andExpectations(宏观经济学-加州大学-詹姆斯·布

Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-1,CHAPTER12,ThePhillipsCurveandExpectations,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-2,Questions,WhatisthePhillipscurve?HowhasthenaturalrateofunemploymentchangedintheU.S.overthepasttwogenerations?Whatdeterminestheexpectedrateofinflation?Howcanwetellhowexpectationsofinflationareformed-whethertheyarestatic,adaptive,orrational?,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-3,Questions,Howusefulistheaggregatedemand-aggregatesupplyframework-theIS-LMmodelandthePhillipscurve-forunderstandingmacroeconomiceventsintheU.S.overthepasttwogenerations?Howdoweconnectupthesticky-pricemodelwiththeflexible-pricemodel?,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-4,OkunsLaw,OkunslawshowstherelationshipbetweentheunemploymentrateandrealGDP,or,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-5,TheThreeFacesofAggregateSupply,AggregatesupplyrelatesthepriceleveltothelevelofrealGDPAggregatesupplycanalsorelatetheinflationratetothelevelofrealGDPUsingOkunslaw,aggregatesupplycanalsorelatetheinflationratetotheunemploymentratethisrelationshipisknownasaPhillipscurve,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-6,ThePhillipsCurve,AggregatesupplycanrelatetheinflationratetothelevelofrealGDP,Theright-handsideofthisequationcanbesubstitutedintoOkunsLaw,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-7,ThePhillipsCurve,Letting=2.5/,wegetthePhillipscurve,Toallowforsupplyshocks,wewilladdanextratermtothePhillipscurve(s),Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-8,Figure12.1-ThePhillipsCurve,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-9,Figure12.2-ThreeFacesofAggregateSupply,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-10,ThePhillipsCurve,TheslopeofthePhillipscurvedependsonhowstickypricesandwagesarethestickierarewagesandprices,thesmallerisparameter,andtheflatteristhePhillipscurveWhenthePhillipscurveisflat,evenlargechangesintheunemploymentratehavelittleeffectonthepricelevel,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-11,ThePhillipsCurve,Wheneverunemploymentisequaltoitsnaturalrate,inflationisequaltoexpectedinflationthepositionofthePhillipscurvecanbedeterminedifweknowthenaturalrateofunemploymentandtheexpectedinflationrate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-12,ThePhillipsCurve,ThePhillipscurveshiftsifeitherexpectedinflationorthenaturalrateofunemploymentchangesorifasupplyshockoccursahighernaturalratemovesthePhillipscurvetotherighthigherexpectedinflationmovesthePhillipscurveupadversesupplyshocksmovethePhillipscurveup,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-13,Figure12.3-ShiftsinthePhillipsCurve,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-14,AggregateDemand,TheaggregatedemandfunctiondevelopedinChapter11showshowrealGDPrelatestotheinflationrate,WecanuseOkunsLawtodevelopanaggregatedemandequationwithunemploymentontheleft-handside,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-15,AggregateDemand,TheparameteristheproductofthreethingshowmuchthecentralbankraisestherealinterestrateinresponsetoinflationhowmuchrealGDPchangesinresponsetoachangeintherealinterestratehowlargeachangeinunemploymentisproducedbyachangeinrealGDP,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-16,EquilibriumLevelsofInflationandUnemployment,Together,theunemploymentformoftheaggregatedemandrelationshipandthePhillipscurveequationallowustodeterminewhattheinflationandunemploymentrateswillbeintheeconomytheeconomysequilibriumiswherethetwocurvescross,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-17,Figure12.4-EquilibriumLevelsofUnemploymentandInflation,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-18,Equilibrium,Theeconomysequilibriuminflationandunemploymentratesdependonthenaturalrateofunemployment(u*)theexpectedrateofinflation(e)supplyshocks(s)thelevelofunemploymentwhentherealinterestrateisatwhatthecentralbankthinksisitslong-runaverage(u0)thecentralbankstargetlevelofinflation(),Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-19,SolvingforEquilibrium,Tosolvefortheequilibriumunemploymentrate,substitutethePhillipscurveequationintothemonetarypolicyreactionfunction