技术经济学英文版演示文稿C32课件

Example:P=$500A=$140n=10NPV=?

i(％)01020253040∝ NPV900

360

87

0

-67

-162-500

ROR的意义：从收益的观点看，ROR就是项目所能达到的最高收益水平。ROR的意义：从收益的观点看，ROR就是项目所能达到的最高收益水平。当ic=0，当ic趋向于无穷大，NPV=NCF03.4RateofReturnAnalysisTherateofreturnanalysisisprobablythemostpopularcriterionineconomicanalysis.It'spopularitystemsfromtheeasewithwhichacommonpersoncanunderstandthemeaningofrateofreturn.Mostoftheinvestmentbrochureswilluserateofreturnonyourinvestmentasacriteriontoshowhowgoodagiveninvestmentopportunityis.Itismucheasiertounderstandthat"aprojectwillprovide20%returnonyourinvestment"than"theprojectwillresultinaNPVof$5,000."Unfortunately,althoughsimpletounderstand,thetechniquehassomemajordrawbacks.Inthissection,inadditiontoexplaininghowtocalculatetherateofreturn(ROR),wewilldiscusstheadvantagesanddisadvantagesofthistechnique.Rateofreturnhastwodefinitions.Onedefinitioncanbestatedas“theinterestrateearnedontheunpaidbalanceofaloansuchthatthepaymentschedulemakestheunpaidbalanceequaltozerowhenthefinalpaymentismade.”Considerasimpleexampletoillustratethisdefinition.

1001,000$1,00010010012n-1nFigure3.9:ALoanof$1,000withaUniformPaymentofInterestThisdefinitioncanbeturnedaroundtostatethatthe"rateofreturnistheinterestrateearnedontheunrecoveredinvestmentsuchthatthepaymentschedulemakestheunrecoveredinvestmentequaltozeroattheendofthelifeoftheinvestment."Usingasimilarexampleasbefore,letusassumethatyouhaveinvested$10,000inthebankataninterestrateof6%forfiveyears.Attheendofeachyear,youwithdraw$600ininterestandattheendoffiveyears,youwithdraw$10,000.Theinvestmentinthebankattheendoffiveyearsis,therefore,zero.Youcanconsiderthattherateofreturnontheinvestmentis(600/10,000=)6%.Schematically,thecashflowproshowninFig.3.10Figure3.10:Investmentof$10,000withaUniformPaymentofInterest12n-1n60010,000$10,000600600Mathematically,therateofreturn(ROR)isdefinedastherateatwhichnetpresentworth(NPV)foragiveninvestmentisequaltozero.Inequationform,therateatwhich,(3.4)istherateofreturn.Inotherwords,therateatwhichNPV=03.5)IfweassumethatthecashflowforaparticularprojectisgivenbyAjwhereAjrepresentsthecashflowinyearj,wecanwritetheequationforNPVas,(3.6)IfwedefinetherateiRcorrespondingtotherateatwhichNPViszero,wecanwritetheequationforiRas,

(3.7)Example3.17Calculatetherateofreturnforthefollowingcashflow.Year01234CashFlow-4,0002,5001,8001,300900SolutionUsingthecashflows,wecanwritetheequationforNPVas,Sincethisisapolynomialequationini,wewillhavetosolveitbytrialanderror,

