.fj.二SHSH二一工S S0 0一三，匚 2TcTcacac*=qcqEiNauoa 一巴 j 里表

41、1-1:2000-2005年世界經(jīng)濟(jì)和地區(qū)經(jīng)濟(jì)年增長(zhǎng)率及其與中國(guó)比較低收入國(guó)家6.0中等收入國(guó)家5.1其中：低中等收入國(guó)家6.0高中等收入國(guó)家5.1中、低收入國(guó)家5.3高收入國(guó)家2.2樂(lè)業(yè)與環(huán)太平洋國(guó)家8.3其中：中國(guó)9.6歐洲與中亞國(guó)家5.4拉美和加勒比海國(guó)家2.3中東與北非國(guó)家4.1南亞國(guó)家6.4非洲撒哈拉地區(qū)4.2資料來(lái)源：Worlddevelopmentreport2007:developmentandthenextgeneration.WorldBank,2007.增長(zhǎng)理論：Harrod-DomarmodelbasicformulasY(t)=C(t)+S(t)2-1Y(t)=C(t

42、)+I(t)2-2S(t)=I(t)2-3K(t+1)=(1-S)K(t)+I(t)2-40(capital-outputratio)=K(t)/Y(t)g(growthrate)=Y(t+1)-Y(t)/Y(t)s/0=g+S2-5org=s/0-S2-5aIfthereispopulationgrowth,thegrowthrateofGDPpercapitaisg*and(2-5)becomess/0=(1+g*)(1+n)-(1-S)2-6s/0?g*+n+S2-7org*?s/0-n-82-7a(1-2)LimitationsofthemodelTheendogeneityofsav

43、ings:Incomeleveleffectonsavings;incomedistributioneffectonsavings.Theendogeneityofpopulationgrowth:Demographictransition;relationshipbetweenpopulats(savingsrate)=S(t)/Y(t);iongrowthandeconomicgrowth(Figure3.2).TheSolowmodel(2-1)Basicideas:oneassumption:thelawofdiminishingreturnstoindividualfactorsof

44、production.0(capital-outputratio)isendogenous.(2-2)TheSolowequationsK(t+1)=(1-S)K(t)+sY(t)Withpopulationgrowthataconstantrate(n),(1+n)k(t+1)=(1-S)k(t)+sy(t)(2-3)ThedynamicsoftheSolowmodelProductionfunction;To川ustrateFigure3.4inRay(1998).(2-4)ThesteadystateToillustrateFigure3.4inRay(1998).Steadystate

45、islevelofpercapitacapitalstock,towhichpercapitacapitalstock,startingfromanyinitiallevel,mustconverge.(2-5)Howtheparametersaffectthesteadystatek*/y*=s/(n+8)(2-6)Leveleffectandgrowtheffectofpopulationgrowth2-92-8ToillustrateFigure3.5inRay(1998)(2-7)TechnicalprogressTwogrowthsources:technicalprogressan

46、daccumulationofcapitalinputs.ThebasicSolowmodelcanbeadaptedeasilytoincludetechnicalprogress.SupposeworkingpopulationP(t),amountoflaborinefficientunitsL(t),soL(t)=E(t)P(t)2-11E(t)isefficiencyindex.Ifefficiencygrowsat兀，soE(t+1)=(1+兀)E(t).(1n)(1)k(t1)(1)k(t)sy(t)2-12Evenifthereistechnicalprogress,stead

47、ystateisstillexistingastheoutput-capitalratiotendstofall.Thelong-runincreaseinpercapitaincometakesplacepreciselyattherateoftechnicalprogress.Theconvergenceanddivergence(3-1)Whatmeansconvergence?(3-2)UnconditionalconvergenceInthefaceofsimilarparametersgoverningevolution,thedifferentinitialconditionsd

48、oesnotmatter.ToillustrateFigure3.7inRay(1998).Convergenceisindicatedbyastrongnegativerelationshipbetweengrowthrateofpercapitaincomeandtheinitialvalueofpercapitaincome.log(yt+1)-log(yt)=a+blog(yt)+&2-13Illustratethefiguresbelow(nextpages)ParenteandPrescott(1993)studies102countriesovertheperiodof1

49、960-85andfindsstandarddeviationincreasingovertime.DoesitmeantheSolowmodeliswrongandHarrod-Domarmodelisright?(3-3)ConditionalconvergenceUnconditionalconvergencehastheassumptionthatacrossallcountriestheleveloftechnicalprogress,therateofsavings,therateofpopulationgrowthandtherateofdepreciationareallthe

