Gantt and PERT charts

Representing and Scheduling Project Plans Gantt Charts

Useful for depicting simple projects or parts of large projects

Show start and completion dates for individual tasks

PERT Charts PERT = Program Evaluation Review

Technique Show order of activities or dependencies

between activities

Figure 3-16Graphical diagrams that depict project plans (a) A Gantt Chart (b) A PERT chart

Sample PERT Chart

Comparison of Gantt and PERT Charts Gantt

Visually shows duration of tasks

Visually shows time overlap between tasks

Visually shows slack time

PERT Visually shows

dependencies between tasks

Visually shows which tasks can be done in parallel

Shows slack time by data in rectangles

Critical Path Analysis

The PERT Algorithm

By Example

3

2

5

7

2

4

2

A

B

C

D

E

F

G

The Original Graph

Label all vertices without predecessors. (A & B)

3

2

5

7

2

4

2

A

B

C

D

E

F

G3

2

Red numbers are the new labels.

Label all vertices whose predecessors are all labeled. (C)

3

2

5

7

2

4

2

A

B

C

D

E

F

G3

2

8

Red numbers are the new labels. Blue labels are from previous steps.

Label all vertices whose predecessors are all labeled.(D, E, F)

Red numbers are the new labels. Blue labels are from previous steps.

3

2

5

7

2

4

2

A

B

C

D

E

F

G3

2

8

12

10

15

Label all vertices whose predecessors are all labeled.(G)

Red numbers are the new labels. Blue labels are from previous steps.

3

2

5

7

2

4

2

A

B

C

D

E

F

G3

2

8

12

10

15

17

The largest number, 17, is the minimum amount of time needed to complete the task and ACFG is the critical path.

Red arrows represent the critical path.

3

2

5

7

2

4

2

A

B

C

D

E

F

G3

2

8

12

10

15

17