Chapter 5 Limiting Factors and Throughput Accounting5章限制因素和产出会计.docx

Chapter 5 Limiting Factors and Throughput Accounting5章限制因素和产出会计.docx

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Chapter5LimitingFactorsandThroughputAccounting5章限制因素和产出会计

Chapter5LimitingFactorsandThroughputAccounting

1.Objectives

1.1Identifylimitingfactorsinascarceresourcesituationandselectanappropriatetechnique.

1.2Determinetheoptimalproductionplanwhereanorganizationisrestrictedbyasinglelimitingfactor.

1.3Explaintheconceptofoptimizedproductiontechnology.

1.4Explainthetheoryofconstraints.

1.5Explaintheconceptofthroughputaccounting.

1.6Calculateandinterpretathroughputaccountingratio（TPAR）.

1.7Comparethetechniquesoflimitingfactorsandthroughputaccountinginthedeterminationofoptimalproduction.

2.LimitingFactors

2.1

LimitingFactors

Alimitingfactorisanyfactorthatisinscarcesupplyandthatstopstheorganisationfromexpandingitsactivitiesfurther,thatis,itlimitstheorganisationsactivities.

2.2Anorganisationmightbefacedwithjustonelimitingfactor（otherthanmaximumsalesdemand）buttheremightalsobeseveralscarceresources,withtwoormoreofthemputtinganeffectivelimitonthelevelofactivitythatcanbeachieved.

2.3Examplesoflimitingfactorsincludesalesdemandandproductionconstraints.

（a）Labour.Thelimitmaybeeitherintermsoftotalquantityorofparticularskills.

（b）Materials.Theremaybeinsufficientavailablematerialstoproduceenoughunitstosatisfysalesdemand.

（c）Manufacturingcapacity.Theremaynotbesufficientmachinecapacityfortheproductionrequiredtomeetsalesdemand.

2.4Itisassumedinlimitingfactoranalysisthatmanagementwouldmakeaproductmixdecisionorservicemixdecisionbasedontheoptionthatwouldmaximiseprofitandthatprofitismaximizedwhencontributionismaximised（givennochangeinfixedcostexpenditureincurred）.Inotherwords,marginalcostingideasareapplied.

（a）Contributionwillbemaximisedbyearningthebiggestpossiblecontributionperunitoflimitingfactor.ForexampleifgradeAlabouristhelimitingfactor,contributionwillbemaximisedbyearningthebiggestcontributionperhourofgradeAlabourworked.

（b）Thelimitingfactordecisionthereforeinvolvesthedeterminationofthecontributionearnedperunitoflimitingfactorbyeachdifferentproduct.

（c）Ifthesalesdemandislimited,theprofit-maximisingdecisionwillbetoproducethetoprankedproduct（s）uptothesalesdemandlimit.

2.5Inlimitingfactordecisions,wegenerallyassumethatfixedcostsarethesamewhateverproductorservicemixisselected,sothattheonlyrelevantcostsarevariablecosts.

2.6Whenthereisjustonelimitingfactor,thetechniqueforestablishingthecontribution-maximisingproductmixorservicemixistoranktheproductsorservicesinorderofcontribution-earningabilityperunitoflimitingfactor.

2.7

Example1

Sausagemakestwoproducts,theMashandtheSauce.Unitvariablecostsareasfollows.

Mash

Sauce

$

$

Directmaterials

1

3

Directlabour（$3perhour）

6

3

Variableoverhead

1

1

8

7

Thesalespriceperunitis$14perMashand$11perSauce.DuringJulytheavailabledirectlabourislimitedto8,000hours.SalesdemandinJulyisexpectedtobeasfollows.

Mash

3,000units

Sauce

5,000units

Required:

Determinetheproductionbudgetthatwillmaximizeprofit,assumingthatfixedcostspermonthare$20,000andthatthereisnoopeninginventoryoffinishedgoodsorworkinprogress.

Solution:

1.Determinethelimitingfactor

Mash

Sauces

Total

Labourhoursperunit

2hrs

1hr

Salesdemand

3,000units

5,000units

Labourhoursneeded

6,000hrs

5,000hrs

11,000hrs

Labourhoursavailable

8,000hrs

Shortfall

3,000hrs

Labouristhelimitingfactoronproduction.

2.Identifythecontributionearnedbyeachproductperunitofscarceresource,thatis,perlabourhourworked.

Mash

Sauce

$

$

Salesprice

14

11

Variablecost

8

7

Unitcontribution

6

4

Labourhourperunit

2hrs

1hr

Contributionperlabourhour（=perunitoflimitingfactor）

$3

$4

Ranking

2

1

3.Determinethebudgetedproductionandsales.

Product

Units

Hoursneeded

Contributionperunit

Total

$

$

Sauces

5,000

5,000

4

20,000

Mashes（Bal.）

1,500

3,000

6

9,000

8,000

29,000

Less:

fixedcosts

20,000

Profit

9,000

Conclusion:

（1）Unitcontributionisnotthecorrectwaytodecidepriorities.

（2）Labourhoursarethescarceresource,thereforecontributionperlabourhouristhecorrectwaytodecidepriorities.

（3）TheSauceearns$4contributionperlabourhour,andtheMashearns$3contributionperlabourhour.Saucesthereforemakemoreprofitableuseofthescarceresource,andshouldbemanufacturedfirst.

