IthasbeenjokedthatthelettersIMFstandfor“it’smostlyfiscal”.TheInternationalMonetaryFundhaslongbeenastalwartadvocateofausterityastherouteoutoffinancialcrisis,andeveryyearitchastisesdozensofcountriesfortheirfiscalindiscipline.Fiscalconsolidation–aeuphemismforcutstogovernmentspending–isastapleofthefund’srescueprogrammes.AyearagotheIMFwassuggestingthattheUShadafiscalgapofasmuchas10percentofgrossdomesticproduct.國際貨幣基金組織(IMF)曾被戲稱為“以財政為主的組織(itsmostlyfiscal)”。長期以來，該組織一直是緊縮政策的忠實擁躉，認為它是走出金融危機的必由之路。每年IMF都會因數十個國家財政上的放縱而譴責它們。“財政整固”（削減政府開支的委婉說法）是IMF眾多救援計劃的主要內容。一年前，該組織曾暗示美國財政缺口高達其國內生產總值(GDP)的10%。AllofthismakestheIMF’srecentlypublishedWorldEconomicOutlookaremarkableandimportantdocument.Initsflagshippublication,theIMFadvocatessubstantiallyincreasedpublicinfrastructureinvestment,andnotjustintheUSbutmuchoftheworld.Itassertsthatwhenunemploymentishigh,asitisinmuchoftheindustrialisedworld,thestimulativeimpactwillbegreaterifinvestmentispaidforbyborrowing,ratherthancuttingotherspendingorraisingtaxes.Mostnotably,theIMFassertsthatproperlydesignedinfrastructureinvestmentwillreduceratherthanincreasegovernmentdebtburdens.Publicinfrastructureinvestmentscanpayforthemselves.所有這些都令IMF最近發布的《世界經濟展望》(WorldEconomicOutlook)成為一份非同尋常的重要文件。在這份IMF頭號出版物中，該組織提議大幅增加公共基礎設施投資，這一倡議的對象不僅包括美國，還包括世界許多國家。該報告稱，在失業率高企之際——正如許多工業化國家目前的狀況，以借債而不是削減其他開支或增稅為投資籌措資金，對經濟會有更大的刺激效果。最值得注意的是，IMF稱經過精心規劃的基建投資會減輕而不是加重政府的債務負擔，因為公共基礎設施投資本身就能帶來回報。WhydoestheIMFreachtheseconclusions?Considerahypotheticalinvestmentinanewhighwayfinancedentirelywithdebt.Assume–counterfactuallyandconservatively–thattheprocessofbuildingthehighwayprovidesnostimulativebenefit.Furtherassumethattheinvestmentearnsonlya6percentrealreturn,alsoaveryconservativeassumptiongivenwidelyacceptedestimatesofthebenefitsofpublicinvestment.Then,annualtaxcollectionsadjustedforinflationwouldincreaseby1.5percentoftheamountinvested,sincethegovernmentclaimsabout25centsoutofeveryadditionaldollarofincome.Realinterestcosts,thatisinterestcostslessinflation,arebelow1percentintheUSandmuchoftheindustrialisedworldoverhorizonsofupto30years.Soinfrastructureinvestmentactuallymakesitpossibletoreduceburdensonfuturegenerations.IMF為何會得出這樣的結論？考慮一筆假想的對一條新公路的投資，這筆資金完全通過舉債籌集。假定建設公路的過程中不會產生任何刺激性好處（這一假設違反事實并且保守）。除此以外，假定投資的實際收益只有6%——考慮到人們普遍接受的對公共投資收益的估計，這一假定也極為保守。那么，由于政府將從每一美元的新增收入中征收大約25美分的稅，經通脹調整后的年度稅收增幅將為投資額的1.5%。而在長達30年的時間跨度內，這筆投資在美國及眾多工業國家的實際利率成本（即扣除通脹因素后的利率成本）不到1%。因此，基建投資實際上可能會減輕未來幾代人的債務負擔。