宏观经济学 (多恩布什 著) 人民大学出版社 课后答案 第五篇 课后答案 28页

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SolutionstotheProblemsintheTextbook:ConceptualProblems:1.a.TheKeynesianexplanationfortheGreatDepressionconcentratesonthefallofinvestmentspendingandreductioninaggregateconsumption.Thedecreaseinaggregatedemandwasreinforcedbyrestrictivefiscalpolicyasthegovernmenttriedtobalancethebudget.凯恩斯主义对大萧条的解释是投资支出的减少和总消费的减少。总需求的减少是因为政府平衡预算而实行的紧缩财政政策1.b.Themonetarists"explanationfortheGreatDepressionconcentratesonthedeclineinmoneysupply.TheFedfailedtopreventthelargenumberofbankfailuresandconsumerslostconfidenceinthebankingsystem.Thisledtoanenormousincreaseinthecurrency-depositratio,causingadecreaseinthemoneymultiplier.Theresultingseveredeclineinthesupplyofmoneythenleadtotheeconomicdownturn.货币主义对大萧条的解释基于货币供给的减少。美联储没能阻止大量的银行破产，消费者对银行系统失去了信心。这导致巨大的货币的通货存款比率，使货币乘数减小。货币供给的大量减少导致了经济的衰退。1.c.Bothexplanationsgivenabovefitthefactsandthereisnoinherentconflictbetweenthem;infact,theycomplementoneanotherquitenicely.Thecombinationofineptfiscalandmonetarypolicymayhaveturnedwhatcouldhavebeenanaveragerecessionintoamajordepression.以上的两种解释都是符合事实的，并且两者没有本质的分歧；事实上，两者彼此是很好的补充。不当的财政政策和货币政策结合会使本来是一般的衰退变成成大萧条。1.d.TheGreatDepressionisoneofthemostdrasticeconomiceventsinrecenthistoryandanytheorythatcanadequatelyexplainitscauses(orfindremediestopreventsimilaroccurrencesinthefuture)willattractattention.SomeeconomistsarguethattheGreatDepressionprovesthattheeconomyisinherentlyunstableandrequiresalongtimetoadjustbacktoafull-employmentequilibrium.Othersarguethatitprovesthatgovernmentpolicyisoftenmisguidedandthatitmaybebettertorelyonmarketforcestobringusbacktoanequilibrium.大萧条是近代历史上最大的经济灾难之一，任何能完全解释这是怎么发生的（或者找到阻止它在未来发生）理论都会吸引大家的注意。一些经济学家说大萧条证明了经济是的不稳定是固有的，并且需要一个较长的时间调整到充分就业均衡。另一些人认为这些证明了政府的政策往往误导了经济，依靠市场力量使它回到均衡会更好。2.Inthelongrunnomajorinflationcanpersistwithoutrapidmoneygrowth,sincetheinflationrateisequaltothegrowthrateofmoneysupplyadjustedforthetrendinrealoutputandchangesinvelocity.Intheshortrun,however,changesinoutputgrowthandvelocityarequiteunpredictableandaffecttheinflationrate.Suchshort-runfluctuationscanbecausedbysupplyshocksorpolicychanges.在长期，没有快速的货币供给增加就不会有严重的通货膨胀发生，因为通货膨胀率应该等于根据实际产出增长趋势调整的货币供给增长率。但是在短期，产出增加的速率对通货膨胀率的影响是不可预测的。这些短期波动也可以由供给冲击或政策改变引起。283 3.a.Thekeyquestionforgovernmentsdesiringtoreduceinflationishowcheaply(intermsoflostoutput)theywanttoachieveadesiredinflationrate.Agradualstrategyattemptsaslowandsteadyreturntoalowinflationratebyreducingmonetarygrowthslowlyinanattempttoavoidasignificantincreaseinunemployment.Thisapproachtakesalotlongerthanthecold-turkeyapproachthatattemptstoreduceinflationquicklybyimmediatelyandsharplyreducingmonetarygrowth.Whileinflationandinflationaryexpectationswillbereducedfaster,ahigherlevelofunemploymentleadingtoadecreaseinthelevelofoutputwillresultintheshortrununtiltheeconomyhastimetoadjustbacktothefull-employmentlevelofoutput.Whichstrategywillbechosenbypolicydecision-makersalsodependsonhowfastwagesandpricesarebelievedtoadjusttotheirequilibriumlevel.政府的核心问题是期望以最小的成本（也就是最小的产出损失）获得合理的通货膨胀率。渐近的政策尽量通过减少货币供给而不会造成失业显著的增加，使经济缓慢稳步地回到低的通货膨胀。这种做法比休克政策要花更多的时间，休克政策是通过剧烈的减少货币供给而快速减少通货膨胀。当通货膨胀和通货膨胀预期可以很快消除的时候，短期更高的失业率会使产出水平减少，直到经济调整回充分就业的产出水平。哪种策略会被决策者采用还取决于工资和物价会在多长时间内回到均衡水平。3.b.Ifpolicymakershaveacredibilityproblem,inflationaryexpectationswillnotadjustdownwardsquicklyanditwilltakealotlonger(andprobablyamuchhigherincreaseintheunemploymentrate)toreduceinflation.Withagradualapproach,peoplewillbeveryreluctanttochangetheirinflationaryexpectations,sincetheymaynotbeconvincedthatthecentralbankwillactuallysticktoitsannouncedpolicyobjectiveofreducinginflation.Acold-turkeyapproachmaybemoreattractivesinceithasacredibilitybonus,thatis,thereisanimmediateconfirmationthatthecentralbankiscommittedtoreducinginflation.Thereforeanewfull-employmentequilibriumcanbereachedmorequickly.如果决策者遇到一个实际的问题，通货膨胀预期不会很快下降并且会花更长时间来（可能还会带来更高的失业率）。渐进的做法，人们很难改变他们的通货膨胀预期，因为他们可能不会相信央行会真的采用宣布的政策来减少通货膨胀。休克疗法会更吸引人，因为它更可信，让人们确实央行会减少通货膨胀，因此新的充分就业均衡会很快达到。4.Peopleoftenworryaboutbudgetdeficits,relatingthemtotheirownfinancialsituationsandinferringthatnobody,noteventhegovernment,canliveonborrowedmoneyforalongperiodoftime.Therealissuessurroundingbudgetdeficits,however,aremuchmorecomplicated,andmostpeopledonotfullycomprehendhowlargebudgetdeficitsactuallyaffecttheeconomyandtheirdailylives(throughincreasedinterestratesand,possibly,increasedinflationorincreasedfuturetaxrates).人们往往会担心预算赤字，这些关系到他们个人的财务状态，没有人甚至政府会拿借来的钱生活很长时间。事实上围绕预算赤字的结果是更复杂的，绝大多数人都不会完全知道到底多大的预算赤字会影响到经济和他们的日常生活(未来利率可能会增加，还有可能通货膨胀和税率升高)。Intheshortrun,budgetdeficitscausedbyexpansionaryfiscalpolicywillstimulatetheeconomy.However,theincreasedneedofthegovernmenttoborrowwilldriveupinterestratesandcrowdoutprivatespending,especiallyinvestmentandnetexports.Thelowerrateofcapitalaccumulationmeanslessfutureeconomicgrowth.Partofthebudgetdeficitmayhavebeenfinancedfromabroad,soforeignerswillhavetoberepaid(withinterest)andthiswilldiminishdomesticlivingstandards.Finally,iftheFedisworriedabouthigherinterestratesanddecidestomonetizethedebt,ahigherrateofinflationwillresult.Toavoidinflation,continuedhighbudgetdeficitseventuallyrequirehigher284 taxesorbudget-cuttingmeasurestocounteracttheincreasedhighinterestpaymentsonthedebt.