Effective Project Management:
Traditional, Agile, Extreme
Managing Complexity in
the Face of Uncertainty
Ch04: How to Plan a Project
Presented by
(facilitator name)
Ch04: How to Plan a Project
Summary of Chapter 4
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The Importance of Planning
Using application software packages to plan projects
Planning & conducting the Joint Project Planning Session
(JPPS)
Writing a Project Description Statement
Building the Work Breakdown Structure (WBS)
Estimating task duration
Estimating resource requirements
Estimating cost
Constructing the project network diagram
Analyzing the project network diagram
Leveling resources
Writing work packages
Writing an effective project proposal
Ch04: How to Plan a Project
The Pain Curve
Pain
Good
Planning
Poor
Planning
18-36%
Time
Figure
04-01
Ch04: How to Plan a Project
The Importance of Planning
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Planning Reduces Uncertainty: consider the likely
outcomes and to put the necessary corrective measures in
place when things don’t happen according to plan.
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Planning Increases Understanding: better
understanding of the goals and objectives of the project
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Planning Improves Efficiency: take advantage of
resource availability (schedule work in parallel)
Ch04: How to Plan a Project
Using Software Packages to Plan a Project
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Yes
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Very large projects
Distributed teams
Extensive use of vendors and contractors
No
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Small projects
Short duration project increments
Adds too much non-value-added work
Frequent scope and requirements changes
Ch04: How to Plan a Project
Project Planning Tools
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Sticky notes (assorted colors)
Marking pens (assorted colors)
Plenty of whiteboard space
Ch04: How to Plan a Project
Uses for Sticky Notes
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Task ID
Unique task name
Task duration
Task labor
Resource requirements
Task manager
ES, EF, LS, and LF (calculated values)
Critical Path (calculated)
Uses for Sticky Notes…
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Color-coded sticky notes offer a number of alternatives
for the creative planner. For example, you can use a
different color to represent each of the following:
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The type of task (critical, for example)
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Specific parts of the WBS (design, build, test, and implement,
for example)
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A position on the team (a critical or scarce skill, for example)
Ch04: How to Plan a Project
Uses for Marking Pens
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Define dependency relationships
Identify the critical path
Ch04: How to Plan a Project
Uses for the Whiteboard
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Project Overview Statement
Work Breakdown Structure
Dependency Diagram
Initial Project Schedule
Final Project Schedule
Resource Schedule
Issues Log
Updated Project Schedule
Ch04: How to Plan a Project
How Much Time Should Planning Take?
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Very small projects
Small projects
Medium projects
Large projects
Very large projects
< ½ day
< 1 day
2 days
3-4 days
???
Ch04: How to Plan a Project
How to Run a Project Planning Session
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Planning team reviews POS for clarity
Planning team creates the complete WBS
Estimate task duration and resource needs
Construct project network diagram
Determine critical path
Revise and approve project completion date
Finalize resource schedule
Gain consensus on the project plan
Planning and Conducting Joint Project Planning
Sessions
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The JPPS is a group session in which all of the people who are
involved in the project meet to develop the detailed plan.
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The session can last from one to three days, and it can be workintensive.
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Objective: Develop a project plan that meets the COS as
negotiated between the requestor and the provider, and as
described in the POS.
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Simple? No
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Why?
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The client and the project team are generally impatient to get on with
the work of the project.
Team members don’t have time for planning — there is too much
work to do and too many clients to satisfy.
Planning the JPPS
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Team planning has always been viewed as
advantageous over other forms of project planning,
such as the project manager planning the project by
walking around gathering data for the plan.
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The first document considered in the JPPS is the POS.
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The project team might write the Project Definition
Statement (PDS) — their understanding of the project.
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The PDS is nothing more than an expanded version of
the POS, but from the perspective of the planning
team.
Ch04: How to Plan a Project
The Planning Meeting Components
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Attendees
Facilities
Equipment
Agenda
Deliverables
Project Proposal
Attendees
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The JPPS participants are invited from among those
who might be affected by or have input into the project.
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If the project involves deliverables or is a new process
or procedure, then anyone who has input to the
process, receives output from the process, or handles
the deliverables should be invited to participate in the
JPPS.
Ch04: How to Plan a Project
The Planning Meeting Attendees
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Facilitator: not have an interest or bring biases
Project manager: concentrate on the plan itself
Another project manager: facilitator
JPP consultant: another source of qualified JPPS facilitators
Technographer: expert in the software tools used to document
the project plan
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Core project team: individuals (from the client and from the
provider) who will stay with the project from the first day to the last day.
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Client representative: contribute to resolutions of change requests.
Resource managers
Project champion : drives the project and sells it to senior
management
The Planning Meeting Attendees
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Functional managers: manage areas that can either provide
input to or receive output from the project deliverables
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Process owner: If the project deliverables do not smoothly
integrate into their processes, either the project plan or the
affected processes will have to be altered.
Ch04: How to Plan a Project
The Planning Session Facilities & Equipment
