chap20宏觀經(jīng)濟(jì)學(xué)曼昆

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SHORT-RUNECONOMICFLUCTUATIONS短期經(jīng)濟(jì)波動(dòng)20AggregateDemandandAggregateSupply總需求與總供給本章我們將探索這些問(wèn)題的答案：什么是經(jīng)濟(jì)波動(dòng)？它們的特點(diǎn)是什么？總需求與總供給模型如何解釋經(jīng)濟(jì)波動(dòng)？為什么總需求曲線向右下方傾斜？什么使總需求曲線移動(dòng)？短期總供給曲線的斜率是多少？長(zhǎng)期的呢？什么使總供給曲線移動(dòng)？3Short-RunEconomicFluctuationsEconomicactivityfluctuatesfromyeartoyear.Inmostyearsproductionofgoodsandservicesrises.Onaverageoverthepast50years,productionintheU.S.economyhasgrownbyabout3percentperyear.Insomeyearsnormalgrowthdoesnotoccur,causingarecession.短期經(jīng)濟(jì)波動(dòng)經(jīng)濟(jì)活動(dòng)每年都有波動(dòng)。在大多數(shù)年份，物品與勞務(wù)的產(chǎn)量增加了。在過(guò)去的50年間，美國(guó)經(jīng)濟(jì)的產(chǎn)量平均每年增長(zhǎng)3%左右。在一些年份，并沒(méi)有出現(xiàn)這種正常增長(zhǎng)，導(dǎo)致衰退。Short-RunEconomicFluctuations

短期經(jīng)濟(jì)波動(dòng)Arecession

isaperiodofdecliningrealincomes,andrisingunemployment.衰退——實(shí)際GDP下降和失業(yè)增加的時(shí)期。Adepression

