Chap-17壟斷競爭(經(jīng)濟學(xué)原理 中英文雙語)

Chap_17壟斷競爭(經(jīng)濟學(xué)原理中英文雙語)MonopolisticCompetition

壟斷競爭Imperfectcompetitionreferstothosemarketstructuresthatfallbetweenperfectcompetitionandpuremonopoly.

不完全競爭是指介于完全競爭與純壟斷之間的市場結(jié)構(gòu)。TheFourTypesofMarketStructureMonopoly（Chap15）Oligopoly(Chap16)MonopolisticCompetition(Chap17)PerfectCompetition（Chap14）

TapwaterCableTV

TennisballsCrudeoil

NovelsMovies

WheatMilkNumberofFirms?TypeofProducts?ManyfirmsOnefirmFewfirmsDifferentiatedproductsIdenticalproducts市場結(jié)構(gòu)的四種類型壟斷（15章）寡頭（16章）壟斷競爭（17章）完全競爭（14章）自來水

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牛奶企業(yè)數(shù)量?產(chǎn)品類型？許多企業(yè)一家企業(yè)幾家企業(yè)有差別產(chǎn)量相同產(chǎn)品TypesofImperfectlyCompetitiveMarketsMonopolisticCompetition

Manyfirmssellingproductsthataresimilarbutnotidentical.OligopolyOnlyafewsellers,eachofferingasimilaroridenticalproducttotheothers.不完全競爭市場的類型壟斷競爭

許多出售相似但不相同產(chǎn)品的企業(yè)組成的市場結(jié)構(gòu)。寡頭只有很少賣者，出售相似或相同的產(chǎn)品。MonopolisticCompetition

壟斷競爭Marketsthathavesomefeaturesofcompetitionandsomefeaturesofmonopoly.有某些競爭特點又有某些壟斷特點的市場結(jié)構(gòu)。AttributesofMonopolisticcompetition

壟斷競爭的特點Manysellers

很多賣者Productdifferentiation

產(chǎn)品有差異Freeentryandexit

自由進入和退出ManySellersTherearemanyfirmscompetingforthesamegroupofcustomers.Productexlesincludebooks,CDs, movies,computergames,restaurants, pianolessons,cookies,furniture,etc.很多賣者有許多企業(yè)爭奪同樣的顧客群體。產(chǎn)品例子包括書籍、CD、電影、電腦游戲、餐館、鋼琴課、點心、家居等等。ProductDifferentiationEachfirmproducesaproductthatisatleastslightlydifferentfromthoseofotherfirms.Ratherthanbeingapricetaker,eachfirmfacesadownward-slopingdemandcurve.產(chǎn)品差異化每個企業(yè)生產(chǎn)的一種產(chǎn)品至少與其他企業(yè)生產(chǎn)的這種產(chǎn)品略有不同。每個企業(yè)不是價格接受者，而是面臨一條向右下方傾斜的需求曲線。FreeEntryorExitFirmscanenterorexitthemarketwithoutrestriction.Thenumberoffirmsinthemarketadjustsuntileconomicprofitsarezero.自由進入或退出企業(yè)可以沒有限制地進入或退出一個市場。市場上企業(yè)的數(shù)量要一直調(diào)整到經(jīng)濟利潤為零時為止。MonopolisticCompetitionintheShortRunShort-runeconomicprofitsencouragenewfirmstoenterthemarket.This:Increasesthenumberofproductsoffered.Reducesdemandfacedbyfirmsalreadyinthemarket.Incumbentfirms’demandcurvesshifttotheleft.Demandfortheincumbentfirms’productsfall,andtheirprofitsdecline.短期中的壟斷競爭企業(yè)短期經(jīng)濟利潤激勵新企業(yè)進入市場。這種進入增加了顧客可以選擇的產(chǎn)品數(shù)量。減少了市場已有的每家企業(yè)面臨的需求。使市場已有企業(yè)面臨的需求曲線向左移動。市場已有企業(yè)的產(chǎn)品需求減少，利潤下降。Figure1MonopolisticCompetition

intheShortRunQuantity0PriceProfit-maximizingquantityPriceDemandMRATC(a)FirmMakesProfitAveragetotalcostProfitMC圖1.短期中的壟斷競爭企業(yè)(a)企業(yè)有利潤產(chǎn)量0價格需求MRATC利潤MC利潤最大化產(chǎn)量價格平均總成本MonopolisticCompetitionin

theShortRunShort-runeconomiclossesencouragefirmstoexitthemarket.This:

