Project Time Management SEII - Lecture 6

Project Time ManagementSEII-Lecture 6Dr. Muzafar KhanAssistant ProfessorDepartment of Computer ScienceCIIT, Islamabad.RecapDefining activitiesActivity list containing activity name, identifier, attributes, and brief descriptionSequencing activitiesdetermining the dependencies Mandatory, discretionary, externalevaluating the reasons for dependenciesEstimating activity resourceslist of activity resource requirements, resource breakdown structure, project document updatesEstimating activity durationsDuration VS effort, activity duration estimatesThree point estimatesDeveloping the scheduleProject schedule, Gantt charts2Tracking Gantt ChartsComparison of planned and actual datesTo evaluate the project progressPlanned schedule dates: baseline datesEntire approved planned schedule: baseline scheduleEasy to create and understand3Example – Tracking Gantt Chart4Figure source: IT Project Management, K. Schwalbe, 6th ed., p. 227Critical Path Method [1/2]Also called critical path analysisNetwork diagramming techniquePredict total project durationCritical path is the earliest time to complete the projectIt is the longest path through the network diagramIt has least amount of slack or floatThe amount of time an activity may be delayed without delaying a succeeding activity or the project finish date5Critical Path Method [2/2]Several tasks done in parallelMultiple paths through a network diagramLongest path or path containing critical tasks derive the completion dateHow to calculate critical pathDevelop a good network diagramEstimate activities durationsAdd durations of all activities on each pathThe longest path is the critical path6Example – CPM7Figure source: IT Project Management, K. Schwalbe, 6th ed., p. 229Issues related to CPMCreativity to manage critical pathStuffed gorilla and Apple computer projectConfusions about critical pathCritical does not mean critical activitiesIt is concerned with time dimensionCritical path is not the shortest pathExample: growing grassMore than one critical pathsCritical path can change8Schedule Trade-Offs using CPM [1/2]If the task on critical path is behind scheduleProactive role of project manager and teamTechnique to do trade-offsFree slack / floatThe amount of time activity can be delayed without delaying the early start date of any immediately following activitiesEarly start date is the earliest possible time to start an activity9Schedule Trade-Offs using CPM [2/2]Total slack / floatThe amount of time activity can be delayed from its early start without delaying the planned project finish dateProject managers calculate free and total slack by doing forward and backward passForward pass: early start and finish dates for each activityBackward pass: late start and finish dates for each activity10Example11Figure source: IT Project Management, K. Schwalbe, 6th ed., p. 231How to Shorten Project Schedule Using CPM [1/2]Stakeholders always want to shorten project scheduleDifferent duration compression techniquesOne is to reduce the duration of activities on the critical pathBy adding more resources or changing the scopeCrashingTo do cost and schedule trade-offsGreatest schedule compression for least incremental cost12How to Shorten Project Schedule Using CPM [2/2]Fast trackingTo do activities in parallel (rather than sequential)Risk of lengthening the project scheduleImportance of updating critical path dataUpdate the schedule with actual dataDocument revised estimatesInformed decisions based on updated plans13Critical Chain Scheduling [1/2]Based on Theory of Constraints (TOC)A chain with its weakest linkAny complex system at any point in time often has only one constraint that limits the ability to achieve more of its goalThat constraint must be identified for improvementCCS considers limited resources to create schedule and includes buffers to protect the completion date14Critical Chain Scheduling [2/2]Availability of limited/critical resourcesCCS avoids multitaskingA resource works on more than one tasksMurphy’s law: if something can go wrong, it willParkinson’s law: work expands to fill the time allowedCCS prefers project buffer and feeding buffers rather than individual tasks buffer15Example – CCS16Figure source: IT Project Management, K. Schwalbe, 6th ed., p. 235Example – Multitasking17Figure source: IT Project Management, K. Schwalbe, 6th ed., p. 234Program Evaluation and Review Technique (PERT)Another network analysis techniqueUsed when high degree of uncertainty about activity estimatesUses critical path method to a weighted average duration estimateUses probabilistic time estimatesOptimistic, most likely, and pessimistic time estimates18PERT weighted average = optimistic time + 4 * most likely time + pessimistic time 6Controlling the Schedule [1/2]Part of integrated change control under project integration managementMain objectives: schedule status information, influencing the factors that cause schedule changes, managing schedule changes Main inputs: project management plan, project schedule, work performance dataMain outputs: work performance measurements, change requests, lesson learned reports19Controlling the Schedule [2/2]ToolsProgress reportsSchedule change control systemSchedule comparison bar charts e.g. tracking Gantt chartVariance analysisWhat-if scenario analysisAdjusting leads and lagsSchedule compression e.g. crashing and fast trackingProject management software20Reality Checks on SchedulingShould have realistic schedule goalsReview the draft schedulePreparation of detailed scheduleSeeking stakeholders’ approvalInvolvement and commitment from all team members, top management, the customer, and other key stakeholdersProgress meetings with stakeholders21SummaryDeveloping the scheduleTracking Gantt chartsCritical path methodLongest path, earliest timeSchedule trade-offs using CPMFree slack, total slackShortening the scheduleCrashing, fast trackingCritical chain schedulingAvailability of critical resources, project and feeding bufferControlling the schedule22