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Facilities
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Comfortable
Away from interruptions (off-site or on-site)
Break-out rooms?
Equipment
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Break-out group work areas (table, chairs, bflip charts)
Whiteboards
Projection equipment
Ch04: How to Plan a Project
The Complete Planning Agenda
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Session #1
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Session #2
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Negotiate the COS or generate the RBS
Write the POS
Session #3
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Part 1: Planning Kick-off
Part 2: Working session
Session #3 (JPPS)…
1. The entire planning team creates the first-level WBS.
2. Subject matter experts develop further decomposition,
with the entire planning team observing and
commenting.
3. Estimate activity durations and resource requirements.
4. Construct a project network diagram.
5. Determine the critical path.
6. Revise and approve the project completion date.
7. Finalize the resource schedule.
8. Gain consensus on the project plan.
Deliverables
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The deliverables from the JPPS are:
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Work Breakdown Structure
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Activity Duration Estimates
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Resource Requirements
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Project Network Schedule
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Activity Schedule
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Resource Assignments
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Project Notebook
Ch04: How to Plan a Project
Definition of the WBS
The Work Breakdown Structure (WBS) is a
hierarchical description of all of the work
that must be done to meet the needs of the
client.
The Requirements Breakdown
Structure (RBS) is the input to the
WBS construction process.
Ch04: How to Plan a Project
Hierarchical visualization of the WBS
Figure
04-02
WBS…
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Terms
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An activity is simply a chunk of work.
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A task is a smaller chunk of work.
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An activity is composed of two or ore tasks.
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When the tasks that make up an activity are complete,
the activity is complete.
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A work package is a complete description of how the
tasks that make up an activity will actually be done. It
includes a description of the what, who, when, and how
of the work.
WBS terms…
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Breaking down work into a hierarchy of activities, tasks,
and work packages is called decomposition.
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Decomposition is important to the overall project plan
because it enables you to estimate the duration of the
project, determine the required resources, and
schedule the work.
Ch04: How to Plan a Project
Why is the WBS Important?
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Thought process tool: It helps the project manager and the
planning team visualize exactly how the work of the project can be
defined and managed effectively.
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Architectural design tool: WBS is a picture of the work of the
project and how the items of work are related to one another.
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Planning tool: It is at the lowest activity level of the WBS that you
will estimate effort, elapsed time, and resource requirements; build
a schedule of when the work will be completed; and estimate
deliverable dates and project completion.
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Project status reporting tool: Shading is often used to highlight
completed tasks and activities. the WBS defines milestone events
that can be reported to senior management and the client.
Ch04: How to Plan a Project
How to Build a WBS
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Top-Down Approach
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Team Approach
Subteam Approach
Bottom-Up Approach
Which is best?
When?
Why?
Top-Down Approach
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A sufficient level of detail to enable you to estimate
time, cost, and resource requirements first at the
activity level and then aggregate to the project level.
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Many activities should be performed in parallel, rather
than in sequence.
Two variations of the top-down approach:
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Team Approach: need longer time but is the better
Subteam Approach: divide the planning team into as many
subteams as there are activities at Level 1 of the WBS. the
entire planning team decides on the approach for the first-level
breakdown. After that, the group is partitioned into subteams,
with each subteam having some expertise for that part of the
WBS.
Bottom-Up Approach
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This approach is more like a brainstorming session
than an organized approach to building the WBS.
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The first steps in the bottom-up approach are the same
as those for the top-down approach. Namely, the entire
planning team agrees to the first-level breakdown.
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The planning team is then divided into as many groups
as there are first-level activities.
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Each group makes a list of the activities that must be
accomplished in order to complete the first-level
activity.
Which is best?
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The bottom-up approach randomly identifies activities
and tasks, which increases the possibility of missing
something.
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On the other hand, the top-down approach is a
logically organized approach, and the likelihood of
missing an activity or task is minimal.
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The author recommend the top-down approach
Using the WBS for Large Projects
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As project size increases, it becomes unwieldy to build
the entire WBS with the all of the planning team
assembled.
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Begin by decomposing the WBS down to Level 3
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At that point, develop intermediate estimates of time,
resources, and dependencies for all Level 3 activities.
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The planning session is adjourned, and the Level 3
activity managers are charged with completing the
WBS for their part of the project.
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Then the full JPPS team can be reassembled, and the
planning process continues from that point.
Ch04: How to Plan a Project
WBS Completion Criteria
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Status and completion are measurable
