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Prof. Roy Levow Session 4.  The Work Breakdown Structure  Uses for the WBS  Generating the WBS  Six Criteria to Test for Completeness in the WBS 

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Presentation on theme: "Prof. Roy Levow Session 4.  The Work Breakdown Structure  Uses for the WBS  Generating the WBS  Six Criteria to Test for Completeness in the WBS "— Presentation transcript:

1 Prof. Roy Levow Session 4

2  The Work Breakdown Structure  Uses for the WBS  Generating the WBS  Six Criteria to Test for Completeness in the WBS  Approaches to Building the WBS  Representing the WBS

3  “A hierarchical description of the work that must be done to complete the project as defined in the Project Overview Statement.”  Inputs  POS  Requirements Document  Terms  Activity: Chunk of work  Tasks: Smaller chunk of work. Activities are made up of tasks  Work Package: Complete description of how the tasks that make up the activity will actually be done

4 The process of breaking down work into a hierarchy of activities, tasks, and work packages Uses Estimate Duration Determine Resources Schedule Work

5  Thought Process Tool  Architectural Design Tool  Planning Tool  Project Status Reporting Tool

6  Top-Down Approach: Start with goal and continue to partition work until it has been sufficiently defined  Team Approach Variation  Subteam Approach Variation  Bottom-Up Approach: First-level tasks are identified. Then groups are formed around first-level tasks where these groups brainstorm the activities needed to complete the first-level task.

7  Small Projects – Consider mindmapping  Diagram relating components radiating out from central element (Ref: Wikipedia article)Wikipedia article  Large Projects – Intermediate WBS  Adaptive and Extreme Projects – Iterative WBS

8  Status/Completion is measurable  The activity is bounded  The activity has a deliverable  Time and cost are easily estimated  Activity duration is within acceptable limits  Work assignments are independent Seventh Criteria – Project manager’s judgment that the WBS is not complete

9  Stopping Before Completion Criteria Are Met  Decomposing Beyond Completion of the Criteria

10  Noun-type: In terms of the components of the deliverable  Physical Decomposition  Functional Decomposition  Verb-type: In terms of the actions that must be done to produce the deliverable  Design-build-test-implement  Objectives  Organizational: In terms of the units that will create the deliverable  Geographic  Departmental  Business Process




14 Outline  Estimating Duration  Estimating Resource Requirements  Estimating Duration as a Function of Resource Availability  Estimating Cost  Using a JPP Session to Estimate Duration, Resource Requirements, and Cost

15  The difference between Duration and Work Effort

16  Crashing the task – adding more resources to preserve duration  Diminishing returns  Crashpoint: adding more resources INCREASES task duration  Considerations  Not always feasible (Can nine women have a baby in one month?)  Communication overhead increases  Risk increases

17  Varying skill levels  Unexpected events  Efficiency of work time  Mistakes and misunderstandings  Common cause variation

18  Similarity to other activities  Historical Data  Expert Advice  Delphi Technique  Group of experts individually estimate duration  Then, average of the estimates is calculated  Do it two more times  Three-Point Technique  most optimistic estimate, most pessimistic estimate, and most likely estimate, which are then averaged  Wide-band Delphi Technique  Combination of Delphi and Three-Point techniques

19 “Early estimates will not be as good as later estimates.”

20  Types of resources  People  Facilities  Equipment  Money  Materials

21  Skills Matrices  Skills needed inventory  Skills currently on hand inventory  Skill Categories: uniform listing of skills  Skill Levels: level of expertise in a particular skill

22 Used to estimate resource and costs by showing the positions needed for a particular project

23  Three variables influence Duration Estimate  Duration  Total amount of work (hours/days)  Percent per day that person can devote to task  Methods for Estimating Duration  Assign as a Total Work and a Constant Percent/Day  40 hours / 0.50 = 80 hours  Assign as a Duration and Total Work Effort  5 person days / 10 days = 0.5  Assign as a Duration and Percent/Day  10 days X 0.50 = 5 person days  Assign as a Profile (when using multiple resources)

24  Resource Planning  Trading money for time (depends on skill level)  Part-time workers (think of ramp-up time)  Don’t overschedule resources  Cost Estimating  Order of magnitude estimate  Estimate is 25% above and 75% below final number  Budget estimate  Estimate is 10% above and 25% below final number  Definitive estimate  Estimate is 5% above and 10% below final number

25  Cost Budgeting – Assign costs to tasks on the WBS  Cost Control – Two major issues  How often report of costs is needed  Depends on risk and need to spot developing problems  Use of a cost baseline to spot cost variances when you receive actual figures

26 Advice from the author:  Get it roughly right  Spend more effort on front-end activities than on back-end activities  Consensus is all that is needed

27 Outline  The Project Network Diagram  Building the Network Diagram Using the Precedence Diagramming Method  Analyzing the Initial Project Network Diagram  Using the JPP Session to Construct and Analyze the Network

28  Definition: “A pictorial representation of the sequence in which the project work can be done.”  What is needed to construct diagram  Tasks  Task Duration  Earliest time to start task  Earliest expected completion date for the project

29  Older than the project network diagram  Rectangular bars that show the duration by length  Placed along a timeline in sequence  Does not indicate what task needs to be done before and after a task  Does not indicate if the project planning is most effective or efficient

30  Planning – Visual overview of the project that is easy to use for scheduling  Implementation – Software exists that automatically updates task dates and duration  Control – Project manager can better schedule tasks and spot variances

31 Early Method – Task-On-the-Arrow (TOA)

32 Precedence Diagramming Method (PDM)

33  First, every task in the WBS has a task node

34  Second, determine the sequence of tasks  Every task has at least one predecessor and at least one successor  EXCEPT  Start Task has no predecessor  End Task has no successor  Diagram the connections

35 Diagramming connections between tasks

36 Four Kinds of Task Dependencies

37  Technical Constraints  Discretionary  Best-Practices  Logical  Unique  Management Constraints  Interproject Constraints  Date Constraints

38  Pauses or delays between tasks  Can be intentional  Also created by constraints

39  Compute two schedules  Early schedule – use Forward Pass  Late schedule – use Backward Pass Forward PassBackward Pass What’s different?

40  “The longest duration path in the network diagram”  “The sequence of tasks whose early schedule and late schedule are the same”  “The sequence of tasks with zero slack or float” The Critical Path Determines the Completion Date of the Project

41  First method – add up all of the path’s durations. The longest one is the critical path.

42  Second method – Compute the slack time  The amount of delay (in time units) in starting a task that will not affect the project completion date  Difference between late finish and early finish of a slack time  Do not include holidays, weekends, and similar such time  Two types of slack  Free slack – amount of delay for a task without causing a delay in the early start of immediate successor task(s)  Total slack – amount of delay for a task without delaying the project completion date

43  Crashing the schedule: necessary when the initial project network diagram shows a projected completion date that is later than the requested completion date.  Strategies  Examine the Critical Path to see if you can move tasks off the Critical Path  Partition tasks into parallel subtasks  Concerns  Increase in risk  More communication and coordination needed


45  Padding task duration  Individual task level  Project level  Bad at the task level  BUT, good at the project level  Accounts for risk  Incentive (management reserve time not used can be the basis for bonus)

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