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Time Estimation

The PERT technique is one of the best time estimation tools, widely spread to provide accurate estimates and schedule the tasks in a project by a Gantt chart.

   Any IT Project is defined by what the user really needs and by how much it will cost them so by the end we can get the scope of the Project and the metrics that will define the success of the Project. The cost of any IT project is defined by the amount of time it will be required from all the teams which need to be involved in the project. Project Managers and the Business Analyst are the people who usually provides those estimates. There are certain ways to get an accurate time estimation, in this blog we will talk about the PERT technique.

   The program (or project) evaluation and review technique, commonly abbreviated PERT is one of the most used techniques to get an accurate time estimation for any project, especially when you need high level estimates in order to define the scope of the project with the user and will help to provide an idea of how much it will cost.  
The business analyst or the project manager should go to each member of each team to get the estimates in three ranks which are the following:

- Must likely time: The best estimate of the time required to accomplish each task, considering everything goes normal.

- Pessimistic time: The maximum possible time it be required to accomplish each task, assuming everything goes wrong.

- Optimistic time: The minimum possible time it be required to accomplish each task, assuming everything goes well.

   Once you have all the estimates from all the members for all the teams, you sum each category giving you a global must likely time, a global pessimistic time and a global optimistic time. After getting the PERT technique says that you should proceed to do the following formula in order to get an accurate estimate:

Accurate estimate= (Optimistic time + 4 Must likely time + pessimistic time)/6

When you have an accurate estimate now you can know how much time approximately it will be required to accomplish each task. For big IT projects usually the Project Managers define the schedule for each task and after having the estimates for each task will be easier to organize all the work of each team member. The Gantt chart is one of the most used graphs to visualize the schedule of each task. An example of Gantt chart once you know the estimates for each task is as follows:

Gantt chart

In conclusion- the time estimation is very important since it defines how much time it is needed to accomplish all the tasks and could provide an idea to the user of how much it will cost them to do the project. The PERT is a very popular technique that is used by project managers to provide accurate estimates and help them to schedule all the tasks that will be needed in the project by a Gantt chart.


Carlos M.

Born and raised in Monterrey NL, Carlos family is also very attached to Hermosillo, Sonora, so the visits to the aforesaid city are usually constant. He has been working as a Business Analyst for about 3 years with experience in ERP for the Retail industry and Financial Industry. His favorite things to do is watch and play sports, especially soccer and football; he’s an occasional xbox player as well.


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