恩格爾系數(shù)在中國

1、經(jīng)典名篇85KeynesLucasScientificProgressALANS.BLINDERInoneofthosemarvelouscoincidencesofintellectualhistyRobertLucaswasbntheyearafterthepublicationofKeynes’GeneralThey.Fthefirstthirtyfiveyearsoftheirmutuallivesthetwoapparentl

2、ycoexistedinharmony.Buttheirrelationshiphasbeentumultuouseversince.LucashasfrequentlycriticizedKeynesianeconomicsasposcienceitispreciselyinthatspiritthatⅠwanttoaddressthedebatetoday.Weallknowtheoldjokeabouttheprofesswhou

3、sesthesameexamquestionsyearafteryearbutchangestheanswers.Thatjokeencapsulatesalltoowellwhathashappenedtomacroeconomicstheselastfifteenyearsseemstoreflectpolyoneconomicsasascience.doesitOnsecondthoughtthebestanswerstoscie

4、ntificquestionsdochangeasnewobservationsaremadeasnewexperimentsarerunasbettertheiesaredeveloped.Theissueiswhethertheanswerstoimptantquestionsinmacroeconomicshavechangedfgoodscientificreasonsoffotherreasons.Thejokeprovide

5、stheframewkfmytalk.IwillposeeightexamquestionsfeachoneIwillsummarizetheanswersgivenbyKeynesbyLucashisfollowersbymodernKeynesians.IpickonlyquestionsthatareanswereddifferentlybyKeynesiansLocationsthatarecentraltocontempary

6、macroeconomicdebates.ThefocusisonwhethertheKeynesiannewclassicalanswershavegreaterclaimtobeing“scientific.”Eachstudentmustanswereveryquestion.Ⅰ.AreExpectationsRationalKeynesthoughnostrangertoprobabilitytheywasnohelessune

7、quivocalinhisdenialthatexpectationsarewhatwenowcallrational:…alargeproptionofourpositiveactivitiesdependonspontaneousoptimismratherthanonamathematicalexpectation…OnlyalittlemethananexpeditiontotheSouthPoleisitbasedonanex

8、actcalculationofbenefitstocome.Thusifanimalspiritsaredimmedthespontaneousoptimismfaltersleavingustodependonnothingbutamathematicalexpectationenterprisewillfadedie…[1936pp.16162]ThatattitudeleftabiglooseendinTheGeneralThe

9、y.Businessinvestmentissupposedlydrivenby“thestateoflongtermexpectations”butexpectationsarenotpinneddownbythetheyleavingsubstantialroomfgyrationsinmacroeconomicactivitydrivenbyautonomouschangesinanimalspirits.Thathardlyco

10、nstitutesatightscientifictheybutKeyneswasprobablyhappytoleavethelooseendloose.Modern“sunspottheists”havetighteneduptheargumentconsiderablyinwaysthatKeynesmighthavefoundcongenial.Lucasofcoursechangestheanswertoyes.Wasthis

11、changemotivatedbyempiricalevidencethatsubjectiveexpectationsmatchtheconditionalexpectationsgeneratedbymodelseventhatactualPrincetonUniversityPrincetonNJ08544.IamgratefulfstimulatingdiscussionscrespondencewithBenBrakerewC

12、apelinMarkGentlerStephenGoldfieldDavidRoomerreShellfireRobertSolowLawrenceSummers.Aversionofthispaperwithfootnotescompletereferencesisavailableonrequesttotheauth.經(jīng)典名篇87unemployedwkersnmallyaccepttheirfirstjobofferthosewh

13、oarelookingfwkspendanaverageofonly4hoursperweekonsearchactivity.Thathardlysuggestsapredominantrolefsearchinexplainingunemployment.Ⅲ.DoWageMovementsQuicklyCleartheLabMarketKeynescertainlythoughtnotfsuchreasonsastradeunion

14、aggressivenesscustominertiaoutrightstubbnness.Lucasanswersyes—thoughperhapsonlyinabroadsense.Hehasfexamplecitedapprovinglythecompetitivecontractequilibriumapproachinwhichwkershave100percentunemploymentinsurancebecauseofi

15、ndivisibilitiesarechosenromlytowkeithersay40hoursaweekzero—meaningofcoursethatunemployedwkershavehigherutilitythanemployedones.InLucas’sopinionthereis“noreasontobelieve”thatcompetitivemodelsoflabmarketsthattreatunemploym

16、entlikeleisurecommit“aseriousstrategicerr.”NoreasonIthinkthepreponderanceoftheevidencesaysotherwise.Unemploymentinsurancereplacesonlyabout40percentoflostearning.LatelyonlyaboutonethirdoftheunemployedcollectitWhereistheev

17、idencethattheunemployedarehappierthantheemployedMosteconomiststhinkLucas’sdistinguishedpredecessattheUniversityofChicagohaditrightwhenhewrote“UnderanyconceivableinstitutionalarrangementscertainlythosethatnowprevailintheU

18、nitedStatesthereisonlyalimitedamountofflexibilityinpriceswages.”itishardfmeatleasttolookatwhathasgoneoninthiscountry—nottomentioninEurope—since1974seeclearinglabmarkets.Thatthemarketclearingapproachcaughtoninthisenvironm

19、entistestimonytoLucas’skeenintellectprofoundinfluencenottoeconomists’respectffacts.Methanjustcasualempiricismsupptsthisviewnumerousfmaleconometricstudiesrejectthemarketclearinghypothesisagainstsomestofdisequilibriaaltern

20、ative.Unftunatelyitisusuallyspotmarketclearingthatisrejected.Equilibriumcontractingmodelsinwhichthewageplayslittlenoshtrunalocativerolearedifficulttofmulateeconometricallymuchlesstoreject.Indeeditishardtoknowwhatobservat

21、ionscouldcontradictsuchmodelstheyjustleavestoomanyopenpossibilities.Nohelesscertainobservationsarewthmaking.Foneseveralauthshavepointedtointerindustrywagedifferentialsthatarepersistentacrossbothtimespace—differentialswhi

22、charenoteasilysquaredwithmarketclearing.Theeticallyweknowthatthewageratemaynotbeabletoclearthelabmarketinawldofimperfectinfmation—noteveninthelongrun.Ofcoursethatefficiencywagemodelscanbebuiltdoesnotimplythattheydescribe

23、reality.Butitdoesmeanthatmarketclearingmodelshavenoparticularclaimtothetheeticalhighground.Insumthescientificbasisfmodelinglabmarkets—goodsmarketsfthatmatter—ascontinuouslyclearingescapesme.Ⅳ.IstheNaturalRateofUnemployme

24、ntaStrongAttractftheActualRateofUnemploymentKeynesthoughtnot.IndeedinhisrevolutionaryzealKeynesspokeloosely（loosetalkwasaproblemfKeynes）ofan“unemploymentequilibrium”—whichwouldseemtodenythenaturalrateanyattractivefceatal