Example of CPM

The software project consists of a list of tasks along with their estimated durations which are shown in the estimation table below. The project manager also knows the dependencies among those tasks. Please make a CPM graph to show how to organize all the tasks so that the project can be down in the shortest time by Nancy and Julia.

Tasks	Dependency	Duration
A		4
B		3
C	A	8
D	A	7
E	B and C	9
F	B and C	12
G	D and E	2
H	D and E	5
I	F and G	6

Solution:

Step 1. Draw the dependency graph

Step 2. Find the critical path

Tasks	Dependency	Duration	Earliest finish time
A		4	4
B		3	3
C	A	8	12
D	A	7	11
E	B and C	9	21
F	B and C	12	24
G	D and E	2	23
H	D and E	5	26
I	F and G	6	30

The critical path is A®C®F®I.

The earliest completion time is 4 + 8 + 12 + 6 = 30.

Step 3. Assign the tasks to Nancy and Julia, and compute the earliest start time

Step 4. Compute the latest possible start time given the earliest completion time, 30.