isasevererecession.蕭條——嚴(yán)重的衰退。20.1THREEKEYFACTSABOUTECONOMICFLUCTUATIONS(1)Economicfluctuationsareirregularandunpredictable.Fluctuationsintheeconomyareoftencalledthebusinesscycle.(2)Mostmacroeconomicvariablesfluctuatetogether.(3)Asoutputfalls,unemploymentrises.20.1關(guān)于經(jīng)濟(jì)波動(dòng)的三個(gè)事實(shí)(1)經(jīng)濟(jì)波動(dòng)是無(wú)規(guī)律的和無(wú)法預(yù)測(cè)的。經(jīng)濟(jì)中的波動(dòng)通常被稱為經(jīng)濟(jì)周期。(2)大多數(shù)宏觀經(jīng)濟(jì)變量同時(shí)波動(dòng)。(3)隨著產(chǎn)量減少，失業(yè)增加。Figure1ALookAtShort-RunEconomicFluctuationsBillionsof1996DollarsRealGDP(a)RealGDP$10,0009,0008,0007,0006,0005,0004,0003,0002,00019651970197519801985199019952000圖1.觀察短期經(jīng)濟(jì)波動(dòng)1996的10億美元RealGDP(a)實(shí)際GDP$10,0009,0008,0007,0006,0005,0004,0003,0002,00019651970197519801985199019952000Mostmacroeconomicvariablesfluctuatetogether大多數(shù)宏觀經(jīng)濟(jì)變量一起波動(dòng).Mostmacroeconomicvariablesthatmeasuresometypeofincomeorproductionfluctuatecloselytogether大多數(shù)衡量某種收入或產(chǎn)出的宏觀經(jīng)濟(jì)變量同時(shí)波動(dòng).Althoughmanymacroeconomicvariablesfluctuatetogether,theyfluctuatebydifferentamounts盡管很多宏觀經(jīng)濟(jì)變量一起波動(dòng)，但是它們波動(dòng)的大小并不同.Figure1ALookAtShort-RunEconomicFluctuationsBillionsof1996Dollars(b)InvestmentSpending$1,8001,6001,4001,2001,00080060040020019651970197519801985199019952000Investmentspending圖1.觀察短期經(jīng)濟(jì)波動(dòng)(b)投資支出$1,8001,6001,4001,2001,00080060040020019651970197519801985199019952000Investmentspending1996的10億美元Asoutputfalls,unemploymentrises隨著產(chǎn)量減少，失業(yè)增加.ChangesinrealGDPareinverselyrelatedtochangesintheunemploymentrate實(shí)際GDP的變化與失業(yè)率的變化是反向相關(guān)的.Duringtimesofrecession,unemploymentrisessubstantially在衰退期間，失業(yè)率大幅上升.Figure1ALookAtShort-RunEconomicFluctuationsPercentofLaborForce(c)UnemploymentRate02468101219651970197519801985199019952000UnemploymentrateCopyright?2004South-Western圖1.觀察短期經(jīng)濟(jì)波動(dòng)勞動(dòng)力的百分比(c)失業(yè)率02468101219651970197519801985199019952000Unemploymentrate20.2EXPLAININGSHORT-RUNECONOMICFLUCTUATIONS(1)HowtheShortRunDiffersfromtheLongRunMosteconomistsbelievethatclassicaltheorydescribestheworldinthelongrunbutnotintheshortrun.Changesinthemoneysupplyaffectnominalvariablesbutnotrealvariablesinthelongrun.Theassumptionofmonetaryneutralityisnotappropriatewhenstudyingyear-to-yearchangesintheeconomy.20.2解釋短期經(jīng)濟(jì)波動(dòng)(1)長(zhǎng)期與短期有什么不同大多數(shù)經(jīng)濟(jì)學(xué)家認(rèn)為，古典經(jīng)濟(jì)理論描述長(zhǎng)期世界，并不描述短期世界。在長(zhǎng)期中，貨幣供給的變化影響名義變量，而不影響實(shí)際變量。在研究逐年的經(jīng)濟(jì)變動(dòng)時(shí)，貨幣中性的假設(shè)就不再適用了。TheBasicModelofEconomicFluctuations(2)Twovariablesareusedtodevelopamodeltoanalyzetheshort-runfluctuations.Theeconomy’soutputofgoodsandservicesmeasuredbyrealGDP.TheoverallpricelevelmeasuredbytheCPIortheGDPdeflator.經(jīng)濟(jì)波動(dòng)的基本模型(2)兩個(gè)變量被用來(lái)建立模型分析短期經(jīng)濟(jì)波動(dòng)。用實(shí)際GDP衡量的經(jīng)濟(jì)中的物品與勞務(wù)的產(chǎn)量。用CPI或GDP平減指數(shù)衡量的物價(jià)總水平。(3)TheBasicModelofEconomicFluctuations

經(jīng)濟(jì)波動(dòng)的基本模型TheBasicModelofAggregateDemandandAggregateSupply

總需求與總供給基本模型Economistusethemodelofaggregatedemandandaggregatesupply

toexplainshort-runfluctuationsineconomicactivityarounditslong-runtrend.

經(jīng)濟(jì)學(xué)家用總需求與總供給模型來(lái)解釋經(jīng)濟(jì)活動(dòng)圍繞其長(zhǎng)期趨勢(shì)的短期波動(dòng)的模型。Theaggregate-demandcurve

showsthequantityofgoodsandservicesthathouseholds,firms,andthegovernmentwanttobuyateachpricelevel.總需求曲線——一條表示在每一種物價(jià)水平時(shí)家庭、企業(yè)和政府想要購(gòu)買的物品與勞務(wù)量的曲線。Theaggregate-supplycurve

showsthequantityofgoodsandservicesthatfirmschoosetoproduceandsellateachpricelevel.總供給曲線——一條表示在每一種物價(jià)水平下企業(yè)選擇生產(chǎn)并銷售的物品與勞務(wù)量的曲線。Figure2AggregateDemandandAggregateSupply...QuantityofOutputPriceLevel0AggregatesupplyAggregatedemandEquilibriumoutputEquilibriumpricelevel圖2.總需求與總供給…產(chǎn)量物價(jià)水平0總供給總需求均衡產(chǎn)量均衡物價(jià)水平20.3TheAggregateDemandCurve

總需求曲線ThefourcomponentsofGDP(Y)contributetotheaggregatedemandforgoodsandservices.