短期，经济扩张政策造成的预算赤字会刺激经济。但是，政府借贷需求增加会降低利率，进而挤出个人消费，特别是投资和净出口。低的资本积累率意味着未来经济增长的减少。部分预算赤字可能来自国外，所以外国人必须得到回报（利息），这将降低国内生活水平。最终，如果联储担心利率过高，决定印货币偿债，高通货膨胀就会到来。为了避免通货膨胀，持续的高预算赤字就需要更高的税率或者减少赤字来应对高的利息支出。AslongasthenationaldebtgrowsmoreslowlythanGDP,financingthenationaldebtdoesnotcreateamajorproblem.Ifthedebt-incomeratioincreases,however,thefinancingoffurtherbudgetdeficitscreatesdifficulties.Thereforepeopleshouldbeworriedlessaboutthesizeofthedeficitorthedebtandmoreaboutthedebt-incomeratio,thewayinwhichgovernmentdeficitsarefinanced,andthepossibilityoflowerfutureeconomicgrowthduetoalowerrateofcapitalaccumulation.在国债增加比GDP缓慢的时候，国债筹措不会造成大的问题。但是如果债务收入比例增加，远期的预算赤字就会很难融资。因此人们不会对赤字或负债的金额担心，而更担心政府赤字融资的债务收入比，因为较低的资本积累而导致未来的经济增长降低。5.Thefurthertheeconomyisfromthefull-employmentlevelofoutput,themoretheFedshouldbewillingtomonetizethedeficit.Forone,atatimewhenunemploymentishigh,inflationarypressureisprobablylow,soincreasingmoneysupplywillnotcauserapidpriceincreases.Secondly,asmallincreaseininflationmaybetolerablesinceahighlevelofunemploymentiscostlyintermsoflostoutput.Thereforeitmightbedesirabletoreturntofullemploymentfastbyincreasingmoneysupply.However,whentheeconomyisclosetofullemployment,bottlenecksdevelopmoreeasily.Inthissituation,monetizingthedeficitwillultimatelyfailtokeepinterestratesdownorstimulatingtheeconomyfurther.Insteadahigherrateofmonetarygrowthwillcauseinflationtoincreasesharply.经济离充分就业产出越远，美联储越应该货币化赤字。首先，当失业率高时，通货膨胀压力可能偏低，所以增加货币供应量不会引起物价上涨迅猛。其次，小的通货膨胀增加是可以忍受的，因为高失业率造成的产出失业是昂贵的。所以应该通过增加货币供应量使经济较快回到充分就业。然而,当经济接近充分就业，发展的瓶颈更容易出现。在这种情况下,货币化赤字最终未能促使利率进一步下跌或刺激经济。货币供给增长率反而会造成通货膨胀急剧增加。6.Theabilityofthegovernmenttoraiseadditionaltaxrevenuethroughthecreationofmoney(andthereforeinflation)iscalledseigniorage.Inflationtaxrevenueisdefinedastheproductoftheinflationratetimestherealmoneybase.Inflationactsjustlikeataxsincethegovernmentisabletospendmorebyprintingmoneywhilepeopleareforcedtospendlesssincepartoftheirincomeisusedtoincreasetheirnominalmoneyholdings.政府通过发行货币（因此通货膨胀）来增加附加税收入的作法叫做货币铸造税。通货膨胀税可以定义为通货膨胀率数倍于真实货币的产物。通货膨胀只是扮演税收的角色，因为政府可以通过多发行货币的方式迫使人们减少消费，使他们持有的名义货币增加。7.a.Duringthehyperinflationof1922-23,theGermangovernmentfinancedalmostallofitsspendingthroughthecreationofmoney.Naturally,theexcessivemonetaryexpansioncausedinflationtoskyrocket,reachinganaveragemonthlyinflationrateof322percent.在1922－23年的恶性通货膨胀时期，德国政府几乎全靠发行货币的方式来筹措资金。自然的，过量的货币造成了通货膨胀的高峰，达到了月平均通货膨胀率高达322%。7.b.Thetaxrevenuethatcanbegainedthroughanincreaseintheinflationrateisdefinedas:285 inflationtaxrevenue=(inflationrate)*(‘).Figure18-3showsthatitispossibleforthegovernmenttoincreasetheinflationtaxrevenuetemporarilyaslongasmoneyisprintedfasterthanpeopleexpect.Butexcessivemonetarygrowthcausesinflationtoincreaserapidlyandpeoplewillstarttoreducetheirmoneyholdingsinanattempttoavoidtheinflationtax.Eventually,themonetarybasewilldecline,andthewholeprocesswillbreakdown.税收收入可以通过增加通货膨胀率的方式取得，如下式：通货膨胀税收入＝通货膨胀率×真实货币基础表18－3表明当发行货币比人们预期快的时候，政府可能暂时增加通货膨胀税收入。但是过量的货币增长会造成通货膨胀增加更快，人们会减少持有的货币去避免通货膨胀税。最终，真实货币基础会开始减少，整个过程就会停下来。8.Russiawasburdenedwithanhugebudgetdeficitandalargeexternaldebtasittriedtotransformitscentrallyplannedeconomytoafreemarketeconomy.Realoutputdecreasedsubstantiallyandallkindsofbottlenecksoccurred.Muchoftheeconomicactivitywasontheblackmarket,socollectingtaxrevenuesbecamedifficult.Withgovernmentrevenuesfaroutpacingtaxrevenues,thegovernmentbudgetgottotallyoutofbalanceandhyperinflationresultedasthecentralbankcreatedmoneytoallowformoregovernmentspending.Inflationpeakedat2,600%in1993.TherubletotallycollapsedinvalueandtheRussianeconomyisnowburdenedwithahugeforeigndebtthatitisunabletoservice.Tobringthebudgetbackintobalance,subsidiestoloss-makingstateenterprisesmustbecutandtaxcollectionmustbestrictlyenforced.Lawsalsomustbepassedtoprotectprivatepropertyandencourageprivateenterprises,andinflationmustbebroughtundercontrol.BorisYeltsin,Russia’spresidentatthetime,introducedanewlineofrublenotesinJanuary,1998,replacingtheold1,000-rublebillswiththenewone-rublenotesinanefforttocurtailmoneygrowth.当俄罗斯想完成中央计划经济到自由市场经济转换时，他负担着巨大的预算赤字和大量的外债。真实产出大量减少，各种瓶颈也出现了。很多经济活动在地下市场，所以征税就变得相当困难。当政府收入大大超过税收收入时，政府预算严重失衡，因为央行为了满足政府花费发行货币，恶性通货膨胀也就因此发生。通货膨胀的顶峰发生在1993年，达到2,600%。在俄罗斯经济负担着大量外债不能偿还时，泡沫破灭了。为了使预算回到平衡，落后地区的事业津贴必须削减，征税必须更严厉。必须通过立法保护私人财产，鼓励私人企业，并且必须控制通货膨胀。当时的俄罗斯总统BorisYeltsin在1998年1月宣布1000旧卢布换1新卢布来缩减货币增长。9.a.Interestpaymentsonthenationaldebtcanbedividedintorealpaymentsandpaymentsduetoinflation.Inotherwords,wehavetodistinguishbetweenrealandnominalinterestrates.Duringperiodsofinflationmostinterestpaymentsareoffsetbythedecreaseintherealvalueofthedebt.Whatweshouldbeconcernedabout,however,istheinterestpaymentsinrealterms.国债的利息支付可以分成真实支付和由于通货膨胀的支付两部分。换句话说，我们必须区分实际的和名义的利息率。在通货膨胀时期里，绝大多数利息支付缩水了，因为债务的实际价值减少了。