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TheMarketsfor“Lemons”:QualityuncertaintyandTheMarketMechanism檸檬市場:質(zhì)量的不確立性和市場體制GeogreA.Akerlof阿克洛夫一、前言Thispaperrelatesqualityanduncertainty.Theexistenceofgoodsofmanygradesposesinterestingandimportantproblemsforthetheoryofmarkets(.本文闡述的是質(zhì)量和不確立性問題?,F(xiàn)實(shí)中存在大批多種品位的物件給市場理論提出了饒有興趣而十分重要的難題)Ontheonehand,theinteractionofqualitydifferencesanduncertaintymayexplainimportantinstitutionsofthelabormarket.(一方面,質(zhì)量差異和不確立性的互相作用能夠解說勞動力的重要體制)Ontheotherhand,thispaperpresentsastrugglingattempttogivestructuretothestatement:"Businessinunder-developedcountriesisdifficult";inparticular,astructureisgivenfordeterminingtheeconomiccostsofdishonesty(.另一方面,本文試圖經(jīng)過議論獲取這樣的結(jié)論:在不發(fā)達(dá)國家,商業(yè)交易是困難的,此中,特別論及了欺詐性交易的經(jīng)濟(jì)成本)Additionalapplicationsofthetheoryincludecommentsonthestructureofmoneymarkets,onthenotionof"insurability,"ontheliquidityofdurables,andonbrand-namegoods(.本文的理論還可以夠用來研究錢幣市場、保險可行性、耐用品的流動性和名牌商品等問題)Therearemanymarketsinwhichbuyersusesomemarketstatistictojudgethequalityofprospectivepurchases.(在很多市場中,買者利用市場的統(tǒng)計(jì)數(shù)據(jù)來判斷他們將要購置的商品的質(zhì)量)Inthiscasethereisincentiveforsellerstomarketpoorqualitymerchandise,sincethereturnsforgoodqualityaccruemainlytotheentiregroupwhosestatisticisaffectedratherthantotheindividualseller.Asaresulttheretendstobeareductionintheaveragequalityofgoodsandalsointhesizeofthemarket.(在這類狀況下,賣者有動力供應(yīng)低質(zhì)量商品,因?yàn)槟撤N商品的價錢主要取決于全部同類商質(zhì)量量的統(tǒng)計(jì)數(shù)據(jù)而非該商品的實(shí)質(zhì)質(zhì)量。結(jié)果,商品的均勻質(zhì)量將趨于降落,市場規(guī)模將不停減?。㊣tshouldalsobeperceivedthatinthesemarketssocialandprivatereturnsdiffer,andtherefore,insomecases,governmentalinterventionmayincreasethewelfareofallparties.Orprivateinstitutionsmayarisetotakeadvantageofthepotentialincreasesinwelfarewhichcanaccruetoallparties(.我們還可以察看到在這類市場上,對個人和社會有不一樣的回報(bào),所以,某種狀況下,政府的干涉能夠增進(jìn)社會的整體福利水平?;蛟S說,個人組織利用了整個社會福利水平潛伏的增添時機(jī)而使自己贏利)Bynature,however,theseinstitutionsarenonatomistic,andthereforeconcentrationsofpower-withillconsequencesoftheirown-candevelop(.實(shí)質(zhì)上,這些個人組織的行動所產(chǎn)生的影響并不是能夠忽視不計(jì),所以,只管集權(quán)自己有很多負(fù)面影響,可是,必定程度上的集權(quán)能夠保證經(jīng)濟(jì)的健康發(fā)展)Theautomobilemarketisusedasafingerexercisetoillustrateanddevelopthesethoughts.Itshouldbeemphasizedthatthismarketischosenforitsconcretenessandeaseinunderstandingratherthanforitsimportanceorrealism(.下邊,我們用汽車市場作為例子來闡釋和進(jìn)一步發(fā)展以上的思想。需要指出的是,之所以選擇舊車市場來議論,是因?yàn)檫@個例子很詳細(xì),并且簡單理解,而不是因?yàn)樗闹匾院陀泻维F(xiàn)實(shí)意義)二、以汽車市場模型為例(一)汽車市場Theexampleofusedcarscapturestheessenceoftheproblem.Fromtimetotimeonehearseithermentionoforsurpriseatthelargepricedifferencebetweennewcarsandthosewhichhavejustlefttheshowroom.Theusuallunchtablejustificationforthisphenomenonisthepurejoyofowninga"new"car.(舊車市場的例子能夠抓住問題的實(shí)質(zhì)。人們不只一次的聽聞或驚訝于新車與剛才開出樣品陳設(shè)室的汽車之間的價錢存在巨大差異。對于這類狀況最廣泛的解說是人們有一種對“新”車的特別偏好)Weofferadifferentexplanation.Suppose(forthesakeofclarityratherthanreality)thattherearejustfourkindsofcars.Therearenewcarsandusedcars.Therearegoodcarsandbadcars(whichinAmericaareknownas"lemons").Anewcarmaybeagoodcaroralemon,andofcoursethesameistrueofusedcars(假.設(shè)(作出這類假定不過為了簡化剖析,而非從實(shí)質(zhì)出發(fā))用四種汽車:新車和舊車;高質(zhì)量的車和低質(zhì)量的車(低質(zhì)量的車在美國被稱為“檸檬”)。一輛新車可能是高質(zhì)量的,也可能是“檸檬”,自然一輛舊車也相同有兩種狀況)Theindividualsinthismarketbuyanewautomobilewithoutknowingwhetherthecartheybuywillbegoodoralemon.Buttheydoknowthatwithprobabilityqitisagoodcarandwithprobability(1-q)itisalemon;byassumption,qistheproportionofgoodcarsproducedand(1-q)istheproportionoflemons.