GDP(Y)的四個(gè)組成部分對(duì)物品與勞務(wù)的總需求做貢獻(xiàn)。Y=C+I+G+NXFigure3TheAggregate-DemandCurve...QuantityofOutputPriceLevel0AggregatedemandPYY2P21.Adecreaseinthepricelevel...2....increasesthequantityofgoodsandservicesdemanded.圖3.總需求曲線…產(chǎn)量物價(jià)水平0總需求PYY2P21.物價(jià)水平下降...2.…物品與勞務(wù)量增加20.3.1WhytheAggregate-DemandCurveIsDownwardSloping

為什么總需求曲線向右下方傾斜（1）ThePriceLevelandConsumption——TheWealthEffect物價(jià)水平與消費(fèi)——財(cái)富效應(yīng)（2）ThePriceLevelandInvestment——TheInterestRateEffect物價(jià)水平與投資——利率效應(yīng)（3）ThePriceLevelandNetExports——TheExchange-RateEffect物價(jià)水平與凈出口——匯率效應(yīng)（1）ThePriceLevelandConsumption:TheWealthEffect物價(jià)水平與消費(fèi):財(cái)富效應(yīng)Adecreaseinthepricelevelmakesconsumersfeelmorewealthy,whichinturnencouragesthemtospendmore.物價(jià)水平下降使消費(fèi)者感到更富裕，這又鼓勵(lì)他們更多地支出。

Thisincreaseinconsumerspendingmeanslargerquantitiesofgoodsandservicesdemanded.消費(fèi)支出增加意味著物品與勞務(wù)的需求量更大了。（2）ThePriceLevelandInvestment:TheInterestRateEffect物價(jià)水平與投資:利率效應(yīng)Alowerpricelevelreducestheinterestrate,whichencouragesgreaterspendingoninvestmentgoods.較低的物價(jià)水平降低了利率，鼓勵(lì)了更多地支出用在投資物品上Thisincreaseininvestmentspendingmeansalargerquantityofgoodsandservicesdemanded.這種投資支出的增加意味著物品與勞務(wù)的需求量更大了（3）ThePriceLevelandNetExports:TheExchange-RateEffect物價(jià)水平與凈出口：匯率效應(yīng)WhenafallintheU.S.pricelevelcausesU.S.interestratestofall,therealexchangeratedepreciates,whichstimulatesU.S.netexports.當(dāng)美國(guó)物價(jià)水平下降引起美國(guó)利率下降時(shí)，實(shí)際匯率貶值，而且這種貶值刺激了美國(guó)的凈出口。Theincreaseinnetexportspendingmeansalargerquantityofgoodsandservicesdemanded.凈出口開(kāi)支的增加意味著物品與勞務(wù)的需求量更大了20.3.2WhytheAggregate-DemandCurveMightShiftThedownwardslopeoftheaggregatedemandcurveshowsthatafallinthepricelevelraisestheoverallquantityofgoodsandservicesdemanded.Manyotherfactors,however,affectthequantityofgoodsandservicesdemandedatanygivenpricelevel.Whenoneoftheseotherfactorschanges,theaggregatedemandcurveshifts.20.3.2為什么總需求曲線會(huì)移動(dòng)總需求曲線向右下方傾斜表明物價(jià)水平下降增加了物品與勞務(wù)的總需求量。但是，許多其他因素也影響既定物價(jià)水平時(shí)的物品與勞務(wù)的需求量。

當(dāng)這些因素中的一種變動(dòng)時(shí)，總需求曲線移動(dòng)。Shiftsarisingfrom

移動(dòng)起因于Consumption消費(fèi)Investment投資GovernmentPurchases政府購(gòu)買NetExports凈出口ShiftsintheAggregateDemandCurveQuantityofOutputPriceLevel0Aggregatedemand,D1P1Y1D2Y2總需求曲線的移動(dòng)產(chǎn)出物價(jià)水平0總需求,D1P1Y1D2Y2在下列各種情形中，總需求曲線會(huì)發(fā)生什么變動(dòng)？A. 一個(gè)十年期的投資稅收優(yōu)惠到期B. 美元匯率下降C. 物價(jià)水平的下降增加了消費(fèi)者財(cái)富的真實(shí)價(jià)值D. 州政府對(duì)利息，紅利和資本收益征收新稅以取代銷售稅課堂練習(xí)1