SincethevalueofNPVchangesasignbetweeni=15%andi=35%,therateofreturnshouldfallinbetweenthetwovalues.Bylinearinterpolation(线形内插法),wecanwriteanapproximateequationfortherateofreturn(ROR)as,(3.8)wherei+andi-respectivelyrepresentthevialvalueswhichresultedinpositiveandnegativeNPVvalues,andNPV+andNPV_representthepositiveandthenegativeNPVvaluesrespectively.Inourexample,Therefore,WecancalculatetheNPVat29.3%.NPV=-66.5Althoughclosetozero,wecantryonemoreinterpolationbetween15%and29.3%.NPVat28.3%=-10.2Wewouldassumethisvaluetobecloseenoughtozero.Youmaynotethathigheristhedifferencebetweenthei+andi-,biggerwillbethedeviation(背离)betweenthetrueRORandtheinterpolatedvalue.Therefore,theinterpolationmayhavetobecarriedoutmorethanoncetoobtainacorrectvalueoftheROR.Fromtheaboveexamples,onecanseethattheRORcalculationhastobedonebytrialanderror.Manytimes,itisverydifficulttoassumetheinitialvalueofinterestrate.Onewaytoovercomethisproblemistousearatioofperiodicpaymenttoinitialinvestment.Wecanshowthatiftheinitialinvestmentisequaltothesalvagevalue,theRORcanbecalculatedas,UsingEq.3.9,ifthesalvagevalueislessthantheinitialinvestment,

Ontheotherhand,ifthesalvagevalueisgreaterthantheinitialinvestment,

Eq.3.9throughEq.3.11areapplicableonlyiftheinvestmentismadeatthebeginningoftheprojectandtheperiodicpaymentsareequaltoeachother.Example3.19Asaninvestment,youboughtahousefor$50,000.Ifyoucanrentthehousefor$800permonth,andcansellthehousefor$70,000attheendoftenyears,whatistheRORonyourinvestment?SolutionLetusassumetheRORtobe.017/month.

where120isthenumberofmonthsinwhichtherentiscollected.Therefore,theRORisl.7%/month.or20.4%/year.Afteroneadditionaltrialanderror,theROR=15.7%.TheRORcanalsobecalculatedusingagraphicalprocedure.Foratypicalinvestmentscenario,wecallassumedifferentinterestratesandcalculatetheNPVasafunctionoftheinterestrate.AsshowninFig.3.ll,byconnectingthepoints,wecancalculatetheRORcorrespondingtoapointonthecurvewhereNPVisequaltozero.Figure3.11:RORDeterminationExample3.23Thefollowingtwoalternativesareconsideredforaproject,(a)(b)InitialInvestment$50,000$500,000AnnualBenefit$25,000$125,000Life,Years55SalvageValue$50,000$500,000IftheMRORis20%,whichalternativeshouldbeselected?SolutionThefirststepistoestimatetheRORoftheindividualalternativesandcomparetheRORwiththeMROR.IftheRORislessthantheMROR,thealternative(s)shouldberejected.Inthisexample,sincethesalvagevalueisequaltotheinitialinvestment,usingEq.3.9.SincetheRORa>MRORandRORb>MROR,bothalternativessatisfythefeasibilitycriterion.ThisnumberindicatesthattheRORonincrementalinvestmentis22.2%whichisgreaterthantheMROR.Inotherwords,byinvestinganadditional$450,000,wewillearnaRORof22.2%.Ontheotherhand,ifwedonotinvestanadditional$450,000inalternativeb,wewillearnonlyMRORonthatadditionalamount.Therefore,itismoreattractivetoinvesttheadditional$450,000inalternativeb.Thatis,toselectalternativebovera.ThisanalysiscanbeeasilyconfirmedbycalculatingtheNPVforboththealternativesatMROR.Foralternativea,Foralternativeb,ince(NPV)b>(NPV)a,alternativebshouldbechosen.Thisisconsistentwiththeanswerweobtainedfromtheincrementalanalysis.Togeneralize,iftwoalternativesrequiringdifferentamountsofinvestmentneedtobecompared,weshouldcarryoutanincrementalanalysis.If△ROR≥MROR,weshouldselectanalternativerequiringalargerinvestment.If△

