1. Project Management: A Managerial Approach
Chapter 8 – Scheduling
© 2006 John Wiley and Sons, Inc.

2. © 2006 John Wiley and Sons, Inc.
Overview
WBS to Schedule Process
PERT
Schedule Types
CPM
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3. © 2006 John Wiley and Sons, Inc.
Scheduling
A schedule is the conversion of a project action plan into an operating timetable
It serves as the basis for monitoring and controlling project activity
Taken together with the plan and budget, it is probably the major tool for the management of projects
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Chapter 8-1

4. Simple Schedule – Gantt Chart
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5. Network Techniques: PERT and CPM
With the exception of Gantt charts, the most common approach to scheduling is the use of network techniques such as PERT and CPM
The Program Evaluation and Review Technique (PERT) was developed by the U.S. Navy in 1958
The Critical Path Method (CPM) was developed by DuPont, Inc during the same time period
© 2006 John Wiley and Sons, Inc.
Chapter 8-7

6. Scheduling Terminology
Activity - A specific task or set of tasks that are required by the project, use up resources, and take time to complete
Event - The result of completing one or more activities. An identifiable end state occurring at a particular time. Events use no resources.
Network - The combination of all activities and events define the project and the activity precedence relationships
© 2006 John Wiley and Sons, Inc.
Chapter 8-9

7. Scheduling Terminology
Path - The series of connected activities (or intermediate events) between any two events in a network
Critical - Activities, events, or paths which, if delayed, will delay the completion of the project. A project’s critical path is understood to mean that sequence of critical activities that connect the project’s start event to its finish event
© 2006 John Wiley and Sons, Inc.
Chapter 8-10

8. Scheduling Terminology
An activity can be in any of these conditions:
It may have a successor(s) but no predecessor(s) - starts a network
It may have a predecessor(s) but no successor(s) - ends a network
It may have both predecessor(s) and successor(s) - in the middle of a network
Interconnections from horizontal links in vertical WBS
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9. © 2006 John Wiley and Sons, Inc.
Hypothetical Network 2 5 6 1 4 3 16 20 13 30
TE=64
Calculate t(e) and Z for this network……
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10. Activity and Project Frequency Distributionsm b TE
(A)
(B)
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11. PERT Activity Calculation
t(e) = a + 4m + b a = Most Optimistic (MO)
6 m = Most Likely (ML)
b = Most Pessimistic (MP)
t(e) = Activity Duration
When a single estimate for activity time is not sufficient!
© 2006 John Wiley and Sons, Inc.

12. PERT Schedule Probability
Z = T(S) – T(E) Z = Probability of
SSD(T[E]) Meeting Schedule
T(S) = Scheduled Duration
T(E) = Critical Path Duration
Z is derived from a table of predetermined probabilities
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13. PERT Activity Times & Variancesb
t(e)
1-2 17 29 47
2-3 6 12 24
2-4 16 19 28
3-5 13
4-5 2 5 14
5-6 8
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14. Variance of Activity Estimatesb
t(e)
[(b-a)/6]2
Var
1-2 17 29 47 30
2-3 6 12 24 13
2-4 16 19 28 20
3-5
4-5 2 5 14
5-6 8
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15. Possible Project Durations
TE=64
TS=67
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16. © 2006 John Wiley and Sons, Inc.
Z Table
Z Value
Probability
-2.0
0.02
+2.0
0.98
-1.5
0.07
+1.5
0.93
-1.0
0.16
+1.0
0.84
-0.7
0.24
+0.7
0.76
-0.5
0.31
+0.5
0.69
-0.3
0.38
+0.3
0.62
-0.1
0.36
+0.1
0.54
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17. © 2006 John Wiley and Sons, Inc.
Gantt Charts
The Gantt chart shows planned and actual progress for a number of tasks displayed against a horizontal time scale
It is an effective and easy-to-read method of indicating the actual current status for each set of tasks compared to the planned progress for each item of the set
It can be helpful in expediting, sequencing, and reallocating resources among tasks
Gantt charts usually do not show technical dependencies
© 2006 John Wiley and Sons, Inc.
Chapter 8-14

18. © 2006 John Wiley and Sons, Inc.
Drawing Networks
Activity-on-Arrow (AOA) networks use arrows to represent activities while nodes stand for events
Activity-on-Node (AON) networks use nodes to represent activities with arrows to show precedence relationships
The choice between AOA and AON representation is largely a matter of personal preference
© 2006 John Wiley and Sons, Inc.
Chapter 8-12

19. © 2006 John Wiley and Sons, Inc.
Hypothetical Network 3 1 2 5 6 4
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20. AOA Network Building Blocks80 79
Install software
Event
Activity
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21. Partial Koll Business Center - AOA4 5 1 3 2
A Application approval
D Service availability check
C Traffic study
B Construction plans
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22. © 2006 John Wiley and Sons, Inc.
Partial AOA Network 2 3 1 4 A X C B E
(A)
(B)
(C)
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23. © 2006 John Wiley and Sons, Inc.
Partial AOA Network 2 3 1 4 A B C X E
(D) 5 D 2 3 1 4 A B C X E
(E) 5 D F ?
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24. KOLL BUSINESS CENTER County Engineers Design Department
Full AOA Network 2 3 1 4
A 5 B
C 10 X 5 15 6 7 8 Y
F 10
G 170
H 35
E 15
D 5
Legend
KOLL BUSINESS CENTER County Engineers Design Department
Activity Duration
© 2006 John Wiley and Sons, Inc.

25. Activity-on-Node Network FundamentalsX Y Z
Y and Z are preceded by X
Y and Z can begin at the
same time, if you wish
(B) A B C
A is preceded by nothing B is preceded by A C is preceded by B
(A) J K L M
J, K, & L can all begin at the same time, if you wish (they need not occur simultaneously)
All (J, K, L) must be completed before M can begin
but AA
(C)
(D)
Z is preceded by X and Y
AA is preceded by X and Y
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26. © 2006 John Wiley and Sons, Inc.
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