Question1

TriproductLimitedmakesandsellsthreetypesofelectronicsecuritysystemsforwhichthefollowinginformationisavailable.

Standardcostandsellingpricesperunit

Product

Dayscan

Nightscan

Omniscan

$

$

$

Materials

70

110

155

Manufacturinglabour

40

55

70

Installationlabour

24

32

44

Variableoverheads

16

20

28

Sellingprice

250

320

460

Fixedcostsfortheperiodare$450000andtheinstallationlabour,whichishighlyskilled,isavailablefor25000hoursonlyinaperiodandispaid£8perhour.

Bothmanufacturingandinstallationlabourarevariablecosts.

Themaximumdemandfortheproductis:

Dayscan

Nightscan

Omniscan

2,000units

3,000units

1,800units

Required:

（a）Calculatetheshortfall（ifany）inhoursofinstallationlabour.（2marks）

（b）Determinethebestproductionplan,assumingthatTriproductLimitedwishestomaximiseprofit.（5marks）

（c）Calculatethemaximumprofitthatcouldbeachievedfromtheplaninpart（b）above.

（3marks）

（d）Havingcarriedoutaninvestigationoftheavailabilityofinstallationlabour,thefirmthinksthatbyoffering$12perhour,additionallabourwouldbecomeavailableandthusovercomethelabourshortage.

Required:

Basedontheresultsobtainedabove,advisethefirmwhetherornottoimplementthe

proposal.（5marks）

（Total15marks）

3.ThroughputAccounting（產量會計）

3.1Optimizedproductiontechnology（OPT）

3.1.1Duringthe1980sGoldrattandCox（1984）advocatedanewapproachtoproductionmanagementcalledOPT.OPTisbasedontheprinciplethatprofitsareexpandedbyincreasingthethroughputoftheplant.TheOPTapproachdetermineswhatpreventsthroughputbeinghigherbydistinguishingbottleneckandnon-bottleneckresources.

3.1.2Abottleneckmightbeamachinewhosecapacitylimitsthethroughputofthewholeproductionprocess.Theaimistoidentifybottlenecksandremovethemor,ifthisisnotpossible,ensurethattheyarefullyutilizedatalltimes.

3.1.3Non-bottleneckresourcesshouldbescheduledandoperatedbasedonconstraintswithinthesystem,andshouldnotbeusedtoproducemorethanthebottleneckscanabsorb.TheOPTphilosophythereforeadvocatesthatnon-bottleneckresourcesshouldnotbeutilizedto100%oftheircapacity,sincethiswouldmerelyresultinanincreaseininventory.

3.2Theoryofconstraints

3.2.1GoldrattandCox（1992）describetheprocessofmaximizingoperatingprofitwhenfacedwithbottleneckandnon-bottleneckoperationsasthetheoryofconstraints（TOC）.

3.2.2TheTOCaimstoincreasethroughputcontributionwhilesimultaneouslyreducinginventoryandoperationalexpenses.However,thescopeforreducingthelatterislimitedsincetheymustbemaintainedatsomeminimumlevelforproductiontotakeplaceatall.Inotherwords,operationalexpensesareassumedtobefixedcosts.

3.2.3TheTOCadoptsashort-runtimehorizonandtreatsalloperatingexpenses（includingdirectlabourbutexcludingdirectmaterials）asfixed,thusimplyingthatvariablecostingshouldbeusedfordecision-making,profitmeasurementandinventoryvaluation.

3.2.4Itemphasizesthemanagementofbottleneckactivitiesasthekeytoimprovingperformancebyfocusingontheshort-runmaximizationofthroughputcontribution.

3.2.5

Example1–IllustrationoftheTOC

MachineXcanprocess1,000kgofrawmaterialperhour,machineY800kg.Ofaninputof900kg,100kgofprocessedmaterialmustwaitonthebottleneckmachine（machineY）attheendofanhourofprocessing.

Thetraditionalviewisthatmachinesshouldbeworking,notsittingidle.Soifthedesiredoutputfromtheaboveprocesswere8,100kgs,machineXwouldbekeptincontinualuseandall8,100kgswouldbeprocessedthroughthemachineinninehours.Therewouldbeabacklogof900kgs[8,100–（9hrs×800）]ofprocessedmaterialinfrontofmachineY,however.Allthismaterialwouldrequirehandlingandstoragespaceandcreatetheadditionalcostsrelatedtothesenon-valueaddedactivities.Itsprocessingwouldnotincreasethroughputcontribution.

3.3ThroughputAccounting（TA）

3.3.1GallowayandWaldron（1988）advocateanapproachcalledthroughputaccountingtoapplytheTOCphilosophy.

3.3.2

ThroughoutAccounting

Throughputaccountingisaproductmanagementsystemwhichaimstomaximisethroughput,andthereforecashgenerationfromsales,ratherthanprofit.Ajustintime（JIT）environmentisoperated,withbufferinventorykeptonlywhenthereisabottleneckresource.

3.3.3TAforJITissaidtobebasedonthreeconcepts.

（a）Concept1

Intheshortrun,mostcostsinthefactory（withtheexceptionofmaterialscosts）arefixed（theoppositeofABC,whichassumesthatallcostsarevariable）.Thesefixedcostsincludedirectlabour.ItisusefultogroupallthesecoststogetherandcallthemTotalFactoryCosts（TFC）.

（b）Concept2

InaJITenvironment,allinventoryisa'badthing'andtheidealinventorylevelisze