但是我们应该关注的是，利息还是按照协商支付了。286 9.b.Thenationaldebtisaburdenonsocietyprimarilybecauseofthenegativeeffectithasontherateofcapitalaccumulation.Theincreasedborrowingneedsofthegovernmentdriveuprealinterestrates,whichthencrowdsoutprivatespending,especiallyinvestment.Asaresult,futureeconomicgrowthmaybeimpaired.Highinterestratesmayalsocrowdoutnetexports,whichmayleadtoalossofcompetitivenessandadeclineinthemanufacturingsector.Thiswillalsohaveanegativeeffectonfuturelivingstandards.Inaddition,thepartofthedebtthatisheldbyforeignerswillhavetoberepaid(withinterest),creatingataxburdenonfuturegenerations.Thepartofthedebtthatisfinanceddomesticallydoesnotcreatethesameburden,sincefuturetaxincreaseswillbeusedtopayU.S.citizens.Itwill,however,haveredistributiveeffects,awayfrom(mostlylower-andmiddle-income)taxpayersto(mostlyhigh-income)bondholders.国债对社会来说是个负担，因为它对资本积累是不利的。不断增加的借款需要政府抬高利率，这将挤出私人消费特别是投资。这样，经济增长就会被削弱。高利率同样会使净出口减少，因为高利率将导致竞争力降低和制造业的衰退。这也同样会对未来生活水平造成负面影响。另外，这部分债务必须支付给外国持有者报酬（利息），就给下一代增加了税收负担。通过国内融资的这部分债务不会造成同样的负担，因为未来这部分税收会用来支付给美国公民。但是，这将产出再分配效应，把纳税人（绝大多数是中低收入者）和债券持有人（绝大多数是高收入者）区分开来。10.Ifanamendmenttorequireanannuallybalancedbudgetwereimplemented,thegovernmentwouldnolongerbeabletousediscretionaryfiscalpolicyasastabilizationtool.Inaddition,iftheamendmentcalledforannuallybalancingtheactualbudget,itcoulddomoreharmthangood.Assumethattheeconomyisatfullemploymentandthebudgetisbalanced.Iftheeconomyentersarecession,thecyclicalcomponentofthebudgetsurpluswillbecomenegativeandanactualbudgetdeficitwilldevelop.Tobalancethebudget,thegovernmentcaneitherincreasetaxesordecreasespendingtocreateasurplusinthestructuralcomponent.Thisfiscalrestrictionwillcauseadeeperrecession,increasingthecyclicaldeficitevenmore.Itisdoubtfulthatthegovernmentwouldactuallysucceedinbalancingthebudget.Forthisreasonmosteconomistsdonotfavorabalancedbudgetamendment.如果一个修正案需要每年都要实现债务均衡，政府将不能够用任意的财政政策作为稳定工具。另外，如果修正案要求每年实际预算平衡，它可能是弊多于利。假设经济处于充分就业和预算平衡。如果经济进入衰退期，周期性的预算盈余将带来负面影响，预算赤字将增加。为了平衡预算，政府可以增加支出或减少税收，创造盈余的条件。这一限制将导致更严重的财政衰退，更增加周期性赤字。实在令人怀疑政府是否真正能做到收支平衡。因此大多数经济学家并不主张平衡预算修正案。11.Itismoreimportanttolookatthedebt-incomeratiothanattheabsolutevalueofthenationaldebt,sincethedebt-incomeratiotellsushowmuchofourcurrentincomewewouldhavetogiveuptopaybackthedebt.Obviouslya$5.6trillionnationaldebtismuchhardertodealwithinaneconomywithaGDPof$5trillionthaninaneconomywithaGDPof$10trillion.Similarly,iftheeconomygrowsatahigherratethanthedebt,287 wehavelessreasontoworryaboutwhetheritispossibletoservicethedebt.However,ifthenationaldebtgrowsfasterthanGDPoveralongtimeperiod,wemayhavetoworryaboutourabilitytoservicethedebt.但债务收入比率比国债的绝对数值要更重要，由于债务收入比率告诉我们目前的收入要放弃多少来偿还债务。很明显，5.6万亿美元的国债对GDP为500万亿经济来说比GDP为10万亿美元的经济更难处理。同样地，如果经济增长率高于债务增长率，我们没有理由担心是否可能偿还债务。但是，如果国债的增长在很长时期内超过GDP增长，我就必须担心国家偿债的能力。12.Theanswertothisquestionisstudentspecific.TherewasnoeasywaytofinancethemassiveincreaseingovernmentexpendituresthatwasrequiredtobuilduptheinfrastructureinthenewEasternstatesandtoensuretransferpaymentstothelargenumbersofunemployedandretiredpeople.TheGermangovernmentstruggledwiththisquestionandthetransitionperiodhasnotbeeneasy.这个问题的答案对专门针对学生的。前东德的基础设施建设和大量失业以及退休人员的转移支付需要大量的政府支出，在筹资方面政府是不大可能的。德国政府在这个问题上苦苦挣扎，这个过渡时期确实不容易。Thehugeamountoffundsrequiredtofinancetheseexpendituresshouldnotberaisedsolelybyincreasingtaxes.Taxincreasesarenotonlyhighlyunpopularbutmayalsoprovidedisincentivestowork,saveandinvestandmaythushaveasignificantnegativeimpactontheperformanceoftheeconomy.ChancellorKohlinitiallypromisedthatGermany’sre-unificationwouldnotbefinancedthroughataxincrease,butwhenthecostsofthere-unificationbecamemoreapparent,hehadtobreakthatpromise.巨大的资金缺口不应该仅仅靠征税来弥补。增加税收不仅是非常不常用的，并且可能抑制就业、储蓄和投资，因而可能造成对经济状况有巨大的负面影响。德国总理Kohl起初承诺两德统一不会增加税收负担，但是当统一两德成本明显增加时，他不得不违背承诺。Anincreaseinexpendituresthatisdebtfinancedleadstohigherinterestrates,crowdingoutsomeprivatespending(investmentandnetexport).Inaddition,itleadstoacapitalinflowthatstrengthensthevalueofthedomesticcurrency.InGermany,thisprocesscreatedaproblemsinceexchangeratesamongcountriesoftheECwerefixedwithinarelativelysmallrange.TheEuropeancurrencycrisisof1992wascausedbytheincreaseintheGermanbudgetdeficitthatwaslargelydebtfinanced.ThesubsequentinflowoffundsfromotherEC-countriesrequiredmassivegovernmentinterventiontokeepexchangerateswithintheirassignedrangeandcausedproblemsforotherEuropeancountries.Eventuallythesecountrieshadtodevaluetheircurrencies.Inaddition,GermanyexperiencedacurrentaccountdeficitbecauseofthehighvalueoftheD-Markrelativetothecurrenciesofnon-ECcountries.Thus,thesituationinGermanyintheearly1990sstronglyresembledthesituationintheU.S.inthe288 early1980s,withitshighinterestratesduetolargegovernmentborrowing(andfairlytightmonetarypolicy)andsubsequenttradeimbalance.花费通过负债筹集的资金增加将导致更高的利率，会挤出一些私人支出（投资和净出口）。另外，这导致的资金流入也会使国内货币增值。在德国，当欧盟国家汇率固定在一个不大的区间时，这个过程出现问题。1992年的欧洲货币危机就是由德国预算赤字大部分通过负债筹集引起的。后来，来自其他欧盟国家的资金流入需要政府干涉，这样才能使汇率保持在约定的区间内，这给欧洲的其他国家造成了麻烦。最终这些国家不得不使本国货币贬值。另外，德国经历了往来账户的赤字，因为德国马克相对其他非欧盟国家货币太高了。