宏觀經(jīng)濟(jì)學(xué)課件 Chapter 2

?CHAPTER2TheDataofMacroeconomicsAPowerPointTutorialToAccompany

MACROECONOMICS,7th.EditionN.GregoryMankiwTutorialwrittenby:MannigJ.SimidianB.A.inEconomicswithDistinction,DukeUniversityM.P.A.,HarvardUniversityKennedySchoolofGovernmentM.B.A.,MassachusettsInstituteofTechnology(MIT)SloanSchoolofManagementMANKIW'SMACROECONOMICSMODULES1GDP,CPI,andUemploymentGrossDomesticProduct(GDP)isthedollarvalueofallfinalgoodsandservicesproducedwithinaneconomyinagivenperiodoftime.Theconsumerpriceindex(CPI)measuresthelevelofprices.Theunemploymentratetellsusthefractionofworkerswhoareunemployed.2

GrossDomesticProductisthebestmeasureofhowwelltheeconomyisperforming.TheBureauofEconomicAnalysis(partoftheU.S.Dept.ofCommerce)calculatesGDPviaadministrativedata,whicharebyproductsofgovernmentfunctionssuchastaxcollection,educationprograms,defense,andregulation,andstatisticaldata,whichcomefromgovernmentsurveysof,forexample,retailestablishmentsmanufacturingfirmsandfarmactivity.GrossDomesticProduct3TwowaysofviewingGDPTotalincomeofeveryoneintheeconomyTotalexpenditureontheeconomy’soutputofgoodsandservicesHouseholdsFirmsIncome$LaborGoodsExpenditure$Fortheeconomyasawhole,incomemustequalexpenditure.

GDPmeasurestheflowofdollarsintheeconomy.Income,Expenditure,AndtheCircularFlow4RulesforComputingGDP1)Tocomputethetotalvalueofdifferentgoodsandservices,thenationalincomeaccountsusemarketprices.Thus,if:

$0.50$1.00GDP=(Priceofapples

Quantityofapples) +(PriceoforangesQuantityoforanges)=($0.504)+($1.003)GDP=$5.002)UsedgoodsarenotincludedinthecalculationofGDP.3)Thetreatmentofinventoriesdependsonifthegoodsarestoredoriftheyspoil.Ifthegoodsarestored,theirvalueisincludedinGDP.Iftheyspoil,GDPremainsunchanged.Whenthegoodsarefinallysoldoutofinventory,theyareconsideredusedgoods(andarenotcounted).5MoreRulesforComputingGDP4)IntermediategoodsarenotcountedinGDP–onlythevalueoffinalgoods.Reason:thevalueofintermediategoodsisalreadyincludedinthemarketprice.Valueadded

ofafirmequalsthevalueofthefirm’soutputlessthevalueoftheintermediategoodsthefirmpurchases.5)Somegoodsarenotsoldinthemarketplaceandthereforedon’thavemarketprices.Wemustusetheirimputedvalueasanestimateoftheirvalue.Forexample,homeownershipandgovernmentservices.6Realvs.NominalGDPThevalueoffinalgoodsandservicesmeasuredatcurrentpricesiscallednominalGDP.Itcanchangeovertime,eitherbecausethereisachangeintheamount(realvalue)ofgoodsandservicesorachangeinthepricesofthosegoodsandservices.Hence,nominalGDPY=Py,wherePisthepricelevelandyisrealoutput—andrememberweuseoutputandGDPinterchangeably.RealGDPor,y=YPisthevalueofgoodsandservicesmeasuredusingaconstantsetofprices.Thisdistinctionbetweenrealandnominalcanalsobeappliedtoothermonetaryvalues,likewages.Nominal(ormoney)wagescanbedenotedbyWanddecomposedintoarealvalue(w)andapricevariable(P).Hence,W=nominalwage=P?w

w=realwage=w/PThisconversionfromnominaltorealunitsallowsustoeliminatetheproblemscreatedbyhavingameasuringstick(dollarvalue)thatessentiallychangeslengthovertime,asthepricelevelchanges.7Let’sseehowrealGDPiscomputedinourappleandorangeeconomy.Forexample,ifwewantedtocompareoutputin2009

andoutputin2010,wewouldobtainbase-yearprices,suchas2009

prices.RealGDPin2009wouldbe:(2009PriceofApples

2009QuantityofApples)+(2009PriceofOranges2009QuantityofOranges).RealGDPin2010wouldbe:(2009PriceofApples2010

