中级宏观经济学第十七章

CHAPTER17Expectations,Output,andPolicyExpectations,Output,andPolicyCHAPTER17Preparedby:FernandoQuijanoandYvonnQuijanoCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchardChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard2of2517-1ExpectationsandDecisions:TakingStockExpectations,Consumption,andInvestmentDecisionsExpectationsaffectconsumptionandinvestmentdecisions,bothdirectlyandthroughassetprices.ExpectationsandSpending:TheChannelsFigure17-1Chapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard3of25NotefromFigure17-1:Anincreaseincurrentandexpectedfutureafter-taxreallaborincome,oradecreaseincurrentandexpectedfuturerealinterestrates,increaseshumanwealthandleadstoanincreaseinconsumption.Anincreaseincurrentandexpectedfuturerealdividends,oradecreaseincurrentandexpectedfuturerealinterestrates,increasesstockpriceswhichleadstoanincreaseinnonhumanwealthandanincreaseinconsumption.17-1ExpectationsandDecisions:TakingStockExpectations,Consumption,andInvestmentDecisionsChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard4of25NotefromFigure17-1:Adecreaseincurrentandexpectedfuturenominalinterestratesleadstoanincreaseinbondprices,whichleadstoanincreaseinnonhumanwealthandanincreaseinconsumption.Anincreaseincurrentandexpectedfuturerealafter-taxprofits,oradecreaseincurrentandexpectedfuturerealinterestrates,increasesthepresentvalueofrealafter-taxprofits,whichleadstoanincreaseininvestment.17-1ExpectationsandDecisions:TakingStockExpectations,Consumption,andInvestmentDecisionsChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard5of25Consumptionandinvestmentdependonexpectationsofthefuture.Totakeintoaccounttheeffectofexpectations,wedothefollowing:Earlier,theISrelationwas:AYTrCYTIYr(,,)()(,)YCYTIYrG()(,)Defineaggregateprivatespendingorsimply,privatespending,A,as:RewritetheISrelationas:(,,)YAYTrG(,),17-1ExpectationsandDecisions:TakingStockExpectationsandtheISRelationChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard6of25GivenYCYTIYrG()(,)andYAYTrG(,,)(,),andincorporatingtheroleofexpectations,then:YAYTrGeee(,,,','')TrY(,,),+,*Primesdenotefuturevalues,andedenotesexpectedvalues.YorYe'AorTnAeTrorre'AThepositiveandnegativesignsexplainhow:17-1ExpectationsandDecisions:TakingStockExpectationsandtheISRelationChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard7of2517-1ExpectationsandDecisions:TakingStockExpectationsandtheISRelationGivenexpectations,adecreaseintherealinterestrateleadstoasmallincreaseinoutput:TheIScurveissteeplydownwardsloping.IncreasesingovernmentspendingorinexpectedfutureoutputshifttheIScurvetotheright.Increasesintaxes,inexpectedfuturetaxes,orintheexpectedfuturerealinterestrateshifttheIScurvetotheleft.TheNewISCurveFigure17-2Chapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard8of25ThenewIScurveissteep,whichmeansthatalargedecreaseinthecurrentinterestrateislikelytohaveonlyasmalleffectonequilibriumincome,fortworeasons:Adecreaseinthecurrentrealinterestratedoesnothavemucheffectonspendingiffutureexpectedratesarenotlikelytobeloweraswell.Themultiplierislikelytobesmall.Ifchangesinincomearenotexpectedtolast,theywillhavealimitedeffectonconsumptionandinvestment.17-1ExpectationsandDecisions:TakingStockExpectationsandtheISRelationChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard9of25ChangesinotherthanYandr,shifttheIScurve:ChangesinT(currenttaxes)orG(currentgovernmentspending)shifttheIScurveChangesinexpectedfuturevariablesalsoshifttheIScurve.(,,,','')eeeYAYTrYTrG(,,),+,17-1ExpectationsandDecisions:TakingStockExpectationsandtheISRelationChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard10of25TheLMrelationisnotmodifiedbecausetheopportunitycostofholdingmoneytodaydependsonthecurrentnominalinterestrate,notontheexpectednominalinterestrateoneyearfromnow.MPYLi()TheinterestratethatenterstheLMrelationisthecurrentnominalinterestrate.17-1ExpectationsandDecisions:TakingStockTheLMRelationRevisitedChapter17:Expectations,Output,andPolicyCopyright©2009PearsonEducation,Inc.PublishingasPrenticeHall•Macroeconomics,5/e•OlivierBlanchard11of25theMissionoftheFED“TheCongresshasentrustedtheFederalReservewithgreatresponsibilities.Ineveryphaseofourworkanddecisionmaking,weconsiderthewell-beingoftheAmericanpeopleandtheprosperityofournation.”——ChairJa