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The activity is bounded.
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Can I easily estimate time and cost?
Activity duration is within acceptable limits.
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Does the activity have a deliverable?
Time and cost are easily estimated.
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Is there a defined start and end event?
The activity has a deliverable.
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Can I determine activity status at any point in time?
Is the activity duration within acceptable limits?
Work assignments are independent.
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Can the activity work be done without interruption?
WBS Completion Criteria…
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If the activity does not possess all six of these
characteristics, decompose the activity and check it
again at that next lower level of decomposition.
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As soon as an activity possesses the six
characteristics, there is no need to further decompose
it.
Status and Completion Are Measurable
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What has been actually completed (that is approved)
and what remains to be done, along with an estimate to
completion.
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A simple metric that has met with some success is to
compute the proportion of tasks completed as a
percentage of all tasks that make up the activity.
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For example, if the activity has six tasks associated with it and
four of the tasks are complete, the ratio of tasks completed to
total tasks is 4/6 — that is, the activity is 60 percent complete.
Even if work is done on the fifth task in this activity, because
the task is not complete on the report date, it cannot be
counted in the ratio.
The Activity Is Bounded
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Each activity should have a clearly defined start and
end event.
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After the start event has occurred, work can begin on
the activity.
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The deliverable is most likely associated with the end
event that signals work is closed on the activity.
The Activity Has a Deliverable
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The deliverable is a visible sign that the activity is
complete.
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This sign could be an approving manager’s signature,
a physical product or document, the authorization to
proceed to the next activity, or some other sign of
completion.
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The deliverable from an activity is output from that
activity, which then becomes input to one or more other
activities that follow its completion.
Time and Cost Are Easily Estimated
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Estimating time and cost at the lowest level of
decomposition in the WBS enables you to aggregate to
higher levels and estimate the total project cost and the
completion date.
Activity Duration Is Within Acceptable Limits
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The author recommend that an activity have a duration
of less than two calendar weeks.
Work Assignments Are Independent
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An activity should continue reasonably well without
interruption and without the need for additional input or
information until the activity is complete.
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The work effort could be contiguous, but it can be
scheduled otherwise for a variety of reasons. You can
choose to schedule it in parts because of resource
availability, but you could have scheduled it as one
continuous stream of work.
Ch04: How to Plan a Project
WBS Completion Criteria – The 7th criterion
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The client didn’t participate in building the WBS like
you expected.
You have an uncomfortable feeling
Scope change is likely to be a big part of the project
Choose a PMLC model that accommodates frequent
change
Ch04: How to Plan a Project
WBS Completion Criteria – Exceptions
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Stopping Before Completion Criteria Are Met
Decomposing Beyond Completion of the Criteria
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Short duration projects
High risk activities
Large duration variance
Ch04: How to Plan a Project
RBS is a subset of the WBS
Project goal
and solution
Requirement
1
Function
1.1
Sub-function
1.2.1
Feature
1.2.1.1
Activity
1.2.1.1.1
Function
1.2
Sub-function
1.2.2
Feature
1.2.1.2
Activity
1.2.1.1.2
Task
1.2.1.1.3.1
Feature
1.2.1.3
WBS
Requirement n
Function
1.3
Function
n.1
Function
n.2
Function
n.3
Sub-function
1.2.3
Feature
1.2.1.4
Activity
1.2.1.1.3
Task
1.2.1.1.3.2
RBS
Feature
n.3.1
Feature
n.3.2
Activity
n.3.4.1
Task
1.2.1.1.3.3
Feature
n.3.3
Feature
n.3.4
Activity
n.3.4.2
Task
n.3.4.3.1
Activity
n.3.4.3
Task
n.3.4.3.2
Task
n.3.4.3.3
Figure
04-03
Ch04: How to Plan a Project
Approaches to Building the WBS
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Noun-type Approaches
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Verb-type Approaches
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Physical components
Functional components
Design-build-test-implement
Objectives
Organizational approaches
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Geographic
Departmental
Business process
Which is best?
When?
Why?
Ch04: How to Plan a Project
Approaches to Building the WBS
Noun-type Approaches:
 defines the deliverable of the project in terms of
the components:
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Physical components
Functional components
Currently recommended by PMI.
Closed to the RBS.
RBS is a part of the WBS
Ch04: How to Plan a Project
Building the WBS
Ch04: How to Plan a Project
RBS is a subset of the WBS
Project goal
and solution
Requirement
1
RBS: what
must be
done
Function
1.1
Sub-function
1.2.1
Function
1.2
Sub-function
1.2.2
RBS
WBS
Requirement n
Function
1.3
Function
n.1
Function
n.2
Function
n.3
Sub-function
1.2.3
WBS: How it
will be done
Feature
1.2.1.1
Activity
1.2.1.1.1
Feature
1.2.1.2
Activity
1.2.1.1.2
Task
1.2.1.1.3.1
Feature
1.2.1.3
Feature
1.2.1.4
Activity
1.2.1.1.3
Task
1.2.1.1.3.2
Feature
n.3.1
Feature
n.3.2
Activity
n.3.4.1
Task
1.2.1.1.3.3
Feature
n.3.3
Feature
n.3.4
Activity
n.3.4.2
Task
n.3.4.3.1
Activity
n.3.4.3
Task
n.3.4.3.2
Task
n.3.4.3.3
Figure
04-03
Ch04: How to Plan a Project
Approaches to Building the WBS
Verb-type Approaches
Define the deliverable of the project in terms of
action that must be done to produce the deliverable.
Design-build-test-implement
used in projects that involve methodology such
as system development
Objectives:
used when frequent progress reports submitted
to the senior management.
Objectives are almost always related to business
value and will be well received by senior
management as well as the client.
Cause some difficulty because objectives always
overlap.
Ch04: How to Plan a Project
Approaches to Building the WBS
Organizational approaches
Used only when forced by senior management
and organizational structure
Types include:
Geographic
Departmental
Business process
Organizational approaches: Geographic

