How does Retained Logic, Progress Override and Actual Dates in Scheduling Options work? 

These three options control how P6 calculates “Out of Sequence Progress”. 

We have a simple project with 3 activities:

The activity logic dictates that A2 should not begin until A1 has been completed, but in the real world sometimes A2 can be started and finished even though A1 has not been started – this is known as Out of Sequence Progress. 

So, how is P6 handle this case.  It depend on which option you choose. 

Scheduling using the Retained Logic option:

The logic of the activity is retained and enforced, and so Activity A3 cannot be started until activity A1 has been completed, as shown below. 

Scheduling using the Progress Override option:

The out of sequence progress overrides the logic of the activity, and so activity A3 is scheduled independently of the predecessor of A2.  In other words, activity A1 is no longer considered to be a predecessor of activity A3. 

Scheduling using the Actual Dates option:

When scheduling the project using the Actual Dates option, the actual dates override the logic of the activity, and so activity A3 is scheduled to begin as soon as activity A2 is complete, even if activity A2 has an actual finish date after the data date.