因此二十世纪九十年代早期国家的情况像美国二十世纪早期的情况，大量政府借款（紧缩的货币政策）造成了高利率和接下来的贸易失衡。Financinglargeincreasesingovernmentexpendituresthroughmoneycreationwouldservetokeepinterestrateslow,whichwouldnotonlyreduceinterestpaymentsonthenationaldebtbutalsohelptokeepthevalueoftheD-Markfromrising.However,moneycreationwouldalsoleadtoincreasedinflation.TheBundesbank,knownforitsindependenceanditsaversiontoinflation,chosetoletmoneysupplygrowonlytoasmalldegree.Asaresult,Germaninterestratesrosesubstantially,leadingtoaninflowoffundsandaweakerperformanceoftheeconomy.政府通过发行货币来筹集大量资金将保持低利率，这不仅减少国债利息支付还会帮助德国马克保持升值。但是，发行货币也会造成通货膨胀。以独立和厌恶通货膨胀而为人们所知的德意志银行，就选择了让货币供给小幅度的增加。结果，德国利率升高相大多，导致了外部资金流入和经济衰退。13.a.Thepay-as-you-gofinancingoftheSocialSecuritysystemresultsinatransferofincomefromtheyoungtotheold.Thisispossibleforthreereasons.Agrowingpopulationwillmakefinancingpublicpensionsystemseasier.Ahighgrowthinincomeduetohigherproductivitywillallowretirementbenefitstobehigherthanpastcontributions.Finally,sinceolderpeoplearemorelikelytovotethanyoungerpeopletheycanenforcethisintergenerationaltransferthroughthepoliticalsystem.随收随支的社会保障体系导致了资金由年轻人看老年人转移。这可能有三个原因。增长的人口会较容易的建立养老金系统。更高的生产率产生的收入增长允许退休金比过去更高。最后，老年人比年轻人更容易投票给通过政治加强两代间转移支付的人。13.b.Thepay-as-you-gofinancingofSocialSecuritycausesasavingsreplacementeffect,thatis,thegovernmentdoesnotsaveSocialSecuritycontributionsbutusesthemimmediatelytopayforthebenefitsofthosecurrentlyretired.Thisdecreaseinnationalsavingreducestherateofcapitalaccumulationandnegativelyaffectsfuturelivingstandards.随收随支的社会保障体系引起了储蓄替代效应，也就是政府不会储蓄社会保障资金，而会马上用于支付给那些刚刚退休的人。这些国家储蓄的减少会降低资本积累和对未来生活水平有负面影响。289 13.c.CurrentproposalsforSocialSecurityreformincludethefollowingsuggestions:first,allowpeopletoinvestatleastpartoftheirfundsinprivateretirementaccountstoensurethattheyareproductivelyinvested;second,increasepayrolltaxes,taxretirementbenefits,andincreasetheretirementagetomakefinancingthesystemeasier.现在对社会保障体系的改革的建议包括：首先，允许人们至少把部分资金投资到他们私人的退休账户，保证投资有效；其次，提高薪税，征退休金税，提高退休年龄使融资体系更容易建立。TechnicalProblems:1.a.Period%changeinrealGNP1929-1930(285.2-314.7)/314.7=-9.37%1930-1931(263.3-285.2)/285.2=-7.68%1929-1931(263.3-314.7)/314.7=-16.33%1.b.Period%changeinrealGDP1990-1991(6,079.0-6,138.7)/6,138.7=-0.97%(ThenumbersoftherealGDPin1990and1991aretakenfromtheEconomicReportofthePresident,February,1997.Table18-1listsoutputintermsofGNP,usedatthattime,andnotGDP,whichisusednowasameasureoftotaloutput.)这些1990和1991年数据取自1997年2月份的《总统经济报告》。表18－1列出了GNP，而不是GDP（现在用来估价总产出）。1.c.Thereisnoofficialdistinctionbetweenadepressionandasevererecession,anditisobviousthatiftherealGNPhadstoppeddecreasingin1931ratherthanin1933,thedepressionwouldhavebeenmuchlesssevere.FromTable18-1,weseethatrealGNPcontinuedtodeclineto$222.1billionin1933,anoveralldeclineof29.42%(almostdoubletheratecalculatedin1.a.)andthatittookuntil1939toreturntothe1929levelofrealGNP.萧条和严重萧条之间在官方上没有.区别，很明显真实GNP在1931年结束下降而不是在1933年，萧条就不太严重了。从表18－1看出，真实GNP在1933年继续下降到2221亿美元，总体下降29.42%（几乎是1.a中计算数值的两倍），直到1939年才回复到1929年的GNP水平。Whileitisalwayshardtoguess"whatwouldhavehappenedif...,"itseemsaccuratetosaythatifthegovernmenthadtakenimmediatestepstoactivelystimulateeconomicgrowththroughexpansionaryfiscalandmonetarypolicies,theseverityoftheGreatDepressioncouldhavebeengreatlyreduced.Inthisrespect,thefirstsentenceofQuestion1iscorrect.However,itshouldprobablyberevisedtosay:"TheseverityoftheGreatDepressioncouldhavebeengreatlyreducedifactiveexpansionarygovernmentpolicieshadbeenemployedmuchsooner."当通常很难猜“如果…将会发生怎么的情况”时，我们可以确定的说，如果政府积290 极地采取扩张的财政和货币政策，就会降低大萧条的严重性。问题１的第一句话是正确的。但是，应该把它修改为“如果政府更早的采取扩张政策，就会大幅度降低大萧条的严重程度”。2.Theactualgovernmentsurpluswentfrom+1.0%ofGNPin1929to-3.8%in1931andthento-3.1%in1932and-2.5%in1933.However,thefull-employmentbudgetsurplus(aconceptthathadnotasyetbeendevelopedatthetime)wentfrom-0.8%ofpotentialGNPin1929to-3.1%in1931,-0.9%in1932and+1.6%in1933.Thelargesizeoftheactualbudgetdeficitsmayhaveledtotheincorrectconclusionthatfiscalpolicyhadbeentooexpansionary,wheninactualitythesizeofthebudgetdeficitswasduetothedeclineinGNP.Theexistenceofafull-employmentbudgetsurplusin1933indicatesthatfiscalpolicywastoorestrictive,andthisgreatlycontributedtotheseverityofthedepression.Thefull-employmentbudgetsurplusprovidesamuchbetterindicationofwhetherfiscalpolicyisexpansionaryorrestrictivethantheactualbudgetsurplus.真实的政府盈余从1929年GNP的1.0%到1931年的-3.8%，1932年的-3.1%再到1933年的-2.5%。但是，完全就业预算余额(当时还没有这个概念)从1929年潜在GNP的-0.8%到1931年的-3.1%，1932年-0.9%和1933年+1.6%。庞大的预算赤字导致了这样一种错误结论：现在财政政策太扩张了，实际上预算赤字的规模取决于GNP的下降。出现在1933年的充分就业预算盈余说明财政政策太过紧缩了，这对经济严重萧条起了重要作用。充分就业预算盈余比真实预算盈余更能显示出财政政策是扩张的还是紧缩的。3.Withrealoutputremainingconstant,theadditionaltaxrevenuegainedfrominflationis:inflationtaxrevenue=(inflationrate)*(realmoneybase).Iftherealmoneybaseis10%ofGDPandtheinflationrateincreasesfrom0%to10%,weshouldexpectanincreaseingovernmenttaxrevenuesof1%,aslongastherealmoneybaseremainsconstant.However,asinflationincreases,peoplereducetheirmoneyholdingsandbanksreducetheirexcessreservessinceitbecomesmorecostlytoholdmoney.Incountriesthathavesophisticatedbankingsystems,moneyholdings(andthereforetheinflationtaxrevenue)falltoamuchlargerextentthanincountrieswheretherearefeweralternativestocashholdings.