(在這樣的市場上,花費(fèi)者買新車時其實(shí)不知道車輛究竟是高質(zhì)量的仍是“檸檬”,可是他知道這輛車是高質(zhì)量的概率是q,是“檸檬”的概率是“1-q”。這里假定q是高質(zhì)量車占全部汽車的比率,1-q是“檸檬”的比率)Afterowningaspecificcar,however,foralengthoftime,thecarownercanformagoodideaofthequalityofthismachine;i.e.,theownerassignsanewprobabilitytotheeventthathiscarisalemon.Thisestimateismoreaccuratethantheoriginalestimate(車.主在擁有汽車后一段時間內(nèi)就會認(rèn)識到該車的質(zhì)量,也就是說,此時車主能夠給予該車可能是“檸檬”的一個概率值,這個預(yù)計(jì)比初始的預(yù)計(jì)更為正確)Anasymmetryinavailableinformationhasdeveloped:forthesellersnowhavemoreknowledgeaboutthequalityofacarthanthebuyers.Butgoodcarsandbadcarsmuststillsellatthesameprice-sinceitisimpossibleforabuyertotellthedifferencebetweenagoodcarandabadcar(.于是,信息不對稱發(fā)生了:賣主掌握了比買主更多的對于汽車質(zhì)量的信息。對于買主來說,因?yàn)樗豢梢栽谫I車時區(qū)分汽車的質(zhì)量,所以,高質(zhì)量車和低質(zhì)量車只好以同一個價錢水平銷售)Itisapparentthatausedcarcan-othavethesamevaluationasanewcar-ifitdidhavethesamevaluation,itwouldclearlybeadvantageoustotradealemonatthepriceofnewcar,andbuyanothernewcar,atahigherprob-abilityqofbeinggoodandalowerprobabilityofbeingbad.(明顯,一輛新車和一輛舊車不該當(dāng)有相同的評論。假如他們擁有相同的評論,車主經(jīng)過以高質(zhì)量車的價錢銷售“檸檬”后再買一輛新車,該新車是高質(zhì)量的概率q大于原來購置新車的概率)Thustheownerofagoodmachinemustbelockedin.Notonlyisittruethathecannotreceivethetruevalueofhiscar,buthecannotevenobtaintheexpectedvalueofanewcar(.這樣,高質(zhì)量車的擁有者將不會賣出汽車,因?yàn)榧偃缳u出汽車他不但沒法獲取汽車的真切價值,也沒法獲取一輛新車的希望價值)Gresham'slawhasmadeamodifiedreappearance.Formostcarstradedwillbethe"lemons,"andgoodcarsmaynotbetradedatall.The"bad"carstendtodriveoutthegood(inmuchthesamewaythatbadmoneydrivesoutthegood)(.這里出現(xiàn)了一個修正后的格萊欣定律。當(dāng)“檸檬”充滿汽車市場時,高質(zhì)量車根本不會成交,于是,好像劣幣驅(qū)趕良幣一樣,低質(zhì)量車將高質(zhì)量車逐出市場)ButtheanalogywithGresham'slawisnotquitecomplete:badcarsdriveoutthegoodbecausetheysellatthesamepriceasgoodcars;similarly,badmoneydrivesoutgoodbecausetheexchangerateiseven(然.而,該結(jié)果與格萊欣定律其實(shí)不完整相同:低質(zhì)量車驅(qū)趕高質(zhì)量車是因?yàn)榈唾|(zhì)量車和高質(zhì)量車在相同的價錢水平上銷售。相像地,劣幣驅(qū)趕良幣是因?yàn)槎叩幕Q利率相同)Butthebadcarssellatthesamepriceasgoodcarssinceitisimpossibleforabuyertotellthedifferencebetweenagoodandabadcar;onlythesellerknows.InGresham'slaw,however,presumablybothbuyerandsellercantellthedifferencebetweengoodandbadmoney.Sotheanalogyisinstructive,butnotcomplete(.可是低質(zhì)量車之所以與高質(zhì)量以同一個價錢銷售是因?yàn)橘I主沒法區(qū)分一輛車究竟是低質(zhì)量的仍是高質(zhì)量的,這只有賣主才知道的信息。在格萊欣定律中,買主和賣主大體否能夠區(qū)分劣幣和良幣。所以說,這個類比擁有啟迪性,但非完整相同)(二)非對稱信息Ithasbeenseenthatthegoodcarsmaybedrivenoutofthemarketbythelemons.Butinamorecontinuouscasewithdifferentgradesofgoods,evenworsepathologiescanexist.(我們已經(jīng)看到質(zhì)量好的汽車會被“檸檬”逐出市場??墒?,在不一樣質(zhì)量等級的產(chǎn)品連續(xù)散布的情況下,更糟糕的狀況也會發(fā)生)Foritisquitepossibletohavethebaddrivingoutthenot-so-baddrivingoutthemediumdrivingoutthenot-so-gooddrivingoutthegoodinsuchasequenceofeventsthatnomarketexistsatall.(質(zhì)量最差的汽車在將質(zhì)量最好的汽車逐出市場后,會持續(xù)將質(zhì)量較好、質(zhì)量中等和質(zhì)量稍差的汽車挨次逐出市場,進(jìn)而致使二手車交易市場根本沒法存在)Onecanassumethatthedemandforusedautomobilesdependsmoststronglyupontwovariables-thepriceoftheautomobilepandtheaveragequalityofusedcarstraded,d=Dμ(p,μ).(假定對二手車的需求主要取決于兩個變量——二手車的價錢p和進(jìn)入交易的二手車的均勻質(zhì)量μ,即Qd=D(p,)μ)Boththesupplyofusedcarsandalsotheaveragequalitywilldependupontheprice,orμ=μ(p)(and而二S=S(p)手車的.供應(yīng)和均勻質(zhì)量μ都取決于二手車的價錢,即μ=μ(p)和S=S(p))Andinequilibriumthesupplymustequalthedemandforthegivenaveragequality,orS(p)=D(p,μ(p)).Asthepricefalls,normallythequalitywillalsofall.Anditisquitepossiblethatnogoodswillbetradedatanypricelevel(.在平衡狀態(tài)下對于給定的均勻質(zhì)量,二手車的需求等于供應(yīng),即S(p)=D(p,μ。