總需求曲線37A. 一個(gè)十年期的投資稅收優(yōu)惠到期

投資減少，總需求曲線向左移動(dòng)B.美元匯率下降

凈出口增加，總需求曲線向右移動(dòng)C. 物價(jià)水平的下降增加了消費(fèi)者財(cái)富的真實(shí)價(jià)值

沿總需求曲線移動(dòng)（財(cái)富效應(yīng)）D. 州政府對(duì)利息，紅利和資本收益征收新稅以取代銷售稅

消費(fèi)增加，總需求曲線向右移動(dòng)

課堂練習(xí)

1

參考答案3820.4THEAGGREGATE-SUPPLYCURVE

總供給曲線Inthelongrun,theaggregate-supplycurveisvertical.

在長(zhǎng)期中，總供給曲線是垂直的。Intheshortrun,theaggregate-supplycurveisupwardsloping.

在短期中，總供給曲線是向右上方傾斜的。TheLong-RunAggregate-SupplyCurveInthelongrun,aneconomy’sproductionofgoodsandservicesdependsonitssuppliesoflabor,capital,andnaturalresourcesandontheavailabletechnologyusedtoturnthesefactorsofproductionintogoodsandservices.Thepriceleveldoesnotaffectthesevariablesinthelongrun.20.4.1WhytheLong-Runaggregate-supplycurveisvertical.長(zhǎng)期總供給曲線在長(zhǎng)期中，一個(gè)經(jīng)濟(jì)的物品與勞務(wù)供給取決于它的資本、勞動(dòng)和自然資源的供給，以及用來(lái)把資本與勞動(dòng)變?yōu)槲锲放c勞務(wù)的生產(chǎn)技術(shù)。

在長(zhǎng)期中，物價(jià)水平并不影響這些變量。20.4.1為什么長(zhǎng)期總供給曲線是垂直的Figure4TheLong-RunAggregate-SupplyCurveQuantityofOutputNaturalrateofoutputPriceLevel0Long-runaggregatesupplyP21.Achangeinthepricelevel...2....doesnotaffectthequantityofgoodsandservicessuppliedinthelongrun.P圖4.長(zhǎng)期總供給曲線產(chǎn)量自然產(chǎn)量率物價(jià)水平0長(zhǎng)期總供給P21.物價(jià)水平變動(dòng)…2...并不影響長(zhǎng)期中物品與勞務(wù)的供給量PTheLong-RunAggregate-SupplyCurve長(zhǎng)期總供給曲線Thelong-runaggregate-supplycurveisverticalatthenaturalrateofoutput.長(zhǎng)期總供給曲線是在自然產(chǎn)量率時(shí)的一條垂線。Thislevelofproductionisalsoreferredtoaspotentialoutputorfull-employmentoutput.這一產(chǎn)量水平也被稱為潛在產(chǎn)量或充分就業(yè)產(chǎn)量。20.4.2WhytheLong-RunAggregate-SupplyCurveMightShift

為什么長(zhǎng)期總供給曲線會(huì)移動(dòng)Anychangeintheeconomythataltersthenaturalrateofoutputshiftsthelong-runaggregate-supplycurve.經(jīng)濟(jì)中任何改變自然產(chǎn)量率的變動(dòng)都會(huì)使長(zhǎng)期總供給曲線移動(dòng)。Theshiftsmaybecategorizedaccordingtothevariousfactorsintheclassicalmodelthataffectoutput.可以根據(jù)古典模型中影響產(chǎn)量的各種因素把這些移動(dòng)進(jìn)行歸類。Shiftsarisingfrom

移動(dòng)起因于Labor勞動(dòng)Capital資本NaturalResources自然資源TechnologicalKnowledge技術(shù)知識(shí)20.4.3ANewWaytoDepictLong-RunGrowthandInflation

描述長(zhǎng)期增長(zhǎng)與通貨膨脹的新方法Short-runfluctuationsinoutputandpricelevelshouldbeviewedasdeviationsfromthecontinuinglong-runtrends.

