曼昆经济学原理宏观经济学分册英文原版——24measuring_costppt课件.ppt

24 MeasuringtheCostofLiving MeasuringtheCostofLiving Inflationreferstoasituationinwhichtheeconomy soverallpricelevelisrising Theinflationrateisthepercentagechangeinthepricelevelfromthepreviousperiod THECONSUMERPRICEINDEX Theconsumerpriceindex CPI isameasureoftheoverallcostofthegoodsandservicesboughtbyatypicalconsumer TheBureauofLaborStatisticsreportstheCPIeachmonth Itisusedtomonitorchangesinthecostoflivingovertime THECONSUMERPRICEINDEX WhentheCPIrises thetypicalfamilyhastospendmoredollarstomaintainthesamestandardofliving HowtheConsumerPriceIndexIsCalculated FixtheBasket Determinewhatpricesaremostimportanttothetypicalconsumer TheBureauofLaborStatistics BLS identifiesamarketbasketofgoodsandservicesthetypicalconsumerbuys TheBLSconductsmonthlyconsumersurveystosettheweightsforthepricesofthosegoodsandservices HowtheConsumerPriceIndexIsCalculated FindthePrices Findthepricesofeachofthegoodsandservicesinthebasketforeachpointintime HowtheConsumerPriceIndexIsCalculated ComputetheBasket sCost Usethedataonpricestocalculatethecostofthebasketofgoodsandservicesatdifferenttimes HowtheConsumerPriceIndexIsCalculated ChooseaBaseYearandComputetheIndex Designateoneyearasthebaseyear makingitthebenchmarkagainstwhichotheryearsarecompared Computetheindexbydividingthepriceofthebasketinoneyearbythepriceinthebaseyearandmultiplyingby100 HowtheConsumerPriceIndexIsCalculated Computetheinflationrate Theinflationrateisthepercentagechangeinthepriceindexfromtheprecedingperiod HowtheConsumerPriceIndexIsCalculated TheInflationRateTheinflationrateiscalculatedasfollows Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Copyright 2004South Western Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Copyright 2004South Western Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Copyright 2004South Western Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Copyright 2004South Western Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Copyright 2004South Western HowtheConsumerPriceIndexIsCalculated CalculatingtheConsumerPriceIndexandtheInflationRate AnotherExampleBaseYearis2002 Basketofgoodsin2002costs 1 200 Thesamebasketin2004costs 1 236 CPI 1 236 1 200 100 103 Pricesincreased3percentbetween2002and2004 FYI What sintheCPI sBasket Copyright 2004South Western ProblemsinMeasuringtheCostofLiving TheCPIisanaccuratemeasureoftheselectedgoodsthatmakeupthetypicalbundle butitisnotaperfectmeasureofthecostofliving ProblemsinMeasuringtheCostofLiving SubstitutionbiasIntroductionofnewgoodsUnmeasuredqualitychanges ProblemsinMeasuringtheCostofLiving SubstitutionBiasThebasketdoesnotchangetoreflectconsumerreactiontochangesinrelativeprices Consumerssubstitutetowardgoodsthathavebecomerelativelylessexpensive Theindexoverstatestheincreaseincostoflivingbynotconsideringconsumersubstitution ProblemsinMeasuringtheCostofLiving IntroductionofNewGoodsThebasketdoesnotreflectthechangeinpurchasingpowerbroughtonbytheintroductionofnewproducts Newproductsresultingreatervariety whichinturnmakeseachdollarmorevaluable Consumersneedfewerdollarstomaintainanygivenstandardofliving ProblemsinMeasuringtheCostofLiving UnmeasuredQualityChangesIfthequalityofagoodrisesfromoneyeartothenext thevalueofadollarrises evenifthepriceofthegoodstaysthesame Ifthequalityofagoodfallsfromoneyeartothenext thevalueofadollarfalls evenifthepriceofthegoodstaysthesame TheBLStriestoadjustthepriceforconstantquality butsuchdifferencesarehardtomeasure ProblemsinMeasuringtheCostofLiving Thesubstitutionbias introductionofnewgoods andunmeasuredqualitychangescausetheCPItooverstatethetruecostofliving TheissueisimportantbecausemanygovernmentprogramsusetheCPItoadjustforchangesintheoveralllevelofprices TheCPIoverstatesinflationbyabout1percentagepointperyear TheGDPDeflatorversustheConsumerPriceIndex TheGDPdeflatoriscalculatedasfollows TheGDPDeflatorversustheConsumerPriceIndex TheBLScalculatesotherpricesindexes Theindexfordifferentregionswithinthecountry Theproducerpriceindex whichmeasuresthecostofabasketofgoodsandservicesboughtbyfirmsratherthanconsumers TheGDPDeflatorversustheConsumerPriceIndex EconomistsandpolicymakersmonitorboththeGDPdeflatorandtheconsumerpriceindextogaugehowquicklypricesarerising Therearetwoimportantdifferencesbetweentheindexesthatcancausethemtodiverge TheGDPDeflatorversustheConsumerPriceIndex TheGDPdeflatorreflectsthepricesofallgoodsandservicesproduceddomestically whereas theconsumerpriceindexreflectsthepricesofallgoodsandservicesboughtbyconsumers TheGDPDeflatorversustheConsumerPriceIndex Theconsumerpriceindexcomparesthepriceofafixedbasketofgoodsandservicestothepriceofthebasketinthebaseyear onlyoccasionallydoestheBLSchangethebasket whereastheGDPdeflatorcomparesthepriceofcurrentlyproducedgoodsandservicestothepriceofthesamegoodsandservicesinthebaseyear Figure2TwoMeasuresofInflation 1965 Percent perYear 15 10 5 0 1970 1975 1980 1985 1990 2000 1995 Copyright 2004South Western CORRECTINGECONOMICVARIABLESFORTHEEFFECTSOFINFLATION Priceindexesareusedtocorrectfortheeffectsofinflationwhencomparingdollarfiguresfromdifferenttimes DollarFiguresfromDifferentTimes Dothefollowingtoconvert inflate BabeRuth swagesin1931todollarsin2001 Table2TheMostPopularMoviesofAllTimes InflationAdjusted Copyright 2004South Western Indexation Whensomedollaramountisautomaticallycorrectedforinflationbylaworcontract theamountissaidtobeindexedforinflation RealandNominalInterestRates Interestrepresentsapaymentinthefutureforatransferofmoneyinthepast RealandNominalInterestRates Thenominalinterestrateistheinterestrateusuallyreportedandnotcorrectedforinflation Itistheinterestratethatabankpays Therealinterestrateisthenominalinterestratethatiscorrectedfortheeffectsofinflation RealandNominalInterestRates Youborrowed 1 000foroneyear Nominalinterestratewas15 Duringtheyearinflationwas10 Realinterestrate Nominalinterestrate Inflation 15 10 5 Figure3RealandNominalInterestRates 1965 InterestRates percent peryear 15 10 5 0 5 1970 1975 1980 1985 1990 1995 2000 Copyright 2004South Western Summary Theconsumerpriceindexshowsthecostofabasketofgoodsandservicesrelativetothecostofthesamebasketinthebaseyear Theindexisusedtomeasuretheoveralllevelofpricesintheeconomy ThepercentagechangeintheCPImeasurestheinflationrate Summary Theconsumerpriceindexisanimperfectmeasureofthecostoflivingforthefollowingt