Decreasesthenumberofproductsoffered.Increasesdemandfacedbytheremainingfirms.Shiftstheremainingfirms’demandcurvestotheright.Increasestheremainingfirms’profits.短期中的壟斷競爭企業(yè)短期經(jīng)濟虧損激勵企業(yè)退出市場。隨著企業(yè)退出：

顧客可選擇的產(chǎn)品數(shù)量少了。增加了繼續(xù)留在市場中的企業(yè)面臨的需求。使繼續(xù)留在市場中的企業(yè)的需求曲線向右移動。使繼續(xù)留在市場中的企業(yè)的利潤增加。Figure1MonopolisticCompetitors

intheShortRunDemandQuantity0PricePriceLoss-minimizingquantityAveragetotalcost(b)FirmMakesLossesMRLossesATCMC圖1.短期中的壟斷競爭企業(yè)產(chǎn)量0價格需求MR虧損(b)企業(yè)虧損MCATC平均總成本利潤最小化產(chǎn)量價格TheLong-RunEquilibrium

長期均衡Firmswillenterandexituntilthefirmsaremakingexactlyzeroeconomicprofits.企業(yè)進入或退出的過程一直持續(xù)到市場中的企業(yè)的經(jīng)濟利潤正好是零時。Figure2AMonopolisticCompetitor

intheLongRunQuantityPrice0DemandMRATCMCProfit-maximizingquantityP=ATC圖2.長期中的壟斷競爭者產(chǎn)量價格0需求MRATCMC利潤最大化產(chǎn)量P=ATCLong-RunEquilibriumTwoCharacteristicsAsinamonopoly,priceexceedsmarginalcost.Profitmaximizationrequiresmarginalrevenuetoequalmarginalcost.Thedownward-slopingdemandcurvemakesmarginalrevenuelessthanprice.Asinacompetitivemarket,priceequalsaveragetotalcost.Freeentryandexitdriveeconomicprofittozero.長期均衡兩個特點正如在壟斷市場上一樣，價格大于邊際成本。利潤最大化要求邊際收益等于邊際成本。向右下方傾斜的需求曲線使邊際成本小于價格。正如在競爭市場上一樣，價格等于平均總成本。自由進入與退出使經(jīng)濟利潤為零。MonopolisticversusPerfectCompetitionTherearetwonoteworthydifferencesbetweenmonopolisticandperfectcompetition—excesscapacityandmarkup.壟斷競爭與完全競爭壟斷競爭和完全競爭之間有兩個值得注意的差別—過剩生產(chǎn)能力和價格加成。MonopolisticversusPerfectCompetitionExcessCapacityThereisnoexcesscapacityinperfectcompetitioninthelongrun.Freeentryresultsincompetitivefirmsproducingatthepointwhereaveragetotalcostisminimized,whichistheefficientscaleofthefirm.Thereisexcesscapacityinmonopolisticcompetitioninthelongrun.Inmonopolisticcompetition,outputislessthantheefficientscaleofperfectcompetition.壟斷競爭與完全競爭過剩生產(chǎn)能力在長期中，完全競爭企業(yè)沒有過剩生產(chǎn)能力。競爭市場上的自由進入使企業(yè)生產(chǎn)平均總成本最小的產(chǎn)量，即企業(yè)的有效規(guī)模產(chǎn)量。在長期中，壟斷競爭企業(yè)存在過剩生產(chǎn)能力。壟斷競爭企業(yè)的產(chǎn)量低于完全競爭企業(yè)生產(chǎn)的有效規(guī)模產(chǎn)量。Figure3MonopolisticversusPerfectCompetitionQuantity0PriceDemand(a)MonopolisticallyCompetitiveFirmQuantity0PriceP=MCP=MR(demandcurve)(b)PerfectlyCompetitiveFirmMCATCMCATCMREfficientscalePQuantityproducedQuantityproduced=Efficientscale圖3.

