挣值法外文翻译.docx

挣值法外文翻译.docx

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挣值法外文翻译

挣值法外文翻译

1.外文原文

THEEARNEDVALUECONCEPT

Theearnedvalueconcept（sometimesalsocalledachievedvalue）comparesseveralmeasurestoobtainanoverallpictureofprojectstatus.Thefollowingarethethreeprimarydatarequirements:

BCWS:

BudgetedCostofWorkScheduled:

Thismeasure,alsocalledtheprojectplan,isdevelopedattheoutsetoftheprojectasitinvolvesassigningtoactivitiestheamountbudgeted（estimated）foreveryactivity.Knowingtheprojectschedule,itispossibletodeterminetheamountofmoneybudgetedrelativetotime.Thisisessentiallythesameasdevelopingthecumulativecostcurvediscussedearlier.

BCWP:

BudgetedCostofWorkPerformed:

Thisistheearnedvalueasitindicateswhatthebudgetedcostsarefortheworkthathasactuallybeenperformedtodate.Notethatthisrepresentstheperiodicworthoftheworkthatisactuallyperformed,basedontheinitialestimate,andhasnothingtodowiththeactualcostsincurredinperformingthework.Itrequiresmakinganassessmentoftheamountofworkcompleted（timeschedule）todateandthenapplyingtheappropriatebudgetedamountsforthiswork.

BAC:

BudgetedCostatCompletion:

Thisistheoriginalcostestimateofthetotalcostofconstruction.Itisideallythetotalestimatedcosttocompleteaproject.

EAC:

EstimatedCostatCompletion:

Thisistheforecastofthetotalactualcostsrequiredtocompleteaprojectbasedonperformancetodateandestimatesoffutureconditions.

ACWP:

ActualCostofWorkPerformed:

Thisisthemeasurethatbringstogetherthemonitoringofbothtimeschedule（workperformed）andcostrecords（actualcost）.Itgivestheactualcoststodate.（NotethatACWS,ActualCostofWorkScheduled,isnotacomponentofthesystem,becauseiftheworkscheduledhasnotyetbeenperformed,itisimpossibletodetermineitsactualcost!

）

Comparingthefirst（BCES）andlast（ACWP）valuestotheearnedvalue（BCWP）givesusanindicationof“variances”fromtheexpected.

SV:

ScheduleVariances;BCWP-BCWS:

Subtractingthebudgetedcostofworkscheduledfromthebudgetedcostofworkperformedprovidesanindicationofscheduledevianceintermsofdollarsofwork.Thecostsideofthesystemremainsconstant（usingbudgetedcostfigures）sothedifferencebetweenthetwoamountsmustbeduetoscheduledeviationsalone.Anegativevalueindicatesthattheprojectisbehindscheduleasthe“value”ofworkperformedislessthanthatschedule.ThisisshowngraphicallyinFigure10.1.Notethatthescheduledevianceispresentedintermsofdollars,whileinrealitythisisanindicationofprojectstatusintermsofscheduledtime.

SV=BCWP-BCWS（SV>0:

aheadofschedule,SV<0:

behindschedule）

CV:

CostVariance:

BCWP-ACWP:

Thedifferencebetweenthebudgetedcostsofworkperformedclearlyindicatesthestatusoftheprojectintermsofcost.Theworkperformedprovidesthecommonunitofcomparison.AnegativeCVindicatestheprojectisoverbudgetastheactualcostsexceedthebudgetedcosts.ThisisshowngraphicallyinFigure10.2.

CV=BCWP-ACWP（CV>0:

underbudget,CV<0:

overbudge）

Thesevariancescanbefurtherexpressedasratiosinpercentagefigures:

%SV:

%ScheduleVariance:

100×SV/BCWS:

Thisratioindicatesthepercentdeviationfromtheschedulebasedonbudgetedcostvalues.

%CV:

%CostVariance:

100×CV/BCWP:

Thismeasuregivesthepercentagedeviationfromtheactualcostsfromwhatwasbudgetedfortheworkperformedtodate.

