andInternationalTrade(发展经济学-厦门大学,陈涛.ppt

Chapter6,EconomiesofScale,ImperfectCompetition,andInternationalTrade,Copyright2003PearsonEducation,Inc.,Slide6-2,IntroductionEconomiesofScaleandInternationalTrade:AnOverviewEconomiesofScaleandMarketStructureTheTheoryofImperfectCompetitionMonopolisticCompetitionandTradeDumpingTheTheoryofExternalEconomiesExternalEconomiesandInternationalTradeSummary,ChapterOrganization,Copyright2003PearsonEducation,Inc.,Slide6-3,Introduction,Countriesengageininternationaltradefortwobasicreasons:Countriestradebecausetheydiffereitherintheirresourcesorintechnology.Countriestradeinordertoachievescaleeconomiesorincreasingreturnsinproduction.Twomodelsofinternationaltradeinwhicheconomiesofscaleandimperfectcompetitionplayacrucialrole:MonopolisticcompetitionmodelDumpingmodel,Copyright2003PearsonEducation,Inc.,Slide6-4,EconomiesofScaleandInternationalTrade:AnOverview,Modelsoftradebasedoncomparativeadvantage(e.g.Ricardianmodel)usedtheassumptionsofconstantreturnstoscaleandperfectcompetition:Increasingtheamountofallinputsusedintheproductionofanycommoditywillincreaseoutputofthatcommodityinthesameproportion.Inpractice,manyindustriesarecharacterizedbyeconomiesofscale(alsoreferredtoasincreasingreturns).Productionismostefficient,thelargerthescaleatwhichittakesplace.,Copyright2003PearsonEducation,Inc.,Slide6-5,Underincreasingreturnstoscale:Outputgrowsproportionatelymorethantheincreaseinallinputs.Averagecosts(costsperunit)declinewiththesizeofthemarket.,EconomiesofScaleandInternationalTrade:AnOverview,Copyright2003PearsonEducation,Inc.,Slide6-6,EconomiesofScaleandInternationalTrade:AnOverview,Table6-1:RelationshipofInputtoOutputforaHypotheticalIndustry,Copyright2003PearsonEducation,Inc.,Slide6-7,EconomiesofScaleandMarketStructure,Economiesofscalecanbeeither:ExternalThecostperunitdependsonthesizeoftheindustrybutnotnecessarilyonthesizeofanyonefirm.Anindustrywilltypicallyconsistofmanysmallfirmsandbeperfectlycompetitive.InternalThecostperunitdependsonthesizeofanindividualfirmbutnotnecessarilyonthatoftheindustry.Themarketstructurewillbeimperfectlycompetitivewithlargefirmshavingacostadvantageoversmall.Bothtypesofscaleeconomiesareimportantcausesofinternationaltrade.,Copyright2003PearsonEducation,Inc.,Slide6-8,ImperfectcompetitionFirmsareawarethattheycaninfluencethepriceoftheirproduct.Theyknowthattheycansellmoreonlybyreducingtheirprice.Eachfirmviewsitselfasapricesetter,choosingthepriceofitsproduct,ratherthanapricetaker.Thesimplestimperfectlycompetitivemarketstructureisthatofapuremonopoly,amarketinwhichafirmfacesnocompetition.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-9,Monopoly:ABriefReviewMarginalrevenueTheextrarevenuethefirmgainsfromsellinganadditionalunitItscurve,MR,alwaysliesbelowthedemandcurve,D.Inordertosellanadditionalunitofoutputthefirmmustlowerthepriceofallunitssold(notjustthemarginalone).,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-10,TheTheoryofImperfectCompetition,Figure6-1:MonopolisticPricingandProductionDecisions,MR,MC,Copyright2003PearsonEducation,Inc.,Slide6-11,MarginalRevenueandPriceMarginalrevenueisalwayslessthantheprice.Therelationshipbetweenmarginalrevenueandpricedependsontwothings:HowmuchoutputthefirmisalreadysellingTheslopeofthedemandcurveIttellsushowmuchthemonopolisthastocuthispricetosellonemoreunitofoutput.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-12,Assumethatthedemandcurvethefirmfacesisastraightline:Q=ABxP(6-1)ThentheMRthatthefirmfacesisgivenby:MR=PQ/B(6-2)AverageandMarginalCostsAverageCost(AC)istotalcostdividedbyoutput.MarginalCost(MC)istheamountitcoststhefirmtoproduceoneextraunit.