Project Management
Lecture
Network Analysis
Plan


Introduction
Project planning


Project planning


Gantt chart and WBS
Network analysis I
Project planning

Network analysis II

Project planning





Resource analysis
Risk management
Quality
Budgets and cost
control
Project teams
Why Network Diagrams?

Splits up the decision making process into



Method/logic - the order in which tasks have to
be completed
Time – estimates for the time to completion
can be added to each task
Resources – these can be added and then
analysis carried out
Project Exercise 1
Project 1: Verification of a computer system
The followng table shows the activities required for this project.
Activity
ID
1
2
3
4
5
6
7
8
9
Activity
Test Module A
Test Module B
Test Module C
Test Combined Modules
Check User Documents
Print User Documents
Final Systems Check
Prepare Invoice
Ship to Customer
Immediate Predecessor
none
Test Module A
none
Test Module B, Test Module C
Test Combined Modules
Check User Documents
Test Combined Modules
Final Systems Check
Print User Documents, Final
Systems Check
Duration
(Days)
4
6
7
4
5
2
9
1
2
Project Exercise 1
4
6
9
1
1. Test Module A
2. Test Module B
7. Final System
Check
8. Prepare
invoice
4
4. Test Combined
Modules
2
9. Ship to
Customer
7
5
2
3. Test Module C
5. Check User
Documents
6. Print User
Documents
Why Network Diagrams?

Splits up the decision making process into



Method/logic - the order in which tasks have to
be completed
Time – estimates for the time to completion
can be added to each task
Resources – these can be added and then
analysis carried out
Two Parts to the Analysis

Forward Pass


Calculates the Duration of the Project
Backward Pass

Calculates the slack/float for each task and
shows the critical path
Forward Pass
In a game
of rugby
it is a
means of
cheating
often
missed by
referees
(BBC, 2005)
Forward Pass

…but in project management it is used
To calculate the total duration of the Project…

For each task:



Take the earliest start time (EST)
Calculate the Earliest finish time (EFT):
EFT = EST+Duration
What’s in the box?
Earliest
Start
Estimated
Duration
Earliest
Finish
Activity Number
Activity Description
Latest
Start
Float
Latest
Finish
Forward Pass
0
27
27
27
Task A
5
32
Task B
27
10
Task C
37
Forward Pass
0
27
27
Task A
10
12
Task B
27
??
5
Task C
22
32
??
Project Exercise 1
Project 1: Verification of a computer system
The followng table shows the activities required for this project.
Activity
ID
1
2
3
4
5
6
7
8
9
Activity
Test Module A
Test Module B
Test Module C
Test Combined Modules
Check User Documents
Print User Documents
Final Systems Check
Prepare Invoice
Ship to Customer
Immediate Predecessor
none
Test Module A
none
Test Module B, Test Module C
Test Combined Modules
Check User Documents
Test Combined Modules
Final Systems Check
Print User Documents, Final
Systems Check
Duration
(Days)
4
6
7
4
5
2
9
1
2
Exercise 1 – Forward Pass

Carry out a forward
pass on Project in
Exercise 1
Project Exercise 1
4
6
9
1
1. Test Module A
2. Test Module B
7. Final System
Check
8. Prepare
invoice
4
4. Test Combined
Modules
2
9. Ship to
Customer
7
5
2
3. Test Module C
5. Check User
Documents
6. Print User
Documents
Project Exercise 1
0
4
4
4
1. Test Module A
6
Dangler
10
14
9
23
23
7. Final System
Check
2. Test Module B
1
24
8. Prepare
invoice
Dangler
10
Dangler
4
14
4. Test Combined
Modules
23
2
25
9. Ship to
Customer
0
7
7
3. Test Module C
14
5
19
5. Check User
Documents
19
2
21
6. Print User
Documents
Start and Finish Nodes
0
0
Start
0
0
4
4
4
1. Test Module A
6
10
14
9
23
23
7. Final System
Check
2. Test Module B
10
4
1
24
8. Prepare
invoice
14
4. Test Combined
Modules
23
2
25
9. Ship to
Customer
0
7
7
3. Test Module C
14
5
19
5. Check User
Documents
19
2
21
6. Print User
Documents
25
0
Finish
25
What’s in the box?
Earliest
Start
Estimated
Duration
Earliest
Finish
Activity Number
Activity Description
Latest
Start
Float
Latest
Finish
Backward Pass

To calculate the float for each task?

