貨幣和財政政策對總需求的影響

134貨幣政策與財政政策對總需求的影響TheInfluenceofMonetaryandFiscalPolicyonAggregateDemand2總需求

AggregateDemand

除了貨幣與財政政策以外，有許多因素影響總需求。Manyfactorsinfluenceaggregatedemandbesidesmonetaryandfiscalpolicy.特別的，家庭與企業(yè)希望的支出決定了對于物品與服務(wù)的總體需求。Inparticular,desiredspendingbyhouseholdsandbusinessfirmsdeterminestheoveralldemandforgoodsandservices.3總需求

AggregateDemand當希望的支出改變，總需求移動，導致短期產(chǎn)出與就業(yè)的波動。Whendesiredspendingchanges,aggregatedemandshifts,causingshort-runfluctuationsinoutputandemployment.貨幣與財政政策有時能用以彌補這些移動，穩(wěn)定經(jīng)濟。Monetaryandfiscalpolicyaresometimesusedtooffsetthoseshiftsandstabilizetheeconomy.4貨幣政策如何影響總需求

HowMonetaryPolicyInfluencesAggregateDemand在長期中，美聯(lián)儲控制的貨幣供給影響物價水平。Inthelongrun,themoneysupplycontrolledbytheFedaffectsthepricelevel.在短期中，貨幣政策影響總需求，進而影響產(chǎn)出等宏觀經(jīng)濟變量。Intheshortrun,monetarypolicytoolscanshifttheaggregate-demandcurveand,indoingso,affectmacroeconomicvariablesasoutput.通過利率效應(yīng)throughtheinterest-effect5流動性偏好理論

TheTheoryofLiquidityPreference凱恩斯發(fā)展了流動性偏好理論，以解釋決定經(jīng)濟的利率的因素。Keynesdevelopedthetheoryofliquiditypreferenceinordertoexplainwhatfactorsdeterminetheeconomy’sinterestrate.按照這一理論，利率調(diào)整以平衡貨幣供求。Accordingtothetheory,theinterestrateadjuststobalancethesupplyanddemandformoney.流動性偏好理論試圖同時解釋名義和實際兩種利率，只需要假定通脹率不變。Liquiditypreferencetheoryattemptstoexplainbothnominalandrealratesbyholdingconstanttherateofinflation.6貨幣供給

MoneySupply貨幣供給由中央銀行（美國為Fed）通過以下途徑進行控制：ThemoneysupplyiscontrolledbytheFedthrough:公開市場運作Open-marketoperations改變法定準備金Changingthereserverequirements改變貼現(xiàn)率Changingthediscountrate7貨幣供給

MoneySupply貨幣供給的數(shù)量不依賴于利率，因為它被美聯(lián)儲（央行）固定住了。BecauseitisfixedbytheFed,thequantityofmoneysupplieddoesnotdependontheinterestrate.固定的貨幣供給用一條垂直的供給曲線來表示。Thefixedmoneysupplyisrepresentedbyaverticalsupplycurve.8貨幣需求

MoneyDemand貨幣需求決定于若干因素。Moneydemandisdeterminedbyseveralfactors.按照流動性偏好理論，最為重要的因素之一是利率。Accordingtothetheoryofliquiditypreference,oneofthemostimportantfactorsistheinterestrate.9貨幣需求

MoneyDemand人們選擇持有貨幣而不是帶來更高回報率的其他資產(chǎn)，是因為貨幣能夠用來購買物品與服務(wù)。Peoplechoosetoholdmoneyinsteadofotherassetsthatofferhigherratesofreturnbecausemoneycanbeusedtobuygoodsandservices.持有貨幣的機會成本，是從有利息收益的資產(chǎn)中能夠得到的利息。Theopportunitycost

ofholdingmoneyistheinterestthatcouldbeearnedoninterest-earningassets.利率上升，提高了持有貨幣的機會成本。Anincreaseintheinterestrateraisestheopportunitycostofholdingmoney.結(jié)果，貨幣需求數(shù)量下降了。Asaresult,thequantityofmoneydemandedisreduced.10貨幣市場均衡

