it项目管理第六章

Chapter6:

ProjectTimeManagementInformationTechnologyProjectManagement,FifthEditionLearningObjectivesUnderstandtheimportanceofprojectschedulesandgoodprojecttimemanagementDefineactivitiesasthebasisfordevelopingprojectschedulesDescribehowprojectmanagersusenetworkdiagramsanddependenciestoassistinactivitysequencingUnderstandtherelationshipbetweenestimatingresourcesandprojectschedulesExplainhowvarioustoolsandtechniqueshelpprojectmanagersperformactivitydurationestimating2InformationTechnologyProjectManagement,FifthEdition,Copyright2007LearningObjectives(continued)UseaGanttchartforplanningandtrackingscheduleinformation,findthecriticalpathforaproject,anddescribehowcriticalchainschedulingandtheProgramEvaluationandReviewTechnique(PERT)affectscheduledevelopmentDiscusshowrealitychecksandpeopleissuesareinvolvedincontrollingandmanagingchangestotheprojectscheduleDescribehowprojectmanagementsoftwarecanassistinprojecttimemanagementandreviewwordsofcautionbeforeusingthissoftware3InformationTechnologyProjectManagement,FifthEdition,Copyright2007ImportanceofProjectSchedulesManagersoftencitedeliveringprojectsontimeasoneoftheirbiggestchallengesTimehastheleastamountofflexibility;itpassesnomatterwhathappensonaprojectScheduleissuesarethemainreasonforconflictsonprojects,especiallyduringthesecondhalfofprojects4InformationTechnologyProjectManagement,FifthEdition,Copyright2007IndividualWorkStylesandCulturalDifferencesCauseScheduleConflictsOnedimensionoftheMeyers-BriggsTypeIndicatorfocusesonpeoples’attitudestowardstructureanddeadlineSomepeopleprefertofollowschedulesandmeetdeadlines,whileothersdonot(Jvs.P)Differentculturesandevenentirecountrieshavedifferentattitudesaboutschedules5InformationTechnologyProjectManagement,FifthEdition,Copyright2007MediaSnapshotIncontrasttothe2002SaltLakeCityWinterOlympicGames(seeChapter4’sMediaSnapshot),planningandschedulingwasverydifferentforthe2004SummerOlympicGamesheldinAthens,GreeceManyarticleswerewrittenbeforetheopeningceremoniespredictingthatthefacilitieswouldnotbereadyintimeManypeoplewerepleasantlysurprisedbytheamazingopeningceremonies,beautifulnewbuildings,andstate-of-the-artsecurityandtransportationsystemsinAthensTheGreeksevenmadefunofcriticsbyhavingconstructionworkerspretendtostillbeworkingastheceremoniesbegan 6InformationTechnologyProjectManagement,FifthEdition,Copyright2007ProjectTimeManagementProcessesActivitydefinition:

identifyingthespecificactivitiesthattheprojectteammembersandstakeholdersmustperformtoproducetheprojectdeliverablesActivitysequencing:identifyinganddocumentingtherelationshipsbetweenprojectactivitiesActivityresourceestimating:

estimatinghowmanyresourcesaprojectteamshouldusetoperformprojectactivitiesActivitydurationestimating:

estimatingthenumberofworkperiodsthatareneededtocompleteindividualactivitiesScheduledevelopment:

