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您的当前位置:首页Which Nonlinearity in the Phillips Curve The Absence of Accelerating Deflation in Japan

Which Nonlinearity in the Phillips Curve The Absence of Accelerating Deflation in Japan

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WhichNonlinearityinthePhillipsCurve?

TheAbsenceofAcceleratingDeflationinJapan

EmmanuelDeVeirmanReserveBankofNewZealand

January14,2007

Abstract

Itisstandardtomodeltheoutput-inflationtrade-offasalinearrelationshipwithatime-invariantslope.Weassessempiricalevidenceforthreetypesofnonlinearityintheshort-runPhillipscurve.Atanempiricallevel,weaimtodiscoverwhylargenegativeoutputgapsinJapanduringtheperiod1998-2002didnotleadtoacceleratingdeflation,butinsteadcoincidedwithstable,beitmoderatelynegativeinflation.WedocumentthatthisepisodeismostconvincinglyinterpretedasreflectingagradualflatteningofthePhillipscurve.Thebroaderrelevanceofouranalysisliesinitsattempttoshedlightonthedeterminantsofsuchtime-variationinthePhillipscurveslope.Ourresultssuggestthat,inanyeconomywheretrendinflationissubstantiallylower(orsubstantiallyhigher)todaythaninpastdecades,time-variationintheslopeoftheshort-runPhillipscurvehasbecometooimportanttoignore.JELcodes:Keywords:

C22,C32,E31,E32

nonlinearPhillipscurve,time-varyingparametermodels.

ThispaperisbasedonthefirstchapterofmydissertationattheJohnsHopkinsUniversity.Iamgratefultomyadvisor,LaurenceBall,andtoAlanAhearne,CarlChrist,RobertDavies,HaliEdi-son,JonFaust,YasuoHirose,MichaelKiley,TakeshiKudo,KennethKuttner,DouglasLaxton,AndrewLevin,LouisMaccini,AthanasiosOrphanides,AdrianPagan,ErwanQuintin,JohnRoberts,JirkaSlacalek,TsutomuWatanabe,IsamuYamamoto,NaoyukiYoshino,andseminarparticipantsattheFederalReserveBankofDallas,theInternationalMonetaryFund,theCanadianEconomicsAssociation,theJapanEco-nomicSeminar,andJohnsHopkinsUniversityforvaluablecommentsandsuggestions.Anyerrorsaremine.IamcurrentlyaneconomistintheResearchDepartmentoftheReserveBankofNewZealand.Contact:ReserveBankofNewZealand,POBox2498,Wellington6140,NewZealand.E-mail:deveirman@jhu.edu

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1Introduction

TheoriginalPhillipscurvewasnonlinear:AlbanW.Phillips(1958)estimatedanonlinearre-lationshipbetweennominalwageinflationandtheunemploymentrateintheUnitedKingdom.Sincethattime,ithasbecomestandardtomodeltheshort-runPhillipscurveasalinearrela-tionshipwithatime-invariantslope.Thepresentpaperarguesthatthissimplifyingassumptionisnotasinnocentasitseems.

OurpaperassessestheempiricalperformanceofthreeclassesofmodelsinwhichtheslopeofthePhillipscurvevariesendogenouslyovertime.Themodelclassesdifferaccordingtothesetofvariablesdeterminingtheslopeoftheoutput-inflationtrade-off.

InpaperssuchasLaxton,Meredith,Rose(1995),thesizeoftheoutputgapdeterminestheslopeofthePhillipscurve.Inparticular,theoutput-inflationtrade-offbecomessteeperastheoutputgapapproachesthecapacityconstraint,whichisthemaximumpossiblelevelofoutputthatfirmscansupplyintheshortrun.Assuch,theshort-runPhillipscurveisconvex,withaverticalasymptoteatthecapacityconstraint.

InBall,Mankiw,Romer(1988)andDotsey,King,Wolman(1999),trendinflationisamongthedeterminantsofthePhillipscurveslope.Inthesemodelsofcostlypriceadjustment,thefrequencyofpriceadjustmentdependsonfirms’optimizingdecisions.Adecreaseintrendinflation,forone,causesfirmstoadjustpriceslessfrequently,whichinturnimpliesaflatterPhillipscurve.

InLucas(1973),theslopeofthePhillipscurvedependsonthevolatilityofaggregatedemandandsupplyshocks.Forinstance,ifaggregatevolatilitydecreases,alargerfractionofanychangeintheoverallpricelevelismisperceivedbyfirmsasbeingachangeintheirrelativeprice.Inthatscenario,anychangeinaggregatedemandhasalargerimpactonfirms’production,andasmallereffectoninflation.Thatistosay,thePhillipscurveflattens.

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Throughoutthispaper,werefertothethreeclassesofmodelsasimplyingdifferenttypesofnonlinearityinthePhillipscurve.Strictlyspeakinghowever,onlythefirstoftheabovemodelclassesimpliesthattheshort-runPhillipscurveisnonlinearatagivenpointoftime.Intheothercases,thePhillipscurveislinearatanypointoftime,butitsslopechangesovertimeasaconsequenceofchangesintrendinflationoraggregatevolatility.

Totestthesetheoriesofnonlinearity,wegatherevidencefromJapan.Theperiod1991-2002inJapancanbecharacterizedasasuccessionofrecessions,interruptedonlybybrieforlimitedrecoveries.Standardestimatessuggestthattheoutputgapwasnegativeformostofthatperiod.Initially,inflationdeclined,withcoreCPIinflationreachingthezero-levelinthemid-nineties,andturningnegativeinthesecondhalfofthenineties.After1998however,annualcoreCPIinflationremainedfairlystableatmoderatelynegativelevels,reachingitstroughat-0.79%in2002.

Aswedocumentinourpaper,thefactthatdeflationremainedsurprisinglymildnotwith-standingarelativelylongperiodofnegativeoutputgapspresentsapuzzletoanyonewhotakesastandardlinearPhillipscurveliterally.ThismakesJapanaparticularlyinterestingtestcaseforassessingthenatureoftheoutput-inflationtrade-off.

AnadvantageofusingrecentdataforJapanisthat,unlikethesamplestypicallyusedinearlierempiricaltestsofthethreetypesofnonlinearity,oursampleincludesafairlylargenumberofobservationsfromtheregionofthePhillipscurveatwhichinflationisnear-zeroornegative.Theinclusionoflow-andnegative-inflationobservationsincreasesourchancesofobtainingpreciseresultsastotheexistenceandtypeofnonlinearity.Ourresultsareinstructiveforothereconomiesinwhichacomparablylongdeflationaryperiodhasnotoccurredinthepost-1945period,yetwhichbearsufficientresemblancetoJapaninthatinflationhastendedtodeclineand/orbecomelessvolatileoverthecourseofrecentdecades.

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Ourmainresults,andtheirrelationshiptopreviouspapers’findings,canbesummarizedasfollows.

Wefindevidenceforastatisticallysignificant,gradualflatteninginalinearPhillipscurvewhichhasbeenoccurringsincebeforethenineties.ThisfindingisrelatedtoexistingresearchontheflatteningoftheJapanesePhillipscurve,1whichhowevertypicallyfocusesondocumentingaone-timestructural’break’inthePhillipscurveundertheassumptionofaknownbreakdate.

GiventhatweobservedagradualflatteningintheJapanesePhillipscurve,weassesswhethersuchtime-variationisconsistentwithanyofthetheoriesofnonlinearity.ThispartofourpaperisrelatedtoearlierempiricalevidenceonnonlinearityinthePhillipscurve.2Wefindthateachofthethreetypesofnonlinearityisconsistentwiththedata.

Ourpapermovesbeyonddocumentingmereconsistencyofthenonlineartheorieswiththedata.Wefindthateachofthenonlinearmodelsperformssignificantlybetter,inaneconometricsense,thananatheoreticalbenchmarkmodelinwhichthePhillipscurveislinear,butitsslopevariesovertimeasarandomwalk.Thisimpliesthatthetime-variationinthePhillipscurveslopehasbeenlargelysystematic.

Moreover,weperformaseriesofnon-nestedmodelhypothesisteststoassesstherelativeper-formanceofthethreetypesofnonlinearity.Ourresultsfavorthehypothesisthatdecliningtrend

NishizakiandWatanabe(2000)andMourouganeandIbaragi(2004).

AvastbodyofpapersincludingLucas(1973),Alberro(1981)andKormendiandMeguire(1984)investigateswhetherthePhillipscurvetendstobesteeperineconomieswithhighaggregatevolatility,withouthoweverexaminingthedeterminantsofchangesinthePhillipscurveslopeovertime.FroyenandWaud(1980)andIlmakunnasandTsurumi(1985)aremorecloselyrelatedtoourpaperinthattheyprovidesomeintertemporalevidence.

DeFina(1991),HessandShin(1999),andKiley(2000)furthertesttheBall-Mankiw-Romertheory.ThefirsttwopapersaswellasBMRprovidesomeintertemporalevidenceontherelationbetweenchangesinthePhillipscurveslopeandchangesintrendinflation.SeeBonomoandCarvalho(2004)forarecenttheoreticalcontribution.

InadditiontoLaxton-Meredith-Rose,paperswhichsupportthepossibleexistenceofasymmetriesinthePhillipscurveincludeTurner(1995),DebelleandLaxton(1996),Laxton,Rose,Tambakis(1999),andDolado,Maria-Dolores,Naveira(2005).SeeSchaling(2004)forarelatedtheoreticalcontribution.

Dotsey-King-Wolmanandsubsequentpapersprovidemodelsimulations,butnoempiricalevidenceontherelationbetweentrendinflationandthePhillipscurveslope.RecenttheoreticalcontributionsincludeGolosovandLucas(2003),Burstein(2006),GertlerandLeahy(2006),andDotsey,King,Wolman(2007).

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inflationcausedfirmstosettheiroutputpriceslessfrequently,whichwouldexplaintheobservedgradualflatteninginthePhillipscurve.Allbutoneofourtestslendequallystrongsupporttothehypothesisthatadeclineinaggregateinflationvolatilityexacerbatedfirms’misperceptionsaboutrelativeprices,implyingaflatterPhillipscurve.Whilestoriesinwhichcapacityconstraintsengenderaconvexshort-runPhillipscurveareconsistentwiththedata,theyperformpoorlyincomparisonwiththetwoothermodels.