EquilibriumintheMoneyMarket按照流動性偏好理論：Accordingtothetheoryofliquiditypreference:利率調(diào)整以平衡貨幣的供求。Theinterestrateadjuststobalancethesupplyanddemandformoney.在均衡利率下，貨幣供求平衡。Thereisoneinterestrate,calledtheequilibriuminterestrate,atwhichthequantityofmoneydemandedequalsthequantityofmoneysupplied.貨幣市場均衡

EquilibriumintheMoneyMarket...QuantityofMoney貨幣量InterestRate利率0Moneydemand貨幣需求QuantityfixedbytheFed央行固定量Moneysupply貨幣供給r2Md

2r1Md

1Equilibriuminterestrate均衡利率12應(yīng)用：總需求曲線向下傾斜

Application:TheDownwardSlopeoftheAggregateDemandCurve回顧：總需求曲線向下傾斜有三個原因。Theaggregatedemandcurveslopesdownwardforthreereasons:財富效應(yīng)Thewealtheffect利率效應(yīng)Theinterest-rateeffect匯率效應(yīng)Theexchange-rateeffect對美國經(jīng)濟來說，總需求曲線向下傾斜的最重要原因是利率效應(yīng)。FortheU.S.economy,themostimportantreasonforthedownwardslopeoftheaggregate-demandcurveistheinterest-rateeffect.13應(yīng)用：總需求曲線向下傾斜

Application:TheDownwardSlopeoftheAggregateDemandCurve價格水平是貨幣需求量的一個決定因素。Thepricelevelisonedeterminantofthequantityofmoneydemanded.更高的價格水平增加了給定利率下貨幣的需求量Ahigherpricelevelincreasesthequantityofmoneydemandedforanygiveninterestrate.更高的貨幣需求導致更高的利率。Highermoneydemandleadstoahigherinterestrate.物品與服務(wù)的需求量下降。Thequantityofgoodsandservicesdemandedfalls.14應(yīng)用：總需求曲線向下傾斜

Application:TheDownwardSlopeoftheAggregateDemandCurve這一分析的最終結(jié)果是：價格水平與物品及服務(wù)的需求量的負向關(guān)系Theendresultofthisanalysisisanegativerelationshipbetweenthepricelevelandthequantityofgoodsandservicesdemanded.15(b)總需求曲線TheAggregateDemandCurveQuantityofOutput0PriceLevelAggregatedemand貨幣市場TheMoneyMarketQuantityofMoneyQuantityfixedbytheFed0r1MoneysupplyInterestRateMoneydemandatpricelevelP1,MD1Y1P1MoneydemandatpricelevelP2,MD22.…增加了貨幣需求increasesthedemandformoney…1.價格水平的上升Anincreaseinthepricelevel…P23.…提高了均衡利率whichincreasestheequilibriuminterestrate…r24.…這又減少了物品與服務(wù)的需求量whichinturnreducesthequantityofgoodsandservicesdemanded.Y2貨幣市場與總需求曲線的斜率TheMoneyMarketandtheSlopeoftheAggregateDemandCurve...16貨幣供給的改變

ChangesintheMoneySupply央行在改變貨幣政策時，能夠移動總需求曲線。TheFedcanshifttheaggregatedemandcurvewhenitchangesmonetarypolicy.貨幣供給的增加將貨幣供給曲線向右移動。Anincreaseinthemoneysupplyshiftsthemoneysupplycurvetotheright.如果貨幣需求曲線沒有變動，利率就會下降。Withoutachangeinthemoneydemandcurve,theinterestratefalls.利率的下降增加了物品與服務(wù)的需求量。Fallinginterestratesincreasethequantityofgoodsandservicesdemanded.Y2AD23.…這增加了給定價格水平下物品與服務(wù)的需求量

whichincreasesthequantityofgoodsandservicesdemandedatagivenpricelevel.1.當央行增加貨幣供給WhentheFedincreasesthemoneysupply…MS2貨幣注入

AMonetaryInjection...Y1PQuantityofOutput0PriceLevelAggregatedemand,AD1

(a)TheMoneyMarketQuantityofMoney0Moneysupply,MS1r1InterestRate(b)TheAggregate-DemandCurver22.…均衡利率下降theequilibriuminterestratefalls…MD18貨幣供給的改變