(p))跟著二手車交易價錢降落,進(jìn)入交易的二手車的均勻質(zhì)量自然也隨之降低,最后致使在任何價錢水平下都不存在二手車交易)Suchanexamplecanbederivedfromutilitytheory.Assumethattherearejusttwogroupsoftraders:groupsoneandtwo.Givegrouponeautilityfunction:(功效理論能夠用開幫助我們解釋二手車市場的例子。假定市場上有兩類交易者,交易者1和交易者2,交易者1的功效函數(shù)為)????1=M+∑??????=1WhereMistheconsumptionofgoodsotherthanautomobiles,??isthequalityofthe??th??automobile,andnisthenumberofautomobiles(.此中,M代表交易者1對二手車以外其余商品的花費(fèi),??表示第??輛汽車的質(zhì)量,n為汽車的數(shù)目)??Similarly,let(同理,交易者2的功效函數(shù)是)??3??2=M+∑2??????=1Threecommentsshouldbemadeabouttheseutilityfunctions:(對于這些功效函數(shù)有三點(diǎn)需要說明)(1)withoutlinearutility(saywithlogarithmicutility)onegetsneedlesslymiredinalgebraiccomplication(第一,這里采納線性功效函數(shù)(如對數(shù)功效函數(shù))來議論問題,這樣我們就無需辦理復(fù)雜的代數(shù)運(yùn)算)(2)Theuseoflinearutilityallowsafocusontheeffectsofasymmetryofinformation;withaconcaveutilityfunctionwewouldhavetodealjointlywiththeusualrisk-varianceeffectsofuncertaintyandthespecialeffectswewishtodiscusshere(.第二,現(xiàn)行功效函數(shù)還可以讓我們專注于對非對稱信息的成效。假如在凹形功效函數(shù)下進(jìn)行研究,我們將不得不在觀察我們最希望關(guān)注的事實(shí)的同時,考慮不確立性所帶來的風(fēng)險改動的影響)(3)U1andU2havetheoddcharacteristicthattheadditionofasecondcar,orindeedakthcar,addsthesameamountofutilityasthefirst.Againrealismissacrificedtoavoidadiversionfromtheproperfocus(.第三,U1和U2擁有邊沿功效不變的特點(diǎn),即增添第二輛車的花費(fèi)所帶來的功效的增添都與增添第一輛車花費(fèi)所帶來的功效增添相等。在此,我們再一次為了研究的需要犧牲了邊沿功效改動的現(xiàn)實(shí))Tocontinue,itisassumed(1)thatbothtypeonetradersandtypetwotradersareonVNeumann-Morgensternmaximizersofexpectedutility;(接下來假定:(1)兩類花費(fèi)者都是馮.諾依曼—摩根斯坦功效函數(shù)中的追求希望功效最大化者)(2)thatgrouponehasNcarswithuniformlydistributedquality??,0≦??≦2,andgrouptwohasnocars;((2)交易者1擁有N輛質(zhì)量為??并且聽從均勻散布的汽車,此中,交易者2沒有汽車)(3)thatthepriceof"othergoods"Misunity.((3)把其余商品M的價錢當(dāng)作為一個單位)Denotetheincome(includingthatderivedfromthesaleofautomobiles)ofalltypeonetradersasY1andtheincomeofalltypetwotradersasY2.(把各樣種類的交易者1的收入(包含銷售二手汽車所帶來的收入)記作Y1,將交易者2的收入記為Y2)Thedemandforusedcarswillbethesumofthedemandsbybothgroups.Whenoneignoresindivisibilities,thedemandforautomobilesbytypeonetraderswillbe(對二手車的需求即是兩類交易者對二手車需求的總和。當(dāng)我們忽視不行整除的可能時,交易者??1=??1?????=01

對二手車需求的數(shù)目能夠表示為)???>?1????<1Andthesupplyofcarsofferedbytypeonetradersis(交易者1對二手車的供應(yīng)是)??2=????2≦??2(1)Withaveragequality(二手車的均勻質(zhì)量為)μ=??2(2)(Toderive(1)and(2),theuniformdistributionofautomobilequalityisused(.)在(1)和(2)兩個表達(dá)式中,我們使用了二手車質(zhì)量聽從均勻散布這一假定)Similarlythedemandoftypetwotradersis(相同,交易者2的需求為)??22??=03??2<??And(供應(yīng)是)2??=02ThustotaldemandD(p,u)is(所以,總需求D(p,u)是)()(21)???假如??<??D??,??=??+??()???假如??<??<3??2D??,??=??2D(??,??)=0假如??>3??2However,withpricep,averagequalityisp/2andthereforeatnopricewillanytradetakeplaceatall:inspiteofthefactthatatanygivenpricebetween0and3therearetradersoftypeonewhoarewillingtoselltheirautomobilesatapricewhichtradersoftypetwoarewillingtopay.(只管有這樣的事實(shí),即在0到3之間的某個價錢下有的交易者1愿意賣掉他們的車,而有的交易者2愿意在這一價錢下購置。但不論怎樣,在價錢為p,均勻質(zhì)量為p/2這類質(zhì)量均勻散布的情況中,在任何價錢水平下都根本不會發(fā)生二手車交易)(三)對稱信息Theforegoingiscontrastedwiththecaseofsymmetricinformation.Supposethatthequalityofallcarsisuniformlydistributed,0≦??≦2.Thenthedemandcurvesandsupplycurvescanbewrittenasfollows:(上邊的剖析將與對稱信息下的情況形成比較。假定全部汽車的質(zhì)量是均勻散布的,0≦??≦2。那么,供應(yīng)曲線和需求曲線就能夠?qū)懗梢韵滦问剑海㏒upply(供應(yīng)曲線是)S(p)=Np>1S(p)=0p<1Andthedemandcurvesare(需求曲線是)D(p)=(Y1+Y2)/pp<1D(p)=(Y2/p)1<p<3/2D(p)=0p>3/2Inequilibrium(平衡時)P=1假如Y2<N(3)P=Y2/N假如2Y2/3<N<Y2(4)p=3/2假如N<2Y2/3(5)IfN<Y2thereisagaininutilityoverthecaseofasymmetricalinformationofN/2.