ROR<MROR,weshouldselectanalternativerequiringasmallerinvestment.Theprocedurecanbeeasilyextendedwhenconsideringmorethantwoalternatives.Briefly,thestepwiseprocedureforincrementalanalysiscanbestatedasa.CalculatetheRORforeachalternative.IfROR>MROR,assumethatthealternativeisfeasibleandretainitforfurtherincrementalanalysis.IftheROR<MROR,removethealternativefromfurtheranalysis.b.Taketwoalternativesrequiringthesmallestinvestments.CalculatetheRORontheincrementalinvestmentbysubtractingthesmallerinvestmentfromthelargerinvestment.WedenotetheRORonincrementalanalysisasROR.If△

ROR≥MROR,selectthealternativerequiringthelargerinvestment;if△

ROR<MROR,selectthealternativerequiringthesmallerinvestment.Removetherejectedalternativefromfurtheranalysis.c.Taketheremainingalternativeandcompareitwiththealternativerequiringthenextlargestinvestment.CalculatetheincrementalROR.If△

ROR≥MROR,selectthealternativerequiringthelargerinvestment;if△

ROR<MROR,selectthealternativerequiringthesmallerinvestment.Removetherejectedalternativefromfurtheranalysis.d.Repeatstep(c)tillonlyonealternativeremains.

Examp1e3.24Thefollowingthreealternativesareconsideredforaproject.IfMRORis15%,selecttheappropriatealternative.(a)(b)(c)InitialInvestment$1,000$3,000$6,000AnnualBenefit$300$1,000$1,800Life,Years101010SalvageValue$1,000$3,000$6,000SolutionSinceRORforallthealternativesisgreaterthantheMROR,allarefeasible.Instep(b)takethetwoalternativesrequiringthesmallestinvestment.Inthisexample,wewillconsideralternatives(a)and(b)forincrementalanalysis,Therefore,Since△