ChangesintheMoneySupply當央行增加貨幣供給，它降低了利率，增加了給定價格水平下物品與服務(wù)的需求量，將總需求曲線向右移動。WhentheFedincreasesthemoneysupply,itlowerstheinterestrateandincreasesthequantityofgoodsandservicesdemandedatanygivenpricelevel,shiftingaggregate-demandtotheright.當央行緊縮貨幣供給，它提高了利率，減少了給定價格水平下物品與服務(wù)的需求量，將總需求曲線向左移動。WhentheFedcontractsthemoneysupply,itraisestheinterestrateandreducesthequantityofgoodsandservicesdemandedatanygivenpricelevel,shiftingaggregate-demandtotheleft.19利率目標在美聯(lián)儲政策中的作用

TheRoleofInterest-RateTargetsinFedPolicy貨幣政策既可以根據(jù)貨幣供給，也可以根據(jù)利率來描述。Monetarypolicycanbedescribedeitherintermsofthemoneysupplyorintermsoftheinterestrate.貨幣政策的改變既可以根據(jù)利率目標的改變，也可以根據(jù)貨幣供給的改變來描述。Changesinmonetarypolicycanbeviewedeitherintermsofachangingtargetfortheinterestrateorintermsofachangeinthemoneysupply.聯(lián)邦基金利率——銀行間短期貸款利率——的目標影響貨幣市場均衡，進而影響總需求。Atargetforthefederalfundsrate,theinterestratebankschargeoneanotherforshort-termloans,affectsthemoneymarketequilibrium,whichinfluencesaggregatedemand.20財政政策如何影響總需求

HowFiscalPolicyInfluencesAggregateDemand財政政策指的是政府對于政府購買或稅收的整體水平的選擇。Fiscalpolicyreferstothegovernment’schoicesregardingtheoveralllevelofgovernmentpurchasesortaxes.財政政策影響長期的儲蓄、投資和增長。Fiscalpolicyinfluencessaving,investment,andgrowthinthelongrun.在短期內(nèi)，財政政策主要影響總需求。Intheshortrun,fiscalpolicyprimarilyaffectstheaggregatedemand.21政府購買的變化

ChangesinGovernmentPurchases當政策制定者改變了貨幣供給或稅收，對總需求的影響是間接的——通過影響企業(yè)或家庭的支出決策來達到。Whenpolicymakerschangethemoneysupplyortaxes,theeffectonaggregatedemandisindirect–throughthespendingdecisionsoffirmsorhouseholds.當政府改變其自身對物品與服務(wù)的購買，它就直接移動了總需求曲線。Whenthegovernmentaltersitsownpurchasesofgoodsorservices,itshiftstheaggregate-demandcurvedirectly.22政府購買的變化

ChangesinGovernmentPurchases政府購買的改變有兩個宏觀效應(yīng)Therearetwomacroeconomiceffectsfromthechangeingovernmentpurchases:

乘數(shù)效應(yīng)Themultipliereffect擠出效應(yīng)Thecrowding-outeffect23乘數(shù)效應(yīng)

TheMultiplierEffect政府購買被認為對總需求有一個乘數(shù)效應(yīng)。Governmentpurchasesaresaidtohaveamultipliereffectonaggregatedemand.政府支出的每一美元能夠增加的對物品與服務(wù)的總需求，將大于一美元。Eachdollarspentbythegovernmentcanraisetheaggregatedemandforgoodsandservicesbymorethanadollar.24乘數(shù)效應(yīng)

TheMultiplierEffect如果政府購買價值200億的波音飛機，波音公司收入增加200億。Ifthegovernmentbuys$20bofplanesfromBoeing,Boeing’srevenueincreasesby$20b.該200億將分配給波音公司的工人（作為工資）和所有者（作為利潤或股息）。ThisisdistributedtoBoeing’sworkers(aswages)andowners(asprofitsorstockdividends).這些人作為消費者將花費其多得收入的一部分。Thesepeoplearealsoconsumersandwillspendaportionoftheextraincome.這一額外的消費將導致更多的總需求增加。Thisextraconsumptioncausesfurtherincreasesinaggregatedemand.25乘數(shù)效應(yīng)