AfewofthepapersprovidingempiricalevidenceontherelationbetweenthePhillipscurveslopeandaverageinflation/aggregatevolatilitydosointhetimedimension(seefootnote2).Typically,thesepapersexaminewhetherchangesinthePhillipscurveslopeacrosssubsamplesarepositivelyrelatedtocross-subsamplechangesinaverageinflationand/oraggregatevolatility.Suchproceduresassumethat,ifthePhillipscurveslopechangesovertime,itdoessointheformofasuddenjumpatthesamplesplitpoint.OurpaperiswritteninthebeliefthattheactualPhillipscurveslopeismorelikelytovarygraduallyovertime.Forone,ourfindingthatthePhillipscurvegraduallyflattenedisbasedonatime-varyingcoefficientsmodelwhichyieldsanestimateforthePhillipscurveslopeateverypointoftimeratherthanonlyanestimatepersubsample.Thisislogicallyconsistentwiththefactthatourregressionstestingthenonlineartheoriessimilarlydonotrestricttime-variationinthePhillipscurveslopetooccurasaone-timejump.

Ourpaperisstructuredasfollows.Section2documentsthat,assumingastandardlinearrelationshipbetweentheoutputgapandinflation,thesizeofthenegativeoutputgapsinJapanwouldhavewarrantedacceleratingdeflationintheperiod1998-2002.Section3givesargumentsagainstpopularexplanationsfortheabsenceofacceleratingdeflationinJapanwhichdonotimplytime-variationintheslopeoftheshort-runPhillipscurve.

Theremainderofthepaperfocusesontime-variationintheslopeoftheshort-runPhillips

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curve.Insection4,wedetectagradual,significantdeclineintheslopeofthePhillipscurvewhichhasbeenoccurringsincebeforethenineties.Sections5through7investigatethedeterminantsoftheflatteningofthePhillipscurve.Insection5,wefindthatallthreeabove-mentionedtypesofnonlinearityareconsistentwiththedata.Insection6,wefindthateachofthetheoriesofnonlinearityoutperformsamodelinwhichthePhillipscurveislinear,yetitsslopeevolvesovertimeasarandomwalk.Section7evaluatestherelativeperformanceofthethreetypesofnonlinearity.Section8concludesandpresentspolicyimplications.

2Background

Thissectiondealswiththreeissues.First,wediscusstheoutputgapseriesusedinthispaperanditsrelationtootheroutputgapestimatesforJapan.Second,wedocumentthatinJapan,theoutputgapandinflationtendedtocomovepositivelythrough1997,tosuchanextentthattheirrelationshipcouldbereasonablywellapproximatedbyastandardlinearPhillipscurve.Third,weshowthat,intheperiod1998-2002,theoutputgapwassufficientlynegativeforalinearPhillipscurvetopredictacceleratingdeflation,apredictionwhichisatoddswiththedata.

Figure1documentstheevolutionofJapan’srealGrossDomesticProduct,alongwithpotentialrealoutputasestimatedforJapanbytheUSFederalReserve.ItisevidentthataverageeconomicgrowthsincethestockmarketcrashofDecember19hasbeenlowerthanitwasinanyoftheprevioustwodecades.

ThepotentialoutputseriesinFigure1correspondstotheFed’sestimatesthrough1998.BecausetheFed’srecentestimatesofpotentialareconfidential,weextrapolatepotentialoutputfor1999Q1-2004Q4.Indoingso,weusetheIMFstaffestimates/forecastsofpotentialgrowth,asquotedinBayoumi(2000),asaguideline.

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Accordingtoourmeasureofpotential,annualpotentialoutputgrowthhastendedtoslowdowngraduallyfrom3.88%in1990to1.20%in1998.Subsequently,potentialoutputgrowthcontinuedtodecline,butataslowpace,untilitreached0.83%in2004.

ThetoppanelofFigure2graphstheoutputgapseriesimpliedbytheactualandpotentialoutputdatafromthepreviousfigure.Potentialoutputgrowthturnsouttohavebeensufficientlyhighforarelativelylargenegativeoutputgaptoexistovermostoftheperiod1993-2003.However,sinceestimatesofpotentialoutputaretypicallyassociatedwithahighdegreeofuncertainty,wecompareouroutputgapserieswithotherexistingoutputgapmeasures.

TheFed’sestimatesaredirectlycomparabletothoseoutputgapestimatesforJapanwhicharebasedonanestimateofpotentialoutputderivedfromaproductionfunctioninvolvingthecapitalstock,thelaborstock,andtheirrespectivelong-runfactorutilizationrates.Inparticular,theBankofJapan(2006)hasrecentlydevelopedaproductionfunctionbasedprocedure,designedtominimizeanyupwardbiasinpotentialoutputgrowthwhichmayhaveexistedinitsearlierproductionfunctionbasedestimates,asreviewedinKamada(2005).3

LiketheFedestimateswhichweuse,theBankofJapan(2006)estimatessuggestthat,evenwhenaccountingforasizeabledeclineinpotentialoutputgrowthfromtheearlyninetiestothemid-nineties,Japanexperiencedrelativelylargenegativeoutputgapsformostofthenineties.TheBankofJapanoutputgapimpliesthat,ifanything,theninetieswasevenworseadecadeforJapanthantheFedestimatessuggest,relativetopastoutputgaps.

Unliketheproductionfunctionapproach,twootherstandardproceduresforestimatingpo-tentialoutputdonotyieldlargenegativeoutputgaps.However,wedonotconsideroutputgaps

Forinstance,thenewmeasuretreatsthefollowingtwodevelopmentsasstructuralfactors,andinsodoingreducestheestimateofpotentiallaborinputwhichenterstheproductionfunction:adeclineinworkinghours,amongothersduetolaborlawchangesattheendoftheeighties,andadeclineinthelaborforceparticipationratesincethemid-nineties,amongothersduetopopulationaging.

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basedontheseprocedurestobevaluabletoolsforassessingtime-variationintherelationbetweentheoutputgapandinflationinJapan.

First,univariatesmoothingmethodssuchastheHodrick-Prescottfilteryieldanoutputtrendwhichisautomaticallyclosetoactualoutputwheneverthelatterstagnatesforafairlylongtimeattheendofthesample.Unsurprisingly,wefind(notshownhere)thatproxyingpotentialoutputbyaHP-filtertrenddoesnotyieldlargenegativeoutputgapsattheendofthesample,asconfirmedbytheHP-filterbasedoutputgapinKamada(2005).

Second,weappliedthemethodologyofHiroseandKamada(2003)toestimatepotentialoutputasthelevelofoutputatwhichinflationisstable.Wefind(notshownhere)thattheHirose-Kamadaoutputgapmovesaroundzeroattheendofthesample.Thisoutcomeisnotsurprising:attimeswheninflationisfairlystable,outputisbydefinitionnearitsstable-inflationlevel.Ingeneral,therewillbelittletonotime-variationintheslopeoftherelationshipbetweeninflationandanoutputgapmeasurewhichispreciselyconstructedtofitinflationaccuratelyatalltimes.

WearenowreadytogainourfirstinsightsaboutthecomovementoftheoutputgapandinflationinJapan.ThelowerpanelofFigure2graphsannualizedquarterlyinflationintheConsumerPriceIndexexcludingfreshfoods,whichtheBankofJapanadjustedforconsumptiontaxreforms.4Notethatasimplecomparisonbetweentheoutputgapandinflationiscloudedbysupplyshocks,suchastheoilpriceshockswhichledcoreCPIinflationtospikeupin1974Q1and1980Q2.Fornow,acasualinspectionofFigure2suggeststhattherelationshipbetweentheoutputgapandinflationwasfairlywell-behavedthroughouttheseventiesandeighties,inthesensethatinflationdeclinedwhentheoutputgapwasnegative,andtendedtoincreaseinbooms.

Tocharacterizetheoutput-inflationcomovementthrough1997somewhatmoreformally,we

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Aconsumptiontaxof3%wasintroducedinApril19.Thatsalestaxwasincreasedto5%inApril1997.

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regressthefollowinglinearPhillipscurveusingdatafor1971Q2-1997Q4:

πt=β1πt−1+β2πt−2+β3πt−3+β4πt−4+γ1ygapt−1+γ2ygapt−2+δimpoilt+et

(1)

Observationsfor1970Q2-1971Q1areusedtoconstructlags.AnnualizedCPIinflationexclud-ingfreshfoodsisafunctionoffourinflationlagsandtwooutputgaplags.Tocontrolforsupplyshocksintheseventies,weincluderelativeinflationintheimportpricesofpetroleum,coal,andnaturalgas.5

Inequation(1),inflationexpectationsareproxiedbylagsofinflation.Insection3.1,wedocumentthatinflationexpectationsinJapanindeedtrackedlaggedinflationrelativelyclosely.

Thelagstructureinequation(1)removesallserialcorrelationfromtheerrortermet,butissufficientlyparsimoniousforourestimationsinvolvingtime-varyingoutputgapcoefficientsand/ornonlinearitiesinthePhillipscurveinsections4through7.Werestrictthesumoftheinflationlagcoefficientstoequalone,andsettheconstanttozero.6

AlinearPhillipscurveestimatedthrough1997Q4fitsthedatawell:theadjustedR-squaredis0.83.Thesumoftheoutputgapcoefficientsispositive(withapointestimateof0.21)andsignificantatthe5%level.Thisconfirmsthat,duringatypicalepisodeintheperiod1971Q2-1997Q4,positiveoutputgapsexertedupwardpressureoninflation,whilenegativeoutputgaps

OilimportpricesareonYenbasis.Inequation(1)asinallPhillipscurvespecificationsbelow,theresultsarecomparablewhenweincluderelativeinflationingeneralimportpricesinstead.BothsupplyshockmeasuresareobtainedfromtheBankofJapan.6

AugmentedDickey-Fullertestsrejectaunitrootintheoutputgap,andinrelativeoilimportprices,atthe1%level.Wecannotstatisticallyrejectaunitrootininflation,butthechangeininflationisstationary.Moreover,inanunrestrictedregressionwithaconstant,thesumoftheinflationlagcoefficientsisnotsignificantlydifferentfromone.Theseconsiderationsleadustorestrictthesumoftheinflationlagcoefficientstoequalone,whichisanalogoustorewriting(1)asanequationforthechangeininflation,withthreelagsofthechangeininflationontheright-handside.SinceourPhillipscurveiseffectivelywrittenintermsofchangesininflation,excludingtheconstantisnecessarytoavoidthepossibilityofalong-runtrendininflation.Ifwedoincludeaconstant,itisvirtuallyzeroandinsignificant.

