It’s important to inspect schedule lag insertions to confirm your schedule is a dynamic and quality schedule. But investigating lag in Primavera P6 schedules requires some effort. Let’s look into this in more detail.
Lag in schedules may be positive or negative. For anyone working on a government contract, negative lag is prohibited in the Defense Contract Management Agency (DCMA) 14-Point Assessment guidelines. These guidelines, however, do not forbid the insertion of positive lag; they recommend the judicious use of positive lag.
Regardless, you will definitely want to investigate your use of lag in your respective schedule. One would think, because of the restrictions placed on lag in the schedule, that investigating schedule lag in Primavera P6 Professional would be efficient. The assessment guidelines clearly compel schedulers to inspect every insertion of lag in their schedule. But investigating schedule lag in P6 is not as straightforward as one would like.
Yes, the bottom activity details displays the lag of activity predecessors and successors, but that is for a single activity. We want to investigate and list all activities in the schedule that have relationships modified by lag.
This article demonstrates how to investigate and report lag assignments in an entire Primavera P6 Professional schedule.
The key to investigating lag in Primavera P6 is to know where to go to find the lag variable. No, it is not located in the columns feature of the layout tool group. Why not? I do not know. But we do find the relationship lag appearing in printable reports. Let’s explore the printing of reports with lag information.
We begin in the reports tab where we click + Add to create a new report in the reports wizard. In Figure 1, report wizard select subject area dialog select activity relationships, as the subject area.
Click next. In the report wizard configure selected subject area dialog, click columns, Figure 2.
In the columns report dialog, Figure 3, we find predecessor variables, successor variables, and, yes, lag. Be sure to select all the options displayed in Figure 3, and click ok.
Next in the report wizard configure selected subject areas, Figure 2, select group & sort. Make the group by none, Figure 4.
Now, again, in the report wizard configure selected subject areas, Figure 2, select filter. Make the filter parameter ‘Lag’, the equivalency ‘is not equal to’ and the value ‘0.0d’, Figure 5.
Our report will now capture all activities that have a non-zero lag value. Click next and in the report wizard report title dialog type in an appropriate report name, Figure 6.
Click next and run report. Toggle print preview and select ok. Your lag report will appear similar to Figure 7.
Note the column for Lag and that activity A1010 ‘A’ is listed twice because it has two relationships modified by lag.
Improper use of lag can make for a static (and not a dynamic) schedule. This means schedulers will have to manually change lag values according to changes in predecessor activity implementation. Ideally, you want the scheduling software to provide automatic activity updates, as per the schedule’s network logic, which includes proper lag relationship modifiers.
Lag also requires documentation to explain why it was inserted to modify an activity relationship. These are good reasons to want to investigate lag in your schedule. But there are not many features in Primavera P6 Professional that support lag variables. Look not to the columns feature in the layout tool group, which is in plain sight. Instead go to reports and the reports wizard configure dialog, where you will find another columns feature that includes the lag variable.
It is possible in Primavera P6 Professional to generate reports, which include lag relationship modifiers. You may want to note that Primavera P6 EPPM release 16.1 includes predecessor details and successor details that put the lag information and relationship type in full view.