Figure10.1EarnedValueAnalysisShowingaProjectthatIsAheadofSchedule

Similarly,costandscheduleindicatorscanbemeasuredas:

SPI:

SchedulePerformanceIndex:

BCWP/BCWS:

Thisratioprovidesadirectrelationshipbetweenworkperformedandworkscheduledbasedonbudgetedcosts.Avaluegreaterthan1.0indicatesthatmoreworkhasbeenperformedthanwasscheduled,andthustheprojectisaheadofschedule.

SPI=BCWP/BCWS（SPI>1:

aheadofschedule,SPI<1:

behindschedule）

CPI:

CostPerformanceIndex:

BCWP/ACWP:

Thisratiodirectlycomparesbudgetedcoststoactualcostsbasedonworkperformed.Avaluegreaterthan1.0indicatesthatthebudgetedamountoftheworkishigherthanwhatitactuallycost,andthereforetheprojectisunderbudget.SincedollarsarenotrepresentedintheCPI,theresultsaresometimeseasiertointerpret.

CPI=BCWP/ACWP（CPI>1:

underbudget,CPI<1:

overbudget）

Itcanbeexpectedthattheseperformanceindiceswillshowvariationsthroughoutthelifeoftheproject.Generally,itcanbeexpectedthattheindiceswillbelessthan1.0earlyintheprojectandriseastheprojectprogresses.Thisisduetostart-upand“learningcurve”factorsthatnormallyinhibitefficientoperationsearlyinaproject.Ifcalculatedseparatelyforeachtimeperiod,thevaluesmayalsoshowaraggedseriesofpeaksandvalues.Calculatingacumulativeindexfromprojectstarttodateshowsasmoothertransitionandovertimeshouldapproach1.0foraprojectthatisclosetoscheduleandbudget.

Figure10.2EarnedValueAnalysisShowingaProjectthatIsOverBudget

Determiningthestatusofpercentcompleteofaprojectcanalsobeaccomplishedwiththevariablesalreadydefined.Thepercentcomplete（PC）issimplytheratioBCWP/BAC,expressedasapercent.Notethatthisassessmentmerelydefinesthepercentcompletionbasedonoriginalestimatesandisnotinfluencedbyactualcostfigures.Anotherwayofviewingearnedvalue（BCWP）isgivesinthefollowingexpression:

EarnedValue=（PC）×（BAC）

Thepercentcompletioncanbecomparedwiththeexpectedoranticipatedpercentcompletionatagivenpointintime.Theplannedpercentcomplete（PPC）isderivedatapointintimewiththeratioBCWS/BAC,expressedasapercent.ThePPCiseasytograspasameasureoftheprojectstatuswhencomparedtothePC.Forexample,ifthePPCisdeterminedtobe60%andthePCisdeterminedtobe65%,itisclearthattheprojectisrunningaheadofschedule.

Informationonthecostindexandhowithaschangedovertimecanbeusedtoforecastwhatthecostswillbeattheendoftheproject,referredtoasEstimatedatCompletion（EAC）.TheforecastoftheEACcanalsobeobtainedatagivenpointintimewiththevariablesthathavealreadybeendefined.AsimplecomputationoftheEACatagivenpointintimeiscomputedasfollows:

EAC=ACWP+（BAC-BCWP）whereBAC-BCWPrepresentsunearnedhours

TheEACisthelatestrevisedofthetotalcostoftheprojectandcanbecomparedtotheBAC（originalestimatedprojectcost）todetermineanestimatedAtCompletionVariance（ACV）.SincetheEACisbasedoncostsincurredtodate,thisestimatewillbeacceptedasbeingmoreaccuratethantheBAC.TheACVisasimplecomputationandprovidesanestimateoftheamount（ACV-EAC）.IdACV>1,theprojectisexpectedtooverrunorexceedthebudget.BecauseoftheimportanceofthevalueofACV,itisimportantthatthedeterminationofEACbeasaccurateaspossible.TheprojectionofEACmayuseacumulativeaverageCPI,theCPIforthemostrecentperiod,orsomeotherselectedfigure.ApplyingtheselectedCPIratiototheBACvaluewillyieldanestimatedEAC（EAC=BAC/CPI）.

