The Critical Path Method (CPM) - Construction Project Scheduling and Control - page 83

path, taking into consideration calendars, constraints, resources, and other impacting
factors.” The part that it represents, the “summation of the durations of activities and
lags along that path,” is well understood. However, we need to explain the part, “tak-
ing into consideration calendars, constraints, resources, and other impacting factors.”
In the solution of example 4.5 (Figure 4.11), there are nine paths:

9,15 15, 22

D
6

J
7

12, 19 19, 29

16, 22 22, 29

4, 9

E
7

H
10

3

B
5

12, 19

2

19, 29

2

4, 9

0, 2 29, 30

9, 13

19, 27

A
2

K
1

1

F
4

I
8

2, 8

0, 2 29, 30

13, 17

C
6

20, 28

8, 13

7, 13

G
5

15, 20

1. A-B-D-J-K 23

2. A-B-D-H-K 26

3. A-B-E-H-K 30

4. A-B-E-I-K 29

5. A-B-F-H-K 26

6. A-B-F-I-K 23

7. A-C-F-H-K 25

8. A-C-F-I-K 22

9. A-C-G-I-K 23

Path 3 fulfills the portion of the Critical Path definition, “the summation of the
durations of activities and lags along that path,” with 30 days (25 days of activities'
durations and 5 days of lags). However, let's imagine these possible scenarios in what
pertains to the other portion of the definition, “taking into consideration calendars,
constraints, resources, and other impacting factors:”

• Scenario 1 : All activities on path 3 are on a 5-workday/week calendar. Activ-
ity I is on a 6-workday/week calendar. This will likely make path 4 longer than
path 3, considering calendar days (since the length of the project is usually spec-
ified in contracts in calendar days).
• Scenario 2 : Assume a constraint, “Start on Day 18,” is assigned to activity G;
thus, it won't finish until day 23. Activities I and K will follow, with dates