QuantityofApples)+(2009PriceofOranges2010QuantityofOranges).RealGDPin2011wouldbe:(2009PriceofApples2011

QuantityofApples)+(2009PriceofOranges2011QuantityofOranges).Notethat2009pricesareusedtocomputerealGDPforallthreeyears.Becausepricesareheldconstantfromyeartoyear,realGDPvariesonlywhenthequantitiesproducedvary.8GDPDeflatorNominalGDPmeasuresthecurrentdollarvalueoftheoutputoftheeconomy.RealGDPmeasuresoutputvaluedatconstantprices.TheGDPdeflator,alsocalledtheimplicitpricedeflatorforGDP,measuresthepriceofoutputrelativetoitspriceinthebaseyear.Itreflectswhat’shappeningtotheoveralllevelofpricesintheeconomy.GDPDeflator=NominalGDP RealGDPTHEIMPLICITPRICEDEFLATORFORGDP9Chain-WeightedMeasuresofGDPInsomecases,itismisleadingtousebase-yearpricesthatprevailed10or20yearsago(i.e.,computersandcollege).In1995,theBureauofEconomicAnalysisdecidedtousechain-weightedmeasuresof realGDP.Thebaseyearchangescontinuously overtime.Thisnewchain-weighted measureisbetterthanthemore traditionalmeasurebecauseit ensuresthatpriceswillnotbe toooutofdate.Averagepricesin2009and2010areusedtomeasurerealgrowthfrom2009to2010.Averagepricesin2010and2011areusedtomeasurerealgrowthfrom2010to2011,andsoon.Thesegrowthratesareunitedtoforma“chain”thatisusedtocompareoutputbetweenanytwodates.10GovernmentpurchasesofgoodsandservicesComponentsofExpenditureY=C+I+G+NXTotaldemandfordomesticoutput(GDP)iscomposedofConsumptionspendingbyhouseholdsInvestmentspendingbybusinessesandhouseholdsNetexportsornetforeigndemandThisisthecalledthenationalincomeaccountsidentity.11GDPandItsComponentsIn2007,U.S.GDPtotaledabout13.8trillion.Thisnumberisincomprehensible.So,ifwedividethisnumberbythetotalpopulationof$302million,wegetGDPperperson—theamountofexpenditurefortheaverageAmerican–whichequaled$45,707in2007.Let’sbreakitdownvisuallyonthenextslide.AMankiwMacroeconomicsCaseStudy12GDP(Y)was$45,707perperson

HerearetheComponentsofYin2007:Y=C+I+G+NX$45,707=$32,144+$7,052+$8,854+$2,343Rememberthatthesecalculationsareperformedperpersonjustforcomprehensionpurposes.Note:ThenumbersabovemustbemultipliedbytheU.S.Population302milliontoobtainthetotalsfortheabovenationalincomeaccountsidentityY=C+I+G+NX.OtherMeasuresofIncomeToseehowthealternativemeasuresofincomerelatetooneanother,westartwithGDPandaddorsubtractvariousquantities.Toobtaingrossnationalproduct(GNP),weaddreceiptsoffactorincome(wages,profit,andrent)fromtherestoftheworldandsubtractpaymentsoffactorincometotherestoftheworld.GNP=GDP+FactorPaymentsfromAbroad-FactorPaymentstoAbroadWhereasGDPmeasuresthetotalincomeproduceddomestically,GNPmeasuresthetotalincomeearnedbynationals(residentsofanation).Toobtainnetnationalproduct(NNP),

wesubtractthedepreciationofcapital—theamountoftheeconomy’sstockofplants,equipment,andresidentialstructuresthatwearsoutduringtheyear:

NNP=GNP–DepreciationInthenationalincomeaccounts,depreciationiscalledtheconsumptionoffixedcapital.Itequalsabout10%ofGNP.Becausedepreciationofcapitalisacostofproducingtheoutputoftheeconomy,subtracting depreciationshowsthenetresultofeconomicactivity.14Moreonnetnational...

