AGING AND PRODUCTIVITY AMONG ECONOMISTS语言文化论文.docx

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1、AGINGANDPRODUCTIVITYAMONGECONOMISTS语言文化论文AGINGANDPRODUCTIVITYAMONGECONOMISTS语言文化论文生产力经济学是研究社会生产方式统一体中的生产力及其运动规律的经济学分支学科。研究社会生产力发展运动规律的学科。把人们对生产力认识的注意力从过去局限于生产力要素分解引导到从生产力要素的构成和结合上来把握生产力，从生产力要素不同的构成和结合方式上去求得最佳的经济效益的一门新兴科学。下面是学习啦我为大家精心准备的语言文化论文：AGINGANDPRODUCTIVITYAMONGECONOMISTS。仅供大家参考!AGINGANDPRODUC

2、TIVITYAMONGECONOMISTS衰老和生产力经济学家全文如下：Abstract：-Economistsproductivityovertheircareersandasmeasuredbypublicationinleadingjournalsdeclinesverysharplywithage.Thereisnodifferencebyageintheprobabilitythatanarticlesubmittedtoaleadingjournalwillbeaccepted.Ratesofdecliningproductivityarenogreateramongthevery

3、toppublishersthanamongothers,andtheprobabilityofacceptanceisincreasinglyrelatedtotheauthorsqualityratherthantheauthorsage.Itiswellknownthatproductivitydeclineswithageinawiderangeofactivities.Lehman(1953)suggestsanearlypeakinproductivityinavarietyofscientificandartisticendeavors,andDiamond(1986)docum

4、entsthepatternforseveralscholarlypursuits.LevinandStephan(1992)provideclearevidencethatthisdeclineexistsevenaftercarefulattemptstoaccountforindividualandcohortdifferences.Fair(1994)findsdeclinesinphysicalabilityamongeliterunners,asdoesLydall(1968,pp.113passim)inphysicalabilitiesofthepopulationgenera

5、lly.Inthisstudyweexamineproductivitydeclinesinourownfield.Themainnewresultsarisefromouruseoftwodifferenttypesofinformation,theequivalentofhouseholdandestablishmentdata,tostudythestonefieldoveressentiallythesameperiodoftime.SectionIdiscussesthegeneralresultsonagingandproductivity,whereassectionIIpres

6、entsevidenceoftheimportanceofheterogeneity.I.DecliningProductivitywithAgeUsingtheAmericanEconomicAssociation(AEA)DirectoryofMembers,weidentifiedtenuredeconomicsfacultyat17topresearchinstitutionsandobtainedtheyearsoftheirPh.D.degrees.1WiththecitationindexoftheJournalofEconomicLiteraturewereplicatedpo

7、rtionsofthecurricalavitaeofeachofthe208economistscurrentlyintheeconomicsdepartmentsofthoseinstitutionswhoreceivedPh.D.degreesbetween1959and1983.2Tomeasureproductivityweconstructthreeindexes,combiningpaperspublishedinrefereedjournals.Priorresearchsuggeststhat,atleastintermsofsalarydetermination,there

8、turnsfromnonreferredpublicationsarequitelowSauer(1988),sothatweignoresuchpublicationsincalculatingthesemeasures.I1weightsanarticlebythejournalwhereitappearsbasedoncitationstothatjournal,usingvaluesgeneratedbyLabandandPiette(1994).Thisindexdistinguishesstronglyamongjournals.Forexample,theJournalofPol

9、iticalEconomyhasaweightof59.1,whereasEconomicInquiryhasaweightof7.9.InconstructingI1weusetheweightsassociatedwiththedecadeinwhichthearticleswerepublished.I2distinguishessomewhatlessamongjournalsbyassigningallarticlesintheninecorejournalsidentifiedbyLabandandPietteavalueof1,whereasallotherjournalsare

10、valuedat0.5.3Finally,I3givesallpapersaweightof1.Coauthoredarticlesweregivenhalfcredit,consistentwithSauers(1988)findingsontheeconomicreturnstocoauthorship.4Wemeasurethechangeinproductivityoverthelifecyclebythepercentagechangeinthenumberofpublicationsfrom9-10yearspastthePh.D.totheperiods14-15yearsand

11、then19-20yearsafter.Formostoftheeliteeconomiststhebaseperiodisequivalent(accountingforpublicationlags)tothetimeoftenure,whenonemightexpectthatincentivestoproduceareatapeak.Usingtwo-yearpublicationrecordsateachpointreducestheeffectsofnoiseintheperformancemeasures.Onemightarguethatstillotherscientific

12、life-cyclemileposts(e.g.,attainingafullprofessorship)shouldbeaccountedfortoo(andtosomeextentthe14-15-yearpointdoesthis).Butourmainpurposeissimplytoprovidedetailedevidenceontherelationshiptoage,andourdataarenotsufficienttoinfertheimpactofeverypossiblemilepost.Table1containsdataonproductivitylossbyPh.