For each task:


Take the latest start time (LST)
Calculate the latest finish time (LFT):
LST = LFT-Duration
Backward Pass
0
27
27
27
Task A
0
10
22
Task B
15
32
Task C
27
12
5
27
27
32
Backward Pass
27
7
34
34
Task A
29
7
41
Task B
36
41
34
48
9
43
Task C
36
45
Project Exercise 1
Project 1: Verification of a computer system
The followng table shows the activities required for this project.
Activity
ID
1
2
3
4
5
6
7
8
9
Activity
Test Module A
Test Module B
Test Module C
Test Combined Modules
Check User Documents
Print User Documents
Final Systems Check
Prepare Invoice
Ship to Customer
Immediate Predecessor
none
Test Module A
none
Test Module B, Test Module C
Test Combined Modules
Check User Documents
Test Combined Modules
Final Systems Check
Print User Documents, Final
Systems Check
Duration
(Days)
4
6
7
4
5
2
9
1
2
Exercise 1 – Backward Pass

Carry out a backward pass on project
exercise 1
Ex1 - After Backward Pass
0
0
0
Start
0
0
4
4
4
1. Test Module A
0
0
6
10
14
4
23
23
7. Final System
Check
2. Test Module B
4
9
14
10
10
4
24
8. Prepare
invoice
23
24
25
14
4. Test Combined
Modules
10
1
23
14
7
7
3. Test Module C
3
10
25
25
9. Ship to
Customer
23
0
2
14
5
19
5. Check User
Documents
15
21
19
2
21
6. Print User
Documents
21
23
25
0
25
Finish
25
25
What about the float?

Float = LFT-EFT


Or
Float = LST-EST
What about the float?


Float represents the amount of time that
the task can be delayed without affecting
the outcome of the project
A task with zero float cannot be delayed
and is therefore critical to the timely
completion of the project
What about the float?


A time optimised project will have a
sequence of tasks from start to finish that
have zero float
This sequence of tasks is called the critical
path
Project Exercise 1
Project 1: Verification of a computer system
The followng table shows the activities required for this project.
Activity
ID
1
2
3
4
5
6
7
8
9
Activity
Test Module A
Test Module B
Test Module C
Test Combined Modules
Check User Documents
Print User Documents
Final Systems Check
Prepare Invoice
Ship to Customer
Immediate Predecessor
none
Test Module A
none
Test Module B, Test Module C
Test Combined Modules
Check User Documents
Test Combined Modules
Final Systems Check
Print User Documents, Final
Systems Check
Duration
(Days)
4
6
7
4
5
2
9
1
2
Exercise 1 – Critical Path

Calculate the float for each task and
identify the critical path through the project
Ex1 – Float
0
0
0
Start
0
0
0
4
4
4
1. Test Module A
0
0
0
6
10
14
4
0
23
23
7. Final System
Check
2. Test Module B
4
9
14
10
10
4
0
0
24
8. Prepare
invoice
23
24
1
25
14
4. Test Combined
Modules
10
1
23
14
7
7
3. Test Module C
3
3
10
25
25
9. Ship to
Customer
23
0
2
14
5
19
5. Check User
Documents
15
2
21
19
2
21
6. Print User
Documents
21
2
23
0
25
0
25
Finish
25
0
25
Ex1 – Critical Path
0
0
0
Start
0
0
0
4
4
4
1. Test Module A
0
0
0
6
10
14
4
0
23
23
7. Final System
Check
2. Test Module B
4
9
14
10
10
4
0
0
24
8. Prepare
invoice
23
24
1
25
14
4. Test Combined
Modules
10
1
23
14
7
7
3. Test Module C
3
3
10
25
25
9. Ship to
Customer
23
0
2
14
5
19
5. Check User
Documents
15
2
21
19
2
21
6. Print User
Documents
21
2
23
0
25
0
25
Finish
25
0
25
Questions


My Project has no critical path. What does
this mean?
My programmer has broken his big toe in a
skiing accident and cannot type for two
weeks (he has a valid sick note). How will
this affect my software delivery date?
Directed Study


Find the critical path for Project Exercise 2
(see Lecture 3).
Find the critical path for the large project in
Exercise 3.
Plan


Introduction
Project planning


Project planning


Gantt chart and WBS
Network analysis I
Project planning

Network analysis II

Project planning





Resource analysis
Risk management
Quality
Budgets and cost
control
Project teams