analyzingactivitysequences,activityresourceestimates,andactivitydurationestimatestocreatetheprojectscheduleSchedulecontrol:controllingandmanagingchangestotheprojectschedule7InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-1:ProjectTimeManagementSummaryInformationTechnologyProjectManagement,FifthEdition,Copyright20078ActivityDefinitionProjectschedulesgrowoutofthebasicdocumentsthatinitiateaprojectProjectcharterincludesstartandenddatesandbudgetinformationScopestatementandWBShelpdefinewhatwillbedoneActivitydefinitioninvolvesdevelopingamoredetailedWBSandsupportingexplanationstounderstandalltheworktobedonesoyoucandeveloprealisticcostanddurationestimates9InformationTechnologyProjectManagement,FifthEdition,Copyright2007ActivityListsandAttributesAnactivitylistisatabulationofactivitiestobeincludedonaprojectschedulethatincludes:TheactivitynameAnactivityidentifierornumberAbriefdescriptionoftheactivityActivityattributesprovidemoreinformationsuchaspredecessors,successors,logicalrelationships,leadsandlags,resourcerequirements,constraints,imposeddates,andassumptionsrelatedtotheactivity10InformationTechnologyProjectManagement,FifthEdition,Copyright2007MilestonesAmilestoneisasignificanteventthatnormallyhasnodurationItoftentakesseveralactivitiesandalotofworktocompleteamilestoneThey’reusefultoolsforsettingschedulegoalsandmonitoringprogressExamplesincludeobtainingcustomersign-offonkeydocumentsorcompletionofspecificproducts11InformationTechnologyProjectManagement,FifthEdition,Copyright2007WhatWentWrong?AttheU.S.FederalBureauofInvestigation(FBI),poortimemanagementwasoneofthereasonsbehindthefailureofTrilogy,a“disastrous,unbelievablyexpensivepieceofvaporware,whichwasmorethanfouryearsinthe(un)making.ThesystemwassupposedtoenableFBIagentstointegrateintelligencefromisolatedinformationsiloswithintheBureau.”*InMay2006,theGovernmentAccountingAgencysaidthattheTrilogyprojectfailedatitscoremissionofimprovingtheFBI’sinvestigativeabilitiesandwasplaguedwithmissedmilestonesandescalatingcostsInformationTechnologyProjectManagement,FifthEdition,Copyright200712*Roberts,Paul,“FrustratedcontractorsentencedforhackingFBItospeeddeployment,”InfoWorldTechWatch,(July6,2006).ActivitySequencingInvolvesreviewingactivitiesanddeterminingdependenciesAdependencyorrelationshipisthesequencingofprojectactivitiesortasks Youmustdeterminedependenciesinordertousecriticalpathanalysis13InformationTechnologyProjectManagement,FifthEdition,Copyright2007ThreeTypesofDependenciesMandatorydependencies:inherentinthenatureoftheworkbeingperformedonaproject,sometimesreferredtoashardlogicDiscretionarydependencies:

definedbytheprojectteam;sometimesreferredtoassoftlogicandshouldbeusedwithcaresincetheymaylimitlaterschedulingoptionsExternaldependencies:involverelationshipsbetweenprojectandnonprojectactivities14InformationTechnologyProjectManagement,FifthEdition,Copyright2007NetworkDiagramsNetworkdiagramsarethepreferredtechniqueforshowingactivitysequencingAnetworkdiagramisaschematicdisplayofthelogicalrelationshipsamong,orsequencingof,projectactivitiesTwomainformatsarethearrowandprecedencediagrammingmethods15InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-2:SampleActivity-on-Arrow(AOA)NetworkDiagramforProjectX16InformationTechnologyProjectManagement,FifthEdition,Copyright2007ArrowDiagrammingMethod(ADM)Alsocalledactivity-on-arrow(AOA)networkdiagramsActivitiesarerepresentedbyarrowsNodesorcirclesarethestartingandendingpointsofactivitiesCanonlyshowfinish-to-startdependencies17InformationTechnologyProjectManagement,FifthEdition,Copyright2007ProcessforCreatingAOADiagrams1.Findalloftheactivitiesthatstartatnode1:Drawtheirfinishnodesanddrawarrowsbetweennode1andthosefinishnodes;puttheactivityletterornameanddurationestimateontheassociatedarrow2.Continuedrawingthenetworkdiagram,workingfromlefttoright:LookforburstsandmergesBurstsoccurwhenasinglenodeisfollowedbytwoormoreactivitiesAmergeoccurswhentwoormorenodesprecedeasinglenode3.Continuedrawingtheprojectnetworkdiagramuntilallactivitiesareincludedonthediagramthathavedependencies4.Asaruleofthumb,allarrowheadsshouldfacetowardtheright,andnoarrowsshouldcrossonanAOAnetworkdiagram18InformationTechnologyProjectManagement,FifthEdition,Copyright2007PrecedenceDiagrammingMethod(PDM)ActivitiesarerepresentedbyboxesArrowsshowrelationshipsbetweenactivitiesMorepopularthanADMmethodandusedbyprojectmanagementsoftwareBetteratshowingdifferenttypesofdependencies19InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-3:TaskDependencyTypes20InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-4:SamplePDMNetworkDiagram21InformationTechnologyProjectManagement,FifthEdition,Copyright2007ActivityResourceEstimatingBeforeestimatingactivitydurations,youmusthaveagoodideaofthequantityandtypeofresourcesthatwillbeassignedtoeachactivityConsiderimportantissuesinestimatingresourcesHowdifficultwillitbetodospecificactivitiesonthisproject?Whatistheorganization’shistoryindoingsimilaractivities?Aretherequiredresourcesavailable?Aresourcebreakdownstructureisahierarchicalstructurethatidentifiestheproject’sresourcesbycategoryandtype22InformationTechnologyProjectManagement,FifthEdition,Copyright2007ActivityDurationEstimatingDurationincludestheactualamountoftimeworkedonanactivitypluselapsedtimeEffortisthenumberofworkdaysorworkhoursrequiredtocompleteataskEffortdoesnotnormallyequaldurationPeopledoingtheworkshouldhelpcreateestimates,andanexpertshouldreviewthem23InformationTechnologyProjectManagement,FifthEdition,Copyright2007Three-PointEstimatesInsteadofprovidingactivityestimatesasadiscretenumber,suchasfourweeks,it’softenhelpfultocreateathree-pointestimateAnestimatethatincludesanoptimistic,mostlikely,andpessimisticestimate,suchasthreeweeksfortheoptimistic,fourweeksforthemostlikely,andfiveweeksforthepessimisticestimateThree-pointestimatesareneededforPERTandMonteCarlosimulations24InformationTechnologyProjectManagement,FifthEdition,Copyright2007ScheduleDevelopmentUsesresultsoftheothertimemanagementprocessestodeterminethestartandenddateoftheprojectUltimategoalistocreatearealisticprojectschedulethatprovidesabasisformonitoringprojectprogressforthetimedimensionoftheprojectImportanttoolsandtechniquesincludeGanttcharts,criticalpathanalysis,criticalchainscheduling,andPERTanalysis25InformationTechnologyProjectManagement,FifthEdition,Copyright2007GanttChartsGanttchartsprovideastandardformatfordisplayingprojectscheduleinformationbylistingprojectactivitiesandtheircorrespondingstartandfinishdatesinacalendarformatSymbolsinclude:Blackdiamonds:milestonesThickblackbars:summarytasksLighterhorizontalbars:durationsoftasksArrows:dependenciesbetweentasks26InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-5:GanttChartforProjectXNote:DarkerbarswouldberedinProject2007torepresentcriticaltasks27InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-6:GanttChartforSoftwareLaunchProject28InformationTechnologyProjectManagement,FifthEdition,Copyright2007AddingMilestonestoGanttChartsManypeopleliketofocusonmeetingmilestones,especiallyforlargeprojectsMilestonesemphasizeimportanteventsoraccomplishmentsonprojectsNormallycreatemilestonebyenteringtaskswithazeroduration,oryoucanmarkanytaskasamilestone29InformationTechnologyProjectManagement,FifthEdition,Copyright2007SMARTCriteriaMilestonesshouldbe:SpecificMeasurableAssignableRealisticTime-framed30InformationTechnologyProjectManagement,FifthEdition,Copyright2007BestPracticeScheduleriskisinherentinthedevelopmentofcomplexsystemsLucRichard,thefounderof,suggeststhatprojectmanagerscanreducescheduleriskthroughprojectmilestones,abestpracticethatinvolvesidentifyingandtrackingsignificantpointsorachievementsintheprojectInformationTechnologyProjectManagement,FifthEdition,Copyright200731Thefivekeypointsofusingprojectmilestonesincludethefollowing:1.DefinemilestonesearlyintheprojectandincludethemintheGanttcharttoprovideavisualguide2.Keepmilestonessmallandfrequent3.Thesetofmilestonesmustbeall-encompassing4.Eachmilestonemustbebinary,meaningitiseithercompleteorincomplete5.CarefullymonitorthecriticalpathInformationTechnologyProjectManagement,FifthEdition,Copyright200732BestPractice(continued)Figure6-7:SampleTrackingGanttChart33InformationTechnologyProjectManagement,FifthEdition,Copyright2007CriticalPathMethod(CPM)CPMisanetworkdiagrammingtechniqueusedtopredicttotalprojectdurationAcriticalpathforaprojectistheseriesofactivitiesthatdeterminestheearliesttimebywhichtheprojectcanbecompletedThecriticalpathisthelongestpaththroughthenetworkdiagramandhastheleastamountof