TheMultiplierEffect...Aggregatedemand,AD1

QuantityofOutput0PriceLevelAD21.政府增加200億美元的支出一開始增加了200億美元的總需求Anincreaseingovernmentpurchasesof$20billioninitiallyincreasesaggregatedemandby$20billion…$20billionAD32.…但是乘數(shù)效應(yīng)能夠放大總需求曲線的移動butthemultipliereffectcanamplifytheshiftinaggregatedemand.26支出乘數(shù)的公式

AFormulafortheSpendingMultiplier乘數(shù)效應(yīng)取決于消費者如何對增加的收入做出反應(yīng)。Themultipliereffectdependsonhowmuchconsumersrespondtoincreasesinincome.邊際消費傾向（MPC）是家庭的額外收入中用于消費而不是儲蓄的比例。Marginalpropensitytoconsume

(MPC)isthefractionofextraincomethatahouseholdconsumesratherthansaves.27支出乘數(shù)的公式

AFormulafortheSpendingMultiplier如果MPC=0.8，則政府支出增加200億將導致：IfMPC=0.8，then$20bincreaseingovernmentpurchaseswillresultin第1次消費增加Firstincreaseinconsumption=MPC×$20billion=$0.8*20b第2次消費增加Secondincreaseinconsumption=MPC2×$20billion=$0.82*20b……總支出增加Totalincreaseindemand=(1+MPC+MPC2+MPC3+...)×$20billion=(1+0.8+0.82+……)*$20b=1/(1-0.8)*$20b28支出乘數(shù)的公式

AFormulafortheSpendingMultiplier乘數(shù)公式為：Theformulaforthemultiplieris:Multiplier=1/(1-MPC)如果邊際消費傾向為3/4，那么乘數(shù)將是：IftheMPCis3/4,thenthemultiplierwillbe:乘數(shù)Multiplier=1/(1-3/4)=4在這個例子里，200億美元的政府支出增長產(chǎn)生了800億美元的物品與服務(wù)的需求增長。Inthiscase,a$20billionincreaseingovernmentspendinggenerates$80billionofincreaseddemandforgoodsandservices.29擠出效應(yīng)

TheCrowding-OutEffect財政政策影響經(jīng)濟的程度可能不像乘數(shù)所預(yù)計的那么強烈。Fiscalpolicymaynotaffecttheeconomyasstronglyaspredictedbythemultiplier.政府購買的增加導致了利率的上升。Anincreaseingovernmentpurchasescausestheinterestratetorise.更高的利率減少了投資支出。Ahigherinterestratereducesinvestmentspending.30擠出效應(yīng)

TheCrowding-OutEffect由于財政擴張?zhí)Ц呃仕鸬男枨鬁p少，被稱為擠出效應(yīng)。Thisreductionindemandthatresultswhenafiscalexpansionraisestheinterestrateiscalledthecrowding-outeffect.擠出效應(yīng)傾向于削弱財政政策對于總需求的影響。Thecrowding-outeffecttendstodampentheeffectsoffiscalpolicyonaggregatedemand.AD34.…這進而部分抵消了最初的總需求增加whichinturnpartlyoffsetstheinitialincreaseinaggregatedemand.擠出效應(yīng)

TheCrowding-OutEffect...Aggregatedemand,AD1(b)TheShiftinAggregateDemandQuantityofOutput0PriceLevel(a)TheMoneyMarketQuantityofMoneyQuantityfixedbytheFed0r1Moneydemand,MD1

MoneysupplyInterestRate1.政府購買的增加提高了總需求Whenanincreaseingovernmentpurchasesincreasesaggregatedemand…AD2$20billion3.…這又增加均衡利率whichincreasestheequilibriuminterestrate…r2MD22.…支出上升增加了貨幣需求theincreaseinspendingincreasesmoneydemand…32擠出效應(yīng)

TheCrowding-OutEffect當政府購買增加了200億，對物品與服務(wù)的總需求增加可能大于或小于200億美元，依賴于乘數(shù)效應(yīng)大還是擠出效應(yīng)大。Whenthegovernmentincreasesitspurchasesby$20billion,theaggregatedemandforgoodsandservicescouldrisebymoreorlessthan$20billion,dependingonwhetherthemultipliereffectorthecrowding-outeffectislarger.33稅收的變動