(IfN>Y2,inwhichcasetheincomeoftypetwotradersisinsufficienttobuyallNautomobiles,thereisagaininutilityofY2/2units.)(假如N<Y2,那么沒在非對稱信息的狀況下有N/2單位的功效利潤。假如N>Y2,此時交易者2的收入不足以購置到N輛汽車,那么,將有Y2/2單位的功效利潤)Finally,itshouldbementionedthatinthisexample,iftradersofgroupsoneandtwohavethesameprobabilisticestimatesaboutthequalityofindividualautomobiles-thoughtheseestimatesmayvaryfromautomobiletoautomobile-(3),(4),and(5)willstilldescribeequilibriumwithoneslightchange:pwillthenrepresenttheexpectedpriceofonequalityunit(.最后,對于該例子應(yīng)該提到的是,假如兩類交易者對每輛汽車的質(zhì)量擁有相同的概率預(yù)計(jì)——只管這類預(yù)計(jì)因汽車的不一樣而不一樣——(3)、(4)和(5)仍將能描繪平衡,只可是此時p將代表每單位質(zhì)量的希望價錢)三、例證和應(yīng)用(一)保險Itisawell-knownfactthatpeopleover65havegreatdifficultyinbuyingmedicalinsurance.Thenaturalquestionarises:whydoesn'tthepricerisetomatchtherisk?(總所周知,年紀(jì)超出歲的人很難買到醫(yī)療保險。這就產(chǎn)生了一個問題:為何保險費(fèi)不可以向來上漲到風(fēng)險相當(dāng)?shù)乃??)Ouransweristhatasthepricelevelrisesthepeoplewhoinsurethemselveswillbethosewhoareincreasinglycertainthattheywillneedtheinsurance;forerrorinmedicalcheck-ups,doctors'sympathywitholderpatients,andsoonmakeitmucheasierfortheapplicanttoassesstherisksinvolvedthantheinsurancecompany.(我們的回答是,當(dāng)保險費(fèi)提升時,只有那些愈來愈確信自己有必需投保的人材會買保險。醫(yī)療體檢中的缺點(diǎn)、醫(yī)生對病人的憐憫等要素,使得保險申請人比保險公司更為認(rèn)識自己的風(fēng)險狀況)Theresultisthattheaveragemedicalconditionofinsuranceapplicantsdeterioratesasthepricelevelrises-withtheresultthatnoinsurancesalesmaytakeplaceatanyprice.(結(jié)果,當(dāng)保險費(fèi)上漲時,投保申請人的均勻健康狀況不停惡化,致使最后將不會在任何保險費(fèi)水平上簽署保險合同)Thisisstrictlyanalogoustoourautomobilescase,wheretheaveragequalityofusedcarssuppliedfellwithacorrespondingfallinthepricelevel.Thisagreeswiththeexplanationininsurancetextbooks:(這與我們汽車市場的例子十分相像,在那邊,待售舊車的均勻質(zhì)量隨著市場價錢的降落而降落。對于這一點(diǎn),保險學(xué)教科書的解說是這樣:

)Generallyspeakingpoliciesarenotavailableatagesmateriallygreaterthansixty-five....Thetermpremiumsaretoohighforanybutthemostpessimistic(whichistosaytheleasthealthy)insuredstofindattractive.Thusthereisasevereproblemofadverseselectionattheseages(.往常,65歲以上人的保單是無效的。此時,保險費(fèi)太高以致于除了那些最消極的(即健康狀況最差的)投保人而沒有其余人會對投保感興趣,因此在這一年紀(jì)存在著嚴(yán)重的逆向選擇問題)Thestatisticsdonotcontradictthisconclusion.Whiledemandsforhealthinsurancerisewithage,a1956nationalsamplesurveyof2,809familieswith8,898personsshowsthathospitalinsurancecoveragedropsfrom63percentofthoseaged45to54,to31percentforthoseover65.(以上結(jié)論與統(tǒng)計(jì)數(shù)據(jù)是一致的。1956年對2809個家庭8898個人進(jìn)行的全國性檢盤問卷顯示,當(dāng)人們跟著年紀(jì)的增添愈來愈需要保險時,醫(yī)療保險的覆蓋率從45~65歲人群的63%降落到65歲以上人群的31%)Andsurprisingly,thissurveyalsofindsaveragemedicalexpensesformalesaged55to64of$88,whilemalesover65payanaverageof$77(.令人驚訝的是,檢查顯示,55~64歲之間男性的均勻醫(yī)療支出是88美元,超出65歲男性的該項(xiàng)支出是77美元)Whilenoninsuredexpenditurerisesfrom$66to$80intheseagegroups,insuredexpendituredeclinesfrom$105to$70(.但是,在該年紀(jì)段的人的非保險支出從66美元上漲到80美元,保險支出則從105美元降落到70美元)Theconclusionistemptingthatinsurancecompaniesareparticularlywaryofgivingmedicalinsurancetoolderpeople(.結(jié)論是饒有興趣的:保險公司對向老人供應(yīng)保險尤其慎重)Theprincipleof"adverseselection"ispotentiallypresentinalllinesofinsurance.ThefollowingstatementappearsinaninsurancetextbookwrittenattheWhartonSchool:(逆向選擇問題是全部種類的保險都存在的廣泛問題。下邊的看法摘自沃頓商學(xué)院的一本教科書:)Thereispotentialadverseselectioninthefactthathealthyterminsurancepolicyholdersmaydecidetoterminatetheircoveragewhentheybecomeolderandpremiumsmount.(當(dāng)漸漸變老的那些健康保險的投保人面對保費(fèi)上漲時,他們就有可能決定退出保險,這類狀況中便存在潛伏的逆向選擇)Thisactioncouldleaveaninsurerwithanundueproportionofbelowaveragerisksandclaimsmightbehigherthananticipated.