RORb-a>MROR,select(b)over(a).Eliminatealternative(a)fromfurtheranalysis.Inthenextstep(stepc),compare(b)withtheremainingalternative(c).Forincrementalanalysis,(b)-(a)InitialInvestment$2,000AnnualBenefit$700Life,Years10SalvageValue$2,000Therefore,SinceROR.c-b>MROR,select(c)over(b).Aftereliminating(b),weareleftwithonlyalternative(c).Thiswillbeourchoice.(c)-(b)InitialInvestment$3,000AnnualBenefit$800Life,Years10SalvageValue$3,000Tosummarize,theeconomiccriterionappliedfortherateofreturnanalysisforasingleproject:iftheROR>MROR,theprojectisselected;iftheROR<MROR,theprojectisrejected.Foraprojecthavingmultiplealternatives,anincrementalanalysisneedstobeconductedsolongasthereisadifferenceinthecashflowprofilesoftwoprojects.Onlyafterapplyingtheincrementalanalysis,thesolutionwillbeconsistentwiththeNPVanalysis.3.4.2MultipleRatesofReturnInadditiontotherequirementofincrementalanalysis,theRORanalysismethodalsohasanotherdrawback.Thismethodworkswellwhenagivenalternativerequiresaninitialinvestmentwhichisfollowedbyfuturebenefits.Forthistypeofalternative,thecashflowprobeshownasnegativecashflowinthefirstyearfollowedbypositivecashflowinthefutureyears.Forexample,ifweconsideraninvestmentof$1,000whichwillresultina$300annualbenefitforthenextsixyearswitha$500salvagevalueattheendofsixyears,thecashprobewrittenas.Year01234567CashFlow-1,000300300300300300300300+500Inthisprofile,thereisonlyonesignchangeincashproYears0and1.SuchproamenabletoconventionalRORanalysis.NotethattheRORcalculationrequiressolvingapolynomialofi.WecalculatethevalueofiforwhichtheNPViszero.Foreconomicanalysis,weareonlyinterestedinobtainingpositive,realvaluesofiforwhichtheNPVisequaltozero.Whenthereisonlyonesignchangeinthecashflowprofile,asshownabove,wecanonlyobtainoneorzeropositivesolutions.Insomeinstances,however,thesignchangesmorethanonceinacashflowprofile.Underthesecircumstances,wemayobtainmorethanonerealROR.Theruleofsignsforpolynomialsolutionstatesthatthenumberofrealsolutionsbetween-land∞isnevergreaterthanthenumberofsignchanges.Thatis,ifwehavetwosignchanges,wemayobtainamaximumoftworatesofreturnvaluesbetween-100%and∞.Thefollowingexampleillustratesthecalculationofthenumberoffeasiblesolutions.Example3.25ForthefollowingfourcashRORbetween-100%and∞.PeriodABCD0-100-100300-500120120-200300220-3010030033050100-1004207020010053030-30-1006202010050SolutionTocalculatethemaximumnumberofpossiblerealsolutionsbetween-100%and∞,wecancalculatethenumberofsignchanges.ForcashflowA,thereisonlyonesignchangebetweenperiod0andl.ForB,therearethreesignchanges;betweenperiods0andl,periodsland2,and3.Similarly,forcashflowC,therearefoursignchanges,andforcashflowD,therearefivesignchanges.Asstatedbefore,thenumberofsignchangeswillindicatethemaximumnumberofpossiblerealsolutions.Thatis,forcashflowprofileC,thenumberofrealsolutionsbetween–100%and∞canbeeither4,3,2,l.orzero.Thenumberofpossiblerealsolutionscanbenarroweddownevenfurtherbyapplyingcumulativecashflowsigntest.IfweassumeAjtobeacashflowinperiodj,thenwecandefinethecumulativecashflowCjas,IfCjstartswithanegativenumberandchangessignonlyonce,wewillobtainonlyonepositivesolution.ThiscumulativecashflowmethodmayallowustonarrowdownthenumberofpossiblesolutionsfortheROR.Example3.26ReconsiderthecashflowsprovidedinExample3.23.Applyingthecumulativecashflowsigntest,investigatethepossibilityofnarrowingthenumberofpositiveRORsolutions.SolutionWecancalculatethecumulativecashflowsforeachoftheprofilesasfollows:PeriodProjectAProjectBProjectCProjectDAjCjAjCjAjCjAjCj0-100-100-100-100300300-500-500120-8012020-200100300-200220-60-30-10100200300100330-305040100300-1000420-10701102005001001005301030140-30470-100062050201601005705050Asasamplecalculation,forperiod3forProjectA,wecancalculate.C3=-100+20+20+30=-30Forperiod6,C6=-100+20+20+30+20+30+30=50Lookingatthecashflowprofiles,forcashflowprofilesAandD,thereinonlyonesignchangeinthecumulativecashflowprofile.Thatis,wewillobtainonlyoneuniquepositivevalueoftheROR.ForcashflowprofilesBandC,theresultsofcumulativecashflowprofilesareinconclusive.Wecannotreducethepossiblenumberofsolutionsbyusingthecumulativecashflowprothesetwoprofiles.Example3.27Anin-filldrillingprojectisbeingconsideredforanexistingoilfieldtoaccelerateoilrecovery.Thefollowingtwoscenarios,basedontwoalternatives(noin-filldrillingversusin-filldrilling)arepredicted.Whichalternativewouldyouselect?Thenumbersareinmillions.AssumethatMRORis20%.Year0123456A(nodrilling)030201814106B(in-filldrilling)-2060406420SolutionThefirststepinRORanalysisistocompareindividualROR'sforeachalternativewiththeMROR.ForalternativeA,thereisnosignchangeinthecashflowprofile.Therefore,theRORforalternativeAis∞.ForalternativeB,RORcanbeshowntobegreaterthan20%(theRORforalternativeBis260%).Therefore,bothalternativessatisfytherequirementthattheRORbegreaterthantheMROR.Thenextstepistoconducttheincrementalanalysis.Thecashflowproincrementalvaluescanbewrittenas,Thecashflowpromorethanonesignchange.Thecumulativecashflowproshowsmorethanonesignchange.ThisindicatesthepossibilityofmorethanonepositiveRORsolution.NPVforanyinterestratecanbecalculatedas,Year0123456B-A-203020-12-10-8-6Cumulative(B-A)-2010301880-6Fig.3.13showsaplotofNPVasafunctionofi.Figure3.13:PlotofNPVvs.iforExample3.27Asstatedbefore,theRORistherateatwhichtheNPVisequaltozero.BasedonFig.3.13,twoROR’sarepossible;11%and72%.IfweassumeRORtobe11%,thenalternativeA(analternativerequiringasmallerinvestment)shouldbeselected().IfweassumeRORtobe72%,thenalternativeB(analternativerequiringlargerinvestment)shouldbeselected().Obviously,ouranswerchangesdependingupontheselectedvalueofROR.Figure3.13:PlotofNPVvs.iforExample3.27Acorrectanswertotheproblemrequiresfurtheranalysis.BasedonFig.3.13,theNPVispositivebetween11%and72%;thatis,theadditionalinvestmentrequiredforalternativeBwillresultinpositiveNPV.Therefore,iftheMRORisanywherebetween11%and72%,weshouldselectalternativeB.Ontheotherhand,iftheMRORislessthan11%orgreaterthan72%(anunlikelyprospect),thenalternativeAshouldbeselected.Inthisexample,theMRORis20%;therefore,weshouldselectalternativeB.Togeneralize,iftheMRORfallsintherangeofinterestratewheretheNPVispositive,thealternativerequiringthelargerinvestmentshouldbeselected.IftheMRORfallsintherangewheretheNPVisnegative,thealternativerequiringasmallerinvestmentshouldbeselected.

