Construction Scheduling. Schedule Performance Measurement, Part 4. (For Owners).

When monitoring and responding to the Contractor’s schedule performance on the project, how do you know if the schedule update is even valid for use?

When we review a schedule progress update, we need to first determine if the schedule update is a valid update. By that, I mean is the logic still complete? Have there been any revisions with this update that result in the schedule not meeting the contract requirements or best practices? It doesn’t take much to render a schedule useless….

There are most likely logic revisions, changes to lag values, or possible changes to calendars or assignments. There are also deletions and additions of activities and/or Activity Relationships. Then there are changes to quantities or Resources which may impact Activity Durations or Resource Calendars.

For this post, we will address changes to Activity or Relationship Calendars.

Personally, the first schedule “quality check” I make is for complete logic. Please see the previous post, Schedule Performance Measurement, Part 2. (For Owners).

Next, I check for changes to Relationships and Relationship Lags. Please see the previous post, Schedule Performance Measurement, Part 3. (For Owners).

I then check for changes to Activity and Relationship Calendars and Calendar assignments.

When the Contractor is making schedule revisions to recover lost time for the update period, they may decide to work a crew more than the Activity or Relationship Calendar currently allows. If the Activity is assigned to a 5 Day Workweek with Holidays and Weather Days, they may decide to work 6 days a week for a specific resource to recover lost time. To be able to do this, they need to create an additional Calendar and set the work days up accordingly. They then replace the existing Calendar with the new Calendar. This allows the same amount of work, or Work Day Duration, to be scheduled over fewer Calendar Days. This results in shortening the Calendar Day Duration of the Activity Network(s) which contain the affected Activities.

This is the kind of schedule revision the Owner must be aware of and understand. It can be checked for in Primavera P6.

What Primavera P6 is not good at checking are changes to the work days in an existing Activity or Resource Calendar. As long as the Calendar Name does not change, P6 does not report it.

Most of us use third-party software designed to identify changes to Calendars. That’s great, but we still need to understand the impact of the changes identified.

Changes to Calendars and the Work Days in a specific Calendar do not make the schedule invalid for use. But, the owner needs to know what changes were made and what effect the changes have on the affected Logic Path(s).

That said, finding the changes to any Calendars, understanding the impact of the changes found, and reporting those findings is important to the Owner.

As  Planning and Schedule Professionals, we need to provide the Project Team with the “tools” they need to manage the project. The owner needs to know what the performance of the actual work in the field is, compared to the planned performance. Unless we have a valid schedule update to measure with, and against, and understand the impact of acceptable schedule revisions, we cannot provide an accurate measurement.

I’m sure many of you have comments or additional insight into this subject. Please share!

I’d love to hear what you think!

Please visit to learn more about Construction and Schedule Management Services, LLC

Please visit my LinkedIn account to learn more about me.

Please visit my “The Blue Book” ProView.

Paul Epperson CCM, PMP, PSP, PMI-SP