Critical Path Method (CPM) and Program Evaluation Review Technique (PERT) are management and analytical techniques. These methods are most often used to schedule and organize huge and complex projects. CPM and PERT are also collectively called network analysis. These techniques are important for operations research and quantitative analysis. They help make the flow of project implementation fast and efficient.
CPM and PERT were developed as tools for the industrial and military sectors. M.R. Walker of E.I. Du Pont de Nemours & Co. and J.E. Kelly of Remington Rand created CPM as a computation design for the UNIVAC-I computer. In 1958, CPM was first tested and applied to the construction of a chemical plant. PERP was developed through the joint effort of the Program Evaluation Branch of the Special Projects office under the U.S. Navy and the Lockheed Missile Systems division and the consultant firm of Booz-Allen & Hamilton. This calculation technique was originally designed for the Polaris missile program.
The main idea behind CPM and PERT is that projects should be broken down into small sets of activities or tasks. These small activities or tasks should be identified in terms of their level of importance. The more important tasks are determined and are immediately assigned to appropriate team members. With CPM and PERT, the project manager is able to direct major management resources to the few crucial tasks that may determine the project’s success. These techniques also indicate if the project is running according to the set schedule. Some activities follow a serial process. This means that the second task can start after the first task is accomplished. CPM and PERT charts are created for visual illustrations of the flow of tasks.
A PERT chart is composed of initiation nodes from which all tasks originate. Multiple tasks that started at the same time must come from the same node or branch. Each line in the chart represents a specific task. The chart also indicates the task’s duration, as well as the number and initials of those individuals involved in the tasks. At the opposite end of each line is another node that also signifies either the beginning of other tasks or the waiting time in between two tasks. When all final tasks are linked to the completion node, the chart is considered complete.
CPM charts are similar to PERT charts. Aside from regular tasks, the chart also indicates the critical path, which refers to a set of dependent tasks--each task dependent on the preceding ones. The critical path tasks are drawn with double lines instead of one to distinguish them. The project manager and team members have the responsibility to ensure that special attention and focus are given to tasks under the critical path. The critical path might undergo changes during the project. This may be due to crucial tasks being completed either ahead of or behind the set schedule.
CPM and PERT charts allow managers in the planning divisions of organizations to communicate and consolidate ideas. They are also effective for evaluating the performance of teams and individual members. These charts are also an excellent visual basis for gauging the planning and analytical skills of team leaders. CPM and PERT analysis also promotes cost-effectiveness and optimal use of manpower as the process determines the time frame for a project to be completed as well as the risks involved.