When progressing a schedule in P6, schedulers should follow a rigorous three-step process.
The schedule update method in P6 Professional is very controlled. Other software programs like Microsoft Project are much less restrictive in how schedulers calculate and present schedule progress. The P6 schedule update procedure has three steps:
- Enter schedule status
- Move the data date, i.e., status date, to the end of the reporting period
- Calculate the schedule
The P6 Professional regimen ensures meaningful data representing progress to the end of the current reporting period.
This article presents the progress update regime for progressing a schedule in P6 Professional.
The data date (DD) or status date is an important concept in the P6 Professional schedule update process. It indicates all the progress in a schedule, up to and including the data date. Further, it is the dividing line between completed and remaining work.
In the Gantt chart demonstration diagram below, Figure 1, we have a schedule with a weekly reporting period that has progressed by one week.
Figure 1
This schedule’s yellow bars and diamonds represent the baseline, a static copy or picture of the project in time. The black diamonds represent the current project milestones.
The green bars represent the remaining work with total float; they can delay without postponing the project. The red bars represent critical remaining work that cannot be delayed without a proportionate schedule delay. The blue bars display actuals or actual dates entered to show completed work.
The data date represented by the blue vertical line in Figure 1 currently sits at the end of the first week’s reporting period.
Again, the data date is the dividing line separating completed work from remaining. After the schedule calculation for the current reporting period, everything left of the data date besides baseline objects should be blue and represent completed work.
Everything on the right of the data date should be green, red, or other colors (you can define), indicating the remaining work. Again, the data date is all the progress that has taken place in the schedule up to and includes the date.
The schedule advancement update process, again, is a three-step procedure.
Step 1 – Enter Schedule Status: The first step in the update process is to enter status, which describes the work performed in the current reporting period or later. After entering the status of one or more tasks, you will see some blue bars right of the data date, as shown in Figure 2.
Figure 2
Step 2 – Move the Data Date: The second step is to move the data date to the end of the reporting period. This is done by clicking the ellipse for the data date field in the Tools | Schedule dialog, Figure 3.
Figure 3
Remember to include the work on the actual status date; the timestamp should be post-meridiem (PM) until the end of the workday. After moving the data forward but prior to scheduling the project, the situation is like the Gantt chart diagram below, Figure 4.
Figure 4
Observe that the data date vertical blue line sits between weeks two and three. However, unlike the above diagram, P6 Professional will not move the data date on the Gantt chart to the date populated in the data date field until the schedule button clicks.
Step 3 – Calculate the Schedule: When you click the schedule button in the Schedule dialog box, the data date moves forward in the P6 schedule calculation, and then the project is scheduled. As the schedule calculates, all the remaining work (either green or red bars) left of the data date is pushed forward until it falls right of the data date, Figure 5.
Figure 5
Note that if any completed (blue bars) work was right of the data date before calculating the schedule, Figure 4, it would be pushed backward until left of the data date. (In our demonstration, Figure 4, there is none). So, after scheduling, every bar left of the data date should represent completed work (blue bars), and every bar right of the data date should represent the remaining work.
Summary
Progressing a schedule in P6 is rigorous and repetitive process. Repeat the steps above for each following reporting period.
For a more detailed demonstration and comparison with Microsoft Project schedules, refer to the blog Microsoft Project Status Date Primavera P6 Professional Data Date and Updating Schedules.
When the three-step progressing regimen and other good schedule practices are adhered to in preparation for the updates, schedulers can protect project data, improve accuracy and provide a meaningful measurement of achievement.
Schedulers should follow good scheduling update practices in preparing, executing and reporting schedule progress.
Addendum: Schedule Drift
Although not discussed in this article, once you have progressed the schedule, you should check it for schedule drift.
There are three different ways to define schedule progress: units, duration, and physical. The units percentage-complete-type is typically used with P6 Professional time module software, where team members enter their time directly into the schedule.
For the duration percent-complete type, the duration % complete is computed directly from the remaining duration, or vice versa, using the equations below:
The physical percent complete type provides the scheduler with more flexibility; the scheduler specifies the remaining duration separately from achievement. Refer to the article at the following link to learn more about duration and physical percent-complete types.
The physical % complete type offers greater flexibility than duration % complete, but it requires entering both a % complete and the remaining duration (or expected finish)—novice schedulers who skip the latter risk schedule drift from incomplete data entry. This is a classic rookie scheduler mistake.
If the scheduler neglects to enter a remaining duration or an expected finish, the remaining duration of the task stays equivalent to the task’s original duration, which is not your intention. In this neglectful scenario, tasks with a high percentage complete can still appear to show no progress, both in the activity table and in the Gantt chart.
Furthermore, both physical percent complete and duration percent complete exhibit erroneous schedule drift when the scheduler fails to mark activities as started after the data date has passed their planned start dates. These input errors—common when progressing large schedules with numerous tasks—lead to positive schedule drift, making the project appear more delayed than it is.
Although the duration % complete requires less input because of the linear relationship between achievement and remaining duration, it still shows a strong tendency to drift from the schedule, indicating a pattern beyond data-entry errors. The duration % complete assumes linear and uniform work over time. However, if the work accomplished is less than the elapsed time indicates, the duration % complete will show an optimistic bias. Here, the project is ahead of reality.
Schedulers should confirm there is no schedule drift by
- checking each task’s duration variance against the baseline
- checking the finish date variance, and
- resetting the remaining duration of tasks that are falsely extended.
For step one, schedulers can see which tasks have changed in their remaining duration compared to their original duration. Review the Variance – BL Project Duration column option; filter or sort this column to identify tasks with variance other than zero. The tasks with non-zero variance differ from the baseline and should be flagged for further review.
A positive duration variance could indicate poor project performance or schedule drift. Schedule drift could be due to an error in status entry. For the duration % complete type, a positive duration variance may indicate production is much slower than planned; this can produce misleading status updates with optimistic bias in the reported duration % complete when elapsed time exceeds actual work accomplished.
For step 2, a check of the finish date variance will either (a) confirm that there is no schedule drift (or that it is within an acceptable tolerance), assuming the underlying duration variances were checked as instructed in step one, or (b) flag the schedule for further review.
For step 3, after identifying misleading task extensions, adjust the remaining durations (or expected finish dates for the physical percent complete type) where the variance is due to improper status entry or percent complete type behavior, rather than to a schedule with poor performance.
Further discussion of schedule drift will require a separate article to be published later.