壟斷競爭與完全競爭產(chǎn)量(a)壟斷競爭企業(yè)(b)完全競爭企業(yè)產(chǎn)量價格P=MR(需求曲線)MCATC價格需求MCATC過剩生產(chǎn)能力生產(chǎn)量有效規(guī)模P=MC產(chǎn)量=有效規(guī)模產(chǎn)量PMonopolisticversusPerfectCompetitionMarkupOverMarginalCostForacompetitivefirm,priceequalsmarginalcost.Foramonopolisticallycompetitivefirm,priceexceedsmarginalcost.Becausepriceexceedsmarginalcost,anextraunitsoldatthepostedpricemeansmoreprofitforthemonopolisticallycompetitivefirm.壟斷競爭與完全競爭高于邊際成本的價格加成對一個競爭企業(yè)來說，價格等于邊際成本。對一個壟斷競爭企業(yè)來說，價格高于邊際成本。因為壟斷競爭企業(yè)的價格高于其邊際成本，以牌價多銷售出一個單位產(chǎn)品就意味著利潤多了。Figure3MonopolisticversusPerfectCompetitionQuantity0PriceDemand(a)MonopolisticallyCompetitiveFirmQuantity0PriceP=MCP=MR(demandcurve)(b)PerfectlyCompetitiveFirmMarkupMCATCMCATCMRMarginalcostPQuantityproducedQuantityproduced圖3.高于邊際成本的價格加成產(chǎn)量(a)壟斷競爭企業(yè)(b)完全競爭企業(yè)產(chǎn)量價格P=MCP=MR(需求曲線)MCATC生產(chǎn)量價格P需求邊際成本MCATCMR價格加成生產(chǎn)量Figure3MonopolisticversusPerfectCompetitionQuantity0PriceDemand(a)MonopolisticallyCompetitiveFirmQuantity0PriceP=MCP=MR(demandcurve)(b)PerfectlyCompetitiveFirmMarkupExcesscapacityMCATCMCATCMRMarginalcostEfficientscalePQuantityproducedQuantityproduced=Efficientscale圖3.壟斷競爭和完全競爭產(chǎn)量(a)壟斷競爭企業(yè)(b)完全競爭企業(yè)產(chǎn)量價格P=MR(需求曲線)MCATC生產(chǎn)量有效規(guī)模價格P需求MCATCP=MC過剩市場能力邊際成本價格加成MR生產(chǎn)量=有效規(guī)模MonopolisticCompetitionandtheWelfareofSociety

壟斷競爭與社會福利Monopolisticcompetitiondoesnothaveallthedesirablepropertiesofperfectcompetition.壟斷競爭不具有完全競爭所具有的令人合意的特性。MonopolisticCompetitionandtheWelfareofSocietyThereisthenormaldeadweightlossofmonopolypricinginmonopolisticcompetitioncausedbythemarkupofpriceovermarginalcost.However,theadministrativeburdenofregulatingthepricingofallfirmsthatproducedifferentiatedproductswouldbeoverwhelming.壟斷競爭與社會福利壟斷競爭市場存在由于高于邊際成本的價格加成所導(dǎo)致的正常的無謂損失。但是，管制所有生產(chǎn)差異產(chǎn)品的企業(yè)的管理負擔將是巨大的。

MonopolisticCompetitionandtheWelfareofSocietyAnotherwayinwhichmonopolisticcompetitionmaybesociallyinefficientisthatthenumberoffirmsinthemarketmaynotbethe“ideal”one.Theremaybetoomuchortoolittleentry.壟斷競爭與社會福利壟斷競爭可能引起社會無效率的另一個方面是市場上的企業(yè)數(shù)量可能并不是“理想”的數(shù)量，可能有太多或太少的企業(yè)進入。MonopolisticCompetitionandtheWelfareofSociety

壟斷競爭與社會福利Externalitiesofentryinclude:進入的外部性包括：product-varietyexternalities.

