Estimating Activity Durations

The Estimate Activity Durations process attempts to estimate the work effort, resources, and number of work periods needed to complete each activity. The activity duration estimates are the primary output of this process. These are quantifiable estimates expressed as the number of work periods needed to complete a schedule activity. Work periods are usually expressed in hours or days. However, larger projects might express duration in weeks or months. Work periods are the activity duration estimates, and they become inputs to the Develop Schedule process.

When estimating activity duration, make certain to include all the time that will elapse from the beginning of the activity until the work is completed. For example, consider the earlier example of the house-painting project. You estimate that it will take three days, including drying time, to prime the house. Now, let's say priming is scheduled to begin on Saturday, but your crew doesn't work on Sunday. The activity duration in this case is four days, which includes the three days to prime and dry plus the Sunday the crew doesn't work. Most project management software programs will handle this kind of situation automatically once you've keyed in the project calendar and work periods.

Progressive elaboration comes into play during this process also. Estimates typically start at a fairly high level, and as more and more details are known about the deliverables and their associated activities, the estimates become more accurate. You should rely on those folks who have the most knowledge of the activities you're trying to estimate to help you with this process.

Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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