OneeasywaytoconfirmthisanalysisistocalculatetheNPVattheMROR(=20%)forincrementalcashflow.SinceNPVispositive,alternativeBshouldbeselected.Thisisthesamepredictedinthepreviousparagraph.Itisobviousthat,forsuchproblems(wheremorethanonesignchangeoccursincashflowanalysis),theRORanalysisisdifficulttoadopt.Abetteralternativewouldbetousethepresentworthanalysis.

AROR（IRR)的优缺点：

易理解；与基准点无关；

在项目寿命期内任意时刻，使项目收益换算值之和等于费用换算值之和的利率称为ROR(IRR)。

所以，ROR的计算，可以用NPV(i)=0,

NFV(i)=0,NAV(i)=0进行计算。

NPVIRR>0>ic=0=ic<0<icNPVIRR唯一值唯一值；无解；多解同一ic，具有可加性无可加性与基准点有关无关可用于互斥方案优选不可用

ir—再投资利率if—融资成本

3.5GrowthRateofReturnAnalysis

ArelatedtechniquetotheRORanalysisisthegrowthrateofreturn.UnlikeRORcalculations,whichareindependentofwhatwedowiththefuturebenefits,growthrateofreturndependsonthereinvestmentofthefuturebenefits.Itassumesthatthefuturebenefitsarereinvestedatcertaininterestratesandcalculatesthefuturevalueofallthebenefitsattheendoftheusefullifeoftheproject.

Letusillustratethisschematically.InFig.3.14,wehaveacashflowprocalculationoftherateofreturn.Weinvested$l,000inthebankataninterestrateof10%peryear,andwithdrewinterestof$100peryearfor10yearsfinallywithdrawingtheinitialinvestmentof$l,000.Inthissimplescenario,therateofreturnontheinvestmentis10%.TheRORvalueisindependentofwhatwedidwiththe$100wereceivedattheendofeachyear.Wecouldhavegambleditawayorcouldhavereinvesteditinbuyingstocks.TheRORwouldstillbe10%.ThisiswhytheRORissometimescalledinternalrateofreturn.Itonlydependsoninternallygeneratedrevenues,notonexternalrates.