(這一行動能使保險公司的客戶中高風(fēng)險客戶所占比率過高,而使保險公司可能支付比預(yù)期要高的賠償金額)Adverseselection"appears(oratleastispossible)whenevertheindividualorgroupinsuredhasfreedomtobuyornottobuy,tochoosetheamountorplanofinsurance,andtopersistortodiscontinueasapolicyholder.(當(dāng)保險個人或集體能自由選擇購置或不買保險,能都自由選擇保險金和保險計(jì)劃,自由選擇維持保險或中止保險時,逆向選擇便會出現(xiàn),或起碼可能存在逆向選擇)Groupinsurance,whichisthemostcommonformofmedicalinsuranceintheUnitedStates,picksoutthehealthy,forgenerallyadequatehealthisapreconditionforemployment(.集體保險是美國醫(yī)療保險中最廣泛的保險形式,它用于鑒識人們的健康狀況,因?yàn)橥顩r下,健康是被雇用的一個先決條件)Atthesametimethismeansthatmedicalinsuranceisleastavailabletothosewhoneeditmost,fortheinsurancecompaniesdotheirown"adverseselection."(同時,這意味著保險公司自己的逆向選擇行動可能使那些最需要保險的人輕易獲取保險)Thisaddsonemajorargumentinfavorofmedicare(.醫(yī)療保險市場上的逆向選擇現(xiàn)象為支持政府醫(yī)療保障方案供應(yīng)了一個主要論據(jù))Onacostbenefitbasismedicaremaypayoff:foritisquitepossiblethateveryindividualinthemarketwouldbewillingtopaytheexpectedcostofhismedicareandbuyinsurance,yetnoinsurancecompanycanaffordtosellhimapolicy-foratanypriceitwillattracttoomany"lemons."(經(jīng)過成本利潤剖析,我們能夠看到醫(yī)療保障是值得的,因?yàn)楹苡锌赡苁袌錾先咳硕枷M冻霰囟ǖ尼t(yī)療保險的希望成原來購置保險,但卻沒有保險公司愿意銷售保單,因?yàn)椴徽撛谀莻€價錢水平下,保險合同的購置中都會有太多“檸檬”)Thewelfareeconomicsofmedicare,inthisview,isexactlyanalogoustotheusualclassroomargumentforpublicexpenditureonroads(.從這一方面來看,對醫(yī)療保障方案的經(jīng)濟(jì)剖析與平時我們對于政府利用公共支出建設(shè)馬路的議論十分相像)(二)少量名族就業(yè)TheLemonsPrinciplealsocastslightontheemploymentofminorities.Employersmayrefusetohiremembersofminoritygroupsforcertaintypesofjobs.(檸檬原則還可以用來解說少量民族就業(yè)問題。雇主可能在某些職位上不肯意雇用少量名族的職員)Thisdecisionmaynotreflectirrationalityorprejudice-butprofitmaximization.Forracemayserveasagoodstatisticfortheapplicant'ssocialbackground,qualityofschooling,andgeneraljobcapabilities.(這類決議并不是是帶有偏見或許鄙視,而是追求利潤最大化的結(jié)果。對于求職者的社會背景和工作能力,種族能夠是一個很好的統(tǒng)計(jì)指標(biāo))Goodqualityschoolingcouldserveasasubstituteforthisstatistic;bygradingstudentstheschoolingsystemcangiveabetterindicatorofqualitythanothermoresuperficialcharacteristics.(高質(zhì)量的教育水平能夠用來作為該統(tǒng)計(jì)指標(biāo)的一個增補(bǔ),教育系統(tǒng)經(jīng)過區(qū)分學(xué)生來作為一個比其余表面特點(diǎn)更優(yōu)勝的顯示信號)AsT.W.Schultzwrites,"Theeducationalestablishmentdiscoversandcultivatespotentialtalent.Thecapabilitiesofchildrenandmaturestudentscanneverbeknownuntilfoundandcultivated."(Italicsadded(.)正如舒爾茨所寫的那樣“創(chuàng)辦教育能夠覺察和培育潛伏的天才,少兒和成人的才能假如不經(jīng)挖掘和培育將不會被了解”)Anuntrainedworkermayhavevaluablenaturaltalents,butthesetalentsmustbecertifiedby"theeducationalestablishment"beforeacompanycanaffordtousethem.Thecertifyingestablishment,however,mustbecredible;theunreliabilityofslumschoolsdecreasestheeconomicpossibilitiesoftheirstudents(.固然一名未受過教育的工人可能擁有十分有價值的才能,可是在公司決定雇用他以前,這些才能一定經(jīng)過教育系統(tǒng)的證明。不論怎樣,這類起到證明作用的系統(tǒng)應(yīng)當(dāng)是可信的,窮人區(qū)學(xué)校的低的證明能力相應(yīng)地低估了學(xué)生的經(jīng)濟(jì)潛力)Thislackmaybeparticularlydisadvantageoustomembersofalreadydisadvantagedminoritygroups.Foranemployermaymakearationaldecisionnottohireanymembersofthesegroupsinresponsiblepositions-becauseitisdifficulttodistinguishthosewithgoodjobqualificationsfromthosewithbadqualifications(.教育上的缺點(diǎn)使已經(jīng)是弱勢集體的少量民族更為不理。