If project work is geographically dispersed, it may make
sense from coordination and communication
perspectives to partition the work first by geographic
location and then by some other approach at each
location.
Organizational approaches: Departmental

you might benefit from partitioning the project first by
department and then within each department by
whatever approach makes sense.

You benefit from this structure in that a major portion of
the project work is under the organizational control of a
single manager, which in turn simplifies resource
allocation.

Conversely, using this approach increases the need for
communication and coordination across organizational
boundaries.
Organizational approaches:

This approach involves breaking the project down first
by business process and then by some other method
for each process.

This has the same advantages and disadvantages as
the departmental approach, with the added
complication that integration of the deliverables from
each process can be more difficult when you use this
approach.

The difficulty arises from process interactions at the
boundaries of the involved processes.
Ch04: How to Plan a Project
Graphical WBS for a House
HOUSE
FOUNDATIO
N
SITE
Layout
Grade
FRAMING
WALLS
Install
Sheathing
Excavate
Erect
Forms
ROOFING
Pour
Concrete
Remove
forms
SUBFLOOR
FLOOR
JOISTS
Hang
Sheetrock
STUD
WALLS
Tape
& Bed
Install
1st
Floor
Install
1st
Floor
Install
2nd
Floor
Install
2nd
Floor
Install
2nd
Floor
Install
Cabinets
Install
Appliances
LANDSCAPING
FINISH
WORK
Lay
Shingles
ELECT.
FRAME
ROOF
Install
1st
Floor
UTILITIES
Install
Furnace
GAS
WATER
Do
Rough-in
Work
Do
Rough-in
Work
Do
Rough-in
Work
Get
Building
Inspect.
Get
Building
Inspect.
Get
Building
Inspect.
Do
Finish
Work
Do
Finish
Work
Do
Finish
Work
Lay
Carpet
Paint
Walls &
Molding
Hang
Wallpaper
Lay
Tile
Figure
04-04
Ch04: How to Plan a Project
Indented Outline WBS for a House
1.
2.
3.
SITE PREPARATION
1.1.
Layout
1.2.
Grading
1.3.
Excavation
FOUNDATION
2.1.
Erect Forms
2.2.
2.3.
Pour Concrete
Remove Forms
FRAMING
3.1.
Floor Joists
3.2.
3.3.
3.4.
3.1.1.
Install first floor joists
3.1.2.
Install second floor joists
Sub-flooring
3.2.1.
Install first floor sub-flooring
3.2.2.
Install second floor sub-flooring
Stud Walls
3.3.1.
Erect first floor stud walls
3.3.2.
Erect second floor stud walls
Frame the roof
Figure
04-05
Ch04: How to Plan a Project
WBS for a Waterfall SDM
SYSTEMS DEVELOPMENT PROJECT
Definition
State objectives
Design
Implementation
Functional
Programming
Clarify request
Identify interfaces
Source code
Establish objectives
Design I/O
JCL
Identify key issues
Spec audits/controls
Documentation
Confirm specs
Get approval
Define requirements
Obtain current doc.
Technical
Installation
Define new reqmts
Define pgm specs
Testing
Choose SDM
Prepare system flow
Training
Get approval
Convert data
Cut-over
Build integration test plan
Get approval
Get approval
Construct code
Conduct unit test
Construct JCL
Conduct system test
Finalize test plan
Create test data
Conduct test
Conduct operations training
Conduct user training
Finalize plan
Convert data
Cut-over to production
Operation
Operate system
Review
Establish plan
Review performance
Audit
Get approval
Complete financial analysis
Analyze risks
Figure
04-06
Ch04: How to Plan a Project
Time Estimation

The duration of a project is the elapsed time in
business working days or shifts, not including
weekends, holidays, or other non-work days.

Work effort is labor required to complete a task

Duration and work effort are not the same thing

Example: PM course:


Duration: one semester
Work effort: 42 hrs
Ch04: How to Plan a Project
Elapsed time (duration) versus work time (labor)
Labor
L=D
10
L = .75D
8
6
33% unplanned
interruptions
4
2
Duration
2
4
6
8 10 12 14 16 18 20
MODEL ASSUMPTIONS
*
*
Individuals work at 75 percent efficiency rate.
Unplanned interruptions account for 33 percent of clock time.
Figure
04-07
Ch04: How to Plan a Project
Should I Estimate Task Duration or Task Labor?