Infact,thiscalculationunderstatesthepositivebudgetaryimpactofwell-designedinfrastructureinvestment,astheIMFrecognised.Itneglectsthetaxrevenuethatcomesfromthestimulativebenefitofputtingpeopletoworkconstructinginfrastructure,aswellasthepossiblelong-runbenefitsthatcomefromcombatingrecession.Itneglectstherealitythatdeferringinfrastructurerenewalplacesaburdenonfuturegenerationsjustassurelyasdoesgovernmentborrowing.事實上，正如IMF認識到的，這個計算過程低估了經過精心規劃的基建投資對預算的積極影響。它忽略了人們得以從事基建工作這一刺激性好處帶來的稅收增長，以及對抗衰退可能帶來的長期好處。它還忽略了一個事實：推遲基礎設施更新同政府舉債一樣，必然給未來幾代人造成負擔。Itignoresthefactthatbyincreasingtheeconomy’scapacity,infrastructureinvestmentincreasestheabilitytohandleanygivenlevelofdebt.Critically,ittakesnoaccountofthefactthatinmanycasesgovernmentcancatalyseadollarofinfrastructureinvestmentatacostofmuchlessthanadollarbyprovidingatrancheofequityfinancing,ataxsubsidyoraloanguarantee.它忽略的另一個事實是：通過提高整體經濟的產能，基建投資還提升了經濟應對任何水平債務的能力。還有一個至關重要的問題是，它沒有考慮到如下事實：通過提供股權融資、稅收補貼或貸款擔保，政府促成一美元基建投資的成本可能會遠低于一美元。Whenittakesthesefactorsintoaccount,theIMFfindsthatadollarofinvestmentincreasesoutputbynearly$3.Thebudgetaryarithmeticassociatedwithinfrastructureinvestmentisespeciallyattractiveatatimewhenthereareenoughunusedresourcesthatgreaterinfrastructureinvestmentneednotcomeattheexpenseofotherspending.Ifweareenteringaperiodofsecularstagnation,unemployedresourcescouldbeavailableinmuchoftheindustrialworldforquitesometime.IMF發現，如果將上述因素都考慮在內，每一美元投資會增加近3美元的產出。在這個未利用資源足夠充足的時期，這種與基建投資相關的預算計算尤其具有吸引力，因為加大基建投資不一定會以犧牲其他開支為代價。如果說我們正在進入長期停滯階段，那么對多數工業國家，在相當長的時間內都有未利用資源可用。Whilethecaseforinvestmentappliesalmosteverywhere–possiblyexceptingChina,whereinfrastructureinvestmenthasbeenusedastimulustoolforsometime–theappropriatestrategyfordoingmorediffersaroundtheworld.盡管加大投資的理由適用于幾乎所有地區（也許中國是個例外，那里把基建投資當成刺激手段已有一段時間），但合適的投資策略因地區而異。TheUSneedslong-termbudgetingforinfrastructurethatrecognisesbenefitsaswellascosts.Projectsshouldbeapprovedwithreasonablespeed.Thegovernmentcancontributebysupportingprivateinvestmentsinareassuchastelecommunicationsandenergy.美國需要對基礎設施開展長期預算，在考慮成本的同時，還要考慮由此帶來的收益。對項目的批準應具備足夠的效率。政府可以通過支持電信及能源等領域的私有部門投資發揮作用。Europeneedsmechanismsforcarryingoutself-financinginfrastructureprojectsoutsideexistingbudgetcaps.ThismaybepossiblethroughtheexpansionoftheEuropeanInvestmentBankormoreuseofcapitalbudgetconceptsinimplementingfiscalreviews.歐洲則需要建立相關機制，在現存預算上限之外，開展自籌資金的基建項目。要實現這一點，可以擴大歐洲投資銀行(EuropeanInvestmentBank)的規模，或在財政審核的過程中更多運用資本預算的概念。Emergingmarketsneedtomakesurethat