国际贸易理论与政策

,InternationalTrade:TheoryandPolicy,Chapter1InternationalExchangeandGainsfromTrade,Thischapterestablishesafundamentalresult:Ifrelativepricesdifferbetweencountriesintheabsenceoftrade,both(all)countriescangainbyexchangingcommoditiesatanyintermediatepriceratio.,TheInternationalExchangeandTheGainsfromTrade,TheCausesofInternationalTrade1.GeneralEquilibriumintheClosedEconomy,TheInternationalExchangeandTheGainsfromTrade,Autarkyequilibriumconditions:,TheInternationalExchangeandTheGainsfromTrade,Y,2.GeneralEquilibriumintheOpenEconomy,TheInternationalExchangeandTheGainsfromTrade,Tradingequilibriumconditions:,TheInternationalExchangeandTheGainsfromTrade,II.GainsfromTrade,Acountrytotradeatanypriceratiootherthanitsautarkypricesmustmakethecountrybetteroff.,TheInternationalExchangeandTheGainsfromTrade,1.TheGains-from-TradeTheoremIfthevalueoffreetradeconsumptionatfreetradepricesexceedsthevalueofautarkyconsumptionatfreetradeprices,thenthefreetradeconsumptionbundlemustbepreferredtotheautarkybundle,becauseifitwerenot,consumerswouldpickthecheaperautarky.,TheInternationalExchangeandTheGainsfromTrade,TheInternationalExchangeandTheGainsfromTrade,2.DecompositionofTradeGains,Chapter2TechnologyandTrade：theRicardianModel,Theroleoftechnologyinexplainingtradepatternsisfocusofthischapter.Theearliestmodeloftrade,thatassociatedwiththenameofDavidRicardo,isusedtodiscussthis.Itisassumedthatlaboristheonlyfactorofproductioninthemodel.Bydifferenceintechnology,wemeanthatlaborproductivitiesdifferacrosscountries.Internationaltradeoccursbasedonthedifferenceinlaborproductivitiesamongcountries.,TheRicardianModel,TheBasicFrameworkIntheRicardianmodel,therearetwosectors(X,Y)andonehomogeneousfactor,labor,onseveralassumptionsasfollows:(a)LaboristheonlyfactorusedinproductionofXandY;(b)Laborisperfectlymobilewithineachcountrybutinternationallyimmobile;(c)Laborinputrequiredperunitofoutputremainconstant;(d)Technologiesdifferbetweenthetwocountries.,SolvingEquilibrium,II.ProductionPossibilityFrontier,Fullemploymentcondition:,laborrequiredtoproduceoneunitofX,laborrequiredtoproduceoneunitofY,ProductionPossibilityFrontier(PPF),ThePre-tradeEconomy,Demandhasnoroleindeterminingpre-tradeprices.,III.AutarkyEquilibrium,ProfitMaximization:,ThePre-tradeEconomy,ThePre-tradeEconomy,III.ComparativeAdvantageAssumethatHomehasarelativehigherproductivityinX:SoHomehasacomparativeadvantageingoodX,ThePre-tradeEconomy,X,Y,O,Home,Foreign,IV.Free-TradeEquilibrium,TheWelfareofFreeTrade,V.TheGainsfromTradeandtheRoleofWages1.Realwageinfreetrade,TheWelfareofFreeTrade,ChangesinRealWages(fromAutarkytofreetrade）,2.Internationalwagecomparisonsandproductivities,LaborProductivityandWages,TheExtensionoftheRicardianModel,VI.TheRicardianModelwithManyGoods,TheExtensionoftheRicardianModel,VII.AnApplicationofRicadianModel：TradeandWageInequality,Chapter2TheHeckscher-Ohlin-SamuelsonModel,InthischapterweanalyzetheeffectsofinternationaldifferenceinfactorendowmentsontradeandwelfarebypresentingthefamoustheHeckscher-Ohlin-Samuelsonmodel,whichwasnamedforthetwoSwedisheconomistswhodevelopeditsessentials,andSamuelsonwhoformalisedtheoriginalmodel.ThemodeldepartsfromtheRicardianmodelintwofundamentalways:(1)introductionofsecondfactor,(2)differentfactorabundanceratherthandifferenttechnologiesbetweentwonations.Threeimportantresultsaredemonstratedinthechapter:theH-Otheorem,theStolper-Samuelsontheorem,andtheRybczynskitheorem.,TheHeckscher-Ohlin-SamuelsonModel,TheTwo-Factor,Two-SectorFramework:TheBasicModelThisframeworkhasthefollowingkeyassumptions:(a)Eacheconomyisendowedwithfixedamountsoftwohomogenousfactors,laborandcapital,denotedbyLandKrespectively.