Primavera P6s 3 Types of Activity Percent Complete

Each activity has three percent complete fields that are calculated all the time:1. Duration % Complete2. Units % Complete3. Physical % CompleteOnly one of these values will be selected by the user as the activitys progress, even though all of them are calculated all the time. I will explain how to choose the appropriate activity percent complete in future articles.

Duration % Complete CalculationsThe most common problem with Duration % Complete is that Primavera P6 uses a counterintuitive formula. You may expect it to be something like Microsoft Projects formula:

Duration % Complete(MS Project) = [Actual Duration] / ( [Actual Duration] + [Remaining Duration] )

But this is not the P6 formula. Duration % Complete is calculated with this formula:

Duration % Complete(P6) = ( [Original Duration] [Remaining Duration] ) / [Original Duration]

This formula uses Original Duration, which may be different from the current duration. We will check this on the following sample.

Sample: We have an activity with original duration of 20 days. 15 days have passed and we estimate it to finish in 18 days (yes, its much longer than we expected initially). The Original Duration does not change automatically after activitys start.Original Duration:20dActual Duration:15dRemaining Duration:18d[Duration % Complete] =(20-18)/20 = 10%Intuitive or MSP-like Duration % Complete =15/(15+18) = 45.45%

The following figure shows the initial state of this sample activity (named A1):

Lets say that the activity has started inMay 8th. Well check the Started checkbox and enter the actual start date in its date box.

Learn Primavera P6 Duration Percent CompleteSuppose that its currentlyMay 27th; we will reschedule the plan for this data date.

The Actual Duration is automatically calculated based on Actual Start Date and the Data Date, as follows:[Actual Duration] = [Data Date] [Actual Start] (P6 formula for in-progress activities)

Unfortunately, you cannot change the Actual Duration field manually.

Now we can enter the remaining duration. In this example, we estimate that A1 requires 18 more days to be completed. Well enter18din remaining duration field. By entering a remaining duration, Duration % Complete will be calculated automatically.

In this case,Duration % Completeis calculated as10%.

We could have entered the Duration % Complete instead of the Remaining Duration and P6 would have calculated Remaining Durationautomatically .Now, take a look at the Gantt chart.

When you look at the Gantt chart, you see that about half of the current duration is actualized and you may expect a Duration % Complete of around 50%. The exact number of the intuitive formula is45.45%in this example, which is not equal to our Duration % Complete.

Changing the Original DurationPrimavera P6 uses the following equation for Original Duration is used when an activity is not yet started:[Original Duration] = [Early Finish] [Early Start]However, after the activity has started, Original Duration will not be automatically calculated by Early Start and Early Finish, and you can change it manually.

TheAt Completion Durationrepresents our current duration, calculated as:

[At Completion Duration] = [Actual Duration] + [Remaining Duration]In our example, theAt Completion Durationis calculated to be33d. We will enter the same value for the Original Duration field and this would be the result:

The activitys schedule is not changed, but Duration % Complete is recalculated based on the new Original Duration; and yes, its the intuitive value that we calculated before.

When Original Duration is equal to the At Completion Duration, the Duration % Complete will have the intuitive value. The following equations show how the P6 formula would become the intuitive formula, when the Original Duration is equal to the At Completion Duration:

[Duration % Complete]* = ( [Original Duration] [Remaining Duration] ) / [Original Duration]= ( [At Completion Duration] [Remaining Duration] ) / [At Completion Duration]= [Actual Duration] / ( [Actual Duration] + [Remaining Duration] )* this equation is based on the assumption that Original Duration is equal to the At Completion Duration.

If you would like to have the intuitive Duration % Complete (for any reason), you can create a global change to set the Original Durations of in-progress activities. The following figure shows the appropriate global change setup.

This global change checks each activitys status; if its In Progress, then the At Completion Duration would be copied to the Original Duration. We will then have the intuitive Duration % Completes for all activities.

Duration % Complete for WBS ElementsThe previous explanation was focused on Duration % Complete forActivities. Duration % Complete is also calculated for WBS Elements, but I strongly recommend you not to use Duration % Complete to track a WBS Elements progress. Thus I have not included an explanation of the calculations here.

You should always think of Duration % Complete as an intermediate field and usePerformance % Completeto track activities and WBS Elements actual progresses.

I will explain the calculation and usage of Performance % Complete in a future tutorial.

SummaryThis tutorial has demonstrated the internal calculations of Primavera P6s Duration Percent Complete field.The most common problem in this area is that Primavera P6 does not use the intuitive formula for Duration % Complete which confuses some planners and project managers. We explained the Primavera P6 calculations and the intuitive formula side by side, to show the differences and create a better understanding of the P6 method. Finally, if you absolutely need to use the intuitive formula, try the Global Change described above.Remember, Duration % Complete does not provide a final result; it is used in a system which provides the actual progress. You should use Performance % Complete to read the actual progresses. Well cover that in an upcoming tutorial soon.