Project Time Management’s 5th process is the Estimate Activity Durancies process. It estimates the duration of activities based on a specific estimation technique. Project management professional certification training states that the best estimation technique should be chosen based on the project’s complexity as well as its other aspects. One estimation technique might be suitable for one project, but not for another.
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You must have tried some sample PMP exam questions in your PMP Study Plan. It is important to know that the PMP Time Management decision of choosing an estimation method is crucial. What is the most popular estimation technique? Do you know which estimation method is best if you have similar activities from past projects? Let’s look at 5 options for choosing an estimation method and give examples for each.
How to choose the right estimation technique for your project
Let’s take a look at each estimation technique one by one!
One-Point Estimate is the first estimation technique. In one-point estimate technique estimators submit one estimate per activity. The activity description and details are reviewed by the estimator. Based on the information, they give an estimate of how long it will take to complete this activity. For example, installation will take approximately 4 days.
For projects that don’t require a detailed schedule, one-point estimates can be used. This means that if you don’t need a detailed and exact schedule for your project, this estimation method can be used.
One-point estimation can have negative consequences if you need a more detailed schedule for your project. These are:
One-point estimate technique forces people into padding. The estimator feels obliged to give an estimate, even though he may not be able to provide a precise estimate due to limited information. He will often add padding to account for ambiguities in estimates.
He/she hides information about risks. Because the task assignee provides an estimate based upon available information during estimation. In other techniques, such as the PERT technique, three estimates are made for an activity: optimistic (most likely), and pessimistic (pessimistic). If there is a lot of difference between optimistic, most probable, and pessimistic values this indicates the activity’s risk level.
This schedule is impossible to believe. This is due to the fact that the estimate is only a one-point estimate. This is because assignees give an estimate for activities without any analysis or backing. This can lead to unrealistic schedules.
Trust could be damaged if the activity is not performed as estimated. Let’s say that you used a one-point estimation technique during the Estimate Activity Durations process. One developer stated that he estimated that a screen would take ten days to develop, but you see that the actual results show that the developer completed his work within six days. Another developer’s estimate was 20 days. He completed his task in 13 working days. This type of early completion of project activities will make your client question the accuracy of your estimates. You may have given a high estimate at the beginning, but the actual results show that they can be completed in a shorter time.
This estimation method is not appropriate for projects that have precise and exact schedules.
Analogous estimation is the second method of estimation. This estimation technique is also known as top-down estimating. Similar estimation techniques are used if similar activities are involved.