Estimate duration to build the schedule and
determine when the project will be completed

Estimate labor when you have to contain
expenses within a budget
Ch04: How to Plan a Project
Resource Loading vs. Task Duration
1. Pick up the chair
Time
2. Carry it to the door
3. Set the chair down
4. Open the door
5. Hold the door open
with your foot as you
pick up the chair
6. Carry the chair out the
door
7. Set the chair in the
hallway
1
2
3
# of people on the team
4
Ch04: How to Plan a Project
Resource Loading vs. Task Duration
 Adding more
resources to hold a
task’s duration within
the planning limits can
be effective. This is
called ‘‘crashing the
task”
The crash-point is the
point where adding
more resources will
increase task duration
Time
1
2
3
# of people on the team
4
Ch04: How to Plan a Project
Resource Loading vs. Task Duration
Considerations of adding new resources:
The amount of reduction in duration that results
from adding resources
The impact on risk that results from adding
another resource.
Partitioning the task so that more than one
resource can work on it simultaneously. For some
tasks, this will be easy; for others it may be
impossible.
Ch04: How to Plan a Project
Causes of Variation in Duration


Varying skill levels
Unexpected events


Efficiency of work time




e.g. Random acts of nature, vendor delays, incorrect
shipments of materials, traffic jams, and power failures.
Some will be more affected by interruptions than others.
Mistakes and misunderstandings
Variation within the capability of the system
Common cause variation

duration is a random variable.
Ch04: How to Plan a Project
Six Simple Ways to Estimate Task Duration
1. Extrapolating based on similarity to other activities.
2. Historical data


Simple way: extract similar tasks from the database and
compute an average
More complicated: use sophisticated regression models based
on full info. about characteristics of the task, the skill set of the
people working on it, actual vs. planned duration and other
variables.
3. Expert advice


e.g. when technology is being used for the first time in the
organization, consult outside experts.
Vendors may be a good source, as are non-competitors who
use that technology
Ch04: How to Plan a Project
Six Simple Ways to Estimate Task Duration
4. Delphi technique


The original version
 use a small panel of experts asked for their estimate
independently of one another.
 The results are tabulated and shared with the panel
members, who are then asked to submit their own second
and third estimate.
The modified version
 In the absence of experts, each individual in the project
group is asked to make his or her best guess of the task
duration.
 Participants whose estimates fall in the outer quartiles are
asked to share the reason for their guess.
 After listening to the arguments, each group member is
asked to guess again, and so on.
Ch04: How to Plan a Project
The Delphi Technique
Third Pass
Second Pass
First Pass
Figure
04-08
Ch04: How to Plan a Project
Ways to Estimate Task Duration
5. The Three-Point Method
O
M
O: Optimistic
P: Pessimistic
M: Most Likely
P
E
E=
O + 4M + P
6
Figure
04-09
Ch04: How to Plan a Project
Ways to Estimate Task Duration
6. Applying the Wide-Band Delphi Technique
 Combining the Delphi and three-point methods
Members are asked, at each iteration, to give their optimistic,
pessimistic, and most likely estimates for the duration of the
chosen task.
 Averages are computed for each of the three estimates
Ch04: How to Plan a Project
Estimates Have a Life Cycle Too
range
time
You will be smarter tomorrow
than you are today.
Figure
04-10
Ch04: How to Plan a Project
Estimating Resource Requirements

Six techniques discussed previously can be
used to estimate resources.

Resource types:






People
Facilities
Equipment
Money
Materials
Tools used to schedule people:



Skills matrices
Skill categories
Skill levels
Ch04: How to Plan a Project
Assigning Staff to Activities
In the first (needs inventory) matrix, rows represent the
activities and columns are the skills.
In the second (skills inventory) matrix, rows identify the
staff and columns represent the current skills.
Staff members are assigned to activities according to their
skills
Figure
04-11
Ch04: How to Plan a Project
Assigning Staff to Activities
Skills requirement example
Ch04: How to Plan a Project
Assigning Staff to Activities
Current skills
Ch04: How to Plan a Project
Resource Breakdown Structure
Figure
04-12
Ch04: How to Plan a Project
Resource Breakdown Structure
Used as the basis for identifying the
positions and levels that are needed to staff
the project.
Used to construct the staffing budget.
Ch04: How to Plan a Project
Assign as profile
In reality, we cannot presume that the resource is going to
work at about the same percent per day for each day of the
task. In other words, they are not flat-loaded at a constant
rate.
The duration is estimated first and then the work is
assigned at different percents
 For example, you might assign the worker 75 percent for
20 hours and 50 percent for 20 hours
Ch04: How to Plan a Project
Estimating Cost

Order of magnitude estimate



Budget estimate



The number given for the estimate is somewhere between 25
percent above and 75 percent below the number.
Often used at the very beginning of the estimation process
when very little detail is known
Has a range of 10 percent over and 25 percent below the
stated estimate
Used during the project planning.
Definitive estimate


It has a range of 5 percent over and 10 percent below the
stated estimate.
Done frequently during project execution when new information
helps further improvement
Ch04: How to Plan a Project
Estimating Cost

Cost Budgeting:




This is the phase when you assign costs to tasks on the WBS.
You take the needed resources and multiply the costs by the
number of hours they are to be used.
Is more detailed than cost estimation.
Cost Control


Weekly reports of the costs
Baseline versus actual
The Project Network Diagram

The tasks and the task duration are the basic building
blocks needed to construct a graphic picture of the
project.