slackorfloatSlackorfloatis

theamountoftimeanactivitymaybedelayedwithoutdelayingasucceedingactivityortheprojectfinishdate34InformationTechnologyProjectManagement,FifthEdition,Copyright2007CalculatingtheCriticalPathFirstdevelopagoodnetworkdiagramAddthedurationestimatesforallactivitiesoneachpaththroughthenetworkdiagramThelongestpathisthecriticalpathIfoneormoreoftheactivitiesonthecriticalpathtakeslongerthanplanned,thewholeprojectschedulewillslipunlesstheprojectmanagertakescorrectiveaction35InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-8:DeterminingtheCriticalPathforProjectX36InformationTechnologyProjectManagement,FifthEdition,Copyright2007MoreontheCriticalPathAprojectteamatApplecomputerputastuffedgorillaonthetopofthecubicleofthepersoncurrentlymanagingacriticaltaskThecriticalpathisnottheonewithallthecriticalactivities;itonlyaccountsfortimeRemembertheexampleofgrowinggrassbeingonthecriticalpathforDisney’sAnimalKingdomTherecanbemorethanonecriticalpathifthelengthsoftwoormorepathsarethesameThecriticalpathcanchangeastheprojectprogresses37InformationTechnologyProjectManagement,FifthEdition,Copyright2007UsingCriticalPathAnalysistoMakeScheduleTrade-offsFreeslackorfreefloatistheamountoftimeanactivitycanbedelayedwithoutdelayingtheearlystartofanyimmediatelyfollowingactivitiesTotalslackortotalfloatistheamountoftimeanactivitymaybedelayedfromitsearlystartwithoutdelayingtheplannedprojectfinishdateAforwardpassthroughthenetworkdiagramdeterminestheearlystartandfinishdatesAbackwardpassdeterminesthelatestartandfinishdates38InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-9:CalculatingEarlyandLateStartandFinishDates39InformationTechnologyProjectManagement,FifthEdition,Copyright2007Table6-1:FreeandTotalFloatorSlackforProjectX40InformationTechnologyProjectManagement,FifthEdition,Copyright2007UsingtheCriticalPathtoShortenaProjectScheduleThreemaintechniquesforshorteningschedulesShorteningdurationsofcriticalactivities/tasksbyaddingmoreresourcesorchangingtheirscopeCrashing