應(yīng)該把短期產(chǎn)量與物價(jià)水平波動(dòng)作為與持續(xù)的長(zhǎng)期趨勢(shì)的背離。Figure5Long-RunGrowthandInflationQuantityofOutputY1980AD1980AD1990AggregateDemand,AD2000PriceLevel0Long-runaggregatesupply,LRAS1980Y1990LRAS1990Y2000LRAS2000P19801.Inthelongrun,technologicalprogressshiftslong-runaggregatesupply...4....andongoinginflation.3....leadingtogrowthinoutput...P1990P20002....andgrowthinthemoneysupplyshiftsaggregatedemand...圖5.長(zhǎng)期增長(zhǎng)與通貨膨脹產(chǎn)量Y1980AD1980AD1990總需求AD2000物價(jià)水平0長(zhǎng)期總供給LRAS1980Y1990LRAS1990Y2000LRAS2000P19801.在長(zhǎng)期中，技術(shù)進(jìn)步使長(zhǎng)期總供給移動(dòng)….4.....及持續(xù)的通貨膨脹.3.....引起產(chǎn)量增長(zhǎng)….P1990P20002.....以及貨幣供給增長(zhǎng)使總需求移動(dòng)…20.4.4WhytheAggregate-SupplyCurveSlopesUpwardintheShortRun

為什么短期中總供給曲線向右上方傾斜Intheshortrun,anincreaseintheoveralllevelofpricesintheeconomytendstoraisethequantityofgoodsandservicessupplied.在短期中,經(jīng)濟(jì)中物價(jià)總水平的上升傾向于增加物品與勞務(wù)的供給量。Adecreaseinthelevelofpricestendstoreducethequantityofgoodsandservicessupplied.物價(jià)總水平的下降傾向于減少物品與勞務(wù)的供給量。Figure6TheShort-RunAggregate-SupplyCurveQuantityofOutputPriceLevel0Short-runaggregatesupply1.Adecreaseinthepricelevel...2....reducesthequantityofgoodsandservicessuppliedintheshortrun.YPY2P2圖6.短期總供給曲線產(chǎn)量物價(jià)水平0短期總供給1.物價(jià)水平下降….減少了短期中物品與勞務(wù)的供給量。YPY2P2Why

theAggregate-SupplyCurveSlopesUpwardintheShortRun

為什么短期中總供給曲線向右上方傾斜TheMisperceptionsTheory

錯(cuò)覺(jué)理論TheSticky-WageTheory粘性工資理論TheSticky-PriceTheory粘性價(jià)格理論（1）TheMisperceptionsTheoryChangesintheoverallpriceleveltemporarilymisleadsuppliersaboutwhatishappeninginthemarketsinwhichtheyselltheiroutput:Alowerpricelevelcausesmisperceptionsaboutrelativeprices.Thesemisperceptionsinducesupplierstodecreasethequantityofgoodsandservicessupplied.

（1）錯(cuò)覺(jué)理論物價(jià)總水平的變動(dòng)會(huì)暫時(shí)誤導(dǎo)供給者對(duì)他們出售其產(chǎn)品的市場(chǎng)發(fā)生的變動(dòng)的看法:低物價(jià)水平引起對(duì)相對(duì)價(jià)格的錯(cuò)覺(jué)。這些錯(cuò)覺(jué)引起供給者減少物品與勞務(wù)的供給量。（2）TheSticky-WageTheoryNominalwagesareslowtoadjust,orare“sticky”intheshortrun:Wagesdonotadjustimmediatelytoafallinthepricelevel.Alowerpricelevelmakesemploymentandproductionlessprofitable.Thisinducesfirmstoreducethequantityofgoodsandservicessupplied.（2）粘性工資理論名義工資調(diào)整緩慢，或者說(shuō)在短期中是“粘性的”:工資不能根據(jù)物價(jià)水平迅速調(diào)整。較低的物價(jià)水平使就業(yè)和生產(chǎn)不利。這就引起企業(yè)減少物品與勞務(wù)的供給量。（3）TheSticky-PriceTheory

