Chap-17壟斷競(jìng)爭(zhēng)(經(jīng)濟(jì)學(xué)原理 中英文雙語(yǔ))

Chap_17壟斷競(jìng)爭(zhēng)(經(jīng)濟(jì)學(xué)原理中英文雙語(yǔ))MonopolisticCompetition

壟斷競(jìng)爭(zhēng)Imperfectcompetitionreferstothosemarketstructuresthatfallbetweenperfectcompetitionandpuremonopoly.

不完全競(jìng)爭(zhēng)是指介于完全競(jìng)爭(zhēng)與純壟斷之間的市場(chǎng)結(jié)構(gòu)。TheFourTypesofMarketStructureMonopoly（Chap15）Oligopoly(Chap16)MonopolisticCompetition(Chap17)PerfectCompetition（Chap14）

TapwaterCableTV

TennisballsCrudeoil

NovelsMovies

WheatMilkNumberofFirms?TypeofProducts?ManyfirmsOnefirmFewfirmsDifferentiatedproductsIdenticalproducts市場(chǎng)結(jié)構(gòu)的四種類型壟斷（15章）寡頭（16章）壟斷競(jìng)爭(zhēng)（17章）完全競(jìng)爭(zhēng)（14章）自來(lái)水

有線電視網(wǎng)球

原油小說(shuō)

電影小麥

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(jìng)爭(zhēng)市場(chǎng)的類型壟斷競(jìng)爭(zhēng)

許多出售相似但不相同產(chǎn)品的企業(yè)組成的市場(chǎng)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(jìng)爭(zhēng)Marketsthathavesomefeaturesofcompetitionandsomefeaturesofmonopoly.有某些競(jìng)爭(zhēng)特點(diǎn)又有某些壟斷特點(diǎn)的市場(chǎng)結(jié)構(gòu)。AttributesofMonopolisticcompetition

壟斷競(jìng)爭(zhēng)的特點(diǎn)Manysellers

很多賣者Productdifferentiation

產(chǎn)品有差異Freeentryandexit

自由進(jìn)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(zhēng)奪同樣的顧客群體。產(chǎn)品例子包括書(shū)籍、CD、電影、電腦游戲、餐館、鋼琴課、點(diǎn)心、家居等等。ProductDifferentiationEachfirmproducesaproductthatisatleastslightlydifferentfromthoseofotherfirms.Ratherthanbeingapricetaker,eachfirmfacesadownward-slopingdemandcurve.產(chǎn)品差異化每個(gè)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(gè)企業(yè)不是價(jià)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(jìn)入或退出企業(yè)可以沒(méi)有限制地進(jìn)入或退出一個(gè)市場(chǎng)。市場(chǎng)上企業(yè)的數(shù)量要一直調(diào)整到經(jīng)濟(jì)利潤(rùn)為零時(shí)為止。MonopolisticCompetitionintheShortRunShort-runeconomicprofitsencouragenewfirmstoenterthemarket.This:Increasesthenumberofproductsoffered.Reducesdemandfacedbyfirmsalreadyinthemarket.Incumbentfirms’demandcurvesshifttotheleft.Demandfortheincumbentfirms’productsfall,andtheirprofitsdecline.短期中的壟斷競(jìng)爭(zhēng)企業(yè)短期經(jīng)濟(jì)利潤(rùn)激勵(lì)新企業(yè)進(jìn)入市場(chǎng)。這種進(jìn)入增加了顧客可以選擇的產(chǎn)品數(shù)量。減少了市場(chǎng)已有的每家企業(yè)面臨的需求。使市場(chǎng)已有企業(yè)面臨的需求曲線向左移動(dòng)。市場(chǎng)已有企業(yè)的產(chǎn)品需求減少，利潤(rùn)下降。Figure1MonopolisticCompetition

intheShortRunQuantity0PriceProfit-maximizingquantityPriceDemandMRATC(a)FirmMakesProfitAveragetotalcostProfitMC圖1.短期中的壟斷競(jìng)爭(zhēng)企業(yè)(a)企業(yè)有利潤(rùn)產(chǎn)量0價(jià)格需求MRATC利潤(rùn)MC利潤(rùn)最大化產(chǎn)量?jī)r(jià)格平均總成本MonopolisticCompetitionin

theShortRunShort-runeconomiclossesencouragefirmstoexitthemarket.This:

Decreasesthenumberofproductsoffered.Increasesdemandfacedbytheremainingfirms.Shiftstheremainingfirms’demandcurvestotheright.Increasestheremainingfirms’profits.短期中的壟斷競(jìng)爭(zhēng)企業(yè)短期經(jīng)濟(jì)虧損激勵(lì)企業(yè)退出市場(chǎng)。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(chǎng)中的企業(yè)面臨的需求。使繼續(xù)留在市場(chǎng)中的企業(yè)的需求曲線向右移動(dòng)。使繼續(xù)留在市場(chǎng)中的企業(yè)的利潤(rùn)增加。Figure1MonopolisticCompetitors

intheShortRunDemandQuantity0PricePriceLoss-minimizingquantityAveragetotalcost(b)FirmMakesLossesMRLossesATCMC圖1.短期中的壟斷競(jìng)爭(zhēng)企業(yè)產(chǎn)量0價(jià)格需求MR虧損(b)企業(yè)虧損MCATC平均總成本利潤(rùn)最小化產(chǎn)量?jī)r(jià)格TheLong-RunEquilibrium

長(zhǎng)期均衡Firmswillenterandexituntilthefirmsaremakingexactlyzeroeconomicprofits.企業(yè)進(jìn)入或退出的過(guò)程一直持續(xù)到市場(chǎng)中的企業(yè)的經(jīng)濟(jì)利潤(rùn)正好是零時(shí)。Figure2AMonopolisticCompetitor

