Critical Path

You will need…….• Pen & Notepad• Network Diagram and activity sheet from last week• All your notes on Titanic

Leadership (Unit 19 Pass 4)

Objectives

By the end of the lesson you will……..

• Be comfortable evaluating the use of CPM in a project

• Be confident designing a network diagram

• Be able to identify the CPM by looking at a network diagram

Work in groups of 3

• Write down every task you need to do and how long it will take• Now list them in order• Are there any tasks that you can do at the same time?• Now create a flow diagram from left to right (use flip chart)• Identify your critical path • How long will the whole process take?

Think about the process you have to go through to make a cup of tea for 1 person who takes milk and sugar and likes it

to be made in a tea pot

Put water in kettle and switch on

Wait for kettle to boil (3mins)

Pour boiled water into empty teapot

Wait 3mins for tea to mast

Pour tea into prepared cup Add sugar Stir sugar into tea

Take sugar bowl out of cupboard and

place on bench next to cups

Take spoon out of drawer and put next

to sugar bowl

Take cup out of cupboard (10secs)

Take milk out of fridge(5secs)

Pour milk into cup (10secs)

Take teabag out of caddy(5secs)

Empty tea pot (5 secs)

Put teabag in tea pot (2 secs)

Put water in kettle and switch on

(5secs)

Wait for kettle to boil (3mins)

Pour boiled water into empty teapot

(5secs)

Wait 3mins for tea to mast

(3mins)

Pour tea into prepared cup (5secs) Add sugar (5secs) Stir sugar into tea

(3secs)

Take sugar bowl out of cupboard and place on

bench next to cups (5secs)

Take spoon out of drawer and put next to

sugar bowl (5secs)

Take cup out of cupboard (10secs)

Take milk out of fridge(5secs)

Pour milk into cup (10secs)

Take teabag out of caddy(5secs)

Empty tea pot (5 secs) Put teabag in tea pot (2 secs)

Name the diagram????

QUALITY

SCOPETIM

E COST

What can you remember about it?

Project information:Scope – To paint a red equilateral triangle on the wall of every room in the collegeTime- 1 hourQuality- Red equilateral triangleCost- Budget £10

Price List:• £1 per person• £7 Red Paint • £1 Blue Paint• £1 Paint Brush• £1 Measuring tape

Extra Information:• It would take 1 person 10 hours to complete the project.

Activity

In groups I want you to look at the following and decide how you would run this project

Project 11 person Time= 10 HoursRed Paint Quality = Red Equilateral TrianglePaint Brush Cost= £10Measuring Tape

Project 210 people Time= 1 HourRed Paint Quality = Red Equilateral TrianglePaint Brush Cost= £37Measuring Tape

Project 310 people Time= 1 HourBlue Paint Quality = Blue Equilateral TrianglePaint Brush Cost= £31Measuring Tape

Project 410 people Time= 1 HourRed Paint Quality = Red TrianglePaint Brush Cost= £27

Project 55 people Time= 2 HoursRed Paint Quality= Red Equilateral TrianglePaint Brush Cost= £22Measuring Tape

Project information:Scope – To paint a red equilateral triangle on the wall of every room in the college

Time- 1 hour

Quality- Red equilateral triangle

Cost- Budget £10

Price List:• £1 per person• £7 Red Paint • £1 Blue Paint• £1 Paint Brush• £1 Measuring tape

Extra Information:• It would take 1 person 10 hours to

complete the project.

What is the critical path method?

How do you find the critical path?• A network diagram to establish the earliest time to complete a

project.Characteristics of a activity on the critical path?• 0 Float time (can’t be delayed without delaying the project)• Always the longest route from start to finish

How to create a network diagram?

1. List all the activities needed to be completed for the project2. List in a logical and chronological sequence3. Find all the relationships between the activities (what depends on

another activities completion?)4. What are the 2 types of relationships? 1= 2= 5. A realistic network diagram will contain both

EST D EFTActivity A

LST F LFT

Forward Pass= EFT= EST+DIf there are two or more activities going into one is it the Highest or Lowest EFT that becomes the next activities EST?

Backward Pass= LST= LFT-DIf there are two or more activities going into one is it the Highest or Lowest LST that becomes the next activities LFT?

Float= LST-EST or LFT-EFT

Completing the node

Parallel Activities

 Activity A

      

Activity C 

Activity Duration

A- Walls 14

B- Plumbing 7

C- Electrics 5

D- Plastering 8

     Activity D

     

EST D EFTActivity

LST F LFT

Backward Pass- LST= LFT - DFloat= LST – EST/ LFT - EFT

Forward Pass- EFT= EST + D

   Activity B

   

Go over the activity

What did you find the easiest about critical path?

What did you find the hardest about critical path?

