CPM Pert New

7/31/2019 CPM Pert New

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CPM-PERT

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Course on Project Management

Purpose of CPM

Finish fast

Quantify progress

Communicate effectively

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PM Today Necessary?

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Frustration with cost & schedule overruns Frustration with reliability of production estimates Management challenges exist today:

Only44% of projects are completed on time On average, projects are 189% over-budget 70% of completed projects do not perform as expected 30% of projects are canceled before completion On average, projects are 222% longer than expected

PM has been shown to improve this performanceThese statistics were compiled by an independent monitoring group, TheStandish Group, and represent the US national average for 1998


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Advantages and Disadvantages of FormalSchedules

Saves time and money on large complex projects

Effective communication tool

Too much work

Assessment of duration of tasks Assessment of interdependencies

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Resource Oriented and Time Oriented Schedules

Resource oriented

Time oriented

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Elements of a Critical Path Chart

Activity

Precedence

Duration/cost

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8/45Course on Project Management


Activity

Precedence

Duration/cost

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Activity

Precedence

Duration/cost

Activity Description Precedents

A Select satisfaction survey tool

B Print survey tool A

C Select list of patientsD Sample from list C

E Mail surveys to selected patients D

F Collect responses E

G Analyze data F

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Activity

Precedence

Duration/cost

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Activity

Precedence

Duration/cost

Activity Description Precedents Duration

A Select satisfaction survey tool 2 weeks

B Print survey tool A 3 weeks

C Select list of patients 1 week

D Sample from list C 1 week

E Mail surveys to selected patients D 2 weeks

F Collect responses E 4 weeks

G Analyze data F 3 weeks

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Branch and Node Charts

Activity on branch

Activity on node

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Activity In Node

A B

C




C Obtain list of patients

D Sample from list C

E Mail surveys to selected patients D,B


G Analyze data F

D

E F G

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Activity On Branches

1 3

2




C Obtain list of patients

D Sample from list C

E Mail surveys to selected patients D,B


G Analyze data F

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5 6 7A B E F

C D

EndG

Start

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Earliest and Latest Start and Finish Times

A B

C D

E F G2 3 2 4 3

1 1

End

Start

Activity Description


B Print survey tool

C Select list of patients

D Sample from list

E Mail surveys to patients

F Collect responsesG Analyze data

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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Forward pass calculates early start and finish



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Backward pass calculates latest start and end times



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Critical Path includes activities where earliest starttime and latest start time are equal



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Activities not on the critical path have slack.

The latest start time and the earliest start date aredifferent



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Start Finish

Early 0

Late



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

Start Finish

Early 0 2

Late



B Print survey tool


D Sample from list



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B Print survey tool


D Sample from list




A B

C D

E F G2 3 2 4 3

1 1

End

Start

Start Finish

Early 2 5

Late

S F

E 0 2

L

S F

E 2 5

L

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B Print survey tool


D Sample from list




A B

C D

E F G2 3 2 4 3

1 1

End

Start

Start Finish

Early 1 2

Late

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

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B Print survey tool


D Sample from list




A B

C D

E F G2 3 2 4 3

1 1

End

Start

Start Finish

Early 5 7

Late

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

S F

E 1 2

L

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B Print survey tool


D Sample from list




A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

S F

E 1 2

L

S F

E 5 7

L

S FE 7 11

L

S FE 11 14

L

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A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

S F

E 1 2

L

S F

E 5 7

L

S FE 7 11

L

S F

E 11 14

L 14

Latest finish is the minimum of latest start ofsucceeding tasks. Latest start is the latest finish

minus duration.

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A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

S F

E 1 2

L

S F

E 5 7

L

S FE 7 11

L

S FE 11 14

L 11 14

Latest finish is the minimum of latest start ofsucceeding tasks. Latest start is the latest finish

minus duration.

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A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L

S F

E 2 5

L

S F

E 0 1

L

S F

E 1 2

L

S F

E 5 7

L

S F

E 7 11

L 7 11

S FE 11 14

L 11 14



B Print survey tool


D Sample from list



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A B

C D

E F G2 3 2 4 3

1 1

End

Start

S FE 0 2

L 0 2

S FE 2 5

L 2 5

S F

E 0 1

L 3 4

S F

E 1 2

L 4 5

S FE 5 7

L 5 7

S FE 7 11

L 7 11

S FE 11 14

L 11 14



B Print survey tool


D Sample from list



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Slack Time

A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L 0 2

S F

E 2 5

L 2 5

S F

E 0 1

L 3 4

S F

E 1 2

L 4 5

S F

E 5 7

L 5 7

S FE 7 11

L 7 11

S FE 11 14

L 11 14

Slack time = Latest start Earliest start

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Critical Path

A B

C D

E F G2 3 2 4 3

1 1

End

Start

S F

E 0 2

L 0 2

S F

E 2 5

L 2 5

S F

E 0 1

L 3 4

S F

E 1 2

L 4 5

S F

E 5 7

L 5 7

S FE 7 11

L 7 11

S FE 11 14

L 11 14

Critical path includes activities with no slack.

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Communicating Project Schedule

Time scaled network of activities

Gantt chart

Time an activity graphs and completion graphs

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Gantt chart


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Gantt chart


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Software

Discovery of Critical Path

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PERT analysis37

Draw the network. Analyze the paths through the network and find the critical path.

The length of the critical path is the mean of the project durationprobability distribution which is assumed to be normal

The standard deviation of the project duration probabilitydistribution is computed by adding the variances of the criticalactivities (all of the activities that make up the critical path) andtaking the square root of that sum

Probability computations can now be made using the normaldistribution table.


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Probability computation38

Determine probability that project is completed within specified time

Z =

x -

where = tp = project mean time

= project standard mean time

x = (proposed ) specified time


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Normal Distribution of Project Time39

= tp Timex

Z

Probability

l


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PERT Example

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Immed. Optimistic Most Likely Pessimistic

Activity Predec. Time (Hr.) Time (Hr.) Time (Hr.)

A -- 4 6 8B -- 1 4.5 5C A 3 3 3D A 4 5 6E A 0.5 1 1.5F B,C 3 4 5G B,C 1 1.5 5

H E,F 5 6 7I E,F 2 5 8J D,H 2.5 2.75 4.5K G,I 3 5 7

l


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PERT Example

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A

D

C

B

F

E

G

I

H

K

J

PERT Network

PERT E l


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PERT Example

42Activity Expected Time Variance

A 6 4/9B 4 4/9C 3 0D 5 1/9

E 1 1/36F 4 1/9G 2 4/9H 6 1/9

I 5 1J 3 1/9K 5 4/9


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PERT Example43

Activity ES EF LS LF SlackA 0 6 0 6 0 *criticalB 0 4 5 9 5

C 6 9 6 9 0 *D 6 11 15 20 9E 6 7 12 13 6F 9 13 9 13 0 *G 9 11 16 18 7H 13 19 14 20 1

I 13 18 13 18 0 *J 19 22 20 23 1K 18 23 18 23 0 *


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PERT Example44

Vpath = VA+ VC + VF + VI + VK= 4/9 + 0 + 1/9 + 1 + 4/9

= 2

path = 1.414

z= (24 - 23)/ (24-23)/1.414 = .71

From the Standard Normal Distribution table:

P(z < .71) = .5 + .2612 = .7612


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Thank You for Your

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