NetNationalisapproximatelyequaltoanothermeasurecallednationalincome.Thetwodifferbyasmallcorrectioncalledthestatisticaldiscrepancy,whicharisesbecausedifferentdatasourcesmaynotbecompletelyconsistent.15ComputingtheCPITheConsumerPriceIndex(CPI)turnsthepricesofmanygoodsandservicesintoasingleindexmeasuringtheoveralllevelofprices.TheBureauofLaborStatisticsweighsdifferentitemsbycomputingthepriceofabasketofgoodsandservicesproducedbyatypicalcustomer.TheCPIisthepriceofthisbasketofgoodsrelativetothepriceofthesamebasketinsomebaseyear.16Let’sseehowtheCPIwouldbecomputedinourappleandorangeeconomy.Forexample,supposethatthetypicalconsumerbuys5applesand2orangeseverymonth.Thenthebasketofgoodsconsistsof5applesand2oranges,andtheCPIis:CPI=(5CurrentPriceofApples)+(2CurrentPriceofOranges)

(52009PriceofApples)+(22009PriceofOranges)InthisCPIcalculation,2009isthebaseyear.Theindextellshowmuchitcoststobuy5applesand2orangesinthecurrentyearrelativetohowmuchitcosttobuythesamebasketoffruitin2009.17CoreInflationThisstatisticmeasurestheincreaseinthepriceofaconsumerbasketthatexcludesfoodandenergyproducts.Becausefoodandenergypricesexhibitsubstantialshort-runvolatility,coreinflationissometimesviewedasabettergaugeofongoinginflationtrends.18CPIVersustheGDPDeflatorTheGDPdeflatormeasuresthepricesofallgoodsproduced,whereastheCPImeasurespricesofonlythegoodsandservicesboughtbyconsumers.Thus,anincreaseinthepriceofgoodsboughtonlybyfirmsorthegovernmentwillshowupintheGDPdeflator,butnotintheCPI.Also,anotherdifferenceisthattheGDPdeflatorincludesonlythosegoodsandservicesproduceddomestically.ImportedgoodsarenotapartofGDPandthereforedon’tshowupintheGDPdeflator.Thefinaldifferenceisthewaythetwoaggregatethepricesintheeconomy.TheCPIassignsfixedweightstothepricesofdifferentgoods,whereastheGDPdeflatorassignschangingweights.19MeasuringUnemploymentThelaborforceisdefinedasthesumoftheemployedandunemployed,andtheunemploymentrateisdefinedasthepercentageofthelaborforcethatisunemployed.Thelabor-forceparticipationrate

isthepercentageoftheadultpopulationwhoareinthelaborforce.UnemploymentRate=NumberofUnemployed LaborForce100Labor-ForceParticipationRate=LaborForce AdultPopulation10020TheBureauofLaborStatistics(BLS)computesthesestatisticsfortheoverallpopulationandforgroupswithinthepopulation:menandwomen,whitesandblacks,teenagersandprime-ageworkers.In2008,thestatisticsbrokedownasfollows:LaborForce=145.0+10.1=155.1millionUnemploymentrate=(10.1/155.1)x100=6.5%Labor-ForceParticipationRate=(155.1/234.6)x100=66.1%Hence,abouttwo-thirdsoftheadultpopulationwasinthelaborforce,andabout6.5percentofthoseinthelaborforcedidnothaveajob.TheBureauLaborStatisticsLaborForce=147.4millionUnemploymentrate=5.5%LaborForceParticipationRate=66.0%21TheHouseholdS