Determining Percent Complete of Project Tasks

The first step in performing Earned Value Analysis (EVA) is to determine the percent complete of each of the project tasks. There are several techniques that can be employed to determine the percent complete of a task. Within a given project, you should select the most appropriate method by task.

Fixed Formula (Weighted Milestones)

Fixed formula works best for discrete tasks comprising less than 80 hours of work. In this technique, you assign a fixed percentage to tasks depending on the status. The most conservative approach is to assign a value of 0% to incomplete tasks and 100% to complete tasks. For more granularity, it is also common to assign a value to tasks in progress, for example, 50% or 20%.

Units Completed

Measuring units completed works well when the task is quantifiable and can be broken down into equivalent units. For example, if you need to install 500 fence posts and you’ve done 100, then you are 20% complete. The benefit of this approach is that it is objective; however, it only works when the task is truly capable of being broken down into equal units of work.

Level of Effort (LOE)

LOE is used for support tasks that do not produce discrete deliverables, such as project management, quality assurance, ongoing maintenance, etc. In this technique, percent complete is tied directly to time elapsed. For example, with a start date of 1/1 and an end date of 1/10, if today is 1/6, then the task is considered 60% complete.

LOE tasks will never have a schedule variance, since the Earned Value will always equal Planned Value. Categorizing too much work by LOE, or using LOE when another method is more appropriate, can therefore mask scheduling variances within a project.

Apportioned Effort

Apportioned effort ties one task’s percent complete to another. For example, if inspection is tied to manufacturing, when manufacturing is 60% complete, then inspection is 60% complete.

It’s also possible to tie one task to multiple tasks. In this scenario, it is common to use a weighted average based on the Planned Value, or budget, of the tied tasks to determine the percent complete.

For example, if Task A is tied to Tasks B, C, and D, and

• Task B (budget $5000) is 80% complete
• Task C (budget $3000) is 50% complete
• Task D (budget $2000) is 20% complete

Task A’s percent complete would be

$\frac{(0.80 * 5000 + 0.50 * 3000 + 0.20 * 2000)}{(5000 + 3000 + 2000)} = \frac{(4000 + 1500 + 400)}{10000} = 59\%$

Expert Judgment

In this method, someone who is knowledgeable about the task provides their best estimate as to its completion percentage. It is a common error to overrely on expert judgment to determine the percent complete of project tasks. Expert judgment should be used judiciously and in combination with more objective methods where appropriate. For tasks involving detailed knowledge work, it’s often unavoidable to rely on expert judgment to determine their completion percentage.