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-13,Whenaveragecostsdeclineinoutput,marginalcostisalwayslessthanaveragecost.Supposethecostsofafirm,C,taketheform:C=F+cxQ(6-3)Thisisalinearcostfunction.Thefixedcostinalinearcostfunctiongivesrisetoeconomiesofscale,becausethelargerthefirmsoutput,thelessisfixedcostperunit.Thefirmsaveragecostsisgivenby:AC=C/Q=F/Q+c(6-4),TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-14,Figure6-2:AverageVersusMarginalCost,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-15,MonopolisticCompetitionOligopolyInternaleconomiesgenerateanoligopolymarketstructure.Thereareseveralfirms,eachofwhichislargeenoughtoaffectprices,butnonewithanuncontestedmonopoly.Strategicinteractionsamongoligopolistshavebecomeimportant.Eachfirmdecidesitsownactions,takingintoaccounthowthatdecisionmightinfluenceitsrivalsactions.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-16,MonopolisticcompetitionAspecialcaseofoligopolyTwokeyassumptionsaremadetogetaroundtheproblemofinterdependence:Eachfirmisassumedtobeabletodifferentiateitsproductfromitsrivals.Eachfirmisassumedtotakethepriceschargedbyitsrivalsasgiven.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-17,Arethereanymonopolisticallycompetitiveindustriesintherealworld?Someindustriesmaybereasonableapproximations(e.g.,theautomobileindustryinEurope)Themainappealofthemonopolisticcompetitionmodelisnotitsrealism,butitssimplicity.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-18,AssumptionsoftheModelImagineanindustryconsistingofanumberoffirmsproducingdifferentiatedproducts.Weexpectafirm:TosellmorethelargerthetotaldemandforitsindustrysproductandthehigherthepriceschargedbyitsrivalsToselllessthegreaterthenumberoffirmsintheindustryandthehigheritsownprice,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-19,where:QisthefirmssalesSisthetotalsalesoftheindustrynisthenumberoffirmsintheindustrybisaconstanttermrepresentingtheresponsivenessofafirmssalestoitspricePisthepricechargedbythefirmitself,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-20,MarketEquilibriumAllfirmsinthisindustryaresymmetricThedemandfunctionandcostfunctionareidenticalforallfirms.Themethodfordeterminingthenumberoffirmsandtheaveragepricechargedinvolvesthreesteps:Wederivearelationshipbetweenthenumberoffirmsandtheaveragecostofatypicalfirm.Wederivearelationshipbetweenthenumberoffirmsandthepriceeachfirmcharges.Wederivetheequilibriumnumberoffirmsandtheaveragepricethatfirmscharge.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-21,ThenumberoffirmsandaveragecostHowdotheaveragecostsdependonthenumberoffirmsintheindustry?,TheTheoryofImperfectCompetition,Weconcludethataveragecostdependsonthesizeofthemarketandthenumberoffirmsintheindustry:AC=F/Q+c=nxF/S+c(6-6)Themorefirmsthereareintheindustrythehigheristheaveragecost.,Copyright2003PearsonEducation,Inc.,Slide6-22,Figure6-3:EquilibriuminaMonopolisticallyCompetitiveMarket,TheTheoryofImperfectCompetition,P2,Copyright2003PearsonEducation,Inc.,Slide6-23,ThenumberoffirmsandthepriceThepricethetypicalfirmchargesdependsonthenumberoffirmsintheindustry.Themorefirms,themorecompetition,andhencethelowertheprice.Inthemonopolisticcompetitionmodelfirmsareassumedtotakeeachotherspricesasgiven.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-24,Profit-maximizingfirmssetmarginalrevenueequaltotheirmarginalcost,c.ThisgeneratesanegativerelationshipbetweenthepriceandthenumberoffirmsinthemarketwhichisthePPcurve:P=c+1/(bxn)(6-10)Themorefirmsthereareintheindustry,thelowerthepriceeachfirmwillcharge.