真实产出保持不变，在通货膨胀中获得的附加税收入为：通货膨胀税＝通货膨胀率×真实货币基础如果真实货币基础是GDP的10%并且通货膨胀率从0增加到10%，我就可以预期政府税收收入增加1％，直到真实货币基础保持不变。但是，随着通货膨胀增加，人们会减少货币持有，银行也会减少多余的储备，因为这时持有货币将花费更多的成本。在一些银行体系复杂的国家，货币持有（因此产生通货膨胀税）会比没有选择只能持有现金的国家下降更快。4.Theinflation-adjustedbudgetdeficitcanbecalculatedinthefollowingway:inflation-adjusteddeficit=totaldeficit-(inflationrate)*(nationaldebt)=4%-(12%)(30%)=291 4%-3.6%=0.4%,thatis,theinflation-adjusteddeficitis0.4%ofGDP.校正通货膨胀后的赤字可以用下面的式子计算：校正通货膨胀后的赤字＝总赤字－通货膨胀率×国债＝4%-(12%)(30%)=4%-3.6%=0.4%也就是说，校正通货膨胀后的赤字是GDP的0.4%5.FromtheequationMV=PY==>%M+%V=%P+%Y==>%P=%M-%Y+%V==>=m-y+v.Inotherwords,inflation()isthedifferencebetweenM2growth(m)andeconomicgrowth(y)adjustedforchangesintheincomevelocityofM2(v).Ifwesubtractthesecondcolumn(outputgrowth)fromthefirstcolumn(moneygrowth)inTable18-9,wegettheinflationrateminusthechangeinthevelocity.Inotherwords,Column3(theinflationrate)wouldonlybeequaltothedifferenceofthefirsttwocolumnsifvelocityremainedconstant.Thenumbersinthistableimplythatthechangesinvelocityvariedfrom-6.3%in1880-1889to+3.1%in1920-1929.Butfrom1960to1989thechangesinvelocitywereverycloseto0%.Thereforeoverthelastthreedecades,therateofinflationcanbeexplainedverywellbythedifferencebetweenM2growthandeconomicgrowth.从等式MV=PY==>%M+%V=%P+%Y==>%P=%M-%Y+%V==>=m-y+v换句话说，通货膨胀()就是M2的增长率(m)加上经济增长率(y)再减去收入变动速率M2(v)。如果在表18-9中第二栏（产出增长率）减去第一栏（货币增长率），就得到负的通货膨胀变化率。换句话说，如果变动速率恒定，第三栏（通货膨胀率）只能等于前两栏的差。表中数据表明，变动速率由1880-1889的-6.3%变化到1920–1929的+3.1%。但从1960年到1989年，变动速率非常接近0。因此在过去的30年里，通货膨胀率就可很好的解释为M2增长率和经济增长率的差。6.a.AccordingtoTable18-8,totalgovernmentoutlayswere18.8%ofGDPinthe1960sand20.7%ofGDPinthe1990s.Thisisanincreaseofroughly10%,whichwecancalculateinthefollowingway:(20.7-18.8)/18.8=0.101064=10.1%根据表18－8，在60年代占GDP的18.8%，在90年代占20.7%，通过下面的式计算出政府总支出将近增长了10%(20.7-18.8)/18.8=0.101064=10.1%6.b.NationaldefensedecreasedfromofGDPinthe1960sto4.1%ofGDPinthe1990s.292 However,entitlementsandothermandatoryspendingincreasedfrom6.3%to11.2%ofGDP.Thesearenowthelargestcomponentofgovernmentoutlays.国防支出由60年代占GDP8.6%下降到90年代的4.1%。但是应得权利和法定支出从占GDP的6.3%升高到11.2%。这些占了现在政府支出的大部分。6.c.Besidestheincreaseinentitlements,whichalmostdoubledoverthelastthreedecades,interestpaymentsonthenationaldebtmorethandoubledfrom1.3%inthe1960sto3.0%inthe1990s.除了权利支出在过去30年增加了一倍，国债利息支出也从60年代的1.3%增加到了90年代的3.0％，增加了一倍多。7.a.AccordingtoTable18-9,totalfederalrevenueswere17.9%ofGDPinthe1960sand18.6%ofGDPinthe1990s.Thisconstitutesanincreaseofalmost4%,whichwecancalculateinthefollowingway:(18.6-17.9)/17.9=0.03911=3.9%根据表18－9，联储收入在60年代占GDP的17.9%，90年代占GDP的18.6%。增加了几乎4%，可以按下式计算：(18.6-17.9)/17.9=0.03911=3.9%7.b.Inthe1960sthecorporateincometaxwasthesecondlargestcomponentoffederalrevenueswith3.8%,butitdecreasedto1.9%inthe1990s.Socialinsurancetaxesandcontributionsincreasedfrom3.5%to6.6%andarenowthesecondlargestcomponentoffederalrevenues,onlyslightlybehindthe8.4%comingfromtheindividualincometax.在60年代，公司收入税是联储收入的第二大组成部分，占到了3.8%，但在90年代降到了1.9%。社会保险税3.5%增加到6.6%，现在是联储收入的第二大组成部分，仅次于占8.4%的个人所得税收入。7.c.Sincethecorporateincometaxandotherrevenuesdecreasedandtheindividualincometaxincreasedonlyslightlyfrom7.8%to8.4%,theincreaseintaxrevenuesfromthe1960stothe1990scameprimarilyfromsocialinsurancetaxesandcontributions.因为公司所得税和其他收入减少，个人所得税也只是从7.8%增加到8.4%，从60年代到90年代税收收入的增加主要来自社会保险税和捐赠。8.FromthenumbersinTables18-8and18-9wecancalculatethebudgetdeficit(definedasgovernmentoutlaysminusgovernmentrevenues)asapercentageofGDP.1960s:18.8%-17.9%=0.9%1970s:20.1%-18.0%=2.1%1980s:22.3%-18.4%=3.9%1990s:20.7%-18.6%=2.1%Aswecansee,federalbudgetdeficitsasapercentageofGDPmorethanquadrupledfrom293 the1960stothe1980s,butthenstartedtodeclineagaininthe1990stoabitmorethandoublethepercentageinthe1960s.从表18-8和18-9我们可以计算出预算赤字（政府支出减去政府收入）占GDP的百分比。60年代:18.8%-17.9%=0.9%70年代:20.1%-18.0%=2.1%80年代:22.3%-18.4%=3.9%90年代:20.7%-18.6%=2.1%就像看到的那样，从60年代到80年代预算赤字占GDP的百分比增加了四倍多，但是在90年代开始下降到只有60年代的两倍多。9.Thedebt-incomeratioisdefinedas(nationaldebt)/GDP.Thereforeifthenationaldebtgrowsby5%ayearbutGDPgrowsbyonly4%thedebt-incomeratiowillincrease.债务收入比可以定义为国债/国内生产总值。因此，如果国债一年增加5%但GDP只增加4%，债务收入比就会升高。294 ConceptualProblems:概念性问题：1.a.Alossofexportmarketsleadsnotonlytoanexternaldeficitbutalsotoadecreaseinthelevelofoutput.Sinceapolicydilemmabetweenanexternalandaninternalbalanceexists,acombinationofexpenditure-switchingandexpenditure-raisingpoliciesisrequired.Thelevyingoftariffshelpstoachieveanexternalbalance,whileanincreaseingovernmentspendinghelpstoachieveaninternalbalance.出口市场的损失不仅导致外部赤字，还将导致产出水平的降低。在内部均衡和外部均衡之间有政策两难存在，就需要增加支出和减少支出政策结合起来。征收关税可以帮助达到外部均衡，政府支出增加帮助达到内部均衡。1.b.Areductioninsavingandanincreaseinthedemandfordomesticgoodswillleadtoanincreaseinnationalincome.Asaresult,importswillincrease,leadingtoabalanceofpaymentsdeficit.Thisisnotadilemmasituationandanexpenditure-reducingpolicy(acutinspending)willremedythesituation.储蓄的减少和国内产品需求增加会增加国民收入。