因犯難以區(qū)分少量民族中工作能力高和工作能力低的職員,雇主的理智選擇是在責(zé)任重要的崗位上不雇用少量民族的工人)ThistypeofdecisionisclearlywhatGeorgeStiglerhadinmindwhenhewrote,"inaregimeofignoranceEnricoFermiwouldhavebeenagardener,onVNeumannacheckoutclerkatadrugstore(."這類決議早已清楚地反應(yīng)在喬治.斯蒂格利茨的思想中,他寫道:“假如沒有接受教育,恩萊科.費(fèi)米可能不過個花匠,而馮.諾依曼則可能是商鋪里的一名查驗(yàn)員”)Asaresult,however,therewardsforworkinslumschoolstendtoaccruetothegroupasawhole-inraisingitsaveragequality-ratherthantotheindividual.(不論怎樣,窮人區(qū)的學(xué)校的工作不但能夠使那邊受教育的個人利潤,還可以經(jīng)過提升人們的均勻素質(zhì)增添對整個社會集體的回報(bào))Onlyinsofarasinformationinadditiontoraceisusedisthereanyincentivefortraining(.僅從教育水皮能夠作為種族的附帶信息這個角度來說,人們是用動機(jī)接受教育的)AnadditionalworryisthattheOfficeofEconomicOpportunityisgoingtousecost-benefitanalysistoevaluateitsprograms.Formanybenefitsmaybeexternal(我.們的另一個但有就是企業(yè)向來用成本利潤剖析法來評論他們的項(xiàng)目好壞,因?yàn)檫@類方法可能忽視很多外面性)Thebenefitfromtrainingminoritygroupsmayariseasmuchfromraisingtheaveragequalityofthegroupasfromraisingthequalityoftheindividualtrainee;and,likewise,thereturnsmaybedistributedoverthewholegroupratherthantotheindividual(.對少量民族集體進(jìn)行培訓(xùn)的利處在于它提升個人素質(zhì)的同時,也提升了整體集體的均勻素質(zhì)。相同,這類回報(bào)其實(shí)不但僅在個體間獲取分派,并且使得整個集體得益)(三)欺詐性交易的成本TheLemonsmodelcanbeusedtomakesomecommentsonthecostsofdishonesty.Consideramarketinwhichgoodsaresoldhonestlyordishonestly;qualitymayberepresented,oritmaybemisrepresented(.檸檬模型也能夠用于解說欺詐性交易的成本。假定,在市場上貨物買賣或是誠實(shí)地進(jìn)行或是帶有欺詐性的進(jìn)行,即質(zhì)量可能是被真是標(biāo)志,也可能是被虛假標(biāo)志)Thepurchaser'sproblem,ofcourse,istoidentifyquality.Thepresenceofpeopleinthemarketwhoarewillingtoofferinferiorgoodstendstodrivethemarketoutofexistencethecaseofourautomobile"lemons.("買者的困難就是確立質(zhì)量。那些在是市場上供應(yīng)次品的人就像二手車市場上的檸檬相同會使得整個市場崩潰)Itisthispossibilitythatrepresentsthemajorcostsofdishonesty-fordishonestdealingstendtodrivehonestdealingsoutofthemarket.(這類可能性組成了欺詐性交易的成本,即欺詐性交易將誠實(shí)的交易者逐出市場)Theremaybepotentialbuyersofgoodqualityproductsandtheremaybepotentialsellersofsuchproductsintheappropriatepricerange,however,thepresenceofpeoplewhowishtopawnbadwaresasgoodwarestendstodriveoutthelegitimatebusiness(.市場上本來可能有買主想購置高質(zhì)量的商品,并且有賣主愿意在一個合適的價錢范圍內(nèi)銷售該種商品??墒牵?yàn)槌霈F(xiàn)一些蓄意以次充好進(jìn)行欺詐性交易的人,使得合法的誠實(shí)交易者被逐出市場。)Thecostofdishonesty,therefore,liesnotonlyintheamountbywhichthepurchaserischeated;thecostalsomustincludethelossincurredfromdrivinglegitimatebusinessoutofexistence.(所以,欺詐性交易的成本不但是買者受欺騙的部分,還包含正常交易不復(fù)存在所帶來的損失)Dishonestyinbusinessisaseriousprobleminunderdevelopedcountries.Ourmodelgivesapossiblestructuretothisstatementanddelineatesthenatureofthe"external"economiesinvolved.(欺詐性交易在不發(fā)達(dá)國家市場是個嚴(yán)重的問題。我們的模型對這一點(diǎn)進(jìn)行了可能的解說,并且對經(jīng)濟(jì)的外面性賜予闡述)Inparticular,inthemodeleconomydescribed,dishonesty,orthemisrepresentationofthequalityofautomobiles,costs1/2unitofutilityperautomobile,furthermore,itreducesthesizeoftheusedcarmarketfromNto0.Wecan,consequently,directlyevaluatethecostsofdishonesty-atleastintheory.(特別是,在我們描繪的模型中,欺詐行為或許說對汽車質(zhì)量的誤導(dǎo)性的說明耗資了每單位汽車1/2的功效。進(jìn)一步講,這類行為使得汽車市場規(guī)模由N減少到0,這樣,我們能夠直接預(yù)計(jì)欺詐性的成本,這起碼在理論上是行的通的)Thereisconsiderableevidencethatqualityvariationisgreaterinunderdevelopedthanindevelopedareas.Forinstance,theneedforqualitycontrolofexportsandStateTradingCorporationscanbetakenasoneindicator.InIndia,forexample,undertheExportQualityControlandInspectionActof1963,"about85percentofIndianexportsarecoveredunderoneortheothertypeofqualitycontrol."(有大批憑證能夠說明在不發(fā)達(dá)地域商品的質(zhì)量差異要比在發(fā)達(dá)地域大。對于這一點(diǎn),我們能夠從對出口質(zhì)量控制和國家間貿(mào)易合作的需求來權(quán)衡。比如,在印度,在《1963出口監(jiān)察與控制法案》的規(guī)范下,大概85%的印度出口產(chǎn)品要接受一種質(zhì)量控制)Indianhousewivesmustcarefullygleanthericeofthelocalbazaartosortoutstonesofthesamecolorandshapewhichhavebeenintentionallyaddedtotherice.AnycomparisonoftheheterogeneityofqualityinthestreetmarketandthecannedqualitiesoftheAmericansupermarketsuggeststhatqualityvariationisagreaterproblemintheEastthanintheWest(.