13、D.vintagemeasuredbyeachofthethreeindexes.IfweconsiderI1andI2,thetwoindexesthattakejournalqualityintoaccount,thedeclineappearstobequitesubstantial.Betweenyears9-10and14-15eliteeconomistsasagrouplose29to32%oftheiroutput.Fromyears9-10to19-20theylose54to60%.Inotherwords,productivitylossesareontheorderof

14、5%peryearfromthetimeofpeakproductivity.However,thelossesdonotappeartoaccelerateoverthese10yearsoftheeconomistsworklives.Thelossfromyear10toyear20isapproximatelytwicethatfromyear10toyear15.Anotherwaytostudytheage-productivityrelationshipistoexaminejournalsratherthanindividuals.Thefirstrowineachpairof

15、yearsintable2showstheagesofauthorsoffull-lengthrefereedarticlesinseveralleadingjournals(AmericanEconomicReview,JournalofPoliticalEconomy,andQuarterlyJournalofEconomics).5Themedianageofauthorsinthe1980sand1990swas36.Scholarsoverage50whentheirstudiesarepublishedareaminutefractionofallauthorsinthesejou

16、rnals.Creativeeconomicsatthehighestlevelsismainlyfortheyoung.Thatisastrueinthe1990sasitwasinthe1960s,althoughtheagedistributionofauthorsdoesseemtohaveshiftedslightlyrightwardinthelate1970s.Thesecondrowineachpairintable2showstheagedistributionsofrandomsamplesofthemembershipoftheAmericanEconomicAssoci

17、ationinyearsnearthoseforwhichtheauthorsagesweretabulated.6Thedistributionsareheavilyconcentratedbetween36and50.DecadalvariationsreflectrapidexpansionofAmericanuniversitiesinthemiddleandlate1960s,stagnationinthe1970sandmuchofthe1980s,andapossiblefragmentationoftheprofessioninthe1980sasspecializedasso

18、ciationsexpanded.AsubstantialpercentageofAEAmembersisoverage50implyingthatoldereconomistsaregreatlyunderrepresentedamongauthorsinmajorjournalsrelativetotheirpresenceamongthosewhoviewthemselvesaspartoftheeconomicsprofession.7AmongtheseveralgroupsofphysicalscientistsanalyzedbyLevinandStephan(1992)thed

19、eclineofproductivity(high-qualitypublishing)withagewasverypronounced.McDowells(1982)smallsamplesofscholarsinavarietyofdisciplinessuggestlessrapiddeclinesinproductivitywithage(inpublicationsunweightedbyquality),withthesharpestdeclinesandearliestpeaksinthehardsciences,andlaterpeaksamongEnglishprofesso

20、rsandhistorians.Theevidencefromourtwoverydifferenttypesofsamplesofeconomistsandeconomicspublishingthataccountforthequalityofpublicationssuggeststhat,forwhateverreason,economicsisatleastasmuchayoungpersonsgameasarethephysicalsciences.II.HeterogeneityinDecliningProductivityTheevidenceinsectionIdocumen

21、tsthedeclineinproductivityatthesamplemeans.Informationontheage-productivityrelationshipattheextremesofthesampleisinterestinginitsownrightandmighthelpshedsomelightonthepossiblecausesoftheapparentdeclineinproductivitywithage.Thesimplesttestcomparesproductivitylossesamongthetopearlyperformerswiththatof

22、theentiresampleofeconomistsateliteinstitutions.Amongthetop10%ofearlyproducersthemeanvaluesofI1,I2,andI3atyear20were64,50,and22%,respectively.Thesemeansarequiteclosetothoselistedfortheentiresampleintable1.Thusonaverageearlypromiseseemstobesustainedinthissample.Ofthe12topresearchersonwhomwehave20years

23、ofdata,fivewerestillamongthetopdozenproducersatyear20.Theseconclusionsareconfirmedwhenweexaminetheentiresample.ForeachindexIj,j=1,2,3,weestimateb0andb1inMultiplelineequation(s)cannotberepresentedinASCIItext.(1)Table3reportstheparameterestimates.Forallthreeindexesproductivityinyear20ispositivelyandsi

24、gnificantlyrelatedtoproductivityinyear10.Thereisalsosubstantialproductivityloss.Thejointhypothesisthatb0=1andb1=0(i.e.,noproductivityloss)isrejected(F-statisticsof134,152,and39,respectively).ProductivitylossisleastsevereinI3,whichweightsalljournalsequally,regardlessofquality.Ifproductivitylosseswere

25、lessamongeconomistswithhighearlyproductivity(highIj,10),b1wouldbenegative.Infact,fortwoofthethreeindexestheestimatedb1iseffectivelyzero.Wecannotrejectthehypothesisofalinearrelationshipbetweenlateandearlyproductivity.OnlyforI3doesitappearthatproductivitylossishigherfortopearlyproducers,andevenherethe