intheLongRunQuantityPrice0DemandMRATCMCProfit-maximizingquantityP=ATC圖2.長(zhǎng)期中的壟斷競(jìng)爭(zhēng)者產(chǎn)量?jī)r(jià)格0需求MRATCMC利潤(rùn)最大化產(chǎn)量P=ATCLong-RunEquilibriumTwoCharacteristicsAsinamonopoly,priceexceedsmarginalcost.Profitmaximizationrequiresmarginalrevenuetoequalmarginalcost.Thedownward-slopingdemandcurvemakesmarginalrevenuelessthanprice.Asinacompetitivemarket,priceequalsaveragetotalcost.Freeentryandexitdriveeconomicprofittozero.長(zhǎng)期均衡兩個(gè)特點(diǎn)正如在壟斷市場(chǎng)上一樣，價(jià)格大于邊際成本。利潤(rùn)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(jià)格。正如在競(jìng)爭(zhēng)市場(chǎng)上一樣，價(jià)格等于平均總成本。自由進(jìn)入與退出使經(jīng)濟(jì)利潤(rùn)為零。MonopolisticversusPerfectCompetitionTherearetwonoteworthydifferencesbetweenmonopolisticandperfectcompetition—excesscapacityandmarkup.壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)壟斷競(jìng)爭(zhēng)和完全競(jìng)爭(zhēng)之間有兩個(gè)值得注意的差別—過(guò)剩生產(chǎn)能力和價(jià)格加成。MonopolisticversusPerfectCompetitionExcessCapacityThereisnoexcesscapacityinperfectcompetitioninthelongrun.Freeentryresultsincompetitivefirmsproducingatthepointwhereaveragetotalcostisminimized,whichistheefficientscaleofthefirm.Thereisexcesscapacityinmonopolisticcompetitioninthelongrun.Inmonopolisticcompetition,outputislessthantheefficientscaleofperfectcompetition.壟斷競(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)過(guò)剩生產(chǎn)能力在長(zhǎng)期中，完全競(jìng)爭(zhēng)企業(yè)沒(méi)有過(guò)剩生產(chǎn)能力。競(jìng)爭(zhēng)市場(chǎng)上的自由進(jìn)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(zhǎng)期中，壟斷競(jìng)爭(zhēng)企業(yè)存在過(guò)剩生產(chǎn)能力。壟斷競(jìng)爭(zhēng)企業(yè)的產(chǎn)量低于完全競(jìng)爭(zhēng)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(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)產(chǎn)量(a)壟斷競(jìng)爭(zhēng)企業(yè)(b)完全競(jìng)爭(zhēng)企業(yè)產(chǎn)量?jī)r(jià)格P=MR(需求曲線)MCATC價(jià)格需求MCATC過(guò)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(jìng)爭(zhēng)與完全競(jìng)爭(zhēng)高于邊際成本的價(jià)格加成對(duì)一個(gè)競(jìng)爭(zhēng)企業(yè)來(lái)說(shuō)，價(jià)格等于邊際成本。對(duì)一個(gè)壟斷競(jìng)爭(zhēng)企業(yè)來(lái)說(shuō)，價(jià)格高于邊際成本。因?yàn)閴艛喔?jìng)爭(zhēng)企業(yè)的價(jià)格高于其邊際成本，以牌價(jià)多銷售出一個(gè)單位產(chǎn)品就意味著利潤(rùn)多了。Figure3MonopolisticversusPerfectCompetitionQuantity0PriceDemand(a)MonopolisticallyCompetitiveFirmQuantity0PriceP=MCP=MR(demandcurve)(b)PerfectlyCompetitiveFirmMarkupMCATCMCATCMRMarginalcostPQuantityproducedQuantityproduced圖3.高于邊際成本的價(jià)格加成產(chǎn)量(a)壟斷競(jìng)爭(zhēng)企業(yè)(b)完全競(jìng)爭(zhēng)企業(yè)產(chǎn)量?jī)r(jià)格P=MCP=MR(需求曲線)MCATC生產(chǎn)量?jī)r(jià)格P需求邊際成本MCATCMR價(jià)格加成生產(chǎn)量Figure3MonopolisticversusPerfectCompetitionQuantity0PriceDemand(a)MonopolisticallyCompetitiveFirmQuantity0PriceP=MCP=MR(demandcurve)(b)PerfectlyCompetitiveFirmMarkupExcesscapacityMCATCMCATCMRMarginalcostEfficientscalePQuantityproducedQuantityproduced=Efficientscale圖3.壟斷競(jìng)爭(zhēng)和完全競(jìng)爭(zhēng)產(chǎn)量(a)壟斷競(jìng)爭(zhēng)企業(yè)(b)完全競(jìng)爭(zhēng)企業(yè)產(chǎn)量?jī)r(jià)格P=MR(需求曲線)MCATC生產(chǎn)量有效規(guī)模價(jià)格P需求MCATCP=MC過(guò)剩市場(chǎng)能力邊際成本價(jià)格加成MR生產(chǎn)量=有效規(guī)模MonopolisticCompetitionandtheWelfareofSociety

壟斷競(jìng)爭(zhēng)與社會(huì)福利Monopolisticcompetitiondoesnothaveallthedesirablepropertiesofperfectcompetition.壟斷競(jìng)爭(zhēng)不具有完全競(jìng)爭(zhēng)所具有的令人合意的特性。MonopolisticCompetitionandtheWelfareofSocietyThereisthenormaldeadweightlossofmonopolypricinginmonopolisticcompetitioncausedbythemarkupofpriceovermarginalcost.However,theadministrativeburdenofregulatingthepricingofallfirmsthatproducedifferentiatedproductswouldbeoverwhelming.壟斷競(jìng)爭(zhēng)與社會(huì)福利壟斷競(jìng)爭(zhēng)市場(chǎng)存在由于高于邊際成本的價(jià)格加成所導(dǎo)致的正常的無(wú)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(fù)擔(dān)將是巨大的。