This graphic picture provides you with two additional
pieces of schedule information about the project:



The earliest time at which work can begin on every task that
makes up the project
The earliest expected completion date of the project
the required resources must be available at the times
established in this plan.
Envisioning a Complex Project Network Diagram

A project network diagram is a pictorial representation
of the sequence in which the project work can be done.

What tasks must be complete before another task can
begin?

Now a set of tasks is complete, what task or tasks
could come next?
Benefits to Network-Based Scheduling

There are two ways to build a project schedule:


Gantt chart
Network diagram
Design
Build
Test
Install
time
Gantt Chart

There are two drawbacks to using the Gantt chart:

Because of its simplicity, the Gantt chart does not contain
detailed information. You cannot tell from the Gantt chart what
must come before and after what.

The Gantt chart does not tell the project manager whether the
schedule that results from the Gantt chart completes the
project in the shortest possible time or even uses the
resources most effectively.
Ch04: How to Plan a Project
Network-based Scheduling – Gantt Charts
Design
Build
Test
Install
time
Network diagrams

Network diagrams can be used for

Planning.

Implementation:


For those project managers who use automated project
management software tools, update the project file with task
status and estimate-to-completion data. The network diagram
is then automatically updated and can be printed or viewed.
Control
Building the Network Diagram Using the
Precedence Diagramming Method

task-on-the-arrow (TOA) method.
Figure
04-13
Task-on-the-arrow (TOA) method

The node at the left edge of the arrow is the event
“begin the task,” while the node at the right edge of the
arrow is the event “end the task.”

Nodes are numbered sequentially.

One seldom sees this approach used today.
Ch04: How to Plan a Project
Network-based Scheduling – Task on the Node
PDM format of a project network diagram
Figure
04-14
Task on the Node

The basic unit of analysis in a network diagram is the
task.

Each task in the network diagram is represented by a
rectangle called a task node.

Arrows represent the predecessor/successor
relationships between tasks.
Ch04: How to Plan a Project
Task Node
ES
ID
LS
EF
SLACK
E
LF
Figure
04-15
Ch04: How to Plan a Project
Diagramming Conventions
Figure
04-16
Ch04: How to Plan a Project
Dependency Relationships
A
B
FS: When A finishes, B may start
A
FF: When A finishes, B may finish
B
A
SS: When A starts, B may start
B
A
B
SF: When A starts, B may finish
Figure
04-17
Dependency Relationships
Examples:
FS: When design is complete, programming
can begin
FF: When data collection is complete, data
entry can be completed
SS: Once the guests start arriving, the food
can be brought out
SF: Once the patient real heart starts beating
again, the heart lung machine can be turned
off
Ch04: How to Plan a Project
Dependency Constraints

Technical constraints







Management constraints
Inter-project constraints
Date constraints




Discretionary constraints
Best practice constraints
Logical constraints
Unique requirements constraints
No earlier than
No later than
On this date
Lag variables
Technical constraints

arise because one task (the successor) requires output
from another (the predecessor) before work can begin
on it.

In the simplest case, the predecessor must be
completed before the successor can begin.
Discretionary constraints.

Judgment calls by the project manager that result in
the introduction of dependencies.

For example, the data collection and data entry.

a team of recent hires will be collecting the data and that the
usual practice is to have them enter the data as they collect it
(SS dependency).

This introduces some risk to the process; and because new
hires will be doing the data collection and data entry, the
project manager decides to use an FS, rather than SS,
dependency between data collection and data entry.
Best-practices constraints.


Past experiences that have worked well for the project
manager or are known to the project manager based
on the experiences of others in similar situations.
For example, consider the dependency between
software design and software build tasks.

The safe approach is to complete design before beginning
build. But getting to the market faster has become the strategy
for survival.

Changing the FS dependency between design and build to an
SS dependency

At some point in the design phase, enough is known about the
final configuration of the software to begin limited programming
work.
Logical constraints.

arise from the project manager’s way of thinking about
the logical way to sequence a pair of tasks.

For example, in the design-build scenario

There is some concurrency between software design with the
build task.

Part of the software design work, however, involves the use of
a recently introduced technology with which the company has
no experience.

For that reason, the project manager decides that the part of
the design that involves this new technology must be complete
before any of the associated build tasks can start.
Unique requirements.

Occur in situations where a critical resource — say, an
irreplaceable expert or a one-of-a kind piece of
equipment — is involved on several project tasks.

Project manager creates FS dependencies

To ensure that no scheduling conflicts will arise from
the use of scarce resources.
Management Constraints

The result of a management-imposed constraint.