结果，进口增加就会导致国际收支赤字。这不是一个两难的情况并且消费减少政策（花费减少）也会修正这种情况。1.c.Anincreaseingovernmentspendingwillleadtoanincreaseinnationalincomeandthelevelofimports.Thiswillcauseabalanceofpaymentsdeficit.Thisisnotadilemmasituationandanexpenditure-reducingpolicy(acutinspending)willsufficetoreestablishaninternalandexternalbalance.政府支出增加将导致国民收入增加和进口增加。这将产生国际收支赤字。这不是两难的情况，减少消费的政策将重构内外部均衡。1.d.Ashiftinthedemandfromimportstodomesticgoodswillincreaseoutputandleadtoatradesurplus.Thisisadilemmasituationandacombinationofexpenditure-switchingandexpenditure-reducingpoliciesshouldbeemployed.Loweringtariffscombinedwithacutingovernmentspendingwillhelptoachieveanexternalandinternalbalance.从对进口商品的需求转向对国内商品的需求将增加产出并导致贸易顺差。这是一个两难的情况，政府应该采取支出转换和削减支出相结合的政策。降低关税的同时削减政府支出将有助于实现内外部均衡。1.e.Areductioninimportswithacorrespondingincreaseinsavingwillnotaffectthelevelofnationalincomebutitwillleadtoatradesurplus.Anappropriateresponseisareductioninincometaxescombinedwithlowertariffs.Thiswillhelptoreducethetradesurpluswithoutaffectingnationalincome.进口减少的同时储蓄相应增加将不会影响到国民收入但将导致贸易顺差。这时政府适当的反应应是降低所得税和关税。这将有助于在不影响国民收入的情况下降低贸易顺差。2.Temporarytradeimbalancescanbeeasilyfinanced,sincethecentralbankisnotlikelytorunoutofforeigncurrencyreservesrapidly.Acountrythathasatemporarypaymentsimbalancemayevenborrowforeigncurrencyfromabroadaslongasthelevelofdomesticinvestmentspendingissufficienttoincreasethelevelofoutput,someofwhichwilleventuallybeexported.Atemporarydisturbanceintradepatternscancomefromachangeinexchangeratescausedbyunstableexchangerateexpectations.Ifacountrysuffersapermanentimbalance,however,thecentralbankwilleventuallyrunoutofforeigncurrencyreserves.Apermanentimbalancemaybecausedbyalossinforeignmarketshare.Theadjustmentcanhappenthroughtheautomaticadjustmentprocess,butthatcouldinvolvelongperiodsofhighunemployment.Thereforedomesticpolicychangesarerequiredtomovetheeconomymorerapidlytowardbalance.313 暂时的贸易失衡可以很容易通过融资手段加以解决，央行不会在非常短的时间就用光所有的外汇储备。只要国内投资支出水平能够带来足够的产出增加以用于出口，国际收支失衡的国家甚至可以采用从国外借外汇的方式来解决贸易失衡。因为不稳定的交换率预期可以对贸易方式产生暂时的干扰。但是，如果一个国家遭遇永久的不均衡，央行就是最终用完外汇储备。永久的不均衡可能由国外份额损失造成。这可能通过自动调整，但将会有长时间的高失业率。所以使经济更快的回归均衡需要国内经济政策的改变。3.Theanswertothisquestionisstudentspecific.Governmentinterventioncanhelpsmoothouttemporaryfluctuationsinexchangerates.However,thisisoftenproblematicsinceatthetimeacurrencyappreciationoccurs,thegovernmentcanneverbesurewhetheradisturbanceistransitoryandsoonlikelytoreverseitselformorepersistentandfundamentalinnature.Ifunstableexchangerateexpectationsleadtocapitalflowsthatcauseexchangeratemovementsandundesiredchangesindomesticoutput,centralbankinterventionseemsjustified.Butcentralbanksalsooftenintervenetotrytoreduceinflationbypreventingimportpricesfromrising.Thecostofreducinginflationinthiswayisasteadylossincompetitiveness,whichmayevenresultinaforeignexchangecrisis.Ultimately,inflationhastobestoppedbyrestrictivemonetarypolicy.Centralbanksmayalsointervenetoaffecttradeflowsandtobringaboutdesiredchangesindomesticoutput.Inthelongrun,however,governmentsarebetteroffnotopposingstrongmarketforcesbyinterveningintheforeignexchangemarket.Ifagovernmentreallywantstobringaboutchange,itshouldemploydomesticpolicies.Itmaysupplementitspolicybyinterveningintheforeignexchangemarketaswelltoemphasizeitsintent.Governmentinterventionismoreeffectiveifitisbackedupbycrediblepolicies.Thereisevidencethatnon-sterilizedinterventionaffectsexchangeratesmoresuccessfully,sincethereisachangeinmoneysupplyequaltotheamountoftheintervention.Butiftheinterventionissterilized,domesticmoneysupplywillremainunchangedandevenamassiveinterventionmaynotaffecttheexchangeratetothedesireddegree.这个问题的答案是特别针对学生的。政府的干预可以帮助熨平汇率的暂时波动。但是，也存在这样一个问题，政府不能确定这个波动是否是暂时、很快逆转的或者是更持久的。不稳定的汇率预期导致资金流动，从而造成汇率波动和国内产出的不利变化，此时央行的干预就看起来是合理的。但是央行的干预常常是企图通过抑制进口价格的上升来阻止通货膨胀。这样做的成本就是本国产品竞争力的削弱进而导致外汇危机。最终，政府只能通过紧缩的货币政策阻止通货膨胀。央行同样会通过干预贸易流动来得到合适的国内产出变化。但是在长期，政府最好是通过干预外汇市场而不是对抗强大的市场力量。如果政府真的想要改变的话，就会采取国内的政策。干预外汇市场只是强调这一目的的补充。政府干预在有可靠政策支持的情况下才会更有效。证据证明未充销干预会更成功的影响汇率，因为货币供给的变动和干预的总量是平衡的。但如果干预是充销性的，国内的货币供给将保持不变，即使很强的干预也不会使汇率到变动到一个期望的水平。4.Awage-pricespiraloccurswhenpriceincreasesfeedbackintohigherwagedemandsandthehighercostofproduction(duetohigherwages)isthenpassedontoconsumersintheformofstillhigherprices.Forexample,devaluationofthedomesticcurrencywillincreaseimportpricesandthereforethegeneralpricelevel.Tomakeupforthelossinpurchasingpower,laborunionsmaynegotiatehighernominalwages.Firmsthenpassthecostontoconsumersintheformofhigherprices.Ifthegovernmentiscommittedtofull-employmentandthecentralbankcontinuestoincreasemoneysupply,thewage-pricespiralwillcontinue.Inthiscase,wewillencounterhighinflation,butrelative314 priceswillnotchange,andthenominaldevaluationultimatelywillhavenoeffectontherealexchangerate.Toavoidinflation,thecentralbankhastostopincreasingmoneysupply.Inthiscase,higherwageswillcauselayoffsandthusunemployment,whichputsdownwardpressureonwagesandpricestoendthespiral.因为价格水平升高产生更高的工资需求和更高的生产成本（因为高工资），这些成本转嫁给了消费者，也就形成了更高的物价。这时工资－价格螺旋上升就会发生。例如，国内货币的贬值将增加进口成本，也导致国内物价水平的升高。