Avimanyu Datta
NETWORK DIAGRAM AND
CRITICAL PATH
Activity Duration and Preceding Activities
Activity
Duration
(Days)
Preceding Activity
A
1
-
B
2
-
C
3
-
D
4
A
E
5
B
F
4
B
G
6
C
H
6
D,E
I
2
G
J
3
F,H,I
Some Key Definitions
 ET: Estimated Duration
 TE: Earliest Expected Completion Time
TE = Max [TE (Previous Process) ]+ ET (Current Processes)
 TL: Latest Expected Completion Time: Time in which
an activity can be completed without delaying the
project
TL =Min[ TL (Later Process ) – ET (Later Process)]
 SLACK = TL-TE. Zero Slack = Zero Flexibility.
Network Diagram with ET
D ET=4
A ET=1
H ET=6
E ET=5
B ET=2
J
F ET=4
C ET=3
G ET=6
I
ET=2
ET=3
Network Diagram with ET and TE
START
From
HERE
TE= 1
We take the TE from Process E
rather than Process D. Because
TE(E)> TE (D)
TE= 5
D ET=4
TE = 13
A ET=1
TE = 7
TE = 2
H ET=6
E ET=5
TE= 16
B ET=2
J
TE= 6
TE = 3
We take the TE from
Process H rather than
Process I or F. Because
TE (H) >TE(I)> TE (F)
F ET=4
C ET=3
TE = 9
G ET=6
TE = 11
I
ET=2
ET=3
Network Diagram with ET and TE
TE= 5
TE= 1
D ET=4
A ET=1
TL= 7
TL = 3
TE = 7
TE = 2
E ET=5
B ET=2
TL = 7
TL = 2*
TE = 3
C ET=3
TL = 5
* We take TL from Process E rather
that Process F because TL-ET for E is
lover that that of F
TE = 13
H ET=6
TL = 13
TE= 16
J
TE= 6
ET=3
TL = 16
F ET=4
TL = 13
TE = 9
G ET=6
TL=11
TE = 11
I
ET=2
TL = 13
START
From
HERE
Critical Process and Critical
Path
Path comprising of
TE= 5
TE= 1
D ET=4
A ET=1
TL= 7
TL = 3
TE = 7
TE = 2
E ET=5
B ET=2
TL = 7
TL = 2
TE = 3
C ET=3
TL = 5
Process where Slack (
TL-TE) = 0
TE = 13
H ET=6
TL = 13
TE= 16
J
TE= 6
ET=3
TL = 16
F ET=4
TL = 13
TE = 9
G ET=6
TL=11
TE = 11
I
ET=2
TL = 13
CRITICAL
PATH I S
B E H J
Critical Path: Questions to
Ponder upon
 What is the importance of Critical Path?
 How will you distribute your resources when
you know the critical path?
 What happens if process within a critical path
is delayed?