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ETI 4448 Applied Project Management. Prof. Roy Levow Session 4. Building the Work Breakdown Structure (Ch. 4) -- Outline. 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. - PowerPoint PPT Presentation
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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 Approaches to Building the WBS Representing the WBS
“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
The process of breaking down work into a hierarchy of activities, tasks, and work packages
Uses
• Estimate Duration
• Determine Resources
• Schedule Work
Thought Process Tool Architectural Design Tool Planning Tool Project Status Reporting Tool
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.
Small Projects – Consider mindmapping Diagram relating components radiating out
from central element (Ref: Wikipedia article) Large Projects – Intermediate WBS Adaptive and Extreme Projects – Iterative
WBS
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
Stopping Before Completion Criteria Are Met
Decomposing Beyond Completion of the Criteria
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
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
The difference between Duration and Work Effort
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
Varying skill levels Unexpected events Efficiency of work time Mistakes and misunderstandings Common cause variation
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
“Early estimates will not be as good as later estimates.”
Types of resources People Facilities Equipment Money Materials
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
Used to estimate resource and costs by showing the positions needed for a particular project
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)
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
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
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
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
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
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
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
Early Method – Task-On-the-Arrow (TOA)
Precedence Diagramming Method (PDM)
First, every task in the WBS has a task node
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
Diagramming connections between tasks
Four Kinds of Task Dependencies
Technical Constraints Discretionary Best-Practices Logical Unique
Management Constraints Interproject Constraints Date Constraints
Pauses or delays between tasks Can be intentional Also created by constraints
Compute two schedules Early schedule – use Forward Pass Late schedule – use Backward Pass
Forward Pass Backward Pass
What’s different?
“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
First method – add up all of the path’s durations. The longest one is the critical path.
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
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
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)