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tendedtocoincidewithdisinflations.

Therelationshipbetweentheoutputgapandinflationbecamegraduallylesspronounced.Inparticular,wefocusontheepisode1998-2002becauseitconstitutesthemoststrikingpuzzle.Itistheepisodewiththelargestnegativeoutputgaps,yetitisamongtheepisodeswiththemoststableinflationrates.Overtheperiod1998-2002,actualoutputwasonaverage2.97%belowpotential.Meanwhile,annualcoreinflationdidfallfrom0.82%in1997to-0.35%in1998,butfromthatpointondeclinedonlymarginallyuntilitreacheditstroughof-0.79%in2002.

Toillustratethispoint,Figure3showstheresultofadynamicout-of-sampleinflationforecastfromequation(1)fortheperiod1998Q1-2004Q4,contrastedwithactualinflation.Predicteddeflationacceleratesto-8.36%in2002Q3,whileactualannualizedinflationfellbelow-1%inonlytwoquarters,reaching-1.58%in2000Q4.7Thissuggeststhatdeflationwasmilderthanonewouldhaveexpectedconditionalonthelarge,negativeoutputgaps,andassumingalinearrelationshipbetweentheoutputgapandinflation.

Theout-of-sampleforecastofacceleratingdeflationdoesnot,byitself,constituteconclusiveevidenceforastatisticallysignificantbreakinastandardlinearPhillipscurve.WedofindevidenceforstatisticallysignificantstructuralchangeinthePhillipscurveslopeinsection4.BeforeturningourattentiontotheslopeofthePhillipscurvehowever,wefirstevaluatecandidateexplanationsfortheabsenceofacceleratingdeflationwhichdonotrelyontime-variationinthePhillipscurveslope.

WeequallyobtainamassivedeflationforecastfromananalogousequationwiththeGDPdeflator.WiththeGDPdeflator,bothactualandpredictedinflationaremorenegativethanintheCPIcase.

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3Capturingoutput-inflationcomovementwithouttime-varyingPhillipscurveslope?

WegiveargumentsagainstthreepossibleexplanationsfortheabsenceofacceleratingdeflationinJapan,noneofwhichimpliestime-variationintheslopeoftheshort-runPhillipscurve.

3.1Didinflationexpectationsfailtoturnnegative?

Theforecastofacceleratingdeflationinsection2originatedfromanaccelerationistPhillipscurve,inwhichinflationexpectationswereproxiedbylaggedinflation.Thus,equation(1)implicitlyassumesthatinflationexpectationsturnedmoderatelynegative,alongwithactualinflation.Itispossiblethatinflationexpectationsdidinfactnotturnnegativeintheperiod1998-2002,evenattimesofdeflationintheactualcoreCPI.IfJapaneseinflationexpectationshoveredaroundzero,thePhillipscurvewouldloseitsaccelerationistfeature,asapassageinBlanchard(2000)explains.Underthathypothesis,negativeoutputgapswouldimplynegative,butstableinflation.8Thiswouldaccuratelycapturetheoutput-inflationcomovementinJapanintheperiod1998-2002.

However,everyknownmeasureofinflationexpectationsinJapansuggeststhatinflationex-pectationsdidturnnegative.Theone-shot2002METIsurveyfindsthatonly5.6%offirms,andonly3.0%ofconsumers,expecteddeflationtoendwithinoneyear.TheDecember2001ConsensusforecastspredictheadlineCPIinflationof-0.9%for2002.ThefindingthatinflationexpectationsturnednegativeisconfirmedbyqualitativepriceexpectationsdataintheTankanbusinesssurvey,andbyinflationforecastsfromtheOECDandtheUSFederalReserve.

Toseethis,writethePhillipscurveasπt=β.Et−1(πt)+γ1.ygapt−1+γ2.ygapt−2+δ.impoilt+e,whereEt−1(πt)standsforlaggedexpectationsofcurrentinflation.Ifinflationexpectationsremainatzero,thisimpliesthatEt−1(πt)=0.Fromtheaboveequation,itfollowsthatinthatcase,negativeoutputgapstendtocoincidewithnegative,butstableinflation.

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Basiceconometricanalysisconfirmsthatinflationexpectationscontinuedtotracklaggedin-flationrelativelycloselyevenaslaggedinflationturnednegative.Ourresultssuggestthat,iftherewasanystructuralchangeatallintheprocessofexpectationsformation,inflationexpectationsturnedevenmorenegativeintheperiodsincethemid-ninetiesthanwouldotherwisehavebeenwarrantedbylaggedinflation.9

3.2Didexpansionarymonetarypolicypreventmassivedeflation?

Inatextbookworld,fastmoneygrowthexertsupwardpressureoninflation.BetweenMarch2001andMarch2006,theBankofJapantargetedthereserves(’currentaccountbalances’)ofcommercialbanksattheBankofJapan,whichattimesresultedinmassivegrowthinthemonetarybaseandM1.10Isthisamongthefactorswhichpreventeddeflationfromaccelerating?

Ontheonehand,highgrowthinnarrowmonetaryaggregateshasnottranslatedintohighgrowthratesofbroaderaggregatessuchasM2,afactwhichisplausiblyrelatedtoadeclineinbanklendingwhichcontinuedforseveralyearsafterthebankingcrisesof1997and1998.11Ontheotherhand,wecannotexcludethepossibilitythattheBankofJapan’spolicyofmassivequantitativeeasingdidpreventtheoutputgapfrombecomingevenmorenegative,and/ordidkeepagentsfromexpectingmoreextremedeflationinthefuture.However,anysucheffectswouldalreadybereflectedintheoutputgapandinflationexpectationsdatawhichwediscussedintheprevioustwosubsections.Aswedocumented,inflationexpectationsdidturnmoderatelynegative,notwithstandingexpansionarymonetarypolicy.Similarly,theoutputgapdidgrowsufficiently

WeregressConsensusforecastsorOECDforecastsonaconstantandlaggedinflation,andtestforallpotentialbreakdatesstartingin1995.Theresultissubjecttodatalimitations:quarterlyConsensusforecastsareonlyavailablefromabout1990,andtheOECDforecastspertaintoannualinflation.10

AsitdidbeforeMarch2001,theBankofJapannowusestheuncollateralizedovernightcallrateasitsmainpolicyinstrument.11

Growthinlendingbydomesticcommercialbankshasbeennegativethroughouttheperiod1998-2004,andonlyturnedunambiguouslypositiveinearly2006.

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negativetowarrantacceleratingdeflationinalinearframework.

3.3Downwardnominalwagerigidity?

TheexplanationinthissubsectiondealswiththespecificationofthePhillipscurve,butitaltersthestandardmodelinadifferentwaythanbyallowingfortime-variationintheslopeoftheshort-runPhillipscurve.

Akerlof,Dickens,andPerry(1996)developamodelinwhichdownwardnominalwagerigidityimpliesaconvexlong-runPhillipscurveatinflationratesbelow3%.Thelowertheinflationrate,thelargeristhefractionoffirmswhichcanimplementdesiredrealwagecutsonlythroughareductioninthenominalwage.Inthepresenceofdownwardnominalwagerigidity(DNWR),alowerinflationratethusimpliesthatalargerfractionoffirmsisforcedtopayrealwagesexceedingthewagewhichtheydeemoptimal.InthemodelofAkerlof,Dickens,Perry(1996),thisincreasesthelong-runsustainablelevelofunemployment,aneffectwhichbecomesmorepronouncedasinflationfallsfurtherbelow3%.

ForJapan,thisstoryimpliesthat,ifDNWRexists,actualunemploymentdoesnotexceeditslong-runratebyasmuchasunemploymentgapestimatesbasedontheassumptionofaverticalandlinearlong-runPhillipscurvewouldindicate.

However,wageshavenotbeendownwardlyrigidinJapanduringtheperiodofourfocus.Atamicrolevel,KurodaandYamamoto(2003a,b)findevidenceforDNWRwithdataspanning1992-1998.Inamorerecentstudyhowever,KurodaandYamamoto(2005)findnoevidencefordownwardrigidityinthenominalwagesoffull-timeworkersduringtheperiod1998-2001.Sincefull-timeworkers’nominalwagesstartedbeingcutin1998,downwardnominalwagerigiditycanhardlyexplaintheabsenceofacceleratingdeflation,whichbecameapuzzleatexactlythattime.

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Atamacrolevel,Japan’swagesareevenlessrigid.AsdescribedinMorgan(2005),thefractionofnon-standardemployees,suchaspart-timeandtemporaryworkers,hasincreasedfrom19.4%in1995to29.0%in2004.Furthermore,thereisalargewagegapbetweenregularandnon-standardemployees.In2004,apart-timeworker’shourlybasewagewasonly40.5%thatofatypicalregularworker.12Hence,evenifnosinglegroupofworkershadexperiencednominalwagecuts,theshiftfromregulartonon-standardworkershadledtoadeclineintheaggregatewage.

Sincebothmicro-economicandmacro-economicdatasuggestthatwageswerenotdownwardlyrigidduringourperiodofinterest,anystoryinvolvingdownwardnominalwagerigidityisunlikelytoexplaintheabsenceofacceleratingdeflationinJapan.

4EvidenceforaflatteningPhillipscurve

Fromthispointon,ourpaperfocusesonthepathanddeterminantsoftheslopeoftheshort-runoutput-inflationtradeoff.