26、effectisquitesmall.Aneconomistinthetop10%ofthissampleatyear10losesonlyanadditional0.5(unweighted)papercomparedtoanaverageresearcherinthissampleatyear10.Theverytopproducersinthiselitesamplekeeponproducinghigh-qualityresearch,butataslowerrate.Thosewhowerenotatthetopearlyintheircareersslowdownasrapidly

27、asthetoppeople,buttheirslowdownleadsthemtopublishincreasinglyinlowerqualityoutlets.Anotherwayofexaminingheterogeneityistolookathowauthorsofdifferentqualityfreeinthepublicationprocessconditionalontheirefforts.Weobtaineddataonarandomsampleofinitialsubmissionstoamajorgeneraljournalduringafour-monthperi

28、odin1991.(SomeofthedatawereinitiallysuppliedbythejournalsofficeforuseinHamermesh(1994).)Refereeingatthisjournalisdouble-blind,sothatthechancethatreferees(thoughpossiblynottheeditors)wereaffectedbyauthorsreputationsisreduced.Theagesoftheauthorsofthese313papersaremeasuredasof1993toaccountfortheprobabl

29、etwo-yearaveragelagbetweenthesubmissionofapaperanditspublication.Thesimplefactintheseadditionaldataisthatacceptanceratesatthisjournalareremarkablyconstantbyauthorsage.Theprobabilitiesofanarticlebeingacceptedare0.122,0.114,and0.123inthethreeagegroups50,respectively.8Onaveragethereisnodeclinewithagein

30、theacceptancerateofpaperssubmittedtothisjournal.9ProbitsontheacceptanceofasubmissionthatalsoincludedvariablesindicatingwhethertheauthorwasamemberoftheAEA,wasinatop20department(aslistedinBlank,1991),wasresidentinNorthAmerica,orwasfemale,andtheauthorspriorcitationrecordyieldanidenticalconclusion.Thede

31、cliningpresenceofolderauthorsintopeconomicsjournalsdoesnotoccurbecauseolderauthorswhokeepsubmittingpaperssufferhigherrejectionrates.Theprobitsincludedinteractiontermsbetweenindicatorvariablesforageandtheextentofcitations.(Low-citedeconomistsweredefinedasthosewithfewerthan10citationsperyear,well-cite

32、dwithatleast10.)Asfigure1clearlyshows,acceptanceratesforeachagegroupdiffersharplybycitationstatus.Comparingauthorsage36-50tothoseover50,itisquiteclearthatthedegreeofheterogeneityincreaseswithage.Thisappearstobelesstrueincomparingtheoldesttotheyoungestgroup,butthatinferenceisduemainlytoaverysmallsamp

33、le.(Onlysixauthorsunderage36,thefuturesuperstarsoftheprofession,werewellcited.)Thegeneraltenorofthecombinedresultsfromthissampleisthattheprofessionsignalstolessablescholarsthattheirworknolongermeetstheprofessionshigheststandards,andmostofthemrespondbyreducingtheirsubmissionstothehighestqualityjourna

34、ls.III.ConclusionsWehavefollowedthecareersofeconomistsandmeasuredthedemographiccharacteristicsofpublishersinleadingjournals.Theevidenceseemsquiteclearthatpublishingdiminisheswithage,especiallypublishinginleadingjournals,atratesasrapidasinthephysicalsciences.Indeed,remarkablyfewolderpeoplepublishsucc

35、essfullyinthescholarlyoutletsonwhichtheprofessionplacesthehighestvalue.Aseconomistsage,thosewhowerethemostproductiveearlyintheircareersareamongthefewsurvivorsstillcontributingtoscholarshipthroughtheleadingscholarlyoutlets.Whetherthisrelationshipisduetonaturaldeclinesincapacityordecreasedincentivesto

36、produceisextremelydifficulttodiscern.Unlikeathletes,whereitislikelythatpurephysicaldeteriorationcausesthereductioninproductivitywithage,amongscholarseventhefairlysubtlefactsthatwehaveuncoveredcanbemarshaledassupportforeachofthesecompetinghypotheses.Withoutdirectobservationonhowscholarsuseoftimechang

37、esastheyage,weareunlikelytobeabletodistinguishbetweenexplanationsofthedecliningageproductivityrelationshipinscience.REFERENCESBerger,Mark,andFrankScott,ChangesinU.S.andSouthernEconomicsDeparmentRankingsoverTime,GrowthandChange21(Summer1990),21-31.Blank,Rebecca,TheEffectsofDouble-BlindversusSingle-BlindReviewing,AmericanEconomicReview81(Dec.1991),10411067.Diamond,Arthur,TheLife-CycleResearchProductivityofMathematiciansandScientists,JournalofGerontology41(1986),520-525.