PERT Method

The PERT Method – Program Evaluation and Review Technique Example & Definition

The PERT method is something that you need to know about if you are going to consider yourself to be fully knowledgeable about everything that goes on in the world of technology. You surely want to put yourself in a position where you can tell others that you have truly done everything in your power to learn about things like the PERT method.

The PERT Method Has a Military History

Many of the technologies that we use today in a commercial way are things that got started in the military. The same is true of the PERT method. It is something that began in the US Navy. The Navy created it back in 1967. They put this method in place to help control the Polaris missile development program. Now, it has been added to other programs as well to those programs even more useful than they were before.

Why a PERT Chart Might be Used

Project managers are often asked to take care of various estimations that they need to make about various projects that they are responsible for. They are supposed to report those estimates back to the company that they work for. This is helpful to the company so they have some idea of what kind of results they can expect from any given project that they are working on.

The PERT chart may be directly applied to an estimate in order to get the answers about how long it is likely to take to get through a certain project. It is also true that using a PERT chart can help make sure the estimates are as accurate as they possibly can be. The closer the estimates are to reality, the more useful they are to the company that has requested them.

Project managers are likely to use PERT charts in conjunction with other models and projections that they can use in order to create the very best estimates that they possibly can. The PERT chart uses three different estimates combinations to come up with their numbers. Thus, those three estimates can all be taken together to figure out how to produce the very best estimate for any given scenario.


There are some critical differences that you need to know about using the PERT method versus using the CRM method. CRM stands for critical path method, and it is another way that project managers get to the estimates that they are looking for.

It is important to recognize some of the differences between PERT and CRM so you can best use whichever one you believe is most likely to  apply for your needs.

CRM has more fixed figures as far as time is concerned. However it is far more up in the air when you are looking at the PERT method. The reason is because the two methods are very different from one another as far as how they ultimately come to their final conclusions. You should consider using both methods, but you need to understand that there are significant differences between the two that you ought to know about. Simply understanding what those differences are will go a long way in serving your needs.

How to Make Time Estimates with PERT

It is a simple calculation to figure out how to get a time estimation for the total amount of time necessary to spend on a project when you use the PERT method. All that you need to look at are the following figures:

  • Optimistic Estimate – The shortest time required to complete the task
  • Pessimistic Estimate – The longest time required to complete the task
  • Most Likely Estimate – The expected time needed to complete the task

You take those figures and then throw them into the following equation: Optimistic + 4 x Most Likely + Pessimistic / 6

That formula will give you the most likely amount of time necessary to complete the task you are looking at. It will give you an even more likely estimate than you would be able to generate by simply taking a guess at the amount of time you need.

How to Use the PERT Method Step by Step

To get started with the PERT method, you need to know the step by step instructions to use to get the kind of results that you need. Today, we have a breakdown of those various steps that you will need to make the PERT method work properly for you. Here is what you need to look at to find the success that you are looking for.

  • List the activities and milestones that you need to accomplish
  • Determine the sequence of activities that you need to carry through in order to complete the task
  • Build a network diagram
  • Estimate the duration of each of the activities
  • Determine the path you will take to accomplish each of those tasks

It is a lot simpler once you put this in practice than you might have thought. It is all about making sure you can reduce the amount of time necessary to get from Point A to Point B. You are looking at taking on various tasks and making them as easy as possible to accomplish. After all, why should your work be harder than it absolutely needs to be? When you think about it like that, it starts to make a lot more sense why people go after certain tasks in a particular way. It is all about getting them accomplished step by step.

The PERT method is a great way to create useful estimations of the amount of time that is truly necessary to take care of various tasks. You can finally project how long you will need to make each task a success. With those figures in mind, you can begin to apply them to create a system for sorting out the type of work that needs to get done first, what can be handled a little later, and so on from there. Just keep going after each task down the list like that, and you will be in great shape to get it all done.

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