Thepresentsectionpresentstwofindings.First,structuralstabilitytestssuggestthattheslopeofthePhillipscurvehaschangedoverthesampleinastatisticallysignificantfashion.Giventhatresult,weestimatethePhillipscurveslopeasatime-varyingparameterusingtheKalmanfilter.OurresultssuggestthatthePhillipscurvehasflattenedoverthesample,wheremuchoftheflatteningoccurredbeforethenineties.

4.1SignificantstructuralchangeinthePhillipscurveslope

Redefiningγ2=pγ1,werewritethelinearPhillipscurvefromequation(1)as:

Theoverallmonthlycost(includingbonuses,fringebenefits,socialsecuritycontributions,andtrainingexpenses)ofemployingapart-timeworkerwas36.9%thatofemployingafull-timeworker.DataarefromMorgan(2005).

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πt=β1πt−1+β2πt−2+β3πt−3+β4πt−4+γ1(ygapt−1+pygapt−2)+δimpoilt+et

(2)

InordertoassessthepresenceofstructuralchangeintheslopeofthePhillipscurve,wetestforthestabilityofγ1,whileassumingthatpremainsconstantatitsestimatedvalue.Thisprocedureisdirectlycomparabletothatofsubsection4.2.,wherewemodelγ1asatime-varyingparameter,butcontinuetoestimatepasbeingtime-invariant.Wemotivatetheassumptionoftime-invarianceinpinsubsection4.2.

First,weuseastandarddummyvariableproceduretotestforastructuralbreakinthePhillipscurveslope,atahypothesizedbreakdateof1990Q1.13Thetestresultsuggeststhat,conditionalontheabsenceofstructuralchangeintheotherparameters,γ1wassignificantlysmaller,atthe1%level,from1990onwardsthanbeforethattime.EarlierresearchontheflatteningoftheJapanesePhillipscurve,suchasNishizakiandWatanabe(2000)andMourouganeandIbaragi(2004),similarlyimplementeddummyvariabletestsandfoundthattheJapanesePhillipscurvewassignificantlyflatterintheninetiesthanitwasinearlierdecades.

Second,weimplementatestforstructuralchangewhich,unliketheabovetest,doesnotrequireustoassumeanyparticularbreakdate.Inparticular,weapplytheNyblom(19)test,intheversiondevelopedbyHansen(1992).Werejectthenullhypothesisoftime-invarianceinγ1atthe1%level.14Itdeservesemphasisthat,unlikewhatisthecaseforotherstructuralstabilitytestssuchastheabovedummyvariabletest,rejectionofthenullhypothesisdoesnotnecessarily

Weregressπt=β(L)πt+(γ1+γ01breakdum)(ygapt−1+pygapt−2)+δimpoilt+et,wherebreakdum=1forallquartersstartingin1990Q1,and0forallearlierobservations.γ01isestimatedtobenegativeandsignificant.14

ThejointteststatisticforallmodelparameterssuggestssignificantstructuralchangeintheoverallPhillipscurve,atthe1%level.Furthermore,therelevantindividualteststatisticsuggestssignificantchangeinthevarianceoftheerrorterm,atthe1%level.Onthispoint,notethattheHansen(1992)testisasymptoticallyrobusttoheteroskedasticity.Throughoutthepaper,ourOLS/NLSregressionsuseheteroskedasticityrobuststandarderrors.

13

15

implyaone-timejumpinthePhillipscurveslope,yetcouldjustaswellreflectgradualstructuralchange.Infact,theNyblomtesthasoptimalpoweragainstthehypothesisthataparameterfollowsamartingale.Giventhetestresult,wemodelγ1asarandomwalkinthenextsubsection.

4.2State-spaceformofmodelwithtime-varyingPhillipscurveslope

Wewritethemodelinstate-spaceform.Themeasurementequation,intheformofHarvey(1994):

πt=[ygapt−1+pygapt−2]γ1,t+[β(L)πt+δimpoilt]+et

(3)

Whereγ1,tisthestatevariable.Theerrortermetisnormallydistributedwithmeanzeroandvarianceσ2e.

Inequation(3),weimposetherestrictionthatthetwooutputgapcoefficientsareproportionalatanypointoftime,i.e.γ2,t=pγ1,t,wherepisatime-invariantparametertobeestimatedbyMaximumLikelihood.Theestimationresultsaresimilarwhetherweimposeproportionalityornot,exceptforthefactthatthesumoftheoutputgapcoefficientsisimpreciselyestimatediftheassumptionofproportionalityisnotimposed.Wesimplydonothaveenoughobservationstoobtainpreciseestimatesforthesumoftwodistincttime-varyingcoefficients.Inanycase,weareprimarilyinterestedinthesumoftheoutputgapcoefficients,andlesssointheprecisewayinwhichthissumisallocatedoverthetwoindividualoutputgapcoefficients.

Whileequation(3)representsthemeasurementequation,thetransitionequationisasfollows:

γ1,t=γ1,t−1+v1,t

(4)

2Wherev1,tisnormallydistributedwithmeanzeroandvarianceσ2v1=σeq1.Theparameter

16

q1isthesignal-to-noiseratioforthecoefficientontheoutputgap’sfirstlag.Thepathofthecoefficientonthesecondoutputgaplagfollowsfromγ2,t=pγ1,t.

4.3Estimationprocedureandresults

WeapplyMaximumLikelihoodtoestimatethemodelconstitutedbyequations(3)and(4).AsinHarvey(1994)andKimandNelson(1999),wecomputetheloglikelihoodfunction,initspredictionerrordecompositionform,fromtheKalmanfilterpredictionerrorsandtheirvariances.Wemaximizetheloglikelihoodfunctionwithrespecttothehyperparameters.15Finally,weusetheKalmanfilterrunthatmaximizedthelikelihoodinordertocomputeKalmansmoothedestimatesofthetime-varyingoutputgapcoefficientsandtheirsum.

Table1comparestheresultsofthetime-varyingcoefficientslinearPhillipscurvewiththoseofalinearPhillipscurveestimatedbyOLS.Bothestimations,aswellasallotherestimationsintheremainderofthispaper,arecarriedoutover1971Q2-2004Q4,wheredatafor1970Q2-1971Q1areusedtoconstructlags.TheMLEestimatesofthetime-invariantparametersarecomparabletotheirOLScounterparts.Similarly,theaverageofthesumoftheoutputgapcoefficientsisvirtuallyidenticaltothesumoftheoutputgapcoefficientsimpliedbytheOLSestimation.Thesacrificeratio’sareplausibleinbothcases.IntheMLEcase,adisinflationofonepercentagepointrequiresoutputtobe1.39%belowpotentialforfourquarters.ThisisinlinewithearlierestimatesoftheJapanesesacrificeratioinBall(1994)andZhang(2005).16

Figure4graphsKalmansmoothedestimatesoftheoutputgapcoefficientsandtheirsum,alongwitha95%confidenceinterval.Thesumoftheoutputgapcoefficientsdeclinesgradually

WeusetheMatlab-functionfminunctooptimizetheloglikelihoodfunction.Wesetthesignal-to-noiseratio,q1,to1/1600inthebaseline.TheparameterestimatesreportedinTable1arerobustforallvaluesofq1upto1/25.16

Ball(1994)computesasacrificeratioforJapanof0.93%.OurslightlylargerestimateisinlinewithacontinuedflatteningofthePhillipscurveafter1994.Zhang(2005)computesasacrificeratioof1.85%whenaccountingforlong-livedeffects.

15

17

overthesample.Theresultssuggestthatmuchoftheflatteningoccurredbeforethenineties.Theabsenceofacceleratingdeflationin1998-2002isonlyoneamongtheepisodesconsistentwiththetime-pathofthePhillipscurveslope.Forexample,thefindingthatthePhillipscurvewasalreadyrelativelyflatduringthebubbleperiodinthelateeightiesisinlinewiththefactthatinflationremainedsurprisinglymoderateatthattime,notwithstandinglargepositiveoutputgaps.

5WhydidthePhillipscurveflatten?Candidatetypesofnon-linearity

TheflatteningofalinearPhillipscurvemaysuggestthattheoutput-inflationtrade-offshouldac-tuallybemodeledasanonlinearrelationship.Inthissection,weassesstheempiricalperformanceofthreetypesofnonlinearity.ThecoefficientestimatesfromnonlinearPhillipscurveregressionsareinlinewitheachofthenonlineartheories.Moreover,whilesection4detectedstatisticallysignificantstructuralchangeintheoutputgapcoefficientsofalinearPhillipscurve,thereisnosignificantstructuralchangeinthecoefficientsforanyofthethreetypesofnonlinearity.

5.1Aconvexshort-runPhillipscurveduetocapacityconstraints?

Laxton,Meredith,Rose(1995)andrelatedpapers17allowforconvexityintheshort-run

Phillipscurve.InLaxton,Meredith,Rose(LMR),capacityconstraintsconstitutetheeconomicrationalefornonlinearity.Supposethatatthecurrentlevelofoutput,firmsareoperatingnearthecapacityconstraint.Insuchasituation,anyincreaseinaggregatedemandcanhardlybemetbyincreasedproduction.Assuch,theincreaseindemandtranslatesalmostuniquelyintoanincreaseininflation,evenintheshortrun.Hence,thePhillipscurveisnearlyverticalnearthe

17

Seefootnote2forreferencestopapersrelatedtoanyofthetheoriesofnonlinearity.

18

capacityconstraint,wheretheslopebecomesgraduallysteeperastheeconomymovestowardsthecapacityconstraint.ThisstoryimpliesaverticalasymptoteinthePhillipscurveatthecapacityconstraint.ThebaselinefunctionalformwhichLMRuseimpliesthat,ifconvexityispresent,itexistsalongtheentirePhillipscurve.

