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Project Management
Work Breakdown Structures
Minder Chen, Ph.D.
CSU Channel Islands
[email protected]
WBS and Work Packages
• Create WBS is the process of subdividing project
deliverables and project work into smaller, more
manageable components.
• The work breakdown structure (WBS) is a deliverableoriented hierarchical decomposition of the work to be
executed by the project team to accomplish the project
objectives and create the required deliverables, with each
descending level of the WBS representing an increasingly
detailed definition of the project work. The WBS organizes
and defines the total scope of the project, and represents
the work specified in the current approved project scope
statement.
• The planned work is contained within the lowest level WBS
components, which are called work packages.
• A work package can be scheduled, cost estimated,
monitored, and controlled.
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Create WBS: Inputs, Tools & Techniques, and Outputs
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Sample WBS
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Don’t Confusing Effort with Results.
• The WBS was initially defined as a product
oriented family tree, however subsequent
definitions have introduced more flexibility -- so
a WBS can also be deliverable or process
oriented.
• Your WBS can be built on nouns or verbs. If the
results of your project are primarily verbs, then
a verb based or process based WBS may make
more sense.
http://www.hyperthot.com/pm_wbs.htm
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Creating the Work Breakdown Structure
• An hierarchical outline (map)
that identifies the products
and work elements involved
in a project.
• Defines the relationship of
the final deliverable
(the project) to its
subdeliverables, and in turn,
their relationships to work
packages.
• Best suited for design and
build projects that have
tangible outcomes rather
than process-oriented
projects.
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4–7
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How WBS Helps the Project Manager
• Facilitates evaluation of cost, time, and technical
performance of the organization on a project.
• Provides management with information
appropriate to each organizational level.
• Helps in the development of the organization
breakdown structure (OBS). which assigns project
responsibilities to organizational units and
individuals
• Helps manage plan, schedule, and budget.
• Defines communication channels and assists
in coordinating the various project elements.
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4–8
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Process-based WBS Completion Criteria
•
•
•
•
•
Status and completion are 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
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t
Work Packages
• A work package is the lowest level of the WBS.
• It is output-oriented in that it:
1. Defines work (what).
2. Identifies time to complete a work package (how
long).
3. Identifies a time-phased budget to complete
a work package (cost).
4. Identifies resources needed to complete
a work package (how much).
5. Identifies a person responsible for units of work
(who).
6. Identifies monitoring points (milestones)
for measuring success.
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4–10
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Sample WBS with Major Deliverables
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Integrating the WBS with the Organization
• Organizational Breakdown Structure (OBS) depicts how the firm is
organized to allocate its work responsibility for a project.
– Provides a framework to summarize organization work unit
performance. Identifies organization units responsible for work
packages.
– Ties the organizational units to cost control accounts.
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Work Package Estimates
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WBS Component in WBS Dictionary
•
•
•
•
•
•
•
•
•
•
•
Code of account identifier,
Description of work,
Responsible organization,
List of schedule milestones,
Associated schedule activities,
Resources required,
Cost estimates,
Quality requirements,
Acceptance criteria,
Technical references, and
Contract information.
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Coding the WBS for the Information System
• Levels and elements of the WBS
• Organization elements
• Work packages
• Budget and cost information
• Allows reports to be consolidated at any
level in the organization structure.
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4–15
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Direct Labor Budget Rollup
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Sample WBS Organized by Phase
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Sample WBS Organized by Phase
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Process-Oriented vs. Product-Oriented WBS
http://www.hyperthot.com/pm_wbs.htm
http://www.hyperthot.com/pm_wbs_concepts.htm
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Scope Baseline
• The scope baseline is a component of the
project management plan.
• Components of the scope baseline include:
– Project scope statement. The project scope
statement includes the product scope
description, and the project deliverables, and
defines the product user acceptance criteria.
– WBS. The WBS defines each deliverable and
the decomposition of the deliverables into work
packages.
– WBS dictionary. The WBS dictionary has a
detailed description of work and technical
documentation for each WBS element.
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Verify Scope: ITTO & Data Flow Diagram
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Breaking Up Is Hard to Do
• The Story of Cook Ding
• http://www.examiner.com/article/taoism-301-3story-of-cook-ting-the-dextrous-butcher
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General Systems Theory: Level of Abstract
(General Systems Theory) does not seek, of
course, to establish a single, self contained
'general theory' of practically everything which
will replace the theories of particular disciplines.
