Project Management is the most valuable step in any business enterprise. Whenever you are going to launch a new product or new service, embarking in any marketing campaign, want to organize any project; must needed step is to manage all needs of that project in any aspect, this process known as Project management and it was needed by every field to stabilize the working and making all things organized and successful. As every project employs many resources like workers, money, time and every kind of material used in it; these all parameters entangle an efficient management team that can lead them and used them at required time.

Sometime, we encounter several delays in complex project that may pass the budget that was allocated for making to the project or may be for the completion of that project and after that it will make very costly project, many techniques that were used in past failed in solving these issues; two tools that have been proven the efficient tools for this solution are CPM (Critical Path Method) and PERT (Program Evaluation and Review Techniques). 

How CPM and PERT were discovered?

CPM was the discovery of M.R.Walker of E.I.Du Pont de Nemours & Co. and J.E.Kelly of Remington Rand, circa 1957. The computation was designed for the UNIVAC-I computer. The first test was made in 1958, when CPM was applied to the construction of a new chemical plant. In March 1959, the method was applied to a maintenance shut-down at the Du Pont works in Louisville, Kentucky. Unproductive time was reduced from 125 to 93 hours.

PERT was devised in 1958 for the POLARIS missile program by the Program Evaluation Branch of the Special Projects office of the U.S.Navy, helped by the Lockheed Missile Systems division and the Consultant firm of Booz-Allen & Hamilton. The calculations were so arranged so that they could be carried out on the IBM Naval Ordinance Research Computer (NORC) at Dahlgren, Virginia.

Basic Methodology of CPM and PERT:

Essentially, there are six steps which are common to both the techniques. The procedure is listed below:

  1. Define the Project and all of it’s significant activities or tasks. The Project (made up of several tasks) should have only a single start activity and a single finish activity.
  2. Develop the relationships among the activities. Decide which activities must precede and which must follow others.
  3. Draw the “Network” connecting all the activities. Each Activity should have unique event numbers. Dummy arrows are used where required to avoid giving the same numbering to two activities.
  4. Assign time and/or cost estimates to each activity
  5. Compute the longest time path through the network. This is called the critical path.
  6. Use the Network to help plan, schedule, monitor and control the project
Comparison of CPM and PERT:
  • The CPM is a kind of technique commonly known for its use in constructions project; whereas PERT mostly used in research and in development projects like the projects considered being a kind of non-repetitive nature.
  • Both techniques have different concept of working like CPM uses deterministic concept for its work whereas probabilistic concept is used by PERT.
  • Networking approach also varies in both techniques like CPM uses networking that based upon activity oriented; on contrary PERT uses networking that based on event.
  • In PERT technique, an estimation of time for different activities is not perfect and accurate whereas in CPM activities duration are estimated with the quality of accuracy.
  • Both of the techniques used for same purpose but the nature of their working is different and some can do their work efficiently with CPM and some can do same with PERT.
  • Cost optimization is a main point in any project and In CPM, this step has prime importance on other steps because time required for the completion of project is totally dependent on cost optimization stats, as we all know that cost is not directly proportional to time that’s why cost is said to be a controlling factor. On contrary, this concept is totally opposite in PERT; it is assumed that cost and time are interlinked and cost varies with time.
  • The most important thing to solute is to minimize time so that they can get good result for their cost factor. In PERT, time is said to be a controlling factor.
  • Unpredicted activities are managed with the help of Program Evaluation and Review Technique (PERT), whereas CPM is used for dealing those projects that have some alarmed activities. These two techniques said to be a key element for the management of any project.

CPM technique is used for similar projects for which previous data is available and durations can be estimated from this previous data. For example construction projects. PERT technique is used for projects which are usually 1st of their kind and for which previous data is not available. For example research and development projects. In PERT, data is analyzed with probability techniques. However basic methodology of both the techniques is same and it is often called as CPM/PERT technique.

Muhammad Abdul Wajid Rai

Hey! I am Abdul Wajid. I am a Civil Engineer and have done Masters in Project Management. I have served for about 7 years in Planning, Execution, Monitoring and Controlling of large and complex projects. I have conducted a lot of trainings and workshops on Project Management and Primavera P6 software.

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