Advantages And Disadvantages Of PERT And CPM

Definition of PERT –

Program (Project) Evaluation and Review Technique (PERT) is a project network analysis technique that is used to undergo planning and controlling of the projects. The PERT technique focuses on the time and the cost each activity takes. This will hence influence the resultant time and the cost required for the completion of the entire project. This network analysis technique helps to understand the performance of the work throughout the course of the project. It was developed in the late 1950s. It is aimed to reduce the time and cost of the project.

PERT uses time as a variable which represents the planned resource application along with performance specification. In this technique, first of all, the project is divided into activities and events. After that proper sequence is ascertained, and a network is constructed. After that time needed in each activity is calculated and the critical path (longest path connecting all the events) is determined.

Advantages of PERT –

The advantages of PERT are mentioned below:

  • Planning For Large Projects in PERT – The scheduling of project activities is done easily with the help of the PERT system by the project manager. This technique is more active in large sophisticated project works.
  • Visibility of Critical Path in PERT – The PERT method will show the critical path in a well-defined manner. The critical path is the path with activities that cannot be delayed under any circumstances. Proper knowledge about the stack values with limited conditions of dependencies will help the project manager to bring fast and quality decisions that will favor the project performance.
  • Analysis of Activity in PERT – The activity and the events are analyzed from the PERT networks. These are analyzed independently as well as in combination. This will give a picture of the likely completion of the project and the budget.
  • Coordination in PERT – The various departments of the construction organization will deliver data for the PERT activities. Good integration is developed between all the departments which will help in improving the planning and the decision-making capabilities of the project team. The combination of qualitative and quantitative values from a large amount of data will help in improving the coordination of the project activities. This will also improve the communication between various departments of the organization.
  • The What-if Analysis – The possibilities and the various level of uncertainties can be studied from the project activities by properly analyzing the critical path. This type of analysis is called what-if-analysis. For these various sets of permutation and combination are conducted. Among them, the most suitable combination is taken into consideration. This set chosen will be the one with minimum cost, economy, and best result. This analysis helps to identify the risk associated with any activities.

Disadvantages of PERT –

Various Demerits of PERT are mentioned below:

  • Time Focused Method – PERT is a time-bound method, so finishing projects or activities on time is of high importance. If it does not happen than a problem can arise
  • Subjective Analysis – Here, the project activities are recognized according to the available data. However, it is difficult in PEERT projects as it is applicable for the only new project are which is not repetitive in nature, therefore, the collection of information to be subjective in nature.
  • Prediction Inaccuracy – PERT does not have any past records for a framework of a project, so prediction comes into play. The project will be ruined if the prediction is not accurate.
  • Expensive – Too expensive in terms of time consumed, research, prediction, and resources utilized.
  • Other Issues with PERT – This method is highly labor-intensive in nature. As there are chances of an increase in project activities large and complicated networks are developed as many task dependencies come into existence. If two activities share common resources, this technique won’t find very apt for the project.

Definition of CPM –

Developed in the late 1950s, the Critical Path Method or CPM is an algorithm used for planning, scheduling, coordination, and control of activities in a project. Here, it is assumed that the activity duration is fixed and certain. CPM is used to compute the earliest and latest possible start time for each activity.

The process differentiates the critical and non-critical activities to reduce the time and avoid the queue generation in the process. The reason for the identification of critical activities is that, if any activity is delayed, it will cause the whole process to suffer. That is why it is named as Critical Path Method.

Advantages of CPM –

The advantages of the Critical Path Method (CPM) are mentioned below:

  • CPM figures out the activities that can run parallel to each other. It helps the project manager in identifying the most critical elements of the project.
  • CPM gives a practical and disciplined base which helps in determining how to reach the objectives.
  • CPM is effective in new project management. It can strengthen a team’s perception if it is applied properly.
  • CPM provides a demonstration of dependencies which helps in the scheduling of individual activities. It shows the activities and their outcomes as a network diagram.
  • CPM gives a fair and concise procedure of documenting of project. It helps in determining the slack time.
  • An explicit and clear approach of communicating project plans, schedules, time, and cost performance is developed.
  • CPM is extensively used in the industry. It helps in optimization by determining the project duration.

Disadvantages of CPM –

Various Demerits of Critical Path Method (CPM) are mentioned below:

  • The scheduling of personnel is not handled by the CPM.
  • In CPM, it is difficult to estimate the completion time of activity.
  • The critical path is not always clear in CPM.
  • For bigger projects, CPM networks can be complicated too.
  • It also does not handle the scheduling of resource allocation.
  • In CPM, a critical path needs to be calculated precisely.

Actually, PERT is stipulated according to events whilst CPM is ranged towards activities. A deterministic model is used in CPM. While PERT uses a probabilistic model.


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