Contrastthiscashflowproacasewherethe$100revenueperyearisreinvestedintreasurybillsata6%interestrate.TheschematicdiagramisshowninFig.3.15.Wewillassumethatassoonastheannualpaymentisreceived,itisreinvestedata6%interestrate.Attheendof10years,alltheaccumulatedsumiswithdrawnincludingtheinitialinvestmentof$1000,6%rateiscalledanexternalrateofreturn.1000

Inthiscase,wecancalculatethefuturevalueofreinvestedamountbyknowingtherelationshipbetweenthefuturevalueandtheperiodicpayment.Forthisexample,Inadditionto$l,318,wewillalsoreceivetheoriginalinvestmentbackresultinginatotalfuturevalueof$2,318.Ifweknowthatthe$l,000investmenthasresultedinacumulativetheassetof$2,318,wecancalculatetherateatwhichourinvestmenthasgrownbyknowingtherelationshipbetweenthefutureandthepresentvalues.Therefore,i=8.8%

Example3.28

AssumethesamevaluesasgivenintheExample3.17.Assumefurtherthattheannualbenefitearnedisreinvestedatarateof10%.CalculatetheGROR.SolutionGiven:Initialinvestment=$1,000andannualbenefit=$2,700for6years.Wecancalculatethefuturevalueoftheannualbenefitsbyassumingthatthebenefitsareinvestedat10%.UsingEq.2.5,SolvingforGROR,GROR=13%

Growthrateofreturnisausefulcalculationiftherateatwhichfuturebenefitsareinvestedisknown.OnepossibilityisthatthereinvestmentratecanbeassumedtobeequaltotheMROR.Anotherpossibilityistochosearatewhichreflectsthemostconservativeinvestment;i.e.,treasurybills.Sinceanycorporationisassumedtohaveperpetualexistence,theGRORisanaccurateindicatoroftherateatwhichthetreasuryofacorporationwillgrow.

OnemajoradvantageoftheGRORcalculationisthatiteliminatesthetrialanderrorprocedurerequiredfortheconventionalRORanalysis.TheprocedurealsoeliminatesthepossibilityofmultipleROR'sforagivencashflow.Ifthereismorethanonesignchangeinthecashflowprofile,allpositivecashflowsaretransferredattheendoftheusefullifebyassumingthatthepositivecashflowsareinvestedattherateofreinvestment.Thisstepwillresultineliminationofmultiplesignchangesandwillresultinonlyonesignchange.

Inapplyingthegrowthrateofreturn(GROR)asacriterion,weneedtocomparethecalculatedGRORwiththeMROR.IfGROR>MROR,weconsiderthealternativetobefeasible.IfGROR<MROR,wewillrejectthealternative.ItshouldbeunderstoodthattheGRORtechniquedoesnoteliminatetheneedforincrementalanalysis.LiketheRORmethod,ifwearepresentedwithmorethanonealternative,weneedtoconsidertheincrementalanalysis.OncewecalculateGROR,wecancompareitwiththeinvestmentrate(itmaybeMROR);therateatwhichthefuturebenefitsareinvested.If△GRORisgreaterthantheinvestmentrate,weselectthealternativerequiringabiggerinvestment.Ifthevalueof△GRORislessthantheinvestmentrate,weselectthealternativerequiringasmallerinvestment.Thefollowingexampleillustratestheapplication.

Example3.29

AssumethesamedataasgiveninExample3.27.IfweassumethatalltherevenuesareinvestedatthesamerateastheMROR,whichoptionispreferable?SolutionInthisexample,weareconsideringtwoalternatives.Onealternativerequiresnoadditionaldrilling;theotheralternativerequiresin-filldrilling.Thecashflowprofilesareprovidedforboththealternatives.