,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-20,SolvingforEquilibrium,Tosolvefortheequilibriuminflationrate,substitutethemonetarypolicyreactionfunctionintothePhillipscurve,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-21,ADecreaseinExports,Ifexportdemandfalls,andthecentralbankdoesnothing,u0willrisebyu0Theeffectontheequilibriumlevelofunemploymentwillbe,Theeffectontheequilibriumlevelofinflationwillbe,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-22,Figure12.5-EffectsofaFallinExports,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-23,TheNaturalRateofUnemployment,UnemploymentcannotbereducedbelowitsnaturalratewithoutacceleratinginflationIfthenaturalrateofunemploymentishigh,expansionaryfiscalandmonetarypolicyarelargelyineffectiveastoolstoreduceunemploymentMostestimatesofthecurrentnaturalrateintheU.S.liebetween4.5and5.0percent,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-24,Figure12.6-FluctuationsinUnemploymentandtheNaturalRate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-25,TheNaturalRateofUnemployment,Foursetsoffactorsinfluencethenaturalrateofunemploymentdemographytherelativeageandeducationaldistributionofthelaborforceinstitutionslaborunions,workermobility,taxesproductivitygrowthwagegrowthpastlevelsofunemployment,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-26,Figure12.7-RealWageGrowthAspirationsandProductivity,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-27,ExpectedInflation,ThenaturalrateofunemploymentandexpectedinflationtogetherdeterminethepositionofthePhillipscurvehigherexpectedinflationmovesthePhillipscurveupward,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-28,ExpectedInflation,Therearethreebasicscenariosforhowinflationexpectationsareformedstaticexpectationsprevailwhenpeopleignorethefactthatinflationcanchangeadaptiveexpectationsprevailwhenpeopleassumethefuturewillbeliketherecentpastrationalexpectationsprevailwhenpeopleusealltheinformationtheyhaveasbesttheycan,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-29,ThePhillipsCurveunderStaticExpectations,Ifinflationexpectationsarestatic,expectedinflationneverchangesthetrade-offbetweeninflationandunemploymentwillnotchangefromyeartoyearIfinflationhasbeenlowandstable,businesseswillprobablyholdstaticinflationexpectations,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-30,Figure12.9-StaticExpectationsofInflation,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-31,StaticExpectationsofInflationinthe1960s,Inthe1960s,thePhillipscurvedidnotshiftupordowninresponsetochangesinexpectedinflationwhenunemploymentwasabove5.5%,inflationwasbelow1.5%whenunemploymentwasbelow4%,inflationwasabove4%TheeconomymovedalongastablePhillipscurve,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-32,Figure12.10-StaticExpectationsandthePhillipsCurve,1960-1968,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-33,ThePhillipsCurveunderAdaptiveExpectations,Iftheinflationratevariestoomuchforworkersandbusinessestoignoreitandiflastyearsinflationrateisagoodguidetoinflationthisyear,individualsarelikelytoholdadaptiveexpectationsinflationwillbeforecastedbyassumingthatthisyearwillbelikelastyearforecastwillbegoodonlyifinflationchangesslowly,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-34,ThePhillipsCurveunderAdaptiveExpectations,ThePhillipscurvecanbewritten,ThePhillipscurvewillshiftupanddowndependingonwhetherlastyearsinflationwashigherorlowerthanthepreviousyearsinflationaccelerateswhenunemploymentislessthanthenaturalrate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-35,AdaptiveExpectations,Examplethegovernmentpushestheunemploymentratedown2percentagepointsbelowthenaturalrate=1/2lastyearsinflationrate=4%,Thisyearsinflationrate=4+1/22=5Nextyearsinflationrate=5+1/22=6Andsoon,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-36,Figure12.11-AcceleratingInflation,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-37,AdaptiveExpectationsandtheVolckerDisinflation,Attheendofthe1970s,expectedinflationgavetheU.S.anunfavorableshort-runPhillipscurvetrade-offBetween1979andthemid-1980s,FedchairmanPaulVolckerreducedinflationfrom9to3percentperyearThefallininflationtriggeredafallinexpectedinflationthePhillipscurveshifteddown,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-38,Figure12.12-ThePhillipsCurvebeforeandaftertheVolckerDisinflation,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-39,ThePhillipsCurveunderRationalExpectations,Iftheeconomyischangingrapidlyenoughthatadaptiveexpectationsleadtolargeerrors,individualswillswitchtorationalexpectationsPeopleformtheirforecastsoffutureinflationnotbylookingbackwardbutbylookingforwardtheylookatwhatcurrentandexpectedgovernmentpoliciestellusaboutwhatinflationwillbe,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-40,ThePhillipsCurveunderRationalExpectations,ThePhillipscurvewillshiftasrapidlyaschangesineconomicpolicythataffectaggregatedemandAnticipatedchangesineconomicpolicyturnouttohavenoeffectonthelevelofproductionoremployment,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-41,GovernmentPolicytoStimulatetheEconomy,SupposethattheunemploymentrateisequaltoitsnaturalrateandinflationisequaltoexpectedinflationThegovernmenttakesstepstostimulatetheeconomybycuttingtaxesandraisinggovernmentspendingtoreducetheunemploymentratebelowthenaturalrate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-42,Figure12.13-GovernmentAttemptstoStimulatetheEconomy,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-43,GovernmentPolicytoStimulatetheEconomy,Ifthepolicycomesasasurprise,theeconomymovesupandtotheleftalongthePhillipscurveinresponsetothechangeingovernmentpolicyUnemploymentwillbelower,productionwillbehigher,andtherateofinflationwillbehigher,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-44,Figure12.14-ResultsiftheShiftinPolicyComesasaSurprise,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-45,GovernmentPolicytoStimulatetheEconomy,Ifthepolicyisanticipated,individualswilltakethepolicyintoaccountwhentheyformtheirexpectationsofinflationThePhillipscurvewillshiftupTherewillbenoeffectonunemploymentoroutputTherateofinflationwillrise,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-46,Figure12.15-ResultsiftheShiftinPolicyIsAnticipated,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-47,WhatKindofExpectationsDoWeHave?,Ifinflationislowandstable,expectationsareprobablystaticIfinflationismoderateandfluctuatesslowly,expectationsareprobablyadaptiveWhenshiftsininflationareclearlyrelatedtochangesinmonetarypolicy,swifttooccur,andlargeenoughtoseriouslyaffectprofitability,expectationsareprobablyrational,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-48,FromtheShortRuntotheLongRun,Inthecaseofananticipatedshiftineconomicpolicyunderrationalexpectations,thelongrunisnowIntheabsenceofsupplyshocks,Ifexpectationsarerationalandchangesinpolicyforeseen,expectedinflationwillbeequaltoactualinflationandunemploymentwillbeatitsnaturalrate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-49,Figure12.16-RationalExpectations:TheLongRunIsNow,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-50,FromtheShortRuntotheLongRun,Ifexpectationsareadaptive,theeconomywillapproachthelongrungraduallyanexpansionaryshockwilllowerunemployment,increaserealGDP,andleadtoanincreaseintheinflationrateindividualswillraisetheirexpectationsofinflationinthenextperiodsastimepasses,thegapsbetweenactualunemploymentanditsnaturalrateandactualandexpectedinflationwillshrinktozero,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-51,Figure12.17-AdaptiveExpectationsConvergencetotheLongerRun,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-52,FromtheShortRuntotheLongRun,Understaticexpectations,thelongrunneverarrivesthegapbetweenexpectedandactualinflationcangrowarbitrarilylargeasdifferentshockshittheeconomyifthegapbetweenactualandexpectedinflationbecomeslarge,individualswillnotremainsofoolishastoretainstaticexpectations,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-53,ChapterSummary,ThelocationofthePhillipscurveisdeterminedbytheexpectedrateofinflationandthenaturalrateofunemployment(andpossiblybycurrent,activesupplyshocks)intheabsenceofcurrent,activesupplyshocks,thePhillipscurvepassesthroughthepointatwhichinflationisequaltoitsexpectedvalueandunemploymentisequaltoitsnaturalrate,Copyright2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.,12-54,ChapterSummary,TheslopeofthePhillipscurveisdet