ChangesinTaxes當政府減少個人收入征稅，它增加了家庭的可支配收入。Whenthegovernmentcutspersonalincometaxes,itincreaseshouseholds’take-homepay.家庭將這一額外收入的一部分花在消費物品上。Householdsspendsomeofthisadditionalincomeonconsumergoods.家庭支出的增加將總需求曲線向右移動。Increasedhouseholdspendingshiftstheaggregate-demandcurvetotheright.34稅收的變動

ChangesinTaxes稅收變動所引起的總需求移動的大小，受到乘數(shù)與擠出效應(yīng)的影響。Thesizeoftheshiftinaggregatedemandresultingfromataxchangeisaffectedbythemultiplierandcrowding-outeffects.它也取決于家庭所察覺到的稅收變動的持久性Itisalsodeterminedbythehouseholds’perceptionsaboutthepermanencyofthetaxchange.35運用政策來穩(wěn)定經(jīng)濟

UsingPolicytoStabilizetheEconomy從1946年就業(yè)法案起，經(jīng)濟穩(wěn)定就成為了美國政府明確的目標。EconomicstabilizationhasbeenanexplicitgoalofU.S.policysincetheEmploymentActof1946.中國：促進就業(yè)法（2007）；人民銀行法（1995）36積極的穩(wěn)定政策的理由

TheCaseforActiveStabilizationPolicy就業(yè)法案有兩個含義：TheEmploymentActhastwoimplications:政府應(yīng)該避免成為經(jīng)濟波動的原因。Thegovernmentshouldavoidbeingthecauseofeconomicfluctuations.政府應(yīng)該對私人經(jīng)濟的變化做出反應(yīng)，以穩(wěn)定總需求。Thegovernmentshouldrespondtochangesintheprivateeconomyinordertostabilizeaggregatedemand.37反對積極的穩(wěn)定政策的理由

TheCaseAgainstActiveStabilizationPolicy一些經(jīng)濟學家認為，貨幣和財政政策導致了經(jīng)濟不穩(wěn)定。Someeconomistsarguethatmonetaryandfiscalpolicydestabilizestheeconomy.貨幣與財政政策對經(jīng)濟的影響有相當?shù)臅r滯。Monetaryandfiscalpolicyaffecttheeconomywithasubstantiallag.他們建議，應(yīng)該允許經(jīng)濟自己調(diào)節(jié)以對付短期經(jīng)濟波動。Theysuggesttheeconomyshouldbelefttodealwiththeshort-runfluctuationsonitsown.38自動穩(wěn)定器

AutomaticStabilizers自動穩(wěn)定器是指財政政策的某種變動，它在經(jīng)濟進入衰退時能夠刺激總需求，卻無需政策制定者采取任何刻意的行動。Automaticstabilizersarechangesinfiscalpolicythatstimulateaggregatedemandwhentheeconomygoesintoarecessionwithoutpolicymakershavingtotakeanydeliberateaction.自動穩(wěn)定器包括了稅收體系以及某些形式的政府支出。Automaticstabilizersincludethetaxsystemandsomeformsofgovernmentspending.39總結(jié)

Summary凱恩斯提出了流動性偏好理論以解釋利率的決定因素。Keynesproposedthetheoryofliquiditypreferencetoexplaindeterminantsoftheinterestrate.按照這一理論，利率調(diào)整以平衡貨幣供求。Accordingtothistheory,theinterestrateadjuststobalancethesupplyanddemandformoney.40總結(jié)

Summary價格水平的上升提高了貨幣需求和利率。Anincreaseinthepricelevelraisesmoneydemandandincreasestheinterestrate.更高的利率減少了投資，進而減少了物品與服務(wù)的需求量。Ahigherinterestratereducesinvestmentand,thereby,thequantityofgoodsandservicesdemanded.向下傾斜的總需求曲線表示了價格水平與需求量之間的這一負向關(guān)系。Thedownward-slopingaggregate-demandcurveexpressesthisnegativerelationshipbetweentheprice-levelandthequantitydemanded.