Which of the following statements (pertaining to CPM network analysis) are correct?
A. It is an event-oriented method.
B. It is an activity-oriented method.
C. Time and cost are controlling factors.
D. Time alone is the controlling factor.
Choose the most appropriate answer from the options given below:
Step 1: Distinguishing PERT and CPM.
- PERT (Program Evaluation and Review Technique) is an event-driven methodology, emphasizing project duration uncertainties.
- CPM (Critical Path Method) is an activity-driven methodology, focused on project planning, scheduling, and managing both time and cost.
Step 2: Evaluating each assertion.
- (A) Event-driven → Applicable to PERT, not CPM. Therefore, invalid.
- (B) Activity-driven → Accurate for CPM.
- (C) Time and cost as primary controls → Accurate, as CPM optimizes for both time and cost.
- (D) Time as the sole control → Inaccurate, as CPM integrates both time and cost considerations.
Step 3: Final determination.
Statements B and C are the only valid ones.
The time estimates obtained from four contractors (P, Q, R and S) for executing a particular job are as under:
\[\begin{array}{|c|c|c|c|} \hline \textbf{Contractor} & \textbf{Optimistic time, $t_o$} & \textbf{Most likely time, $t_m$} & \textbf{Pessimistic time, $t_p$} \\ \hline \text{P} & 5 & 10 & 13 \\ \hline \text{Q} & 6 & 9 & 12 \\ \hline \text{R} & 5 & 10 & 14 \\ \hline \text{S} & 4 & 10 & 13 \\ \hline \end{array}\]
Which of these contractors is more certain about completing the job in time?