为了补偿购买力的损失，工会就会为更高的工资谈判。厂商就会把增加的成本以更高价格的形式转嫁给消费者。如果政府致力于充分就业并且央行继续增加货币供给，工资－价格螺旋上升就会继续下去。这种情况下，我们就会避免高通货膨胀，但相对价格不会改变，名义的货币贬值最终不会影响到真实汇率。为避免通货膨胀，央行必须停止货币供给增加。这种情况下，高工资将导致解雇因此导致失业，这也降低工资压力，工资－价格螺旋上升就会终止。5.Inatarget-zonearrangementcentralbanksagreetolimittherangeoffluctuationofexchangerates.Suchanarrangementrequirescoordinationoffiscalandmonetarypoliciesamongthegovernmentsofdifferentcountries.Thiscanbeaproblem,sincesomecountriesmaybeunwillingtogiveuptheirabilitytoconductdomesticeconomicpoliciestoachieveothergoals.Ontheotherhand,target-zonearrangementsareattractivesincetheyassurebusinessesthatpricesquotedinforeigncurrencywillnotfluctuatesignificantly,whichsimplifiescross-bordertrade.目标区约定就是央行同意限制汇率波动的区间。这样一个约定需要不同国家政府财政政策和货币政策的组合。这就有一个问题，就是有些国家不愿放弃他们要达到其他目标的经济政策。另一方面，由于他们确定外汇报价不会波动太大，这样就会简化跨国贸易，目标区约定是有吸引力的。6.Indeterminingexchangeratesweassumethatcapitalisperfectlymobile,thatis,thatcapitalmarketsaresufficientlyintegrated.Thisimpliesthatinterestratesacrosscountrieshaveatendencytoadjusttothesamelevel,sinceotherwiseinternationalcapitalflowswouldtakeplaceinresponsetointerestratedifferentials.Thisassumptionisincorrect,however,sincecapitalflowsdoaffectexchangerates,andthereforewemustintegrateexpectationsaboutexchangeratechangesintothemodel.Wemustalsotakeintoconsiderationtaxdifferencesamongcountries,therestrictionssomecountriesputonthetransferofassets,andthepossibilityofpoliticalinstabilityinsomecountries.Thesefactorsmayexplaintheinterestdifferentialsthatweobserveandthereasonscapitalmarketsarenotbesufficientlyintegrated.在可变汇率决定模型中我们假定资本充分流动，也就是说，资本市场是完全有效率的。这就意味着各国利率都会趋于相同，否则利率的不同就会使国际的资本流动。这种假设是不正确的，资本流动确实会影响汇率，我们必须把汇率变动考虑进这个模型中。我们也必须考虑国家间税率的不同，国家对资产交换的限制，有些国家政策的改变等等。这些因素就解释了为什么资本市场不是完全有效率的。7.Equation(7)statesthatinflationdifferentialinterestratedifferentialdepreciationrate.Thisisonlyanapproximate,long-termrelationsinceexchangeratescanmoveindependentlyofprices,andinterestratedifferentialsmayexistduetoobstaclestotheinternationalflowofcapital.315 方程７表明通货膨胀差异、利率的差异和贬值率是近似相等的。这只是近似的相等，在长期，汇率可以独立于价格变动，利率差别也会因为国际资本流动障碍而存在。8.Inasystemoffreelyfloatingexchangerates,domesticmonetarypolicycanbeusedeffectively,whereasinasystemoffixedexchangerates,monetarypolicyiscompletelyineffective.Afreelyfloatingexchangeratesystemislesscrisispronesinceexchangeratesaredeterminedsolelybymarketforces.Itthereforeprovidesabetterframeworkformacroeconomicstability.However,spillovereffectsmakemacroeconomicstabilizationpolicymoredifficultinasystemoffreelyfloatingexchangerates.Thesespillover(orinterdependence)effectscanleadtoalossofcompetitivenessamongotherproblems.Thereisthereforegoodreasonforcountriestocoordinatetheirpolicies.在自由浮动汇率系统里，国内货币政策是有效的，反之，在固定汇率的系统里，货币政策是完全无效的。在自由浮动汇率系统里，汇率只决定于市场，所以这就为宏观经济的稳定提供了一个更好的框架。但是，溢出效应会使自由浮动汇率系统下的宏观经济稳定更加困难。这些溢出效应将导致他们竞争力降低。这也为有些国家调整他们的政策提供了一个好理由。9.Centralbanksoftenintervenetoaffectexchangeratesinthebeliefthattheycanaffecttradeflowsandpreventimportpricesfromrising.Theymayalsobelievethatexchangeratefluctuationshaveoccurredsimplyduetoerraticchangesinexpectations.However,itisoftenunclearwhetherexchangeratemovementsaretransitoryorthebeginningofanewtrendwithstrongmarketforcesatwork.Thismakesinterventionproblematic.Whilenon-sterilizedinterventionwillaffectexchangeratesbecauseitwillaffectthedomesticmoneysupply,itisnotclearthatsterilizedinterventionwillhavethedesiredeffects.央行经常因为相信他们可以影响贸易流动并且阻止进口价格升高面干预汇率。他们同样认为汇率波动只是因为预期的不确定性。但是，汇率波动到底是短时间的还是由于强大市场力量推动的开始往往是不确定的。这就使得干预是有问题的。未充销干预会影响汇率因为它会影响国内货币供给，充销性干预是否会达到想要的效果我们并不清楚。10.Itappearsthatspillover(orinterdependence)effectsaremuchstrongerunderasystemoffloatingexchangerates.Thereforeitcanbearguedthatmacroeconomicstabilizationpolicycanbejustasdifficultunderasystemoffreelyfloatingexchangeratesasunderasystemoffixedexchangerates.溢出效应在浮动汇率制度下更大。这也可以说，制定使宏观经济稳定的政策在浮动汇率制度下和固定汇率制度条件下同样困难。TechnicalProblems:1.Theimpositionofatariffraisestherelativepriceofimportsandincreasesthedemandfordomesticgoods.Thisincreasesthelevelofdomesticoutput,causinginterestratestorise.Higherdomesticinterestrateswillleadtoaninflowoffundsandthedomesticcurrencywillbegintoappreciate.Thehighervalueofthedomesticcurrencywilllowertherelativepriceofimportsagain.Withperfectcapitalmobility,thecurrencyappreciationwillprogresstothepointwheretheoverallchangeinnetexportsiszero.Intheend,thelevelsofoutputandtheinterestratewillbebackattheiroriginallevels.强加的关税增加使进口价格升高并且使国内物品需求增加。这些使国内产出水平升高，造成利率上升。更高的利率导致的资金流入又会使进口价格进一步降低。在资金完全流动的情况下，货币升值会使净出口的变动为零。最后，产出水平和利率会回复到原始的水平。2.Assumea$10billionbalanceofpaymentsdeficitoccurs:假设100亿美元的贸易支付差额赤字发生：316 Thecentralbank"sbalancesheetbeforesterilization:未充销之前央行的资产负债表：AssetsLiabilitiesforeignexchange-10memberbankdeposits-10otherreserves0currency0monetarybase-10monetarybase-10Thecentralbank"sbalancesheetaftersterilization:充销之后央行的资产负债表AssetsLiabilitiesforeignexchange-10memberbankdeposits0govt.securities+10currency0monetarybase0monetarybase03.a.iISoLMoi1BB"=0ioBB=00*YYIfthehomecountryisinitiallyinaninternalandexternalbalance,theIS-,LM-andBB-curvesall*intersectatthefull-employmentlevelofnationalincomeY(seethegraphbelow).Iftheforeigninterestrateincreases,fundswillflowout,leadingtoabalanceofpaymentsdeficit.Torestoreexternalbalance,interestratesmustincreaseorthelevelofnationalincomemustdecrease.Inotherwords,theBB-curvemustshiftup.