Question

Which of the following is NOT correct critical path method (CPM) used in Project scheduling?
1. The path with the longest time sequence the critical path.
2. For each activity earliest start time and latest start time are computed.
3. The length of the critical path determines the minimum time in which the entire project can be completed.
4. The path with the shortest time sequence is the critical path.

Answer 1

Correct Answer - Option 4 : The path with the shortest time sequence is the critical path.

Explanation:

Critical Path Method (CPM):

• The critical path method (CPM) is a technique where you identify tasks that are necessary for project completion and determine scheduling flexibilities. A critical path in project management is the longest sequence of activities that must be finished on time in order for the entire project to be complete. Any delays in critical tasks will delay the rest of the project.
• CPM revolves around discovering the most important tasks in the project timeline, identifying task dependencies, and calculating task durations.
• CPM was developed in the late 1950s as a method to resolve the issue of increased costs due to inefficient scheduling. Since then, CPM has become popular for planning projects and prioritizing tasks.

Program Evolution and Review Technique (PERT):

• Program Evaluation and Review Technique (PERT) is a method used to examine the tasks in a schedule and determine a Critical Path Method variation (CPM). It analyzes the time required to complete each task and its associated dependencies to determine the minimum time to complete a project.
• It estimates the shortest possible time each activity will take, the most likely length of time, and the longest time that might be taken if the activity takes longer than expected.  The US Navy developed the method in 1957 on the Polaris nuclear submarine project.

Difference between PERT and CPM

PERT	CPM
Project Evaluation and Review Technique	Critical Path Method
It is event-oriented.	It is activity-oriented.
It is associated with probabilistic activities.	It is associated with deterministic activities.
It is based upon a three-time estimate to complete an activity. \({t_e} = \left( {\frac{{{t_o} + 4{t_m} + {t_p}}}{6}} \right)\) Where, te = expected time to complete an activity to  = optimistic time, tm = mean time, tp  = pessimistic time	It is based upon a single time estimate to complete an activity.
It usually doesn’t consider cost analysis.	It gives importance to cost analysis & crashing is done to minimize the cost of the CPM project.
Applications: Mainly used for R & D project	Applications: Mainly used for Construction project