在印度的地方市場上購置稻米,主婦們一定認(rèn)真的從中精選出那些與米粒顏色相同,被蓄意增添到稻米中的石粒。而對美國街邊市集的商品和大型商場的商品進(jìn)行比較厚,我們不難發(fā)現(xiàn),與西方國家對比,東方國家市場上質(zhì)量的差異更是大問題)Inonetraditionalpatternofdevelopmentthemerchantsofthepre-industrialgenerationturnintothefirstentrepreneursofthenext.Thebest-documentedcaseisJapan,butthisalsomayhavebeenthepatternforBritainandAmerica(在傳統(tǒng)發(fā)展模式中,前工業(yè)時期的那一代商人成為了工業(yè)化國家的第一批公司家。有記錄的最好例子是日本,并且這一道理也合用于英國和美國)Inourpicturetheimportantskillofthemerchantisidentifyingthequalityofmerchandise;thosewhocanidentifyusedcarsinourexampleandcanguaranteethequalitymayprofitbyasmuchasthedifferencebetweentypetwotraders'buyingpriceandtypeonetraders'sellingprice.Thesepeoplearethemerchants.Inproductiontheseskillsareequallynecessary-bothtobeabletoidentifythequalityofinputsandtocertifythequalityofoutputs.Andthisisone(added)reasonwhythemerchantsmaylogicallybecomethefirstentrepreneurs(.在此,我們把能夠辨別商質(zhì)量量作為商人們的一項(xiàng)重要本事。在檸檬模型中,那些能夠辨別汽車質(zhì)量的人能夠經(jīng)過兩類交易者間的買賣差價來贏利,這些就是商人。在生產(chǎn)領(lǐng)域,這項(xiàng)技術(shù)相同重要,它被用來鑒識投入品的質(zhì)量,保證產(chǎn)出品的質(zhì)量。這就是商人為何理所自然成為第一批公司家的原由)Theproblem,ofcourse,isthatentrepreneurshipmaybeascarceresource;nodevelopmenttextleavesentrepreneurshipunemphasized.Sometreatitascentral(自然,公司家是一種稀缺資源。沒有一個國家發(fā)展的歷史能夠缺乏對公司家的重視,并且有些國家的發(fā)展是以公司家為中心)Given,then,thatentrepreneurshipisscarce,therearetwowaysinwhichproductvariationsimpededevelopment.First,thepay-offtotradeisgreatforwouldbeentrepreneurs,andhencetheyaredivertedfromproduction;second,theamountofentrepreneurialtimeperunitoutputisgreater,thegreaterarethequalityvariations(.假如缺乏公司家,產(chǎn)品的差異性將從以下兩個方面影響到經(jīng)濟(jì)發(fā)展:第一,對于潛伏的公司家階層,進(jìn)行倒賣的利潤過高使他們遠(yuǎn)離生產(chǎn)領(lǐng)域;第二,每單位產(chǎn)出所占用的公司家的時間越多,產(chǎn)品的質(zhì)量差異就會越大)(四)不發(fā)達(dá)國家的信貸市場(1)CreditmarketsinunderdevelopedcountriesoftenstronglyreflecttheoperationoftheLemonsPrinciple.InIndiaamajorfractionofindustrialenterpriseiscontrolledbymanagingagencies(accordingtoarecentsurvey,these"managingagencies"controlled65.7percentofthenetworthofpubliclimitedcompaniesand66percentoftotalassets)(.不發(fā)達(dá)國家的信貸市場也充分反應(yīng)了檸檬原則。在印度,絕大多半的工業(yè)公司被代管公司控制著(近來一項(xiàng)研究報(bào)告指出,這些“代管公司”控制著公共有限責(zé)任公司資本凈值得65.7%和財(cái)產(chǎn)總值的66%))Hereisahistorian'saccountofthefunctionandgenesisofthe"managingagencysystem":(下邊是一位歷史學(xué)家對這類“代管公司系統(tǒng)”的發(fā)源和運(yùn)作的描繪)ThemanagementoftheSouthAsiancommercialsceneremainedthefunctionofmerchanthouses,andatypeoforganizationpeculiartoSouthAsiaknownastheManagingAgency.(南亞的商業(yè)活動仍舊保持著商人家族式的運(yùn)作,此中存在一種特別的組織機(jī)構(gòu)被稱為代管公司)Whenanewventurewaspromoted(suchasamanufacturingplant,aplantation,oratradingventure),thepromoterswouldapproachanestablishedmanagingagency.ThepromotersmightbeIndianorBritish,andtheymighthavetechnicalorfinancialresourcesormerelyaconcession(新公司(如一個制造廠、一個植物園或一個貿(mào)易公司)倡始時,倡始者會與代管公司聯(lián)系。倡始者可能是印度人或英國人,他們可能擁有技術(shù)、金融資源或特許權(quán))Inanycasetheywouldturntotheagencybecauseofitsreputation,whichwouldencourageconfidenceintheventureandstimulateinvestment.(但不論是那種狀況下,他們都要與代管公司聯(lián)系,因?yàn)榇芄镜男庞媚軌蚪o公司經(jīng)營帶來信心和充分的投資)Inturn,asecondmajorfeatureoftheIndianindustrialscenehasbeenthedominanceofthesemanagingagenciesbycaste(or,moreaccurately,communal)groups.Thusfirmscanusuallybeclassifiedaccordingtocommunalorigin.5Inthisenvironment,inwhichoutsideinvestorsarelikelytobebilkedoftheirholdings,either(印度工業(yè)活動的第二個主要特點(diǎn)是這類代管公司被世襲的集體控制著,或許更正確的說被同族的集體控制著,因此眾多的公司能夠依據(jù)種族區(qū)分。在這類狀況下,外面投資者的投資很有可能被詐騙。