• Did anyone find the critical path?• Did anyone successfully complete the network diagram?

Activity- Machine A & Machine B

Making the network diagram……….

How I made the network diagram?

How to decide what order the sequence of activities goes in?

Activity Proceeded by Duration

A None

B None

C A

D A

E C

F D,E

G F

H F

I H

J B,G,I

K J

L J

Complete the activity

• I want you to complete the network diagram for both machines

• Find the duration of both projects and state which machine is the best to use?

• What is the critical path for Machine A & Machine B?

Advantages of critical path method

Critical Path Advantages

• Help to increase efficiency of how time and resources are managed• It enables time scales for the project to be planned (However initial

evaluations of each activity need to be done beforehand)• It enables scheduling of tasks to take place in a logical order• It means that one task isn’t held up because its predecessor wasn’t

started on time• It helps cash flow to be monitored and extra funds to be released

when required• It reduces waste (Time, cost, quality)

Disadvantages of critical path method

Critical Path Disadvantages

• It needs a skilled person to complete it in the first place• Usefulness may be limited in very large scale or complex projects• Accurate estimates of time are required • Reliant on technology• Not very portable (Can’t easily take them to the site of the project)

Titanic Re-visited• Ship of luxury not speed • Virtually unsinkable• Take out the competition through 3 ships 3rd funded by 1st 2 and 75% revenue was from 1st class.• 48 to 16 lifeboats due to interfering with 1st class view 1178 lifeboat places for up to 3600 guests• Olympic had many problems and pulled staff off titanic to fix it therefore titanic was way behind

schedule yet ordered to not be a day late for launch• Sea trials were cut from 8 weeks to half a day• Interest was lost in titanic so to generate interest back into the launch they claimed to beat

Olympics time to New York.• Race towards iceberg alley slowly navigate through then race off afterwards• 53 millionaires on board

Titanic

• What went wrong with the project planning?• Critical Path?• Were activities on the critical path delayed?

Titanic

Was the PM aware of the project management model triple constraint?

He was obsessed with the ship being built for quality (some sacrifices in quality were needed but not willing to be met) Binoculars, lifeboats etc. were sacrificed but at the cost of the project.Was unwilling to accept a change in time (Delay the launch)Needed to keep costs at a minimum due to Olympic and 3rd ship business strategy (Could have employed more staff to cover whilst working on Olympic)The scope of the project was changed at many times throughout the project

By not accepting a change or being aware of the affect it would have the project was doomed to failure.

Critical path for your event

• Think of all the activities needed to be done for your events?• What order do they need to be done in?• Can you create a sequence for the activities?• Then create a network diagram?• Can you identify the Critical path for your event?

Quiz on Critical Path

???????

0 5  5Activity A

 0  0  5

5 6 11 Activity C

 16  11  22

5 7  12Activity B

 15  10  22

5 17  22

Activity D 5  0  22

22 3  25Activity E

 22  0  25

25 8  33Activity F

 25 0   33

What is the critical path?

0 1  1Activity A

 0 0   1

1 2 3 Activity C

 2  1  4

1 3 4 Activity B

 1  0  4

1 1  2

Activity D 3 2   4

4 2 6 Activity E

 4  0  6

6 1 7 Activity F

 8  2  9

6 3 9 Activity G

 6 0   9

What is the critical path?

0 8 8 Activity A

 0 0   8

8 6 14 Activity C

 12  4  18

8 8  16Activity B

 9  1  17

8 7  15

Activity D 8  0  15

14 5  19Activity F

 18  4  23

22 11 33 Activity H

 23  1  34

16 6 22 Activity E

 17 1   23

15 4  19Activity G

 15  0  19

19 15  34Activity I

 19  0  34

What is the critical path?

0 8 8 Activity A

 0 0   8

8 6 14 Activity C

 12  4  18

8 8  16Activity B

 9  1  17

8 7  15Activity D

 8  0  15

14 5  19Activity F

 18  4  23

22 11 33 Activity H

 23  1  34

16 6 22 Activity E

 17 1   23

15 4  19Activity G

 15  0  19

19 15  34Activity I

 19  0  34

How many days would the project be delayed by if?

1. C is delayed by 3 days?

2. D is delayed by 4 days

3. E is delayed by 7 days

4. H is delayed by 1 day

ACTIVITY PROCEDED BY

A -

B A

C B

D B

E C,D

F E

Draw a network diagram for………..

Draw a network diagram for……..ACTIVITY PROCEDED BY

A -

B A

C A

D A

E B

F C

G E

H F

I G,H

J D,I

K J

L K

Draw and complete this network diagram…..

ACTIVITY PROCEDED BY DURATION

A - 1

B A 2

C B 2

D C 3

E C 4

F D,E 3

G F 1

1.What is the duration of the project?2.What is the critical path?