貨幣金融學（第十三版）課件 英文第23章 貨幣政策理論

TheEconomicsofMoney,Banking,andFinancialMarketsThirteenthEditionChapter23MonetaryPolicyTheoryCopyright?2022,2019,2016PearsonEducation,Inc.AllRightsReservedPreviewThischapterusestheaggregatedemand-aggregatesupplyframeworkdevelopedintheprecedingchaptertodevelopatheoryofmonetarypolicy.LearningObjectives(1of2)23.1Illustrateandexplainthepolicychoicesthatmonetarypolicymakersfaceundertheconditionsofaggregatedemandshocks,temporarysupplyshocks,andpermanentsupplyshocks.23.2Identifythelagsinthepolicyprocessandsummarizewhytheyweakenthecaseforanactivistpolicyapproach.23.3Explainwhymonetarypolicymakerscantargetanyinflationrateinthelongrunbutcannottargetaggregateoutputinthelongrun.LearningObjectives(2of2)23.4Identifythesourcesofinflationandtheroleofmonetarypolicyinpropagatinginflation.23.5Explaintheuniquechallengesthatmonetarypolicymakersfaceatthezerolowerbound,andillustratehownonconventionalmonetarypolicycanbeeffectiveundersuchconditions.ResponseofMonetaryPolicytoShocksMonetarypolicyshouldtrytominimizetheinflationgap,i.e.thedifferencebetweeninflationandtheinflationtarget.Inthecaseofbothdemandshocksandpermanentsupplyshocks,policymakerscansimultaneouslypursuepricestabilityandstabilityineconomicactivity.Followingatemporarysupplyshock,however,policymakerscanachieveeitherpricestabilityoreconomicactivitystability,butnotboth.Thistradeoffposesadilemmaforcentralbankswithdualmandates.ResponsetoanAggregateDemandShockPolicymakerscanrespondtothisshockintwopossibleways:NopolicyresponsePolicystabilizeseconomicactivityandinflationintheshortrunInthecaseofaggregatedemandshocks,thereisnotradeoffbetweenthepursuitofpricestabilityandeconomicactivitystability.AresultOlivierBlanchardlabeledthe‘divinecoincidence’Figure1AggregateDemandShock:NoPolicyResponseFigure2AggregateDemandShock:PolicyStabilizesOutputandInflationintheShortRunResponsetoaShortRunSupplyShockWhenasupplyshockistemporary,policymakersfaceashort-runtradeoffbetweenstabilizinginflationandeconomicactivity.Policymakerscanrespondtothetemporarysupplyshockinthreepossibleways:NopolicyresponsePolicystabilizesinflationintheshortrunPolicystabilizeseconomicactivityintheshortrunFigure3ResponsetoaSupplyShock:NoPolicyResponseFigure4ResponsetoaSupplyShock:Short-RunInflationStabilizationFigure5ResponsetoaSupplyShock:Short-RunOutputStabilizationTheBottomLine:TheRelationshipBetweenStabilizingInflationandStabilizingEconomicActivityWecandrawthefollowingconclusionsfromthisanalysis:Ifmostshockstotheeconomyareaggregatedemandshocks,thenpolicythatstabilizesinflationwillalsostabilizeeconomicactivity,evenintheshortrunIfsupplyshocksarethemostcommontype,thenacentralbankmustchoosebetweenthetwostabilizationobjectivesintheshortrunHowActivelyShouldPolicyMakersTrytoStabilizeEconomicActivity?Alleconomistshavesimilarpolicygoals(topromotehighemploymentandpricestability),yettheyoftendisagreeonthebestapproachtoachievethosegoals.Nonactivistsbelievegovernmentactionisunnecessarytoeliminateunemployment.Activistsseetheneedforthegovernmenttopursueactivepolicytoeliminatehighunemploymentwhenitdevelops.LagsandPolicyImplementation

(1of2)Severaltypesoflagspreventpolicymakersfromshiftingtheaggregatedemandcurveinstantaneously:Datalag:thetimeittakesforpolicymakerstoobtaindataindicatingwhatishappeningintheeconomyRecognitionlag:thetimeittakesforpolicymakerstobesureofwhatthedataaresignalingaboutthefuturecourseoftheeconomyLagsandPolicyImplementation

(2of2)Severaltypesoflagspreventpolicymakersfromshiftingtheaggregatedemandcurveinstantaneously:Legislativelag:thetimeittakestopasslegislationtoimplementaparticularpolicyImplementationlag:thetimeittakesforpolicymakerstochangepolicyinstrumentsoncetheyhavedecidedonthenewpolicyEffectivenesslag:thetimeittakesforthepolicyactuallytohaveanimpactontheeconomyF