NotethatitisnotobviouswhetherthepresenceofcapacityconstraintscanbearationaleforconvexityinthePhillipscurveinregionswhicharefarawayfromthecapacityconstraint.Theanswertothisquestionisparticularlyimportantforourpurposes:theLMRmodel’spredictionsforJapanarethat,sincetheeconomywasfarfromthecapacityconstraintin1998-2002,JapanwasonaflatterpartofaconvexPhillipscurveduringthatperiod.Thatwouldexplaintheflatteningwhichweobservedinsection4.Yet,ifconvexityisnotpresentatnegativeoutputgaps,theJapaneseeconomywouldhavemovedalongalinearpartofthePhillipscurveformostofthenineties,suchthattheLMRmodelcouldnotexplainanytime-variationinthePhillipscurveslopeduringthatperiod.Therearesurelywaystomotivateconvexityatnegativeoutputgaps,18butsuchreasoningsarenotcontainedinLMR’soriginalpaper.

WefollowLMRinusingafunctionalformwhichimpliesthatthePhillipscurveiseitherconvexinallregions,orlineareverywhere.Theabsenceofacleartheoreticalmotivationforconvexityatnegativeoutputgapswillenterouroverallmodelassessmentinsection7.2.

WeestimateapotentiallynonlinearPhillipscurvebyNonlinearLeastSquares,wherethefunctionalformoftheoutputgaptermsisequivalenttothatinLMR:

∙µ

µ

¶¸

πt=β(L)πt+γ1

18

φygapt−1φ−ygapt−1

+p

φygapt−2φ−ygapt−2

+δimpoilt+et

(5)

Inthepresenceofsectoralheterogeneity,itispossiblethatevenatnegativeoutputgaps,asmallfractionoffirmsoperatesnearfullcapacity.Ifso,itisplausiblethatthefractionofcapacity-constrainedfirmsincreasesastheoutputgapbecomeslessnegative(ormorepositive).

19

Whereγ1istime-invariant.Forequation(5),theNyblomtestfailstorejectthenullhypothesisofstructuralstabilityinγ1,atthe10%level.Thatis,thereappearstobelittletonotime-variationinthePhillipscurveslopebeyondthatimpliedbythenonlinearityofthefunctionalform.

Thecrucialparametertobeestimatedisφ.Thisparameterindicatestheleveloftheoutputgapatwhichtheeconomyreachesthecapacityconstraint.Bythesametoken,φgovernsthedegreeofnonlinearityinthePhillipscurve.Thesmallerthepointestimateforφis,thesmallerthedistancebetweenthezerooutputgapandthecapacityconstraintwillbe.Thisinturnyieldsahigherdegreeofconvexity.

TherightmostcolumnofTable2presentsestimationresultsforequation(5).WealsoincluderesultsfromapurelylinearPhillipscurve,whichessentiallyimposestherestrictionthatφ=∞.Inthepotentiallynonlinearcase,φispreciselyestimated,withapointestimateofexactly10.00.Thissuggeststhattheeconomywouldreachthecapacityconstraintifactualoutputweretoexceedpotentialoutputby10%.

Toillustratethedegreeofconvexityimpliedbytheestimatesforγ1,p,andφinequation(5),Figure5graphsthesumoftheoutputgaptermsasafunctionoftheoutputgap.Inparticular,theboldcurveinFigure5graphsγ1[(φygapt−1/(φ−ygapt−1))+p(φygapt−2/(φ−ygapt−2))]withrespecttotheoutputgap,whereweimposethatygapt−1=ygapt−2.Forcomparison,thethinsolidlineinthesamefiguregraphsthesamefunction,withexactlythesamevaluesforγ1andp,butimposingthatφ=∞.Visually,weseeafairlystrongdegreeofnonlinearityinthePhillipscurve.19Inotherwords,boomsinrealactivityincreaseinflationbymorethanrecessionsdecreaseit.Theasymmetryintheeffectsofdemandshiftsbecomesmorepronouncedasonemovesfurtherfromthezerooutputgapineitherdirection.Forinstance,anoutputgapof-5%tendstoleadto

Thedottedlinealsousesthesamevaluesforγ1andp,butassumesavalueforφwhichistheupperboundofthe95%confidenceintervalaroundtheestimatednonlinearityparameter.

19

20

adisinflationof0.53percentagepointsaftertwoquarters,whilethetotalimpactofa5%outputgapistoincreaseinflationby1.60percentagepoints.

5.2AflatterPhillipscurveduetoalowerfrequencyofpriceadjustment?

Inthissubsection,weassesstheempiricalvalidityoftwotheoriesinwhichcostsofpriceadjustmentleadfirmstoadjusttheiroutputpricesinfrequently:Ball,Mankiw,Romer(1988),andDotsey,King,Wolman(1999).Inbothmodels,lowertrendinflationdecreasesthefrequencyofpriceadjustment.Lessfrequentpriceadjustmentinturnreducestheeffectofaggregatedemandshiftsoninflation.Thatistosay,thePhillipscurveisflatteratlowerratesoftrendinflation.

InBall,Mankiw,Romer(BMR),firms,whensettingtheirprice,alsochoosethelengthoftimeoverwhichtheirpricewillbeineffect.Firmsminimizealossfunctionwhichdependsontheaveragecostofpriceadjustmentperperiod,andondeviationsoftheiractualnominalpricefromtheprofit-maximizingnominalpriceoverthecourseoftheperiodthatthepriceisineffect.Whentrendinflationishigh,anyfirmexpectsitsrelativepricetochangerapidlyovertime,whichinturnleadsthefirmtoexpectarapidchangeinitsprofit-maximizingnominalprice.Thus,theforward-lookingfirmwillnotfixitsactualpriceforalongtime.Instead,thefirmoptsformorefrequentpriceadjustment,thuspayingahigherper-periodcostofpriceadjustment,inordertoavoidlargedeviationsofitsfuturepricesfromtheirprofit-maximizinglevels.

InDotsey,King,Wolman(DKW),highersteady-stateinflationimpliesthatanyfirm’srela-tivepricehasbeenerodedtoalargerextentsinceitslastpriceadjustment.Thisimpliesthatforalargerfractionoffirms,thebenefitofpriceupdatingwillexceedthe(labor)costofpriceadjustment.Inconclusion,highersteady-stateinflationleadstohighersteady-stateprobabilitiesofpriceadjustment.

21

Thesetwomodels’predictionforJapanisthat,astrendinflationgraduallydecreasedoverthesample,thefrequencyofpriceadjustmentdeclined,whichinturnledtoagraduallyflatteningPhillipscurve.Atthetimeofwriting,wearenotawareofanypubliclyavailabletimeseriesdataontheaveragefrequencyofpriceadjustmentforJapan.Wethereforecannotmodelthefrequencyofpriceadjustmentexplicitly,muchlikewhatwasthecasefortheempiricalanalysesintheearlierstudiesreferencedintheintroduction.However,wecantestwhethertheslopeofthePhillipscurvedependspositivelyontrendinflation.

InspiredbyDeFina(1991),weadoptaone-stepapproach.20Thatistosay,weestimateaPhillipscurveinwhichtheslopedependsontheabsolutevalueoftrendinflation:21

πt=β(L)πt+[a+b|πt|][ygapt−1+pygapt−2]+δimpoilt+et

(6)

WegeneratetrendinflationattimetasageometricaverageofJquartersofpastinflation:

J

1−θXj

πt=θπt−j

θ−θJ+1j=1

(7)

Inthebaseline,θ=0.93andJ=71.Notethattrendinflationdoesnotdependoncurrentinflation,soastoavoidendogeneityissuesinequation(6).Thefactorinfrontofthesummationsignensuresthatthesumoftheweightsonthepastinflationtermsisequaltoone.

Inequation(6),theNyblomtestdoesnotdetectanystructuralchangeinaorbindividually,

EmpiricalfindingsontherelationshipbetweentheslopeofthePhillipscurveandtrendinflationoraggregatevolatility,asreferencedintheintroduction,havemostlybeenbasedonatwo-stepapproach.Inatime-seriessetting,itisundesirabletoenterthePhillipscurveslopeasaleft-handsidevariableinasecond-stageregression,amongothersbecausethetime-varyingPhillipscurveslope(obtained,say,fromrollingwindowsregressions)islikelytobenonstationary.21

Wetaketheabsolutevalueoftrendinflationbasedontheintuitionthattheeffectsofmorepronounceddeflationshouldaffectfirms’relativeprices,andhencethefrequencyofpriceadjustment,inmuchthesamewayasanincreaseininflationdoes.NeitherDKW,BMR,norDeFina(1991)taketheabsolutevalue,yetthiscanbeattributedtotheirdealingwitheconomiesinwhichnegativetrendinflationcouldhardlybeimaginedatthattime.

20

22

oraandbjointly,atthe10%level.Thissuggeststhatthereislittletonotime-variationintheoutputgapcoefficientsbeyondthatassociatedwithchangesintrendinflation.

Table3displaystheestimationresultsforequation(6).Forcomparison,weincluderesultsfromaPhillipscurveinwhichthecoefficientontrendinflationissettozero.Inequation(6),thecoefficientontrendinflation,b,ispositiveandsignificantatthe1%level.ThisresultisinlinewiththeBall-Mankiw-RomerandDotsey-King-Wolmantheories.

Fromtheestimatesfora,b,andp,andourseriesfortrendinflation,wecomputedtheimpliedoutputgapcoefficientsandtheirsum.GiventhatthePhillipscurveslopeisalineartransformationoftrendinflation,itdisplaysasimilarpatternovertimeastrendinflationitself.Inparticular,thesumoftheoutputgapcoefficients(notgraphedhere)increasesuntil1976,anddecreasesquicklythroughthelateeighties.Fromtheearlyninetieson,thePhillipscurveslopestilltendstodecrease,butataslowerpace.Itfallsbelowzeroin1994,yetfrom1996onremainsfairlystableatmoderatelynegativelevels.

5.3AflatterPhillipscurveduetoadeclineinaggregatevolatility?

InLucas(1973),theslopeofthePhillipscurvedependsonthevolatilityofaggregatedemandandsupplyshocks.Firmssetquantitiesproducedbasedontheirperceivedrelativeprice.Asthevarianceofaggregateshocksdecreasesrelativetothevarianceoffirm-specificshocks,alargerfractionofanychangeintheoverallpricelevelismisperceivedbyfirmsasbeingachangeintheirrelativeprice.Inthatway,loweraggregatevolatilityimpliesthatanychangeinaggregatedemandhasalargereffectonatypicalfirm’sproduction,andthusonaggregateoutput.Correspondingly,demandshiftshaveasmallerimpactoninflation.Inconclusion,lowlevelsofaggregatevolatilityimplyaflatterPhillipscurve.