產(chǎn)品多樣化外部性

business-stealingexternalities.

搶走業(yè)務(wù)的外部性MonopolisticCompetitionand

theWelfareofSocietyTheproduct-varietyexternality:Becauseconsumersgetsomeconsumersurplusfromtheintroductionofanewproduct,entryofanewfirmconveysapositiveexternalityonconsumers.Thebusiness-stealingexternality:Becauseotherfirmslosecustomersandprofitsfromtheentryofanewcompetitor,entryofanewfirmimposesanegativeexternalityonexistingfirms.壟斷競爭與社會福利產(chǎn)品多樣化外部性:由于消費者從新產(chǎn)品引進中得到了一些消費者剩余，所以存在與進入相關(guān)的正外部性。搶走業(yè)務(wù)的外部性:由于其它企業(yè)從與新進入者的競爭者中失去顧客和利潤，所以存在與進入相關(guān)的負外部性。Advertising廣告Whenfirmsselldifferentiatedproductsandchargepricesabovemarginalcost,eachfirmhasanincentivetoadvertiseinordertoattractmorebuyerstoitsparticularproduct.當企業(yè)銷售有差異產(chǎn)品并收取高于邊際成本的價格時，每個企業(yè)都有靠做廣告來吸引更多顧客購買自己特殊產(chǎn)品的激勵。AdvertisingFirmsthatsellhighlydifferentiatedconsumergoodstypicallyspendbetween10and20percentofrevenueonadvertising.Overall,about2percentoftotalrevenue,orover$100billionayear,isspentonadvertising.廣告銷售很大差異消費品的企業(yè)，通常都把收益的10％－20％用于廣告支出?？傮w上，廣告支出占企業(yè)總收益的2％左右,或者在1000億美元以上。Advertising廣告Criticsofadvertisingarguethatfirmsadvertiseinordertomanipulatepeople’stastes.

廣告的批評者認為，企業(yè)做廣告是為了操縱人們的嗜好。Theyalsoarguethatitimpedescompetitionbyimplyingthatproductsaremoredifferentthantheytrulyare.

批評者還認為，廣告抑制了競爭。廣告努力使消費者相信產(chǎn)品差異大于實際情況。AdvertisingDefendersarguethatadvertisingprovidesinformationtoconsumersTheyalsoarguethatadvertisingincreasescompetitionbyofferingagreatervarietyofproductsandprices.Thewillingnessofafirmtospendadvertisingdollarscanbeasignaltoconsumersaboutthequalityoftheproductbeingoffered.廣告廣告的辯護者認為，企業(yè)用廣告向顧客提供信息。辯護者還認為，廣告加劇了競爭，為顧客提供了更多的產(chǎn)品和價格。企業(yè)愿意用大量的錢來做廣告，這本身就向消費者傳遞了一個所提供產(chǎn)品質(zhì)量的信息。BrandNames品牌Criticsarguethatbrandnamescauseconsumerstoperceivedifferencesthatdonotreallyexist.

品牌的批評者認為，品牌使消費者感覺到的產(chǎn)品差異大于實際存在的差異。BrandNamesEvidinginformationaboutquality.givingfirmsincentivetomaintainhighquality.品牌經(jīng)濟學(xué)家對品牌的辯護是認為品牌是消費者保證他們購買的物品具有高質(zhì)量的一種有用方法。提供產(chǎn)品質(zhì)量信息。向企業(yè)提供了保持高質(zhì)量的激勵。SummaryAmonopolisticallycompetitivemarketischaracterizedbythreeattributes:manyfirms,differentiatedproducts,andfr