(b)Twosectorsproducetwohomogenousgoods,labeledgood1and2.Theproductionfunctionofsectori,i=1,2,islinearlyhomogenous.Inotherwords,productiontechnologyisconstantreturntoscale.,TheHeckscher-Ohlin-SamuelsonModel,Theproductionfunctionforsectoriis:,(c)Theproductionfunctionforanyparticularsectoristhesameinbotheconomies.(d)Theproductionfunctionsforeachsectorwithineacheconomyaredifferent.Thismeansthatsectorsdifferintheirfactorintensitiesatallfactorprices(factor-intensityreversalsareruledout,whichisknownastheSamuelsonintensitycondition).(e)Preferencesareidenticalandhomotheticinbotheconomies.(f)Competitioninfactorandproductmarkets,TheHeckscher-Ohlin-SamuelsonModel,II.ProductionEquilibrium,where,aretheunitfactorinputrequirement.Threeequilibriumconditions:(a)Profitmaximum,Where,ispercapitaoutputofgoodi.,TheHeckscher-Ohlin-SamuelsonModel,(b)Fullemployment,(c)Competitiveequilibrium,TheHeckscher-Ohlin-SamuelsonModel,FactorIntensity,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,Thefactor-pricefrontier,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,III.FactorAbundanceandthePatternofTrade:theH-OTheorem1.FactorabundanceTherearetwowaysofdefiningrelativefactorabundance:thephysicaldefinitionandthepricedefinition.,TheHeckscher-Ohlin-SamuelsonModel,(a)Thephysicaldefinitionif,thenHomeisrelativelycapital-abundancecomparedtoForeign.,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,(b)Thepricedefinition,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,TheH-OTheorem:Eachcountryexportsthecommoditywhichrequiresforitsproductiontherelativelyintensiveuseofthefactorfoundinrelativeabundanceinthatcountry.,TheHeckscher-Ohlin-SamuelsonModel,IV.TradeandIncomeDistributionalEffects:TheStolper-SamuelsonTheoremAnincreaseintherelativepriceofagoodwillunambiguouslyincreasetherealreturntothefactorofproductionusedrelativelyintensivelyintheproductionofthatgood,whiletherealreturntotheotherfactorofproductionwillbereducedintermsofbothgoods.,TheHeckscher-Ohlin-SamuelsonModel,w1,r1,TheHeckscher-Ohlin-SamuelsonModel,Wherestandforthesharesofrewardsaccruingtofactorj(j=L,K)asaproportionofthetotalearningsofeachindustryi(i=1,2).,TheHeckscher-Ohlin-SamuelsonModel,V.EndowmentChangesandOutputChanges:TheRybczynskiTheoremAtconstantcommodityprices,anincreaseinonefactorendowmentwillcausetheoutputofthegoodintensiveinthatfactortoincreasebyagreaterproportion,andwillreducetheoutputoftheothergood.,TheHeckscher-Ohlin-SamuelsonModel,TheHeckscher-Ohlin-SamuelsonModel,Wherestandsfortheproportionofthecountrysoverallstockoffactorj(j=L,K)intheparticularindustryi(i=1,2).,VI.TheTradingEquilibrium:AnIntegratedApproach,TheHeckscher-Ohlin-SamuelsonModel,PatternofTradeandChinasComparativeAdvantageShifting,MorerapidgrowthinChinastradesincedoor-opening.Chinasmerchandisetrade(imports+exports):17.4%;worldtrade:6%Exports:18.1%Imports:16.7%Chinasshareinworldexportsofgoodsrosefrom1%to11%;Chinabecamethelargestexporterofgoodsin2009.,Itsexportdynamismisgettingmoresophisticated(Rodrik,2006;Schott,2006)SomecriticalquestionsforChinanowlieinthepaceoftheirtechnologicalcatch-up,qualityupgradingofexportsandsustainablegrowthofexports,PatternofTradeandChinasComparativeAdvantageShifting,StructureofChinasexports(%),StructuralchangeofChinasmanufacturedexports,StructureofChinasExportsbyTechnology(%),TechnologycontentofChinasexports,Chapter5EconomiesofScale,ImperfectCompetitionandTrade,Inthischapter,wewillstartingexploringthenewreasonsfortradewithadiscussiontheroleofeconomiesofscale(EOS)otherthanthoseofcomparativeadvantage.Tradeenablescountriestospecializeinfewerproductionlines,henceensuringthattheybenefitfromEOS.Thesetrademodelswillprovideuswithanunderstandingofintra-industrytradethatoccursbetweencountriesthataresimilarinresources,technologyandtastes.ThedirectimplicationoftheexistenceofEOS(internaltothefirm)forourmodelisthatwemustswitchformperfectlycompetitivemarketstoimperfectlycompetitivemarkets.,I.EconomiesofScale,EOS,External,Internal,Perfectcompetition,ImperfectCompetition,TypesofEOS,MarketStructure,EconomiesofScale,ImperfectCompetitionandTrade,EconomiesofScale,ImperfectCompetitionandTrade,II.ExternalEconomiesofScaleandTrade,1.AtrademodelwithexternalEOS,Considerasimpletwo-country(HomeandForeign),two-good,one-factor(labour)model.Assumethatsector1issubjecttoexternaleconomiesofscaleinbothcountries,andsector2exhibitsconstant-return-to-scaleinbothcountries.,EconomiesofScale,ImperfectCompetitionandTrade,ExternalEOSprovideabasisfortradeindependentofcomparativeadvantage.Thus,evenwithnocomparativeadvantage,countriesendupspecializingintheproductionofdifferentgoods,EconomiesofScale,ImperfectCompetitionandTrade,2.Thepatternoftrade,Whentwocountriesareidenticalinthemodel,patternoftradeisunpredictable.Patternoftrademaybedeterminateashistoricaloraccidentalfactors,suchas“firstmoveradvantage”.Thedegreeofunpredictabilityislessifcountriesdifferinatleastoneaspect,suchassize(seefigurebelow).,EconomiesofScale,ImperfectCompetitionandTrade,3.Thegainsfromtrade,EconomiesofScale,ImperfectCompetitionandTrade,4.Dynamiceconomiesofscale,EconomiesofScale,ImperfectCompetitionandTrade,Withaccumulatingtheoutput,unitcostswilldecreaseasaresult.DynamicEOSisfrequentlyviewedastheprocessofcapabilityaccumulationandimprovementsintheskillswhichresultsfromexperience,referredaslearningbydoing,EconomiesofScale,ImperfectCompetitionandTrade,Learningcurve,EconomiesofScale,ImperfectCompetitionandTrade,5.Summary,EconomiesofScale,ImperfectCompetitionandTrade,III.ImperfectCompetitionandthePro-CompetitiveGainsfromtrade,1.Autarkyequilibriumwithamonopoly,IntheleftFigure,relativepricedoesnotreflectopportunitycost.AtequilibriumpointE,theslopeofrelativepricelineislargethantheslopeofthePPF(=MRT).,EconomiesofScale,ImperfectCompetitionandTrade,2.Thepro-competitiveeffect,Profiteffect,EOSeffect,EconomiesofScale,ImperfectCompetitionandTrade,IV.OligopolyandIntra-IndustryTradeinHomogenousGoods:TheReciprocalDumpingModel,1.TheCournotduopolymodel,EconomiesofScale,ImperfectCompetitionandTrade,Firm1sreactioncurve,Firm2sreactioncurve,2.Thetradingequilibrium,EconomiesofScale,ImperfectCompetitionandTrade,Home,Foreign,EconomiesofScale,ImperfectCompetitionandTrade,3.Thegainsfromtrade,EconomiesofScale,ImperfectCompetitionandTrade,EconomiesofScale,ImperfectCompetitionandTrade,V.MonopolisticCompetitionandIntra-IndustryTrade:TheHelpman-KrugmanModel,1.Productiondifferentiationandmonopolisticcompetition,Loveofvariety(therightFigure)Themost-preferredvariety,EconomiesofScale,ImperfectCompetitionandTrade,ThreeAssumptions:Eachfirmproducesonlyonevarietydifferentiatedfromtheonethatotherfirmproducesinthesameindustry.Theremanyfirmsintheindustry.Firmsusethesameproductiontechnologysubjecttotheincreasingreturntoscale.,EconomiesofScale,ImperfectCompetitionandTrade,2.Thefirminmonopolisticcompetition,EconomiesofScale,ImperfectCompetitionandTrade,EconomiesofScale,ImperfectCompetitionandTrade,3.Marketsize,thenumberandsizeoffirms,EconomiesofScale,ImperfectCompetitionandTrade,4.Gainsfromtrade,Consumersgainfromthedropinprice,whichistheresultofdecreasingaveragecost.Therearemoreproductvarietiesavailabletoconsumers,increasingconsumersutility.,Chapter6TradePolicyanddomesticDistortions,Whenthedomesticfactorandgoodmarketsareworkingunderfullycompetitiveconditions,theningeneralfreetradeisthebestandtheuseoftradepolicywillreducewelfare(theonlyexceptionistheuseofoptimaltariffwhencountryislarge).Incontrast,theexistenceofdomesticdistortionmeansfreetrademayreducewelfare,thegovernmentinterventioncanincreasewelfare,buttheuseofatradepolicyinstrumentisneveroptimalandisthereforethesecond-bestpolicy.,TradePolicyandDomesticDistortions,I.Introduction,Theexistenceofdomesticdistortionsraisethreequestions:Doesfreetradenecessarilyleadtoanincreaseinwelfarecomparedtotheautarkystate?Couldinterventionincreasethelevelofwelfare?Istheuseoftradepolicythebestwayinwhichthegovernmentcouldintervene?,Theanswers:NoYesNo,TradePolicyandDomesticDistortions,DomesticDistortionsinCommodityMarkets,Assumethatthereexistsasectorwithanegativeproductionexternality,imposingcostsontherestoftheeconomyforwhichitdoesnotpay,forexample,pollution.Thenrelativepricesinthedomesticmarketwillnotreflectthetrue(social)marginalcostoftransformationinproduction.,TradePolicyandDomesticDistortions,Thetariffwillleadtoanimprovementintheallocationofresources,becauseitwillreducetheproductionofthesectorwithanegativeexternality(Q2),Thefirst-bestpolicywouldbetotackletheexternalityproblemdirectly,byimposingataxonthepollutionandfollowingfreetrade.,TradePolicyandDomesticDistortions,TradePolicyandDomesticDistortions,III.DomesticDistortionsinFactoryMarkets,Inless-developedcountries,therefrequentlyexistssomedistortioninthefactormarkets.Forexample,inadual-economy,thereisawagedifferentialbetweenmanufacturingandagriculture.Thewage-differentialleadstodistorttheeconomysproductionpossibilitycurveinwards.Thewage-differentialalsocausetherelativecommoditypricetodifferfromtheopportunitycostofmanufacturedproduction.,TradePolicyandDomesticDistortions,TradePolicyandDomesticDistortions,TradePolicyandDomesticDistortions,Subsidizethecostoflaborinmanufacturing,Subsidizetheproductionofmanufacturing,Levytariffonmanufacturingimports,Rankofpoliciesbywelfareeffect:,TradePolicyandDomesticDistortions,IV.TheInfant-IndustryArgumentforProtection,Chapter7TradePolicyandImperfectCompetition,Inthepreviouscontext,wediscussedtheeffectsoftradepolicyandsomeprotectionismargumentsinaneoclassicalapproachunderperfectcompetition.Inthischapter,wetransfertodiscusssomenewargumentsthatderivedfromtheNewTradeTheoryinaworldofimperfectcompetition.Thissuggeststhattheanalysisoftradepolicybasedonthemodelsofchapter5leavesmoreroomforgovernmentintervention.Weshallstartbyconsideringtheeffectsoftradepoliceswhenthereismonopoly.Thenweshalldemonstratetheroleoftradepoliciesinavarietyofduopolymodels,whichhasbeenknownasstrategictradepolicy.,I.TariffandMarketPower,TradePolicyandImperfectCompetition,1.Protectingadomesticsingleproducerwithincreasingcost,TradePolicyandImperfectCompetition,2.Tariffasastimulanttoexports,3.Thenon-equivalenceoftariffsandquotas,