Pricesofsomegoodsandservicesadjustsluggishlyinresponsetochangingeconomicconditions:Anunexpectedfallinthepricelevelleavessomefirmswithhigher-than-desiredprices.Thisdepressessales,whichinducesfirmstoreducethequantityofgoodsandservicestheyproduce.（3）粘性價(jià)格理論

一些物品與勞務(wù)的價(jià)格對(duì)經(jīng)濟(jì)狀況變動(dòng)的調(diào)整也是緩慢的:未預(yù)期到的物價(jià)水平下降使一些企業(yè)的價(jià)格高于合意水平。這就抑制了銷售，并引起企業(yè)減少它們生產(chǎn)的物品與勞務(wù)量。20.4.5WhytheShort-RunAggregate-SupplyCurveMightShift

為什么短期總供給曲線會(huì)移動(dòng)Shiftsarisingfrom

移動(dòng)起因于Labor勞動(dòng)Capital資本NaturalResources.自然資源Technology.技術(shù)ExpectedPriceLevel.預(yù)期物價(jià)水平Anincreaseintheexpectedpricelevelreducesthequantityofgoodsandservicessuppliedandshiftstheshort-runaggregatesupplycurvetotheleft.預(yù)期物價(jià)水平上升減少了物品與勞務(wù)供給量，并使短期總供給曲線向左移動(dòng)。Adecreaseintheexpectedpricelevelraisesthequantityofgoodsandservicessuppliedandshiftstheshort-runaggregatesupplycurvetotheright.預(yù)期物價(jià)水平下降增加了物品與勞務(wù)供給量，并使短期總供給曲線向右移動(dòng)。Figure7TheLong-RunEquilibriumNaturalrateofoutputQuantityofOutputPriceLevel0Short-runaggregatesupplyLong-runaggregatesupplyAggregatedemandAEquilibriumprice圖7.長(zhǎng)期均衡自然產(chǎn)量率產(chǎn)量物價(jià)水平0短期總供給長(zhǎng)期總供給總需求A均衡價(jià)格20.5TWOCAUSESOFECONOMICFLUCTUATIONS（1）ShiftsinAggregateDemandIntheshortrun,shiftsinaggregatedemandcausefluctuationsintheeconomy’soutputofgoodsandservices.Inthelongrun,shiftsinaggregatedemandaffecttheoverallpricelevelbutdonotaffectoutput.20.5經(jīng)濟(jì)波動(dòng)的兩個(gè)原因（1）總需求移動(dòng)在短期中，總需求移動(dòng)引起經(jīng)濟(jì)中物品與勞務(wù)產(chǎn)量的波動(dòng)。在長(zhǎng)期中，總需求移動(dòng)影響物價(jià)總水平，但不影響產(chǎn)量。Figure8AContractioninAggregateDemandQuantityofOutputPriceLevel0Short-runaggregatesupply,ASLong-runaggregatesupplyAggregatedemand,ADAPYAD2AS21.Adecreaseinaggregatedemand...2....causesoutputtofallintheshortrun...3....butovertime,theshort-runaggregate-supplycurveshifts...4....andoutputreturnstoitsnaturalrate.CP3BP2Y2圖8.總需求減少產(chǎn)量物價(jià)水平0短期總供給,AS1長(zhǎng)期總供給總需求,ADAPYAD2AS21.總需求減少…..2....引起短期中產(chǎn)量減少

...3……但隨著時(shí)間推移，短期總供給曲線移動(dòng)……4……產(chǎn)量恢復(fù)到其自然產(chǎn)量率水平。CP3BP2Y2畫(huà)出美國(guó)經(jīng)濟(jì)的AD-SRAS-LRAS圖形，從經(jīng)濟(jì)的長(zhǎng)期均衡開(kāi)始加拿大出現(xiàn)經(jīng)濟(jì)繁榮，用你的圖形分析這對(duì)美國(guó)GDP，物價(jià)水平和失業(yè)率的短期與長(zhǎng)期影響課堂練習(xí)

