We are looking for a pattern.
Is the Group trend of going ahead or going behind changing or staying the same?
What's the most overdue this Group has ever been when it was drawn?
How much overdue were the Sub Groups when they were drawn?
These trends might be an indication of what we can expect in the near future for both the Group and Sub Groups.
As an example, if the Group is on a pattern of going ahead of calculations then it might be a good Group to be playing.