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-25,TheequilibriumnumberoffirmsThedownward-slopingcurvePPshowsthatthemorefirms,thelowerthepriceeachfirmwillcharge.Themorefirms,themorecompetitioneachfirmfaces.Theupward-slopingcurveCCtellsusthatthemorefirmsthereare,thehighertheaveragecostofeachfirm.Ifthenumberoffirmsincreases,eachfirmwillsellless,sofirmswillnotbeabletomoveasfardowntheiraveragecostcurve.,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-26,LimitationsoftheMonopolisticCompetitionModelTwokindsofbehaviorariseinthegeneraloligopolysettingthatareexcludedbyassumptionfromthemonopolisticcompetitionmodel:Collusivebehavior:CanraisetheprofitsofallfirmsattheexpenseofconsumersMaybemanagedthroughexplicitagreementsorthroughtacitcoordinationstrategiesStrategicbehavior:IsadoptedbyfirmstoaffectthebehaviorofcompetitorsinadesirablewayDeterspotentialrivalsfromenteringanindustry,TheTheoryofImperfectCompetition,Copyright2003PearsonEducation,Inc.,Slide6-27,Themonopolisticcompetitionmodelcanbeusedtoshowhowtradeleadsto:IncreasedmarketsizeMutualgainsfromaintegratedmarketEconomicsofscaleintra-industrytrade,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-28,Figure6-4:EffectsofaLargerMarket,CC2,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-29,MonopolisticCompetitionandTrade,CC:AC=F/Q+c=nxF/S+cPP:P=c+1/(bxn),Copyright2003PearsonEducation,Inc.,Slide6-30,GainsfromanIntegratedMarket:ANumericalExampleExample:Supposethatautomobilesareproducedbyamonopolisticallycompetitiveindustry.Assumethefollowing:b=1/30,000,F=$750,000,000,c=$5000Therearetwocountries(HomeandForeign)thathavethesamecostsofautomobileproduction.Annualsalesofautomobilesare900,000atHomeand1.6millionatForeign.,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-31,Figure6-5:EquilibriumintheAutomobileMarket,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-32,Figure6-5:Continued,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-33,Figure6-5:Continued,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-34,Table6-2:HypotheticalExampleofGainsfromMarketIntegration,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-35,EconomiesofScaleandComparativeAdvantageAssumptions:Therearetwocountries:Home(thecapital-abundantcountry)andForeign.Therearetwoindustries:manufactures(thecapital-intensiveindustry)andfood.Neithercountryisabletoproducethefullrangeofmanufacturedproductsbyitselfduetoeconomiesofscale.,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-36,Figure6-6:TradeinaWorldWithoutIncreasingReturns,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-37,Ifmanufacturesisamonopolisticallycompetitivesector,worldtradeconsistsoftwoparts:IntraindustrytradeTheexchangeofmanufacturesformanufacturesInterindustrytradeTheexchangeofmanufacturesforfood,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-38,Figure6-7:TradewithIncreasingReturnsandMonopolisticCompetition,Food,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-39,Maindifferencesbetweeninterindustryandintraindustrytrade:Interindustrytradereflectscomparativeadvantage,whereasintraindustrytradedoesnot.Thepatternofintraindustrytradeitselfisunpredictable,whereasthatofinterindustrytradeisdeterminedbyunderlyingdifferencesbetweencountries.Therelativeimportanceofintraindustryandinterindustrytradedependsonhowsimilarcountriesare.,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-40,TheSignificanceofIntraindustryTradeAboutone-fourthofworldtradeconsistsofintra-industrytrade.Intra-industrytradeplaysaparticularlylargeroleinthetradeinmanufacturedgoodsamongadvancedindustrialnations,whichaccountsformostofworldtrade.,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-41,Table6-3:IndexesofIntraindustryTradeforU.S.Industries,1993,MonopolisticCompetitionandTrade,Copyright2003PearsonEducation,Inc.,Slide6-42,TheEconomicsofDumpingPricediscriminationThepracticeofchargingdifferentcustomersdifferentpricesDumpingThemostcommonformofpricediscriminationininternationaltradeApricingpracticeinwhichafirmchargesalowerpriceforanexportedgoodthanitdoesforthesamegoodsolddomestically,Dumping,Copyright2003PearsonEducation,Inc.,Slide6-43,Dumpingcanoccuronlyiftwoconditionsaremet:ImperfectlycompetitiveindustrySegmentedmarketsGiventheseconditions,amonopolisticfirmmayfindthatitisprofitabletoengageindumping.,Dumping,Copyright2003PearsonEducation,Inc.,Slide6-44,Figure6-8:Dumping,Dumping,Exports,Domesticsales,DFOR=MRFOR,PFOR,Copyright2003PearsonEducation,Inc.,Slide6-45,ReciprocalDumpingAsituationinwhichdumpingleadstotwo-waytradeinthesameproductItincreasesthevolumeoftradeingoodsthatarenotquiteidentical.Itsnetwelfareeffectisambiguous:Itwastesresourcesintransportation.Itcreatessomecompetition.,Dumping,Copyright2003PearsonEducation,Inc.,Slide6-46,TheTheoryofExternalEconomies,Economiesofscalethatoccurattheleveloftheindustryinsteadofthefirmarecalledexternaleconomies.Therearethreemainreasonswhyaclusteroffirmsmaybemoreefficientthananindividualfirminisolation:SpecializedsuppliersLabormarketpoolingKnowledgespillovers,Copyright2003PearsonEducation,Inc.,Slide6-47,SpecializedSuppliersInmanyindustries,theproductionofgoodsandservicesandthedevelopmentofnewproductsrequirestheuseofspecializedequipmentorsupportservices.Anindividualcompanydoesnotprovidealargeenoughmarketfortheseservicestokeepthesuppliersinbusiness.Alocalizedindustrialclustercansolvethisproblembybringingtogethermanyfirmsthatprovidealargeenoughmarkettosupportspecializedsuppliers.ThisphenomenonhasbeenextensivelydocumentedinthesemiconductorindustrylocatedinSiliconValley.,TheTheoryofExternalEconomies,Copyright2003PearsonEducation,Inc.,Slide6-48,LaborMarketPoolingAclusteroffirmscancreateapooledmarketforworkerswithhighlyspecializedskills.Itisanadvantagefor:ProducersTheyarelesslikelytosufferfromlaborshortages.WorkersTheyarelesslikelytobecomeunemployed.,TheTheoryofExternalEconomies,Copyright2003PearsonEducation,Inc.,Slide6-49,KnowledgeSpilloversKnowledgeisoneoftheimportantinputfactorsinhighlyinnovativeindustries.Thespecializedknowledgethatiscrucialtosuccessininnovativeindustriescomesfrom:ResearchanddevelopmenteffortsReverseengineeringInformalexchangeofinformationandideas,TheTheoryofExternalEconomies,Copyright2003PearsonEducation,Inc.,Slide6-50,ExternalEconomiesandIncreasingReturnsExternaleconomiescangiverisetoincreasingreturnstoscaleatthelevelofthenationalindustry.Forward-fallingsupplycurveThelargertheindustrysoutput,thelowerthepriceatwhichfirmsarewillingtoselltheiroutput.,TheTheoryofExternalEconomies,Copyright2003PearsonEducation,Inc.,Slide6-51,ExternalEconomiesandthePatterofTradeAcountrythathaslargeproductioninsomeindustrywilltendtohavelowcostsofproducingthatgood.Countriesthatstartoutaslargeproducersincertainindustriestendtoremainlargeproducersevenifsomeothercountrycouldpotentiallyproducethegoodsmorecheaply.Figure6-9illustratesacasewhereapatternofspecializationestablishedbyhistoricalaccidentispersistent.,ExternalEconomiesandInternationalTrade,Copyright2003PearsonEducation,Inc.,Slide6-52,Figure6-9:ExternalEconomiesandSpecialization,ExternalEconomiesandInternationalTrade,ACSWISS,C0,Copyright2003PearsonEducation,Inc.,Slide6-53,TradeandWelfarewithExternalEconomiesTradebasedonexternaleconomieshasmoreambiguouseffectsonnationalwelfarethaneithertradebasedoncomparativeadvantageortradebasedoneconomiesofscaleatthelevelofthefirm.AnexampleofhowacountrycanactuallybeworseoffwithtradethanwithoutisshowninFigure6-10.,ExternalEconomiesandInternationalTrade,Copyright2003PearsonEducation,Inc.,Slide6-54,Figure6-10:ExternalEconomiesandLossesfromTrade,ExternalEconomiesandInternationalTrade,ACTHAI,2,C0,DTHAI,P2,Copyright2003PearsonEducation,Inc.,Slide6-55,DynamicIncreasingReturnsLearningcurveItrelatesunitcos