Y

I:TheActivist/NonactivistDebateOvertheObamaFiscalStimulusPackageManyactivistsarguedthatthegovernmentneededtodomorebyimplementingamassivefiscalstimuluspackage.Ontheotherhand,nonactivistsopposedthefiscalstimuluspackage,arguingthatfiscalstimuluswouldtaketoolongtoworkbecauseoflongimplementationlags.TheObamaadministrationcamedownsquarelyonthesideoftheactivistsandproposedtheAmericanRecoveryandReinvestmentActof2009,a$787billionfiscalstimuluspackagethatCongresspassedonFebruary13,2009.Inflation:AlwaysandEverywhereaMonetaryPhenomenonThisadageissupportedbyouraggregatedemandandsupplyanalysisbecauseitshowsthatmonetarypolicymakerscantargetanyinflationrateinthelongrunbyshiftingtheaggregatedemandcurvewithautonomousmonetarypolicy.Figure6ARiseintheInflationTargetCausesofInflationaryMonetaryPolicyHighemploymenttargetsandinflation:Cost-pushinflationresultseitherfromatemporarynegativesupplyshockorapushbyworkersforwagehikesbeyondwhatproductivitygainscanjustify.Demand-pullinflationresultsfrompolicymakerspursuingpoliciesthatincreaseaggregatedemand.Figure7Cost-PushInflationFigure8Demand-PullInflationApplication:TheGreatInflationNowthatwehaveexaminedtherootsofinflationarymonetarypolicy,wecaninvestigatethecausesoftheriseinU.S.inflationfrom1965to1982,aperioddubbedthe“GreatInflation.”Panel(a)ofFigure11documentstheriseininflationduringthoseyears.JustbeforetheGreatInflationstarted,theinflationratewasbelow2%atanannualrate;bythelate1970s,itaveragedaround8%andpeakedatnearly14%in1980aftertheoilpriceshockin1979.Panel(b)ofFigure11comparestheactualunemploymentratetoestimatesofthenaturalrateofunemployment.Figure9InflationandUnemployment,19

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82MonetaryPolicyattheZeroLowerBoundTheFedcanattempttoreducetherealinterestratebyloweringthefederalfundsrate.Thefederalfundsrate,though,isstatedinnominalterms,andthereforecannotfallbelowzero.Thezeroflooronthefederalfundsrateisreferredtoasthezerolowerbound.DerivingtheAggregateDemandCurvewiththeZeroLowerBoundTheM

Pcurveisnormallyupwardsloping.Withthefederalfundsrateatthefloorofzero,asinflationandexpectedinflationfall,therealinterestraterises,creatingadownwardslopefortheM

Pcurve.TheprocessdescribedabovecreatesakinkintheAggregateDemandcurveaswell.Figure10DerivationoftheAggregateDemandCurveWithanEffectiveLowerBoundTheDisappearanceoftheSelf-CorrectingMechanismattheZeroLowerBoundWhentheeconomyisinasituationinwhichequilibriumoutputisbelowpotentialoutputandthezerolowerboundonthepolicyratehasbeenreached,outputisnotrestoredtoitspotentiallevelifpolicymakersdonothing.Inaddition,inthissituation,theeconomygoesintoadeflationaryspiral,characterizedbycontinuallyfallinginflationandoutput.Figure11TheAbsenceoftheSelf-CorrectingMechanismattheEffectiveLowerBoundApplication:NonconventionalMonetaryPolicyandQuantitativeEasing(1of2)Sometimesthenegativeaggregatedemandshockissolargethatatsomepointthecentralbankcannotlowertherealinterestratefurtherbecausethenominalinterestratehitsafloorofzero,asoccurredaftertheLehmanBrothersbankruptcyinlate2008.Inthissituationwhenthezero-lower-boundproblemarises,thecentralbankmustturntononconventionalmonetarypolicy.Application:NonconventionalMonetaryPolicyandQuantitativeEasing(2of2)Nonconventionalmonetarypolicytakesthreeforms:LiquidityprovisionAssetpurchases(quantitativeeasing)ManagementofexpectationsFigure12ResponsetoNonconventionalMonetaryPolicyLiquidityProvisionAcentralbankcanbringdownfinancialfrictionsdirectlybyincreasingitslendingfacilitiesinordertoprovidemoreliquiditytoimpairedmarketssothattheycanreturntotheirnormalfunctions.Thisdeclineinfinancialfrictionslowerstherealinterestrateforinvestments.AssetPurchasesandQuantitativeEasingThemonetaryauthoritiescanalsolowerfinancialfrictionsbyloweringcreditspreadsthroughthepurchaseofprivateassetsThoughtheFedtookaction,thenegativeaggregatedemandshocktotheeconomyfromtheglobalfinancialcrisiswassogreatthattheFed’squantitative(credit)easingwasinsufficienttoovercomeit,andtheFedwasunabletoshifttheaggregatedemandcurveallthewaybackandtheeconomystillsufferedasevererecession.ManagementofExpectationsForwardguidanceinwhichthecentralbankcommitstokeepingthepolicyratelowforalongperiodoftimeisanotherwayofloweringlong-terminterestratesrelativetoshort-termratesandtherebyloweringfinancialfrictionsandtherealinterestrateforinvestments.Thiscanleadtobothrightwardshiftsinaggregatedemandandbyshiftingtheshort-runaggregatesupplycurvebyraisingexpectationsofinflation.Figure13ResponsetoaRiseinInflationExpectationsAbenomicsandth