Forboththesecashflowprofiles,wecaneasilyshowthattheGROR>MROR.Therefore,bothalternativesarefeasiblealternatives.Thisbringsustothenextstep.Thecashflowprotheincrementalanalysis,alongwiththecashflowproeachalternative,isreproducedbelow.Year0123456A030201814106B-2060406420B-A-203020-12-10-8-6

SolvingforGROR,GROR=21%

YearB-ASTEPS12340-20-20-20-20-2013030*1.220000220202020203-1231.231.2*1.20004-10-1027.4427.44*1.2005-8-8-824.9324.93*1.206-6-6-6-623.91

F=23.91+20(1+0.2)4=65.3856Usingtheequation,F=P(1+GROR)n65.3856=20(1+GROR)nSolving,GROR=21.8%.Althoughinthisexample,wecouldcoverthesubsequentnegativecashflowswithourpositivecashflows,insomecasesinbetweenpositivecashflowsmaynotbeabletocoverallthesubsequentnegativecashflows.Ifthathappens,thenthenetnegativecashflowsinagivenyearshouldbetreatedasoutofpocketexpenseandshouldbeconvertedtothepresentvalueintheGRORanalysis.

Example3.30

Aninvestmentinaproducingpropertyresultsinthefollowingcashprotopricefluctuations.IftheMRORis15%,calculatetheGROR.Year01234567CashFlow(inthousands)-3015-2015101086

SolutionWehavenegativecashflowsinyear0andyear2.Beforeweconsidertheactualoutofpocketexpenses,weneedtocoverthenegativecashflowinyear2withthepositivecashflowinyearl.Investing$15,000atarateof15%willresultin,15,000(1+.15)=17,250Addingthepositivecashflowto-$20,000,thenetcashflowinyear2,-20,000+17,250=-2,750Thisnegativecashflowcannotbecoveredfromanypreviouslygeneratedrevenues.Therefore,itisconsideredout-of-pocketexpenses.Thenewcashflowpropresentedbelow.Year01234567CashFlow(inthousands)-300-2.7515101086

F=15(1+.15)4+10(l+.15)3+10(l+.15)2+8(l+.15)+6=69.9Therefore,tocalculatetheGROR,F=P(l+GROR)n69.9=32.l(l+GROR)7GROR=11.8%

TosummarizetheGRORmethod,itisamodificationoftherateofreturnmethod.Itrequiresanadditionalknowledgeofreinvestmentrate.However,ifsuchinformationisknown,themethodeliminatestheneedoftrialanderrorprocedureasrequiredfortheRORmethod.Further,byusingtheGRORmethod,weeliminatethepossibilityofmultipleratesofreturn.

3.6ProfittoInvestmentRatioProfittoinvestmentratio(PIR)istheratiooftheNPVatMRORtothepresentvalueofoutofpocketinvestment.Wecanwriteitas,

Thisnumberisanindicationoftheefficiencyoftheinvestment.Inotherwords,PIRistheamountofmoneyearnedperdollarinvested.AsinthecaseofGRORcalculations,onlyifthesubsequentinvestmentisnotcoveredbypriorbenefits,thatinvestmentisincludedinthepresentvalueofinvestments.Sincethefuturebenefitscanonlybereceivedifweinitiatetheproject,itiscriticalthatwetrytocoverthesubsequentcostsbypriorbenefitsbeforewecoverthemwithoutofpocketexpenses.TheoutofpocketexpensebeinganadditionalexpenseshouldbereflectedinthedenominatorofEq.3.14.Foraprojecttobefeasible,thePIRhastobegreaterthanzero.Thefollowingexamplesillustratetheapplication.

Example3.31

Anoilcompanyintendstobuyaproducingpropertyforapriceof$lmillion.Itisexpectedtogenerate$280,000netincomeinthefirstyeardecliningat10%peryear.Thepropertywillbeheldforatleast10yearswithanexpectedsalvagevalueof$200,000.IftheMRORis15%,shouldthepropertybebought?UsePIR