23

AtestableimplicationofthismodelforJapanisthatadecreaseinthevarianceofaggregatedemandand/orsupplyshockswouldhavebeenassociatedwiththeflatteningofthePhillipscurvewhichwedocumentedinsection4.22

Wecaptureaggregatevolatilitybythevarianceofinflation.23WeestimateaPhillipscurveinwhichtheslopeisexplicitlymodeledasafunctionofthevarianceofinflation:

πt=β(L)πt+[c+dvart(π)][ygapt−1+pygapt−2]+δimpoilt+et

(8)

Wegeneratethevarianceofinflationattimetasageometricallyweightedaverageofpastsquareddeviationsofinflationfromitstrend:

J

1−θXj

vart(π)=θ(πt−j−πt)2

J+1θ−θj=1

(9)

Wheretrendinflationπtiscomputedasinequation(7).Again,thebaselinevaluesareθ=0.93andJ=71.

Inequation(8),theNyblomtestrejectsthenullofnostructuralchangeincindividually,andincanddjointly,butonlyatthe10%level.Itfailstorejectthehypothesisoftime-invarianceind.Thissuggeststhatchangesinthevarianceofinflationexplainmost,butnotall,ofthetime-variationinthesumoftheoutputgapcoefficients.

Table4containstheestimationresultsforequation(8).AspredictedbytheLucas-theory,thecoefficientdoninflationvolatilityispositiveandsignificantatthe1%level.

Ball,Mankiw,Romer(1988)equallyimpliesthatadecreaseinthevarianceofaggregateshocksleadstoaflatter

Phillipscurve.Yet,inBMR,themechanismworksthroughthefrequencyofpriceadjustment:decliningaggregatevolatility,whichreducesuncertaintyaboutfutureoptimalprices,enablesfirmstosettheirpricesforalongerperiodoftime.AlowerfrequencyofpriceadjustmentinturnimpliesaflatterPhillipscurve.23

Theotherstandardcandidate,thevarianceofnominalGDP,wouldnotbeasappropriateameasuretocapturebothsupplyanddemandshocks.Forinstance,ifaggregatedemandisunit-elastic,aggregatesupplyshockshavenovisibleimpactonnominalGDP,sincetheireffectonpricesisexactlyoffsetbytheireffectonrealactivity.

22

24

Thesumoftheoutputgapcoefficientsimpliedbyequation(8)increasessteeplyfrom1973to1975,thendecreasesquicklythroughthelateeighties.Fromtheearlyninetieson,theimpliedPhillipscurveslopedecreasesonlyslightly.Itstayspositiveatalltimes.

6Dothenonlinearmodelsbeattherandomwalkmodel?

Inthepresentsection,weestimatemodelsinwhichthePhillipscurveslopedependsonarandomwalktermaswellasonafunctionimpliedbyaparticulartheoryofnonlinearity.

Inthecaseswherewetestforit,wefindthatwecanomittherandomwalktermfromtheencompassingmodelwithoutengenderingasignificantdeclineinthevalueofthelikelihoodfunction.Thisisrelatedtoourfinding,insection5,ofnostructuralchangeinthecoefficientsontheoutputgaptermsforeachofthenonlinearmodels.Beyondthat,thepresentsection’sresultsimplythataddinganyofthethreetypesofnonlinearitytoapurerandomwalkmodelyieldsasignificantimprovementinthefit.

6.1Thetrendinflationmodelbeatstherandomwalkmodel

WeestimateamodelwhichencompassestherandomwalkmodelandtheBall-Mankiw-Romer/Dotsey-King-Wolman(BMR/DKW)trendinflationmodel,andtestforthestatisticalrelevanceoftherandomwalktermontheonehand,andthetrendinflationtermontheotherhand.

ThePhillipscurve,aliasmeasurementequationofthestate-spacemodel,isexactlythesameasequation(3):

πt=[ygapt−1+pygapt−2]γ1,t+[β(L)πt+δimpoilt]+et

(10)

Thenoveltyliesinthetransitionequation.Intheencompassingmodel,theoutputgapcoeffi-25

cientγ1,tisallowedtodependbothonitsownlagandontrendinflation.Inthepurerandomwalkmodel,γ1,t=γ1,t−1+v1,t.Ontheotherhand,inthepureBMR/DKWmodel,γ1,t=a+bπt.Nestingthesetwoyieldsthefirstrowofthestateequation:

γ1,t=λ(γ1,t−1+v1,t)+(1−λ)(a+bπt)

(11)

Notethattrendinflationappearsasanexogenousvariableinthefirstrowofthetransitionequation.TextbooktreatmentsoftheKalmanfiltersuchasHarvey(1994),Hamilton(1994),orKimandNelson(1999)donotdiscusssolutionsforhowtoenteranexogenousvariableinthestateequation.Ifwewishtoenterπtinthetransitionequation,weneedtospecifyatransitionprocessfortrendinflation,andenterthisprocessinthesecondrowofthestateequation.Wederivesuchprocessfromthedefinitionoftrendinflationinequation(7).ForθsufficientlysmallandJconvergingtoinfinity,wefind:

πt+1=(1−θ)πt+θπt

(12)

Thetransitionequationthusbecomes:

⎤⎡

⎢γ1,t⎥⎢(1−λ)a⎥⎢λ(1−λ)b⎥⎢γ1,t−1⎥⎢λv1,t⎥

⎥.⎢⎥=⎢⎥+⎢⎥+⎢⎥⎢

⎦⎣⎦⎣⎦⎣⎦⎣⎦⎣

(1−θ)πt0θπt+1πt0

(13)

First,weestimatetheencompassingmodel,consistingofequations(10)and(13).Intheunrestrictedmodel,λisestimatedtobe-0.51.Essentially,theweightontheBMR/DKWmodelinthetransitionequationexceedsunity.

Next,werestrictλ=0,inwhichcasethemodelreducestotheBMR/DKWtrendinflation

26

model.Wetestthatrestrictionbymeansofalikelihoodratiotest.Sincewearetestingonerestriction,thelikelihoodratiostatistichasaχ2(1)distribution.Accordingtothetestresult,relaxingtherestrictionthatλ=0doesnotsignificantlyimprovethefit,notevenatthe10%level.

Finally,werestrictthemodelsuchthatequation(11)reducestoarandomwalk.Inthiscase,thelikelihoodratiohasaχ2(3)distribution.24AbstractingfromtheBMR/DKWtermsignificantlydeterioratesthefitatthe1%level.

Ontheonehand,wefoundthatthepureBMR/DKWmodeldoesnotperformsignificantlyworsethantheencompassingmodel.Ontheotherhand,thepurerandomwalkmodeldoesperformsignificantlyworsethantheencompassingmodel.WeconcludethattheBMR/DKWmodelprovidesamoreaccuratedescriptionofthedatathantherandomwalkmodeldoes.

6.2Themisperceptionsmodelbeatstherandomwalkmodel

ThissubsectionimplementsasimilarprocedurefortheLucasmisperceptionsmodelastheprevioussubsectiondidforBMR/DKW.Themeasurementequationisexactlythesameasequation(10).

Thestateequationisanalogoustoequation(13),butissomewhatcomplicatedbythefactthatthetransitionprocessforthevarianceofinflationismoreinvolvedthantheprocessfortrendinflation.Thefirstrowofthetransitionequationisanalogoustoequation(11):

γ1,t=λ(γ1,t−1+v1,t)+(1−λ)[c+dvart(π)]

(14)

Fromthedefinitionofthevarianceofinflationinequation(9),wederiveitstransitionprocess,

Atfirstsight,thedistributionappearstobenonstandard,sinceaandbpotentiallyactasnuisanceparameters.Yet,rewriteequation(11)asγ1,t=γ1,t−1+v1,t+(λ−1)(γ1,t−1+v1,t)+(1−λ)a+(1−λ)bπt.Redefining(1−λ)aand(1−λ)bsuchthattheyareparametersintheirownright,thisequationisineffectlinearintheparameters.Itreducestotherandomwalkmodelafterimposingthreerestrictions:(λ−1)=0,(1−λ)a=0,and(1−λ)b=0.

24

27

tobeincludedinthesecondrowofthestateequation.ForθsufficientlysmallandJconvergingtoinfinity,wefindthat:

vart+1(π)=(1−θ)Xt+θvart(π)

θ

WhereXt=(2−θ)(πt−πt)2−21−θ(πt−πt)

JXj=1

(15)

θj(πt−j+1−πt).

Thetransitionequationthusbecomes:

⎡⎢

⎢⎣

⎥⎢(1−λ)c⎥⎢λ(1−λ)d⎥⎢γ1,t−1⎥⎢λv1,t⎥

⎥.⎢⎥+⎢⎥=⎢⎥+⎢⎥⎦⎣⎦⎣⎦⎣⎦⎣⎦

0θ(1−θ)Xtvart+1(π)vart(π)0γ1,t

⎤⎡⎤⎡⎤

(16)

WhereXtisasdefinedunderequation(15).

Intheencompassingmodel,whichconsistsofequations(10)and(16),thenestingparameterλisnotsignificantlydifferentfromzero,withapointestimateof-0.13.ThisisevidenceinfavoroftheLucasmodel,relativetotherandomwalkmodel.Asintheprevioussubsection,wefindthatimposingtherestrictionthatλ=0doesnotsignificantlyworsenthefit,whileimposingrestrictionssuchthatequation(14)reducestoarandomwalkleadstoasignificantdeclineintheloglikelihoodfunctionvalueatthe1%level.

Inconclusion,therandomwalkmodelprovidesasignificantlylessaccuratefitthantheen-compassingmodel,whilethefitoftheLucasmodelisstatisticallyindistinguishablefromthatoftheencompassingmodel.Hence,themisperceptionsmodelbeatstherandomwalkmodel.