Example

Asimpleproblemwillhelptoillustratetheapplicationoftheprinciplesofearnedvalue.Aprojecthasbeendefinedthatconsistsof12activities（eachrequiresonemonthtocomplete）forwhichtheestimatedcostsanddurationshavebeendefined（seeFigure10.3）.

Theprojectcostsareestimatedto$257,000（BAC=sumofthecostsofallactivities）.Theprojectisscheduledtobecompletedinsixmonths.Afterthreeandahalfmonths,thesitework,excavation,foundation,fencing,androughelectricalworkarecompleted.Theframingisone-halfcomplete,theroughplumbingisthree-fourthscomplete,andthepavingishalfcomplete.Theincurredcoststodateare$152,000.

Whatisthestatusofthisprojectintermsofthescheduleandthebudget?

ACWP=$152,000（given）

BCWS=（$22,000+$30,000+$50,000+$10,000+$18,000）

+1/2×（$40,000+$6,000+$16,000）=$161,000

BCWP=（$22,000+$30,000+$50,000+$10,000+$6,000）

+1/2×（$40,000）+$3/4（$16,000）+1/2×（$18,000）=$159,000

Projectstatus:

ScheduleVariance=BCWP-BCWS=$159,000-$161,000=-$2,000

SPI=BCWP/BCWS=$159,000/$161,000=0.99

%ScheduleVariance:

100×SV/BCWS=100×（$2,000/$161,000）=-1.2%

Slightlybehindschedule

CostVariance=BCWP-ACWP=$159,000-$152,000=$7,000

CPI=BCWP/ACWP=$159,000/$152,000=1.05

%CostVariance:

100×CV/BCWP=100×（$7,000/$159,000）=+4.4%

Belowbudget

PercentComplete=BCWP/BAC×100%=$159,000/$257,000×100%

=62%complete

EAC=ACWP+（BAC-BCWP）=$152,000+（$257,000-$159,000）

=$250,000

Activity

Cost

Month1

Month2

Month3

Month4

Month5

Month6

Sitework

＄22,000

Fencing

＄10,000

Paving

＄18,000

Excavation

＄30,000

Foundation

＄50,000

Framing

＄40,000

Roughelectric

＄6,000

Roughplumbing

＄16,000

Drywall

＄13,000

Suspendceiling

＄4,000

Interiorfinish

＄34,000

Carpeting

＄14,000

Figure10.3ScheduleofActivitiesandTheirAssociatedCosts

Althoughtheprojectisslightlybehindschedule,itisperformingunderbudget.Theprojectiscurrentlyatthe62%completionstageandisestimatedtobecompletedforarevisedestimatedcostof$250,000,adecreasefromtheoriginalestimate.

2.外文翻译

挣值法的概念

挣值法的概念（有时也被称为实现价值）比较几种措施获得一个全面的了解项目状态。

以下是三种主要的数据要求：

BCWS:

计划工作预算成本：

这一措施，也被称为项目开发计划，在项目一开始就涉及分配活动的预算额（估计）的每一个活动。

了解项目进度，它有可能确定的数额的金钱预算相对时间。

这是基本相同的累计成本曲线前面讨论的发展。

BCWP:

已完成工作的预算成本：

这是挣值表明什么预算成本的工作，实际上已完成日期。

注意，这是周期性的工作，实际上是执行，根据初步估计，并没有实际发生的费用进行工作。

它需要做出评估完成的工作量（时间）的日期和运用适当的预算数额为这项工作。

BAC：

竣工预算费用：

这是用原来的成本估计总建筑成本。

它是理想的总费用估计完成项目。

EAC：

估计完工成本：

这是