成本收益分析課件

成本收益分析

Cost-BenefitAnalysisPublicFinanceMcGraw-Hill/Irwin?2005TheMcGraw-HillCompanies,Inc.,AllRightsReserved.IntroductionCost-benefitanalysisisasetofpracticalproceduresforguidingpublicexpendituredecisions.FutureValue（終值）：

PresentDollarsintotheFutureSupposeyouinvest$100todayinthebank...Attheendofyear1,itisworth(1+.05)x$100,or$105Attheendofyear2,itisworth(1+.05)x$105,or$110.25Theinterestcompoundsovertime,thatis,theinterestisalsoearninginterest.PresentValue（現值）:

FutureDollarsintothePresentSupposesomeonepromisestopayyou$100oneyearfromnow.Whatisthemaximumamountyoushouldbewillingtopaytodayforsuchapromise?PresentValue:

FutureDollarsintothePresentThepresentvalueofafutureamountofmoneyisthemaximumamountyouwouldbewillingtopaytodayfortherighttoreceivethemoneyinthefuture.PresentValue:

FutureDollarsintothePresentDefineR=amounttobereceivedinfuturer=rateofreturnoninvestmentT=yearsofinvestmentThepresentvalue(PV)oftheinvestmentis:PresentValue:

FutureDollarsintothePresentPresentvalueisanenormouslyimportantconceptA$1,000,000payment20yearsfromnowisonlyworthtoday:$376,889ifr=.05$148,644ifr=.10PrivateSectorProjectEvaluation

私人部門的項目評估Supposetherearetwoprojects,XandY.Eachentailscertainbenefitsandcosts,denotedasBX,CX,BY,andCY.Needtoask:Istheprojectadmissible（可行）?Istheprojectpreferable（最好）?PrivateSectorProjectEvaluationDefine:BenefitsfromprojectiattimetCostsfromprojectiattimetThenthepresentvalueofprojectiis:PrivateSectorProjectEvaluationThepresentvaluecriteria

（現值標準）forprojectevaluationarethat:Aprojectisadmissibleonlyifitspresentvalueispositive.Whentwoprojectsaremutuallyexclusive（二選一的）,thepreferredprojectistheonewiththehighestpresentvalue.PrivateSectorProjectEvaluationTable1showstwodifferentprojects(R&DorAdvertising).Thediscountrateplaysakeyroleindecidingwhatprojecttochoose,becausethecashinflowsoccuratdifferenttimes.Thelowerthediscountrate,themorevaluabletheback-loadedproject.PrivateSectorProjectEvaluationSeveralothercriteriaareoftenusedforprojectevaluation,butcangivemisleadinganswersInternalrateofreturn（內部收益率）Benefit-costratio（收益－成本比率）PrivateSectorProjectEvaluationTheinternalrateofreturn,ρ,isdefinedastheρthatsolvestheequation:TheIRRisthediscountratethatwouldmakethepresentvalueoftheprojectequaltozero.Admissibleifρ>r.Theflawedanalysiswouldchooseanadmissibleprojectwiththehigherinternalrateofreturn,ignoringscale.X項目現在投入100，一年后收入110Y項目現在投入1000，一年后收入1080假定企業(yè)按6％的利率借貸X項目賺了4美元，Y項目賺了20美元PrivateSectorProjectEvaluationAdmissibilityusingthebenefit-costratiorequires:Thisratioisvirtuallyuselessforcomparingacrossadmissibleprojects,however.Ratiocanbemanipulatedbycountingbenefitsas“negativecosts”andvice-versa.案例分析方案1：建造垃圾場B=2.5億美