6.3Convexityevenwithindependenttime-variationinthePhillipscurveslope

Insection5,wedetectedastrongdegreeofnonlinearityinaPhillipscurvemodeledasinLaxton,Meredith,Rose(LMR).However,thatsection’sprocedureisnotdesignedtodeterminewhetherthenonlinearityisstatisticallysignificant.Inthepresentsubsection,wedofindthatamodel

28

whichallowsforLMR-stylenonlinearitycapturestheevolutionofthePhillipscurveslopeinasignificantlybetterfashionthanapurerandomwalkmodeldoes.

WespecifyaPhillipscurvewhichneststhelineartime-varyingcoefficientmodelofequations(3)and(4),andthenonlinearLMRmodelofequation(5):

∙µ

µ

¶¸

πt=β(L)πt+γ1,t

φygapt−1φ−ygapt−1

+p

φygapt−2φ−ygapt−2

+δimpoilt+et

(17)

Whereγ1,tevolvesasarandomwalk:

γ1,t=γ1,t−1+v1,t

(18)

Thismodelcollapsestothelineartime-varyingcoefficientsmodelifφ=∞,andreducestothenonlinearmodelwithtime-invariantcoefficientsifv1,t=0forallt.

Weestimatetwomodels,oneinwhichthenonlinearityparameterφisrestrictedtobeaverylargenumber,25andoneinwhichφisfreelyestimated.

Intheunrestrictedmodel,thenonlinearityparameterissmallandpreciselyestimated,beitsomewhatlargerthaninsection5.

Weapplyalikelihoodratiotesttoexaminewhetherthemodelinwhichφisfreelyestimatedperformssignificantlybetterthanthemodelinwhichlinearityisimposed.Thelikelihoodratiostatisticisdistributedχ2(1).Thetestresultsuggeststhatrelaxingtheassumptionoflinearitysignificantlyincreasesthevalueofthelikelihoodfunctionatthe1%level.

Inconclusion,theLMRmodeladdsinformationbeyondthatcontainedinthelineartime-varyingcoefficientsmodel.

25

Weimposeφ=1E20.

29

7WhichtypeofnonlinearityinthePhillipscurve?

Sofar,wehavefoundthateachofthethreemodelsofnonlinearitynotonlyisconsistentwiththedata,butalsooutperformsthebenchmarkrandomwalkmodel.Inthepresentsection,wecomparethethreenonlineartheories’successinexplainingtheflatteningofJapan’sPhillipscurve.

7.1Non-nestedmodelfitcomparison

Weperformthreehypothesistestingprocedurestocomparetheperformanceofthenonlinearmodels.

First,weregressPhillipscurveswhichnesttwononlinearmodels.Forexample,thefollowingequationneststheLaxton,Meredith,Rose(LMR)modelfromequation(5)andtheBall-Mankiw-Romer/Dotsey-King-Wolman(BMR/DKW)modelofequation(6):

∙µ

µ

¶¸

πt=β(L)πt+[a+b|πt|]

φygapt−1φ−ygapt−1

+p

φygapt−2φ−ygapt−2

+δimpoilt+et

(19)

Asitturnsout,thecoefficientontrendinflationbispositiveandsignificantatthe1%level,whichisinlinewiththeBMR/DKWmodel.Thenonlinearityparameterφisestimatedtobe12.94,withasomewhatlargerstandarderrorthaninsections5or6,whichallinallsuggeststhattheLMR-convexitystillplaysarole.

TheresultswithaPhillipscurvenestingtheLMR-andLucas-modelsaresimilar:thereisevidenceforbothmodels.Ontheotherhand,regressingaPhillipscurveinwhichtheoutputgapcoefficientsdependonbothtrendinflationandthevarianceofinflationdoesnotyieldcon-clusiveresults.Toseewhy,notethatthecorrelationbetweentrendinflationandthevarianceofinflationis0.96.Inthepresenceofmulticollinearity,itisnotsurprisingthatbothvariablesenter

30

insignificantly.

Second,wediscussresultsfrompairwisenon-nestedtestsasdevelopedbyDavidsonandMacK-innon(1981).TheLMRconvexityturnsouttoperformpoorlyrelativetotheothertwomodels.ThecoefficientonthefittedvaluefromtheBMR/DKWmodel,whenaddedtoaLMRregres-sion,issignificantatthe5%level.ThissuggeststhattheBMR/DKWmodeladdsinformationbeyondthatcontainedintheLMRmodel.AnanalogousresultholdswhenweaddthefittedvaluefromtheLucasmodeltotheLMRmodel.Ontheotherhand,Davidson-MacKinnontestsfavortheBMR/DKWandLucasmodels.ThefittedvaluefromtheLMRmodeldoesnotentersignificantlyineithermodel.

Third,toassesswhichamongthemodelsinourmodelspaceismostlikelytocorrespondtothetruth,weapplyBayesianmodelaveragingmethodsasinBrock,Durlauf,andWest(2004).Inparticular,weusetheprocedureinKiley(2005)tocomputepseudo-posteriormodeloddsbasedonacomparisonoftheBayesianInformationCriteriafromthethreenonlinearmodelsandthelinearmodel.Thisprocedureassumesauniformpriordistributionoverthemodelspace.AsTable5documents,theresultsstronglyfavortheBMR/DKWendogenouspricingmodel.Accordingtothepseudo-posteriordistribution,theprobabilitythattheBMR/DKWmodelisthetruemodelis81.42%.Thepseudo-posteriormodeloddsfortheLucasmodelare18.58%.TheprobabilityforeithertheLMRmodelorthelinearmodeltobethetruemodelisvirtuallyzero.

7.2Assessment

Twooutofthreeproceduresyieldedconclusiveresults.Davidson-MacKinnontests,aswellasthecomputationofpseudo-posteriormodelodds,suggestedthattheLaxton,Meredith,Rose(LMR)modelprovidesalessaccuratedescriptionofthedatathanthetwoothermodels.

31

Inthissubsection,wetakeamoredetailedlookattheregressionresultsfromsection5,soastoexaminewhytheLMRmodelperformedpoorlyinthenon-nestedmodelhypothesistests.Beforedoingso,rememberfromsection5.1thatitisdoubtfulwhethercapacityconstraintscanbearationaleforconvexityatregionsofthePhillipscurvewhicharefarfromthecapacityconstraint.

ItturnsoutthattheaccuratefitoftheLMRmodelinaregressionofequation(5)over1971Q2-2004Q4ismostlydrivenbyitssuperiorfitaroundthetimeofthefirstoilpriceshock.Muchofthenonlinearityseemstospringfromthe1974Q1observation,whenoilimportpricessurged,annualizedcoreCPIinflationspikedto32%,andthepre-1974boomsuddenlyhalted.Asarobustnesstest,weperformregressionsforthethreenonlinearmodelsasinsection5,butoverasamplewhichexcludesallpre-1975observations.ItturnsoutthatthereisnoevidenceforLMR-typeconvexityoverthesample1975Q1-2004Q4.Moreprecisely,thestandarderroronthenonlinearityparameterφisthatlargethatnoinferencecanbedrawnastowhetherthePhillipscurveisconvexorlinear.Incontrast,theresultsfortheBMR/DKWandLucasmodelsarerobusttotheexclusionofobservationsfromtheoilshockepisode.Trendinflationandthevarianceofinflation,respectively,entersignificantlyatthe1%levelevenwhenpre-1975observationsareexcluded.

8Conclusion

Atadirectempiricallevel,ourpaperinvestigateswhydeflationdidnotaccelerateinJapannotwithstandinglargenegativeoutputgapsduringtheperiod1998-2002.Wefindthattheabsenceofacceleratingdeflationcannotbeadequatelyaddressedbypopularexplanationswhichassumealinearshort-runrelationbetweentheoutputgapandinflationwithatime-invariantslope.Giventhatfinding,thebodyofourpaperfocusesonthepathanddeterminantsofthePhillipscurve

32

slope.Wedocumentagradual,significantflatteningoftheJapanesePhillipscurvewhichpredatesthenineties.

Asforthedeterminantsofsuchtime-variationinthePhillipscurveslope,ourresultsfavortheBall-Mankiw-Romer/Dotsey-King-Wolmanhypothesisthatdecliningtrendinflationcreatedanenvironmentinwhichpricesbecamestickier,whichinturncausedthePhillipscurvetoflatten.AllbutoneofourtestslendequallystrongsupporttotheLucashypothesisthatadeclineinaggregateinflationvolatilityexacerbatedfirms’misperceptionsaboutrelativeprices,implyingaflatterPhillipscurve.WhilestoriessuchasLaxton-Meredith-Roseinwhichcapacityconstraintsengenderaconvexshort-runPhillipscurveareconsistentwiththedata,theyperformpoorlyincomparisonwiththetwoothermodels.

Onabroaderlevel,ourresultsareindicativefortheappropriatetheoreticalframeworktomodeltheoutput-inflationtrade-off.IfitisindeedageneralrulethatthePhillipscurveflattensastrendinflationdeclines,weseetwoimplicationsformonetarypolicymakersineconomieswheretrendinflationislowtodayrelativetopastexperience.

First,theBall-Mankiw-Romer/Dotsey-King-WolmanmodelimpliesthatthePhillipscurveinthosecountriesiscurrentlyflatterthanthestandardlinearmodelwouldsuggest.Allotherthingsbeingequal,thisimpliesahighersacrificeratio:ifthecentralbankbringsaboutadisinflation,theassociatedreductioninoutputwillbelargerthanitwouldappearfromthelinearmodel.

Second,althoughtheendogenouspricingmodelsimplythatthePhillipscurveturnsflatterastrendinflationdeclinestozero,thesemodelsdonotpredictthattheriskofadeflationaryspiralisnegligible.Onthecontrary,boththeBall-Mankiw-RomerandDotsey-King-Wolmanmodelsaresymmetricaroundzero.Oncetrendinflationturnsnegative,thesemodelsimplythatanyfurtherdecreaseintrendinflationisassociatedwithanincreaseinthefrequencyofpriceadjustment.