For example, suppose the product manager on a software
development project is aware that a competitor will soon
introduce a new product with similar features to their own.


Rather than follow the concurrent design-build strategy, the
product manager expects design changes in response to the
competitor’s new product and, rather than risk wasting the
programmers’ time, imposes the FS dependency between the
design and build tasks.
Management Constraints differ from technical
dependencies in that they can be reversed, whereas
technical dependencies cannot.
Interproject Constraints



Interproject constraints result when deliverables from one
project are needed by another project.
For example, suppose a new piece of test equipment is
being manufactured by the same company that is
developing the software that will use the test equipment.

In this case, the start of the testing tasks in the software
development project depends on the delivery of the manufactured
test equipment from the other project.

The dependencies that result are technical but exist between tasks
in two or more projects, rather than within a single project.
Interproject constraints arise when a very large project is
decomposed into smaller, more manageable projects. (For
example, the construction of the Boeing 777)
Date Constraints

Date constraints impose start or finish dates on a task,
forcing it to occur according to a particular schedule.

These constraints generally conflict with the schedule that
is calculated and driven by the dependency relationships
between tasks.

Date constraints come in three types:




No earlier than.
No later than.
On this date.
The result is the creation of a needless complication in the
project schedule and later in reporting the status of the
project.
Using the Lag Variable

Pauses or delays between tasks are indicated in the
network diagram through the use of lag variables.

For example, suppose that you wait 10 days from the
date you mail the surveys until you schedule entering
the data from the surveys.

You defined an SS dependency with a lag of 10 days.

task B (data entry) can start 10 days after task A (mail
the survey) has started.
Ch04: How to Plan a Project
Paths Through the Network

The Forward Pass – Early Schedule




Left to right (start to finish)
Determines Early Start and Early Finish
ES + duration – 1 = EF
Backward Pass – Late Schedule



Right to left (finish to start)
Determines Late Start and Late Finish
LF - duration + 1 = LS
Paths Through the Network

The combination of these two schedules gives you two
additional pieces of information about the project
schedule:
1.
The window of time within which each task must be
started and finished in order for the project to
complete on schedule
2.
The sequence of tasks that determine the project
completion date (the critical path).
Critical path

The critical path can be defined in several ways:

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 is the sequence of tasks that must be
completed on schedule in order for the project to be
completed on schedule.

The tasks that define the critical path are called critical
path tasks.
Any delay in a critical path task will delay the completion of
the project by the amount of delay in that task.

The Forward Pass

The earliest start (ES) time for a task is the earliest
time at which all of its predecessor tasks have been
completed and the subject task can begin.

The ES time of tasks with one predecessor task is
determined from the earliest finish (EF) time of the
predecessor task.

The latest start (LS) and latest finish (LF) times of a
task are the latest times at which the task can start or
finish without causing a delay in the completion of the
project.
Ch04: How to Plan a Project
Forward Pass Calculations – Early Schedule
Figure
04-18
Backward Pass

The window of time between the ES and LF of a task is
the window within which the resource for the work must
be scheduled or the project completion date will be
delayed.

LS is calculated as ((LF – Duration) + One Time Unit).
Ch04: How to Plan a Project
Backward Pass Calculations – Late Schedule
Figure
04-19
Ch04: How to Plan a Project
Critical Path
Figure
04-20
Example
Another example
Another example…
Ch04: How to Plan a Project
Early Start to Late Finish Window
Task
ES
Slack
Duration
LF
Slack is the difference between the late
finish and the early finish (LF – EF)
Figure
04-21
Ch04: How to Plan a Project
Slack Time (also called float)

Total Slack


Time that a task can be delayed without
impacting the early schedule of the
project.
Free Slack

Time a task can be delayed without
impacting the early schedule of its
successor tasks.
Do Not Plan to Use Slack
to Bail Out the Project!
Ch04: How to Plan a Project
Project Network Diagram

Critical Path:




The longest path or sequence of tasks (in terms of task
duration) through the network diagram
The critical path drives the completion date of the project
Critical tasks have zero slack.
Near Critical Path:

Tasks not on the critical path with which the team has
little experience, so the duration estimates have large
estimation variances.
Ch04: How to Plan a Project
PERT


PERT is based on the assumption that an activity’s
duration follows a probability distribution instead of being a
single value
Three time estimates are required to compute the
parameters of an activity’s duration distribution:
 pessimistic time (tp ) - the time the activity would take if
things did not go well
 most likely time (tm ) - the consensus best estimate of
the activity’s duration
 optimistic time (to ) - the time the activity would take if
things did go well
116
Ch04: How to Plan a Project
PERT
Mean (expected time):
tp + 4 tm + to
te =
Variance: Vt = 2 =
6
tp - to
6
2
Ch04: How to Plan a Project
PERT





