Business Department

Session 6

• Exam Question– Draw Network diagram

– Identify Critical path

– Sketch Gantt Chart

– ‘Crash’ the project

• Reduce the project completion time

Business Department 2

Project Constraints

Time

CostQuality / Scope

Business Department 3

Project Scheduling

• 86% of all projects that fail, fail due to poor project planning

• Only 16% of IT projects complete on budget and on time (Standish Group 2000)

• Project objectives inadequately defined• Project activities inadequately established• Project activities inadequately quantified• Poor overall project planning

Business Department 4

Project Scheduling

• Planning of timetables and establishment of dates of activities

• Reduce or eliminate uncertainty• To improve efficiency • Better understanding of the objectives• Provides a basis for monitoring and

controlling work

Business Department 5

Aim of Project Scheduling

• Establish at any given time the cost and time spent on the project

• Establish the additional cost of accelerating the project

• Establish the level of resources required for each activity

• Two methods of scheduling• Gantt Charts • Network analysis (CPM)

Business Department 6

Simple Gantt Chart

Business Department 7

Sample Gantt Chart

Business Department 8

Network Diagram

• Schematic display of the project activities and the logical relationships (dependencies) between them

Activity-on-node

L

KJ

G

FFinishStart

Business Department 9

Network Diagram

• Schematic display of the project activities and the logical relationships (dependencies) between them

Activity-on-arrow

1

5

43

2

Business Department 10

Network diagrams

1 2

Node Arrow

1 2

Node Arrow

Business Department 11

Activity-on-the-node

1

Add coffee to cup

Boil water

Heat milk

Add milk and water

to cup2

3

4

Business Department 12

Activity-on-the-arrow

1 2 3 4Add coffee to cup

Boil water

Heat milk

Add milk and water

to cup

Business Department 13

Network Analysis

A. Taxi to airport (1 hour)B. Wait at airport (2 hours)C. Fly to destination (3 hours)D. Coach to hotel (1 hour)

A B C 7

1 3 60

D

Business Department 14

Network Analysis

1.1 Furniture1.2 Equipment1.3 Carpets1.4 Paint1.5 F&F

1.0 Purchase6 weeks

2.1 Furniture2.2 Carpets2.3 F&F

2.0 Strip-out2 weeks

3.1 Walls3.2 Woodwork

3.0 Decoration4 weeks

4.1 Equipment4.2 Furniture4.3 F&F4.4 Carpet

4.0 Installation2 weeks

Office Refurbishment

Business Department 15

Network Analysis

Start Purchase

6 weeks

Decoration

4 weeks

Strip-out

2 weeks

Installation

2 weeks

Finish

14 weeks

Business Department 16

Logic Table

1.0 Purchase - 6 weeks

2.0 Strip-out - 2 weeks

3.0 Decoration 1.0, 2.0 4 weeks

4.0 Installation 1.0, 2.0, 3.0 2 weeks

WBS code

Description Dependency Duration

Business Department 17

Network Analysis

Start

Purchase

6 weeks

Decoration

4 weeks

Strip-out

2 weeks

Installation

2 weeks

Finish

12 weeks

Business Department 18

Critical Path

• Total project time = total duration of activities on critical path

• Critical Path = longest duration path through the network

• Activities that lie on the critical path have no slack time

• Delay on activities that lie on the critical path delay the project as a whole

Business Department 19

Fully Analysed Network

A

Business Department 20

Fully Analysed Network

Earliest Start Time (EST)

Earliest Finish Time (EFT)

Latest Start Time (LST)

Latest Finish Time (LFT)

Float

Duration

Activity code & Name

Business Department 21

Logic Table

Activity Dependency Duration

A - 3

B A 2

C A 3

D B, C 5

E B 7

F D, E 5

Business Department 22

Create Network

Start

3

B

C D

E

F

FINISH

A

2

3 5

7

5

Business Department 23

Forward pass

• Total Project time • Work from left to right through the network• Earliest start time for each activity (EST)• Earliest finish time for each activity (EFT)

– EFT = EST + Duration

Business Department 24

Forward Pass

Start

3

B

C D

E

F

FINISH

A

2

3 5

7

50 3

3 5

3 6 6 11

5 12

12 17

17

Business Department 25

Backward Pass

• Critical path• Work from right to left through the network• Latest finish time for each activity (LFT)• Latest start time for each activity (LST)

– LST = LFT – Duration

• Float (slack time) = LFT-EFT• Critical Path Activities

– EST = LST and EFT = LFT

Business Department 26

Backward Pass

Start

3

B

C D

E

F

FINISH

A

2

3 5

7

50 3

3 5

3 6 6 11

5 12

12 17

17

1712 0

125 0

127 174 1

53 0

30 0

Business Department 27

Fully Analysed Network

0Start

A3 30

0 0 3

B2 53

3 0 5

C3 63

4 1 7D5 116

7 1 12

E7 125

5 0 12

F5 1712

12 0 17

FINISH1717

17 17

Business Department 28

Weighted Average Technique

• Project evaluation and review technique (PERT)

• a = optimistic time: – Time required if execution goes extremely well

• b = pessimistic time:– Time required if execution goes badly

• m = most likely time:– Time required if execution is normal

Business Department 29

Weighted Average Technique

• Beta Distribution• Mean duration for each activity

= a + 4m + b6

Business Department 30

Final Logic Table

Activity

Depend

Optimistic

Most likely

Pessimistic

Mean (d)

A - 7 8 9

B A 2 5 8

C A 3 6 9

D C, B 1 2 3

E B 7 8 15

Business Department 31

Critical Path

• Mean time for each activity (u) = (a + 4m + b)

6

• Mean activity A = (7 + (4x8) + 9) /6 = 8

• Mean activity B = (2 + (4x5) + 8) /6 = 5

• Mean activity C = (3 + (4x6) + 9) /6 = 6

• Mean activity D = (1 + (4x2) + 3) /6= 2

• Mean activity E = (7 + (4x8) + 15) /6= 9

Business Department 32

Final Logic Table

Activity

Depend

Optimistic

Most likely

Pessimistic

Mean (d)

A - 7 8 9 8

B A 2 5 8 5

C A 3 6 9 6

D B , C 1 2 3 2

E D 7 8 15 9

Business Department 33

Fully Analysed Network

A8 80

0 0 8

B5 138

9 1 14

C6 148

8 0 14

D2 1214

14 0 12E9 2516

16 0 25

Business Department

Next lecture

• For Next Thursday

• Chapter 6– Project Re-Scheduling