2

模型的應(yīng)用68課堂練習(xí)

2

參考答案69LRASYNPYAD2SRAS2AD1SRAS1P1P3CP2Y2BA事件：加拿大經(jīng)濟(jì)繁榮1.影響

NX，AD曲線2. AD曲線向右移動(dòng)3. 短期均衡在點(diǎn)B。P與Y

增加，失業(yè)率降低4. 隨時(shí)間的推移，PE上升，SRAS曲線一直向左移動(dòng)，直到達(dá)到長(zhǎng)期均衡點(diǎn)C。Y與失業(yè)率回到起始水平0（2）AnAdverseShiftinAggregateSupplyAdecreaseinoneofthedeterminantsofaggregatesupplyshiftsthecurvetotheleft:Outputfallsbelowthenaturalrateofemployment.Unemploymentrises.Thepricelevelrises.（2）總供給的不利移動(dòng)總供給決定因素中任何一種降低都使總供給曲線向左移動(dòng):產(chǎn)量下降到自然就業(yè)率水平以下。失業(yè)率上升。物價(jià)水平上漲。Figure10An

AdverseShiftinAggregateSupplyQuantityofOutputPriceLevel0Aggregatedemand3....andthepriceleveltorise.2....causesoutputtofall...1.Anadverseshiftintheshort-runaggregate-supplycurve...Short-runaggregatesupply,ASLong-runaggregatesupplyYAPAS2BY2P2圖10.總供給的不利移動(dòng)產(chǎn)量物價(jià)水平0總需求3....以及物價(jià)水平上升。2....引起產(chǎn)量減少...1.短期總供給曲線的不利移動(dòng)……短期總供給AS長(zhǎng)期總供給YAPAS2BY2P2TheEffectsofaShiftinAggregateSupply（1）StagflationAdverseshiftsinaggregatesupplycausestagflation—aperiodofrecessionandinflation.Outputfallsandpricesrise.Policymakerswhocaninfluenceaggregatedemandcannotoffsetbothoftheseadverseeffectssimultaneously.總供給移動(dòng)的影響（1）滯脹總供給的不利移動(dòng)會(huì)引起滯脹—衰退和通貨膨脹并存的時(shí)期。產(chǎn)量減少而物價(jià)上升。那些能影響總需求的決策者不能同時(shí)抵消這兩種不利的影響。（2）PolicyResponsestoRecessionPolicymakersmayrespondtoarecessioninoneofthefollowingways:Donothingandwaitforpricesandwagestoadjust.Takeactiontoincreaseaggregatedemandbyusingmonetaryandfiscalpolicy.總供給移動(dòng)的影響（2）對(duì)付衰退的政策政策制定者可以用下列手段之一來(lái)對(duì)付衰退:什么也不做，等待價(jià)格和工資調(diào)整。利用貨幣和財(cái)政政策增加總需求。Figure11AccommodatinganAdverseShiftinAggregateSupplyQuantityofOutputNaturalrateofoutputPriceLevel0Short-runaggregatesupply,ASLong-runaggregatesupplyAggregatedemand,ADP2APAS23....whichcausesthepriceleveltorisefurther...4....butkeepsoutputatitsnaturalrate.2....policymakerscanaccommodatetheshiftbyexpandingaggregatedemand...1.Whenshort-runaggregatesupplyfalls...AD2CP3圖11.抵消總供給的不利移動(dòng)產(chǎn)量自然產(chǎn)量率物價(jià)水平0短期總供給AS長(zhǎng)期總供給總需求,ADP2APAS23....這引起物價(jià)水平進(jìn)一步上升……4....但產(chǎn)量保持在自然產(chǎn)量率水平2....決策者可以通過(guò)擴(kuò)大總需求來(lái)抵消這種移動(dòng)……1.當(dāng)短期總供給減少時(shí)…AD2CP3SummaryAllsocietiesexperienceshort-runeconomicfluctuationsaroundlong-runtrends.Thesefluctuationsareirregularandlargelyunpredictable.Whenrecessionsoccur,re