曼昆《经济学原理》(宏观经济学分册)英文原版.ppt

2007ThomsonSouth Western MeasuringtheCostofLiving Inflationreferstoasituationinwhichtheeconomy soverallpricelevelisrising Theinflationrateisthepercentagechangeinthepricelevelfromthepreviousperiod THECONSUMERPRICEINDEX Theconsumerpriceindex CPI isameasureoftheoverallcostofthegoodsandservicesboughtbyatypicalconsumer TheBureauofLaborStatisticsreportstheCPIeachmonth Itisusedtomonitorchangesinthecostoflivingovertime THECONSUMERPRICEINDEX WhentheCPIrises thetypicalfamilyhastospendmoredollarstomaintainthesamestandardofliving HowtheConsumerPriceIndexIsCalculated 1 Fixthebasket Determinewhatpricesaremostimportanttothetypicalconsumer TheBureauofLaborStatistics BLS identifiesamarketbasketofgoodsandservicesthetypicalconsumerbuys TheBLSconductsmonthlyconsumersurveystosettheweightsforthepricesofthosegoodsandservices HowtheConsumerPriceIndexIsCalculated 2 Findtheprices Findthepricesofeachofthegoodsandservicesinthebasketforeachpointintime 3 Computethebasket scost Usethedataonpricestocalculatethecostofthebasketofgoodsandservicesatdifferenttimes HowtheConsumerPriceIndexIsCalculated 4 Chooseabaseyearandcomputetheindex Designateoneyearasthebaseyear makingitthebenchmarkagainstwhichotheryearsarecompared Computetheindexbydividingthepriceofthebasketinoneyearbythepriceinthebaseyearandmultiplyingby100 HowtheConsumerPriceIndexIsCalculated 5 Computetheinflationrate Theinflationrateisthepercentagechangeinthepriceindexfromtheprecedingperiod HowtheConsumerPriceIndexIsCalculated Theinflationrateiscalculatedasfollows Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample Table1CalculatingtheConsumerPriceIndexandtheInflationRate AnExample HowtheConsumerPriceIndexIsCalculated CalculatingtheConsumerPriceIndexandtheInflationRate AnotherExampleBaseYearis2002 Basketofgoodsin2002costs 1 200 Thesamebasketin2004costs 1 236 CPI 1 236 1 200 100 103 Pricesincreased3percentbetween2002and2004 FYI WhatIsintheCPI sBasket ProblemsinMeasuringtheCostofLiving TheCPIisanaccuratemeasureoftheselectedgoodsthatmakeupthetypicalbundle butitisnotaperfectmeasureofthecostofliving 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 2005 CORRECTINGECONOMICVARIABLESFORTHEEFFECTSOFINFLATION Priceindexesareusedtocorrectfortheeffectsofinflationwhencomparingdollarfiguresfromdifferenttimes DollarFiguresfromDifferentTimes DothefollowingtoconvertdollarvaluesfromyearTintotoday sdollars DollarFiguresfromDifferentTimes Dothefollowingtoconvert inflate BabeRuth swagesin1931todollarsin2005 Salary Salary Priceleve lin2005 Priceleve lin1931 2005 1931 80 000 195 15 2 1 026 316 Indexation Whensomedollaramountisautomaticallycorrectedforinflationbylaworcontract theamountissaidtobeindexedforinflation Table2TheMostPopularMoviesofAllTimes InflationAdjusted RealandNominalInterestRates Interestrepresentsapaymentinthefutureforatransferofmoneyinthepast RealandNominalInterestRates Thenominalinterestrateistheinterestrateusuallyreportedandnotcorrectedforinflation Itistheinterestratethatabankpays Therealinterestrateistheinterestratethatiscorrectedfortheeffectsofinflation RealandNominalInterestRates Youborrowed 1 000foroneyear Nominalinterestratewas15 Duringtheyearinflationwas10 Realinterestrate Nominalinterestrate Inflation 15 10 5 Figure3RealandNominalInterestRates 1965 InterestRates percent peryear 15 Realinterestrate 10 5 0 5 1970 1975 1980 1985 1990 1995 2000 2005 Nominalinterestrate Theconsumerpriceindexshowsthecostofabasketofgoodsandservicesrelativetothecostofthesamebasketinthebaseyear Theindexisusedtomeasuretheoveralllevelofpricesintheeconomy ThepercentagechangeintheCPImeasurestheinflationrate Theconsumerpriceindexisanimperfectmeasureofthecostoflivingforthefollowingthreereasons substi