33

Thisinturnmeansthatanynegativeoutputgaphasstrongerdeflationaryeffects,thusincreasingtheriskofamorepronouncednegativeinteractionbetweendeflation,realactivity,andfinancialsectorvulnerabilities.

OuranalysisalsolendssomeempiricalsupporttotheLucasmodel.Thismodelimpliesthat,ineconomieswhereinflationiscurrentlymorestablethaninearlierdecades,thePhillipscurveisflatterthanthestandardlinearmodelwouldsuggest.Hence,thismodelimpliesthatinsucheconomies,theshort-runoutputcostsofdisinflationarehigherthantheywouldappearfromalinearmodel.

34

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39

Figuresandtables

Actual and Potential GDP (trillion 1995 yen), 1970Q1-2004Q4

600550

500

Actual real GDP450

Potential real GDP400

350

300

250

200

15019701975198019851990199520002005Source: US Federal Reserve, Board of Governors

Figure1

Note:sincetheFed’srecentpotentialoutputestimatesareconfidential,weextrapolatepoten-tialoutputfor1999Q1-2004Q4usingIMFstaffestimates/forecastsforpotentialoutputgrowth,asquotedinBayoumi(2000),asaguideline.

40

10

Output Gap (%), 1970Q1-2004Q4

5

0

-51970403020

Source: US Federal Reserve, Board of Governors

1975198019851990199520002005

Annualized Core CPI Inflation (%), 1970Q2-2004Q41050-5-101970

Source: Bank of Japan

1975198019851990199520002005

Figure2

Note:’AnnualizedCoreCPIinflation’standsforannualizedquarterlyinflationintheCon-sumerPriceIndexexcludingfreshfoods,whichtheBankofJapanadjustedforconsumptiontaxreformsinApril19andApril1997.

41

403020

Dynamic Out-Of-Sample Forecast from Linear Phillips Curve

Forecasted core CPI inflationActual core CPI inflationEstimation100-101970

Projection197519801985

Figure3

1990199520002005

Note:ThelinearPhillipscurveisestimatedover1971Q2-1997Q4;theforecastwindowis1998Q1-2004Q4.Theresultsuggeststhat,assumingastandardlinearrelationshipbetweentheoutputgapandinflation,thesizeofthenegativeoutputgapsinJapanwouldhavewarrantedacceleratingdeflationintheperiod1998-2002.

42

LinearModel:Time-invariantvs.Time-varyingOutputGapCoefficients

πt=β(L)πt+γ1,t(ygapt−1+pygapt−2)+δimpoilt+etSample:1971Q2-2004Q4β1β2β3β4γ1,tγ2,t=p.γ1,tδσepSumoutputgapcoefficientsSacrificeratioFitOLS(linear)0.67***(0.17)0.17(0.16)0.39***(0.15)-0.23(0.16)0.87**(0.36)-0.70**(0.35)0.018*(0.009)--0.81***(0.10)0.17**(0.07)1.47R2=0.85R=0.84Standarderrorsareinparentheses.

***indicatessignificanceatthe1%level;**at5%level;*at10%level.

Table1

Note:Therightmostcolumnshowstheresultsfromestimatingthestate-spacemodelconsistingofequations(3)and(4)bymeansoftheKalmanfilterandMaximumLikelihood.ThePhillipscurveislinear,yettheoutputgapcoefficientsareallowedtovaryovertimeasarandomwalk.’avg’indicatestheaverageofatime-varyingcoefficientanditsstandarderroroverthesample.Forcomparison,themiddlecolumnshowstheresultsfromestimatingastandardlinearPhillipscurvewithtime-invariantoutputgapcoefficients.

2MLE(linearTV)0.67***(0.08)0.17**(0.08)0.37***(0.08)-0.21***(0.07)0.75***(0.16)avg-0.58***(0.12)avg0.018***(0.004)1.33***(0.04)-0.77***(0.10)0.18***(0.04)avg1.39LLF=-255.9443

Random Walk Model: Time-Varying Output Gap Coefficients

21010-1TV coefficient on ygap(-2)TV coefficient on ygap(-1)-1197019801990200020100.6

-219701980199020002010

Sum of output gap coefficients0.40.20.0

19701980199020002010

Figure4

Note:ThisfiguregraphstheKalman-smoothedtime-varyingoutputgapcoefficientscorre-spondingtotheestimationresultsinTable1,alongwiththeir95%confidenceinterval.Notethatthesumoftheoutputgapcoefficientsisgraphedonadifferentscalethantheindividualoutputgapcoefficientsinthetoprow.

44

LinearPhillipsCurvevs.Laxton-Meredith-RosePhillipsCurve

h³φygapt−1φ−ygapt−1

πt=β(L)πt+γ1

´+p

³φygapt−2φ−ygapt−2

´i+δimpoilt+et

Sample:1971Q2-2004Q4β1β2β3β4γ1γ2=pγ1δφpFitQ-stat[withp-value]:4thlagQ-stat[withp-value]:12thlagOLS(linear)0.67***(0.17)0.17(0.16)0.39***(0.15)-0.23(0.16)0.87**(0.36)-0.70**(0.35)0.018*(0.009)∞-0.81***(0.10)R2=0.85/R=0.845.61[0.23]6.74[0.16]2NLS(LMR)0.70***(0.14)0.15(0.14)0.37**(0.15)-0.22(0.17)0.69**(0.30)-0.54*(0.29)0.019**(0.008)10.00***(1.83)-0.77***(0.12)R2=0.87/R=0.865.26[0.26]9.27[0.68]2Huber-Whitestandarderrorsareinparentheses.

***indicatessignificanceatthe1%level;**at5%level;*at10%level.

Table2

Note:TherightmostcolumnshowstheresultsfromestimatingaLaxton-Meredith-RosePhillipscurve.Thenonlinearityparameterφispreciselyestimated.AsFigure5demonstrates,itspointestimateimpliesafairlystrongdegreeofconvexityinthePhillipscurve,withaverticalasymptoteatanoutputgapof10%.Forcomparison,themiddlecolumninthetableabovegraphstheresultsfromestimatingalinearPhillipscurve.

45

43210

LMR Phillips Curve and Linear Phillips Curve

LMR Phillips curveEstimate phi=10.00Output gap term in Phillips curveLMR Phillips curveUpper bound 95% CI: phi=13.59Imposing linearity-1

-2-8

-6-4-20Figure5

2468

Output gap (%)

Note:Thisfiguregraphsγ1[(φygapt−1/(φ−ygapt−1))+p(φygapt−2/(φ−ygapt−2))],asestimatedinTable2,withrespecttotheoutputgap.Thedottedlinegraphsthesamefunctionimposingavalueforφwhichequalstheupperboundofthe95%confidenceintervalaroundthepointestimateforφ.

46

StandardPhillipsCurvevs.Ball-Mankiw-Romer/Dotsey-King-WolmanPhillipsCurve

πt=β(L)πt+[a+b|πt|][ygapt−1+pygapt−2]+δimpoilt+et

Sample:1971Q2-2004Q4β1β2β3β4γ1γ2=pγ1δabpFitQ-stat[withp-value]:4thlagQ-stat[withp-value]:12thlagOLS(linear)0.67***(0.17)0.17(0.16)0.39***(0.15)-0.23(0.16)0.87**(0.36)-0.70**(0.35)0.018*(0.009)γ10.00-0.81***(0.10)R2=0.85/R=0.845.61[0.23]6.74[0.16]2OLS(BMR/DKW)0.77***(0.10)0.18(0.12)0.22**(0.09)-0.17*(0.10)0.76avg-0.63avg0.019**(0.008)-0.53***(0.19)0.34***(0.05)-0.82***(0.07)R2=0.90/R=0.0.61[0.96]4.29[0.98]2Huber-Whitestandarderrorsareinparentheses.

***indicatessignificanceatthe1%level;**at5%level;*at10%level

Table3

Note:TherightmostcolumncontainstheresultsfromestimatingaPhillipscurveinwhichtheslopedependsontheabsolutevalueoftrendinflation.InlinewithBall-Mankiw-RomerandDotsey-King-Wolman,thecoefficientbontrendinflationispositiveandsignificantatthe1%level.Forcomparison,themiddlecolumnprovidestheresultsfromastandardPhillipscurveinwhichthecoefficientontrendinflationissettozero.

47

StandardLinearPhillipsCurvevs.LucasPhillipsCurve

πt=β(L)πt+[c+dvart(π)][ygapt−1+pygapt−2]+δimpoilt+et

Sample:1971Q2-2004Q4β1β2β3β4γ1γ2=pγ1δcdpFitQ-stat[withp-value]:4thlagQ-stat[withp-value]:12thlagOLS(linear)0.67***(0.17)0.17(0.16)0.39***(0.15)-0.23(0.16)0.87**(0.36)-0.70**(0.35)0.018*(0.009)γ10.00-0.81***(0.10)R2=0.85/R=0.845.61[0.23]6.74[0.16]2OLS(Lucas)0.83***(0.12)0.14(0.11)0.22**(0.09)-0.19*(0.10)0.66avg-0.52avg0.020**(0.008)-0.05(0.20)0.04***(0.01)-0.79***(0.10)R2=0.90/R=0.0.27[0.99]2.79[1.00]2Huber-Whitestandarderrorsareinparentheses.

***indicatessignificanceatthe1%level;**at5%level;*at10%level.

Table4

Note:TherightmostcolumncontainsresultsfromaPhillipscurveinwhichtheslopedependsonthevarianceofinflation.InlinewiththeLucasmisperceptionstheory,thecoefficientdonthevarianceofinflationispositiveandsignificantatthe1%level.

48

BayesianModelAveraging:Pseudo-PosteriorModelOdds

Ball-Mankiw-Romer/Dotsey-King-WolmanLucasLaxton-Meredith-RoseLinearTable5

81.42%18.58%1.95E-06%1.84E-09%Note:Thistabledisplaysthepseudo-posterioroddsforeachofthefourlistedmodelstobethetruemodel,accordingtoaBayesianModelAveragingprocedureasinBrock,Durlauf,West(2004).Thisprocedureplacesequalpriorprobabilityoneachofthemodels.

49

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