50、same.Iftheseconditionsarechanged,thesteadystateshouldbedifferentfordifferentcountries.Thisleadstoconditionalconvergence.Iftherateofsavingsandpopulationgrowthratesaredifferent,theincomelevelwoulddifferandgrowthratewouldbethesame.Thenewgrowththeories(endogenousgrowththeories):IntroductionWhiletheSolow

51、modelgetssomeofthepredictedcorrelationscorrect,howdowereconcilethehugeobserveddifferencesinpercapitaincomewiththemoremodestpredictionsofthemodel?Canwebesatisfiedwithatheorythatonlyassumesdifferencesinkeyparameterswithoutexplainingthesedifferences?Long-runpercapitagrowthmaywellbedrivenbytechnicalprog

52、ressalone,butthisdoesnotmeanthattechnicalprogressfallsonsocietieslikemannafromheaven.Humanbeings,throughtheirconsciousactions(andsomeluck),determinetherateoftechnicalprogress,andifthisisso,suchactionsshouldbepartofanexplanatorytheory,andnotsimplyblack-boxed.(4-1)ModelofhumancapitalandgrowthContribut

53、ors:Uzawa1965,Lucas(1988),Barro1991,Mankiw,Romer,andWeil1992.Laborisskilledinproduction,laborthatcanoperatesophisticatedmachinery,laborthatcancreatenewideasandnewmethodsineconomicactivity.Itisimportanttocontrastthisformoflaborwithunskilledlabor.AugmenttheSolowmodelbypermittingindividualsto“saveTintw

54、odistinctforms:physicalcapitalandhumancapital.y=kahl-a(2-14)wherehstandsforhumancapitalandunskilledlaborhasbeenomittedfornow.First,afractionsofoutputissaved,permittingtheaccumulationofphysicalcapital:k(t+1)-k(t)=sy(t).(2-15)Anotherfractionqissavedinadifferentway:itisusedtoaugmentthequalityofhumancap

55、ital,sothath(t+1)-h(t)=qy(t).(2-16)Letrdenotetheratioofhumantophysicalcapitalinthelongrun.idesof(2-15)byk(t)anduse(2-14)tonotethat orsrorsrDividebothsiLikewise,dividebothsidesof(4.3)byh(t)anduse(4.1)onceagainBecausethesetwogrowthratesarethesameinthelongrun(sothattheratioofhumantophysicalcapitalalsos

56、taysconstant),wemusthavesr1-a=qr-%,orsimplyr=q/s.Thelargeristheratioofsavinginhumancapitalrelativetothatofphysicalcapital,thelargeristhelong-runratiooftheformertothelatter.Wecannowusethisvalueofrtocomputethelong-rungrowthrate.sothatthelong-rungrowthrateofallthevariables,includingpercapitaincome,isgi

57、venbytheexpressions%q1-%.Implications:Itispossiblefortheretobediminishingreturnstophysicalcapitalandyetfortheretobenoconvergenceinpercapitaincome.Ifcountriesto seethegrowthrateofhumancapital.二qrfh(t)(2-17)havesimilarsavingsandtechnologicalparameters,theydogrowatthesamerateinthelongrun,butthereisnote

58、ndencyfortheirpercapitaincomestocometogether:initialrelativedifferenceswill,byandlarge,bemaintained.Thereisanotherimplicationoftheoverallconstancyofreturns.Boththerateofsavingsandtherateofinvestmentinhumancapitalhavegrowth-rateeffectsonceagainandnotjustleveleffectsasintheSolowmodel.Becausethesedecis

59、ionsaffectthegrowthrateandthepaceofgrowthisdeterminedfromwithinthemodelandisnotsimplyattributedtoexogenoustechnicalprogress.Note,however,thatthegrowtheffectsarerelatedtotheconstancyofreturnstophysicalandhumancapitalcombined.Theintroductionofhumancapitalalsohelpstoexplainwhyratesofreturntophysicalcap

60、italmaynothighinpooripP.AmbiguDdson|ipP.AmbiguDdson|(5a)Conditionalconvergenceaftercontrollingforhumancapital.Byconditioningonthelevelofhumancapitalpoorcountrieshaveatendencytogrowfaster.(5b)Conditionaldivergenceaftpitaincome.Byconditioningqncountriestheinitiallevelofpercapitaincome,countrieswithmorehumanca