所以,這類公司有兩種運(yùn)轉(zhuǎn)方式)(1)firmsestablishareputationfor"honest"dealing,whichconfersuponthemamonopolyrentinsofarastheirservicesarelimitedinsupply,(第一,公司成立起了誠實(shí)交易的信用,當(dāng)他們供應(yīng)的服務(wù)的供應(yīng)是有限時,這類名譽(yù)能夠帶來壟斷租金)or(2)thesourcesoffinancearelimitedtolocalcommunalgroupswhichcanusecommunal-andpossiblyfamilial-tiestoencouragehonestdealingwithinthecommunity(.第二,固然他們金融資源有限,可是,它們能夠借助種族關(guān)系,也可能是家庭的關(guān)系網(wǎng)在族內(nèi)從事誠實(shí)交易)Itis,inIndianeconomichistory,extraordinarilydifficulttodiscernwhetherthesavingsofrichlandlordsfailedtobeinvestedintheindustrialsector(的確,在印度的經(jīng)濟(jì)史中,要想鑒識那些富饒地主的存款是否應(yīng)當(dāng)投資到工業(yè)領(lǐng)域是十分困難的)(1)becauseofafeartoinvestinventurescontrolledbyothercommunities,(2)becauseofinflatedpropensitiestoconsume,or(3)becauseoflowratesofreturn.(一是,因?yàn)樗麄儜峙聦①Y本投入到其余種族控制的公司,二是因?yàn)樗麄儞碛屑ち业幕ㄙM(fèi)偏向,三是因?yàn)榛貓?bào)率很低)Attheveryleast,however,itisclearthattheBritish-ownedmanagingagenciestendedtohaveanequityholdingwhosecommunaloriginwasmoreheterogeneousthantheIndian-controlledagencyhouses,andwouldusuallyincludebothIndianandBritishinvestors.(可是,英國人擁有的代管公司資本凈值得擁有者比印度人的代管公司擁有更大的種族上的多樣性,并且常常既包含英國人也包含印度人)AsecondexampleoftheworkingsoftheLemonsPrincipleconcernstheextortionaterateswhichthelocalmoneylenderchargeshisclients.InIndiathesehighratesofinteresthavebeentheleadingfactorinlandlessness;theso-called"CooperativeMovement"wasmeanttocounteractthisgrowinglandlessnessbysettingupbankstocompetewiththelocalmoneylenders.(第二個有關(guān)檸檬原則運(yùn)用的例子是對于地方性的放貸者向借款者所要高利率的問題。在印度,這類高利率已經(jīng)成為人們沒法擁有土地的首要原由,被稱為“合作行動”的運(yùn)動試圖經(jīng)過成立銀行與地方性放貸者競爭來應(yīng)付這類人們沒法擁有土地的狀況)Whilethelargebanksinthecentralcitieshaveprimeinterestratesof6,8,and10percent,thelocalmoneylendercharges15,25,andeven50percent.Theanswertothisseemingparadoxisthatcreditisgrantedonlywherethegranterhas(1)easymeansofenforcinghiscontractor(2)personalknowledgeofthecharacteroftheborrower(當(dāng)位于中心城市的大銀行索要6%、8%和10%的優(yōu)惠貸款利率時,地方性貸款者卻索要15%、25%甚至是50%的利率。這個看似矛盾的問題的答案在于放貸者方面,只有放他們(1)以為合同簡單被執(zhí)行時,或許(2)認(rèn)識貸款者借款者個人信息時,才愿意供應(yīng)貸款)Themiddlemanwhotriestoarbitragebetweentheratesofthemoneylenderandthecentralbankisapttoattractallthe"lemons"andtherebymakealoss(那.些試圖經(jīng)過地方性貸款者與大銀行間的利率差套利的人,可能因?yàn)槲诉^多的“檸檬”而遭到損失)ThisinterpretationcanbeseeninSirMalcolmDarling'sinterpretationofthevillagemoneylender'spower:(我們能夠從馬爾科姆.達(dá)林對農(nóng)村放貸者的權(quán)力解說中理解上述看法)ItisonlyfairtorememberthatintheIndianvillagethemoney-lenderisoftentheonethriftypersonamongstagenerallythriftlesspeople;andthathismethodsofbusiness,thoughdemoralizingundermodernconditions,suitthehappy-go-luckywaysofthepeasant(.印度小農(nóng)村放貸者常常是總舵不節(jié)約人中的節(jié)約者。固然從現(xiàn)代的看法來看,他們經(jīng)商的套路十分雜亂,但這類方式卻合適那些隨遇而安的農(nóng)民)Heisalwaysaccessible,evenatnight;dispenseswithtroublesomeformalities,asksnoinconvenientquestions,advancespromptly,andifinterestispaid,doesnotpressforrepaymentofprincipal.Hekeepsinclosepersonaltouchwithhisclients,andinmanyvillagessharestheiroccasionsofwealorwoe.Withhisintimateknowledgeofthosearoundhimheisable,withoutseriousrisk,tofinancethosewhowouldotherwisegetnoloanatall.[Italicsadded.](他們?nèi)旌虻亟?jīng)商,省略了那些繁瑣的正式程序,并且,只需借款人支付利息,他們就不會追要本金。他們與顧客保持著優(yōu)秀的接觸,在很多農(nóng)村,放貸者會與顧客們分擔(dān)他們的好運(yùn)與不幸。有了這些詳盡的對于他身旁借款人的資料,他就能進(jìn)行低風(fēng)險投資,而不會借款給那些他根本不認(rèn)識的人)OrlookatBarbaraWard'saccount:(在來看看巴巴拉.沃德的闡述)AsmallshopkeeperinaHongKongfishingvillagetoldme:"Igivecredittoanyonewhoanchorsregularlyinourbay;butifitissomeoneIdon'tknowwell,thenIthinktwiceaboutitunlessIcanfindoutallabouthim."(香港小漁村的小店東告訴我:“我只借款給那些按期??窟@里的人。

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