Such a theory would be almost without content,
for we always pay for generality by sacrificing
content, and we can say about practically
everything is almost nothing. Somewhere
however between the specific that has no meaning
and the general that has no content there must
be, for each purpose and at each level of
abstraction, an optimum degree of generality. It is
the contention of the General Systems Theorists
that this optimum degree of generality is not
always reached by the particular sciences."
Source: http://cimru.nuigalway.ie/david/pdf/SE/Slides/Theory.PDF
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Design: Cohesion and Coupling
• Divide and Conquer
• Software Design Criteria, plus Reusability
• Modularization: Simple, stable, and clearly defined
interface for each module, no need to understand
the internal structure or design of a module to use
it (i.e., treat it as a black box).
• Low coupling between modules and high
cohesiveness within modules
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Coupling
Type of
Coupling
Tightness
of Coupling
Goodness
of Design
Less interdependence
Less coordination
Less information flow
Normal Coupling
Loose
Good
Data Coupling (Sending simple parameters)
Stamp Coupling (sending complex data structures)
Control Coupling (sending flags)
Common Coupling (Sharing global data)
Bad
Tight
Content Coupling (Changing code)
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Functional Cohesion
• Complex, yes; Cohesive, Yes.
Satellite
Trajectory
A Functionally Cohesive
Module Very High
in a Structure Chart
GET
SATELLITE
TRAJECTORY
Ranges
Times
Elevation
GET
ELEVATION
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GET
TIMES
Azimuths
GET
AZIMUTHS
GET
RANGES
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Scale of Cohesion
Closely related activities that make sense to group them together.
Types of
Cohesion
Functional
Visibility
Strength of
Cohesion
Black box
Maintainability
Strong
Good
Weak
Bad
Sequential
Communicational Not-quite so
Procedural
Temporal
Logical
Coincidental
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black box
Gray box
Transparent
or white box
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The Impact of Module Numbers on Cost
Cost
High
Low
Small
Large
Number of Modules
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Decomposition and Integration
• Decomposition (factoring) refers to the process by which a
complex problem or system is broken down into parts that are
easier to conceive, understand, program, and maintain.
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Testing
• Test plan objectives
–
–
–
Is thoroughly tested
Meets requirements
Does not contain defects
• Test plan covers
–
–
–
–
–
Tools
Who
Schedule
Test result analysis
What is being tested?
• Test cases
• Automated testing
–
–
Reproducible
Measurable
Source:
Developing Web Applications with Microsoft
Visual Basic .NET and Microsoft Visual C# .NET
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Types of Tests
Test type
Objectives
Unit test
Each independent piece of code works
correctly
Integration
test
All units work together without errors
Regression
test
Newly added features do not introduce
errors to other features that are
already working
Load test
(also called
stress test)
The product continues to work under
extreme usage
Platform test
The product works on all of the target
hardware and software platforms
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Regression and Regression Test
• Regression testing is the process of validating
modified parts of the software and ensuring that
no new errors are introduced into previously
tested code.
• Unit and integration tests form the basis of
regression testing. As each test is written and
passed, it gets checked into the test library for a
regularly scheduled testing run. If a new
component or a change to an existing component
breaks one of the existing unit or integration tests,
the error is called a regression.
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Stubs and Drivers
The most common build problem occurs when one component tries
to use another component that has not yet been written. This
occurs with modular design because the components are often
created out of sequence.
Driver
Module M
Stub
Module 2
Module 1
Module 2
• Stubs are non-functional components that provide the class, property,
or method definition used by the other component. Stubs are a kind of
outline of the code you will create later.
• To test two components that need to work together through a third
component that has not been written yet, you create a driver. Drivers
are simply test components that make sure two or more components
work together. Later in the project, testing performed by the driver can
© Minder
Chen, 2012 by the actual component.
be performed
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The Myth in The Mythical Man-Month
• Using the man-month as a unit for measuring the size of a
job is a dangerous and deceptive myth. It implies that men
and months are interchangeable. Men and months are
interchangeable commodities only when a task can be
partitioned among many workers with no communication
among them.
Time versus number of workers—perfectly partitionable task
http://www.cs.drexel.edu/~yfcai/CS451/RequiredReadings/MythicalManMonth.pdf
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Partitionability
Time versus number of workers—
unpartitionable task
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Time versus number of workers—
partitionable task requiring
communication
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Task with Complex Interrelationships
• If each part of the task must be separately
coordinated with each other part/ the effort
increases as n(n-1)/2, where n is the number of
parts.
Time versus number of workers—task with complex interrelationships
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