MonopolisticCompetitionandtheWelfareofSocietyAnotherwayinwhichmonopolisticcompetitionmaybesociallyinefficientisthatthenumberoffirmsinthemarketmaynotbethe“ideal”one.Theremaybetoomuchortoolittleentry.壟斷競(jìng)爭(zhēng)與社會(huì)福利壟斷競(jìng)爭(zhēng)可能引起社會(huì)無(wú)效率的另一個(gè)方面是市場(chǎng)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(jìn)入。MonopolisticCompetitionandtheWelfareofSociety

壟斷競(jìng)爭(zhēng)與社會(huì)福利Externalitiesofentryinclude:進(jìn)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(jìng)爭(zhēng)與社會(huì)福利產(chǎn)品多樣化外部性:由于消費(fèi)者從新產(chǎn)品引進(jìn)中得到了一些消費(fèi)者剩余，所以存在與進(jìn)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(jìn)入者的競(jìng)爭(zhēng)者中失去顧客和利潤(rùn)，所以存在與進(jìn)入相關(guān)的負(fù)外部性。Advertising廣告Whenfirmsselldifferentiatedproductsandchargepricesabovemarginalcost,eachfirmhasanincentivetoadvertiseinordertoattractmorebuyerstoitsparticularproduct.當(dāng)企業(yè)銷售有差異產(chǎn)品并收取高于邊際成本的價(jià)格時(shí)，每個(gè)企業(yè)都有靠做廣告來(lái)吸引更多顧客購(gòu)買自己特殊產(chǎn)品的激勵(lì)。AdvertisingFirmsthatsellhighlydifferentiatedconsumergoodstypicallyspendbetween10and20percentofrevenueonadvertising.Overall,about2percentoftotalrevenue,orover$100billionayear,isspentonadvertising.廣告銷售很大差異消費(fèi)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(píng)者認(rèn)為，企業(yè)做廣告是為了操縱人們的嗜好。Theyalsoarguethatitimpedescompetitionbyimplyingthatproductsaremoredifferentthantheytrulyare.

批評(píng)者還認(rèn)為，廣告抑制了競(jìng)爭(zhēng)。廣告努力使消費(fèi)者相信產(chǎn)品差異大于實(shí)際情況。AdvertisingDefendersarguethatadvertisingprovidesinformationtoconsumersTheyalsoarguethatadvertisingincreasescompetitionbyofferingagreatervarietyofproductsandprices.Thewillingnessofafirmtospendadvertisingdollarscanbeasignaltoconsumersaboutthequalityoftheproductbeingoffered.廣告廣告的辯護(hù)者認(rèn)為，企業(yè)用廣告向顧客提供信息。辯護(hù)者還認(rèn)為，廣告加劇了競(jìng)爭(zhēng)，為顧客提供了更多的產(chǎn)品和價(jià)格。企業(yè)愿意用大量的錢來(lái)做廣告，這本身就向消費(fèi)者傳遞了一個(gè)所提供產(chǎn)品質(zhì)量的信息。BrandNames品牌Criticsarguethatbrandnamescauseconsumerstoperceivedifferencesthatdonotreallyexist.

品牌的批評(píng)者認(rèn)為，品牌使消費(fèi)者感覺(jué)到的產(chǎn)品差異大于實(shí)際存在的差異。BrandNamesEvidinginformationaboutquality.givingfirmsincentivetomaintainhighquality.品牌經(jīng)濟(jì)學(xué)家對(duì)品牌的辯護(hù)是認(rèn)為品牌是消費(fèi)者保證他們購(gòu)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(lì)。SummaryAmonopolisticallycompetitivemarketischaracterizedbythreeattributes:manyfirms,differentiatedproducts,andfr