andExpectations(宏观经济学-加州大学-詹姆斯·布

Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-1CHAPTER12ThePhillipsCurveandExpectationsCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-2Questions•WhatisthePhillipscurve?•HowhasthenaturalrateofunemploymentchangedintheU.S.overthepasttwogenerations?•Whatdeterminestheexpectedrateofinflation?•Howcanwetellhowexpectationsofinflationareformed--whethertheyarestatic,adaptive,orrational?Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-3Questions•Howusefulistheaggregatedemand-aggregatesupplyframework--theIS-LMmodelandthePhillipscurve--forunderstandingmacroeconomiceventsintheU.S.overthepasttwogenerations?•Howdoweconnectupthesticky-pricemodelwiththeflexible-pricemodel?Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-4Okun’sLaw•Okun’slawshowstherelationshipbetweentheunemploymentrateandrealGDP*Y*Y-Y-0.4u*-uu*)-(u-2.5*Y*Y-Y•orCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-5TheThreeFacesofAggregateSupply•AggregatesupplyrelatesthepriceleveltothelevelofrealGDP•AggregatesupplycanalsorelatetheinflationratetothelevelofrealGDP•UsingOkun’slaw,aggregatesupplycanalsorelatetheinflationratetotheunemploymentrate–thisrelationshipisknownasaPhillipscurveCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-6ThePhillipsCurve•AggregatesupplycanrelatetheinflationratetothelevelofrealGDP)-(*Y*Y-Ye•Theright-handsideofthisequationcanbesubstitutedintoOkun’sLaw)-(u*)-(u2.5-eu*)-(u2.5-eCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-7ThePhillipsCurve•Letting=2.5/,wegetthePhillipscurve•Toallowforsupplyshocks,wewilladdanextratermtothePhillipscurve(s)u*)-(u-eseu*)-(u-Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-8Figure12.1-ThePhillipsCurveCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-9Figure12.2-ThreeFacesofAggregateSupplyCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-10ThePhillipsCurve•TheslopeofthePhillipscurvedependsonhowstickypricesandwagesare–thestickierarewagesandprices,thesmallerisparameter,andtheflatteristhePhillipscurve•WhenthePhillipscurveisflat,evenlargechangesintheunemploymentratehavelittleeffectonthepricelevelCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-11ThePhillipsCurve•Wheneverunemploymentisequaltoitsnaturalrate,inflationisequaltoexpectedinflation–thepositionofthePhillipscurvecanbedeterminedifweknowthenaturalrateofunemploymentandtheexpectedinflationrateCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-12ThePhillipsCurve•ThePhillipscurveshiftsifeitherexpectedinflationorthenaturalrateofunemploymentchangesorifasupplyshockoccurs–ahighernaturalratemovesthePhillipscurvetotheright–higherexpectedinflationmovesthePhillipscurveup–adversesupplyshocksmovethePhillipscurveupCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-13Figure12.3-ShiftsinthePhillipsCurveCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-14AggregateDemand•TheaggregatedemandfunctiondevelopedinChapter11showshowrealGDPrelatestotheinflationrate)'('-YY0•WecanuseOkun’sLawtodevelopanaggregatedemandequationwithunemploymentontheleft-handside)'(-uu0Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-15AggregateDemand•Theparameteristheproductofthreethings–howmuchthecentralbankraisestherealinterestrateinresponsetoinflation–howmuchrealGDPchangesinresponsetoachangeintherealinterestrate–howlargeachangeinunemploymentisproducedbyachangeinrealGDP)'(-uu0Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-16EquilibriumLevelsofInflationandUnemployment•Together,theunemploymentformoftheaggregatedemandrelationshipandthePhillipscurveequationallowustodeterminewhattheinflationandunemploymentrateswillbeintheeconomy–theeconomy’sequilibriumiswherethetwocurvescrossCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-17Figure12.4-EquilibriumLevelsofUnemploymentandInflationCopyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-18Equilibrium•Theeconomy’sequilibriuminflationandunemploymentratesdependon–thenaturalrateofunemployment(u*)–theexpectedrateofinflation(e)–supplyshocks(s)–thelevelofunemploymentwhentherealinterestrateisatwhatthecentralbankthinksisitslong-runaverage(u0)–thecentralbank’stargetlevelofinflation(’)Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-19SolvingforEquilibrium•Tosolvefortheequilibriumunemploymentrate,substitutethePhillipscurveequationintothemonetarypolicyreactionfunctionse1)'(1*u1u11u0Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-20SolvingforEquilibrium•Tosolvefortheequilibriuminflationrate,substitutethemonetarypolicyreactionfunctionintothePhillipscurvese11)u*u(1'1110Copyright©2002byTheMcGraw-HillCompanies,Inc.Allrightsreserved.12-21ADecreaseinExports•Ifexportdemandfalls,andthecentralbankdoesnothing,u0willrisebyu0•Theeffectontheequilib