Draw the network.
Analyze the paths through the network and find the critical
path.
The length of the critical path is the mean of the project
duration probability distribution which is assumed to be
normal
The standard deviation of the project duration probability
distribution is computed by adding the variances of the
critical activities (all of the activities that make up the critical
path) and taking the square root of that sum
Probability computations can now be made using the normal
distribution table.
118
Ch04: How to Plan a Project
PERT- probability computation
Determine probability that project is completed
within specified time
x-
Z=

where  = tp = project mean time
 = project standard mean time
x = (proposed ) specified time
119
PERT Example
Consider the following table of activities; immediate predecessor(s) (I.P.);
optimistic, most likely, and pessimistic completion times for General
Foundry; and the E(ti) and var(ti) for each activity.
ACT
A
B
C
D
E
F
G
H
I.P.
__
__
A
B
C
C
D,E
F,G
Optimistic
1 week
2
1
2
1
1
3
1
Most Likely
2 weeks
3
2
4
4
2
4
2
Pessimistic
3 weeks
4
3
6
7
9
11
3
E(ti) var(ti)
2 wks. 4/36
3
4/36
2
4/36
4
16/36
4
36/36
3
64/36
5
64/36
2
4/36
PERT Example
ACT
A
B
C
D
E
F
G
H
A
2
C
2
B
3
D
4
I.P.
(a) (m) (b) E(ti) var(ti)
__
1
2
3
2
4/36
__
2
3
4
3
4/36
A
1
2
3
2
4/36
B
2
4
6
4
16/36
C
1
4
7
4
36/36
C
1
2
9
3
64/36
D,E
3
4
11
5
64/36
F,G
1
2
3
2
4/36
F
3
H
2
E
4
G
5
PERT Example
Inspection of the network discloses three paths thru the
project:
A-C-F-H; A-C-E-G-H; and B-D-G-H. Summing the E(ti) on
each path yield time thru each path of 9, 15, and 14 weeks,
respectively.
With an E(t) = 15 for A-C-E-G-H, this path is defined as the
critical path (CP) being the path that govens the completion
time of the project .
variance equal to the sum of the variances of its activities only,
var(t) = 112/36 = 3.11.

what is the probability of the project requiring in
excess of 16 weeks to complete?
P( X > 16) = 1 - P ( X < 16) = 1 - P ( Z < (16 - 15) /
1.76 = .57) = 1 - 0.716
Another CPM Example
0 A
2
2 C
4
0
2
2
4
0
1
2
B
3
3
4
3
2
D 7
4 4
4 F
7
10 3
13
EF
ES
4
E
8
4
4
8
8
critical path
15
13 2
15
LS
8 G 13
8
13 H
5 13
LF
Ch04: How to Plan a Project
PERT Example 2
Immed. Optimistic Most Likely Pessimistic
Activity Predec. Time (Hr.) Time (Hr.) Time (Hr.)
A
-4
6
8
B
-1
4.5
5
C
A
3
3
3
D
A
4
5
6
E
A
0.5
1
1.5
F
B,C
3
4
5
G
B,C
1
1.5
5
H
E,F
5
6
7
I
E,F
2
5
8
J
D,H
2.5
2.75
4.5
K
G,I
3
5
7
125
Ch04: How to Plan a Project
PERT Example
Activity
A
B
C
D
E
F
G
H
I
J
K
Expected Time
6
4
3
5
1
4
2
6
5
3
5
Variance
4/9
4/9
0
1/9
1/36
1/9
4/9
1/9
1
1/9
4/9
126
Ch04: How to Plan a Project
PERT Example
Activity
A
B
C
D
E
F
G
H
I
J
K
ES
EF
LS
0
0
6
6
6
9
9
13
13
19
18
6
4
9
11
7
13
11
19
18
22
23
0
5
6
15
12
9
16
14
13
20
18
LF
6
9
9
20
13
13
18
20
18
23
23
Slack
0 *critical
5
0*
9
6
0*
7
1
0*
1
0*
127
Ch04: How to Plan a Project
PERT Example
Vpath = VA + VC + VF + VI + VK
= 4/9 + 0 + 1/9 + 1 + 4/9
= 2
path = 1.414
z = (24 - 23)/(24-23)/1.414 = .71
From the Standard Normal Distribution table:
P(z < .71) = .5 + .2612 = .7612
darla/smbs/vit
128
Ch04: How to Plan a Project
Schedule Compression Techniques
Replace FS with SS dependencies



Focus on critical activities
Partitionable activities

Replace a team member with a more skilled
person

Add resources



From non-critical path tasks to critical path tasks
From other projects
To where
 critical path tasks
 high-risk tasks
 tasks with large duration variances
Ch04: How to Plan a Project
Schedule Compression Iterations
Figure
04-22
Ch04: How to Plan a Project
Schedule Compression
Schedule compression doesn’t come free.
What is the impact on the project
due to schedule compression?
Ch04: How to Plan a Project
Management Reserve





DO NOT PAD ACTIVITY DURATION
A percentage of total project work hours (5% to
10%)
The last activity in the project
A schedule contingency for the unexpected
delays
Make it visible and manage it