*如果一国最初处在内外部均衡，IS-LMM曲线和BB曲线相交在充分水平的国内收入水平Y（如图）。如果国外利率升高，资金外流，导致贸易支付差额赤字。为了重新回到外部均衡，利率必须升高或者国内收入水平必须降低。换句话说，BB曲线必须向上移动。3.b.Areductioninmoneysupplycombinedwithanincreaseingovernmentspendingwillincreasetheinterestrateandhelptorestoreanexternalandinternalbalance.ThispolicymixwillshifttheLM-curvetotheleftandtheIS-curvetotheright.Anewequilibriumcanbereachedatthefull-employmentlevelofincomebutatahigherinterestrate.InotherwordstheIS"-,LM"-and*BB"-curveswillallintersectagainatY.317 货币供给减少结合政府支出增加会提高利率，帮助回到内外部均衡。这种政策组合会使LM曲线向左移动，IS曲线向右移动。新的均衡点会在充分就业的收入水平，但这时的利率水平会更高。*换句话说，IS"-,LM"和BB"曲线会重新相交在Y。iIS"LM"ISoLMoi1BB"=0ioBB=00*YY3.c.Ifthegovernmenttakesnoaction,thenanautomaticadjustmentprocesswilltakeplacethroughchangesinmoneysupplyandprices.Thebalanceofpaymentsdeficitwillleadtoareductioninmoneysupply(ashiftintheLM-curvetotheleft).Assumingthatpricesareflexible,thepricelevelwilldecreaseduetothereductioninaggregatedemandasaresultofthedecreaseinmoneysupply.Thelowerdomesticpricelevelwillincreasecompetitivenessinglobalmarkets,andnetexportswillincrease(ashiftoftheIS-curvetotheright).ThedecreaseinthepricelevelwillalsoincreaserealmoneybalancessotheshiftoftheLM-curvetotheleftwillbepartiallyreversed.Anewlong-run*equilibriumwilleventuallybeestablishedatthefull-employmentlevelofoutputY.如果政府不采取任何行动，自动调整过程就会通过货币供给和价格变动来取代。贸易支付差额赤字会导致货币供给减少（LM曲线向左移动）。假设价格是灵活的，价格水平会降低，因为货币供给减少导致了总需求减少。更低的国内价格水平会提高本国商品的全球竞争力，净出口增加（IS曲线向右移动）。价格水平的降低也会增加真实货币平衡，向左移动的LM曲线也会部分转向。在充分就业的产出水平上会最终建立长期均衡。4.Acountryexperiencingapermanentincreaseinitsexportswilldevelopatradesurplus.Undertheassumptionthatthecentralbankdoesnotundertakesterilizationoperations,theincreaseinnetexportscombinedwiththeincreaseinmoneysupplywillleadtoanincreaseinaggregatedemand.Thiswillresultinanincreaseindomesticprices,makingimportgoodsrelativelylessexpensiveandexportgoodsrelativelymoreexpensive.Eventually,thiswillleadtoadecreaseinnetexports.Aslongasthesurplusexists,domesticpriceswillcontinuetoriseuntilaninternalandexternalbalanceisreestablished.Inthelongrun,over-employmentwillalsocauseupwardpressureonwagesandprices,causingtheupward-slopingaggregatesupplycurvetoshifttotheleft.一个国家正在经历永远的出口增加会形成贸易盈余。在央行未采取充销措施的假设下，净出口增加会伴随着货币供给的增加，这将导致总需求的增加。这样的结果就是国内物价的提高，使进口商品相对便宜和出口商品相对昂贵。最终，这会造成净出口的减少。在过剩存在的时候，国内价格318 将持续上升直到内外部均衡重新建立。在长期，过多就业将造成工资和价格的上升的压力，向上倾斜的总供给曲线会向左移动。5.Afteracurrencydepreciation,exportsshouldriseandimportsshoulddecline,bothintheshortrunandinthelongrun.However,empiricalevidencesuggeststhatintheshortrunthevolumeeffectsaretoosmalltoovercomethepriceeffect.Onlyinthelongrun,whenconsumersandproducershavehadtimetoadjusttothechangeinrelativeprices,willthevolumeeffectsbelargeenoughtoovercomethepriceeffect.倾向贬值之后，出口增加进口减少，无论在短期还是在长期。但是，经验证据总量效应的强度太小了，不能超过价格效应。只是在长期，当消费者和厂商有时间调整相关价格，这时问题效应就足够超过价格效应。6.AnincreaseinmoneysupplywillshifttheLM-curvetotheright,drivingthedomesticinterestratebelowtheforeigninterestrate.Acapitaloutflowwilloccurandthedomesticcurrencywillstarttodepreciate.Asaresult,exportswillrise,importswilldecline,andtheIS-curvewillshifttotherightduetotheincreaseinnetexports(NX).Thelevelofoutputdemandedandthedomesticinterestratewillriseuntiltheyreachtheleveloftheforeigninterestrate.However,thenewlevelofoutputdemandedwillbeabovethefull-employmentlevelandthiswillcauseupwardpressureonprices.TherisingpricelevelwillreducerealmoneybalancesandtheLM-curvewillstartmovingbacktotheleft.Sincethedomesticinterestratewillbeabovetheforeigninterestrate,fundswillflowinandthedomesticcurrencywillappreciate.Asaresult,importswillriseandexportswilldecline.TheIS-curvewillnowshiftbacktotheleft,duetothisdecreaseinnetexports(NX).Thelevelofoutputdemandedwilldeclineagain,andthedomesticinterestratewilldecreaseuntilitreachestheleveloftheforeigninterestrate.Intheend,thelevelofoutputdemandedwillagainbeatthefull-employmentlevel.iIS1LMo(po)=LM1(p1)ISoLM1(po)4i11=53io20YoY2Y4Y3Y货币供给的增加会使LM曲线向右移动，使国内利率降低到国外利率以下。资金流出就会发生，并且国内货币贬值。这样的结果就是出口增加，进口减少，IS曲线向右移动，净出口增加。产出需求和国内利率会升高，直到达到国外利率。但是，新的产出需求会超过充分就业的产出水平，这就给价格升高的压力。升高的价格会减少真实货币均衡，LM曲线将开始向左移动。当国内利率超过国外利率时，资金会流入，国内货币升值。这样的结果是进口增加出口减少。IS曲线会向左319 移动，造成净出口增加。产出需求会再次降低，国内利率会降低到与国外利率相同。最后，产出需求会重新充分就业水平。7.NewspaperssuchastheWallStreetJournalpublishforeignexchangeratesdaily.Currenteditionsmayprovideentriessimilartotheonesbelow:BritainCanadaJapan(Pound)(Dollar)(Yen)Spot1.5172.6759.009432Forward30days1.5181.6764.00948990days1.5160.6774.009590180days1.5230.6791.009752NotethatthesearethecostsofoneunitofforeigncurrencyinU.S.dollars.NewspapersalsogenerallylisthowmuchoftheforeigncurrencycanbepurchasedforoneU.S.dollar.Forexample,thespotpriceforoneBritishpoundis$1.5172.ThisisequivalenttosayingthatoneU.S.dollarwillpurchase0.6591pounds