Friday 14 December 2018

PERT method

A PERT method is the program evaluation and review technique is a statistical tool used in project management, which was designed to analyze and represent the tasks involved in completing a given project. A PERT chart is a project management tool used to schedule, organize, and coordinate tasks within a project. PERT stands for Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program.

The PERT method is one of the many tools of the Administration to have improve efficiency and effectiveness in developing appropriate processes to develop certain strategies or events that you plan to do in the future.
PERT method example


When the Navy of the United States want to accelerate the Polaris missile program, thought, improve management methods. To improve their effectiveness, it was decide to apply her technique "PERT", acronym of the terms that describe this strategy, whose equivalent in Spanish would be: "Technique of rating and review of a project". It is basically a method for programming and controlling an operation or a procedure of production. While in the Navy was use for a missile program, in many organizations this system applies in the productive and administrative tasks.

In essence, the PERT method is such that a housewife who prepares a multi-course meal. Several kitchen burners are use simultaneously. It begins first with food whose preparation will take more time, but ensuring that all are ready to be serve at dinner.


The PERT technique can be very valuable when coordinate a program of production or a project consisting of several activities that should be run at a time and in a certain space. It helps to avoid costly retraces deficiencies.


Operations that involve a large number of employees, equipment, and materials can be control with the PERT. A simple example demonstrates what is the basic process: the logistics Chief wants to reorganize the store. Change runnier to containers to be transfer from a shelf to another. He develop a relationship of things which should have lists and activities to be carry out:

  • Get a forklift

  • Designate two employees who take care of the move.

  • Make sure that the new area is large enough.

  • Move the container to a new location.

  • Select and tag containers.

  • Check the amount of material that has to move.

  • Inform the appropriate supervisor and obtain your authorization.

  • Stack the container with the new agreement.

Once the logistics Chief has develop the list of elements who are involve in the operation, is in a position to apply the PERT technique. Let's look at a presentation that will help us to better understand the issue.

Using the method PERT.

The above example can be use for polishing the specific steps of the PERT:

  1. Make a list of all the actions to be taken.! The relationship of the mention example shows how.

  2. Order actions sequence. Check the list of steps to follow and sort them as they should be. In the list of the example, the first thing to do was to make sure that the material that was going to store might be in the new area.

  3. Estimate the time which will require the execution of each step. Use specific time units (minutes, hours, days, etc.) to indicate how long it will take each step in the sequence. The new list should look similar to the following:

  • Check the amount of material (48 min)

  • Verify the ability of new areas (24 min)

  • Get the tail-lift (12 min)

  • Join the employees (6 min)

  • Move the material (5 hours)

  • Size and label it (2 hours)

  • Obtain the approval of the supervisor (30 min)

  • Stack (3 hours)

  1. Draw up a diagram of arrows. The schema or 'network' of the PERT is a fundamental element, shows how different parts of the task are interrelating. To make the scheme, an arrow is drawn by each step of the operation. No matter the length of arrows but his address, which is the one that shows how each step relates to the rest. To make the diagram, ask yourself the following three questions with respect to each step of the sequence:

  • What immediately prior to this action?

  • Is what still you?

  • What other actions can perform at the same time!

Below is the PERT diagram for the operation transfer of containers.

Note what indicates the diagram at first sight. In first place, step E, the move itself, cannot be held until they made the steps from point A to the D. Second, it indicates the general scope of the operation. And thirdly, it helps to determine the critical path.

The critical path is the total path of longest consecutive activities. In the diagram, the critical path is indicate by a thicker line.
If you know what is the critical path, you are in a position to do several things:

  • Calculate the total time require to carry out the work. In the example, it would be nine hours.

  • Identify bottlenecks. In theory, all the critical path operations are a bottleneck. Usually, that are not locate on it (these are call "lax" routes) can be run at the same time of the critical path. As they take less time, the critical path is which define the program of preparation,

  • Accelerate the implementation of the program. You have two alternatives if you want to shorten the time of completion: 1) steps of "lax" routes at the same time as the critical path; or (2) shorten the critical path operations to the rias became activities of "impact", i.e. by assigning more men or equipment to the task; the creation of a more effective method etc.

Conclusion for PERT technique

If use wisely, the PERT technique also helps to reduce costs. For example, two alternative diagrams that represent two different ways to perform a task are design. Compare the man-hours, extra likely hours and other elements that influence costs, as well as the execution time of each method, to determine if more a regular program should be or one intensive, depending on the cost and the time require to carry out the task.

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