activitiesbyobtainingthegreatestamountofschedulecompressionfortheleastincrementalcostFasttrackingactivitiesbydoingtheminparalleloroverlappingthem41InformationTechnologyProjectManagement,FifthEdition,Copyright2007ImportanceofUpdatingCriticalPathDataItisimportanttoupdateprojectscheduleinformationtomeettimegoalsforaprojectThecriticalpathmaychangeasyouenteractualstartandfinishdatesIfyouknowtheprojectcompletiondatewillslip,negotiatewiththeprojectsponsor42InformationTechnologyProjectManagement,FifthEdition,Copyright2007CriticalChainSchedulingCriticalchainschedulingAmethodofschedulingthatconsiderslimitedresourceswhencreatingaprojectscheduleandincludesbufferstoprotecttheprojectcompletiondateUsestheTheoryofConstraints

(TOC)AmanagementphilosophydevelopedbyEliyahuM.GoldrattandintroducedinhisbookTheGoal

AttemptstominimizemultitaskingWhenaresourceworksonmorethanonetaskatatime43InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-10:MultitaskingExample44InformationTechnologyProjectManagement,FifthEdition,Copyright2007BuffersandCriticalChainAbufferisadditionaltimetocompleteataskMurphy’sLawstatesthatifsomethingcangowrong,itwillParkinson’sLawstatesthatworkexpandstofillthetimeallowedIntraditionalestimates,peopleoftenaddabuffertoeachtaskanduseitifit’sneededornotCriticalchainschedulingremovesbuffersfromindividualtasksandinsteadcreates:Aprojectbufferoradditionaltimeaddedbeforetheproject’sduedateFeedingbuffersoradditionaltimeaddedbeforetasksonthecriticalpath45InformationTechnologyProjectManagement,FifthEdition,Copyright2007Figure6-11:ExampleofCriticalChainScheduling46InformationTechnologyProjectManagement,FifthEdition,Copyright2007ProgramEvaluationandReviewTechnique(PERT)PERTisanetworkanalysistechniqueusedtoestimateprojectdurationwhenthereisahighdegreeofuncertaintyabouttheindividualactivitydurationestimatesPERTusesprobabilistictimeestimatesDurationestimatesbasedonusingoptimistic,mostlikely,andpessimisticestimatesofactivitydurations,orathree-pointestimate47InformationTechnologyProjectManagement,FifthEdition,Copyright2007PERTFormulaandExamplePERTweightedaverage=

optimistictime+4Xmostlikelytime+pessimistictime

6Example:PERTweightedaverage=

8workdays+4X10workdays+24workdays =12days

6whereoptimistictime=8days,mostlikelytime=10days,andpessimistictime=24daysTherefore,you’duse12daysonthenetworkdiagraminsteadof10whenusingPERTfortheaboveexample48InformationTechnologyProjectManagement,FifthEdition,Copyright2007ScheduleControlPerformrealitychecksonschedulesAllowforcontingenciesDon’tplanforeveryonetoworkat100%capacityallthetimeHoldprogressmeetingswithstakeholdersandbeclearandhonestincommunicatingscheduleissues49InformationTechnologyProjectManagement,FifthEdition,Copyright2007ScheduleControl(continued)Goalsaretoknowthestatusoftheschedule,influencefactorsthatcauseschedulechanges,determinethattheschedulehaschanged,andmanagechangeswhentheyoccurToolsandtechniquesinclude:ProgressreportsAschedulechangecontrolsystemProjectmanagementsoftware,includingschedulecomparisonchartslikethetrackingGanttchartVarianceanalysis,suchasanalyzingfloatorslackPerformancemanagement,suchasearnedvalue(chapter7)50InformationTechnologyProjectManagement,FifthEdition,Copyright2007RealityChecksonSchedulingFirstreviewthedraftscheduleorestimatedcompletiondateintheprojectcharterPrepareamoredetailedschedulewiththeprojectteamMakesurethescheduleisrealisticandfollowedAlerttopmanagementwellinadvanceiftherearescheduleproblems51InformationTechnolo