Good day!
It is understandable that the majority of the efforts in planning and scheduling are centered around activities to the right of the data date line on the Gantt chart. What is surprising to me is the apparent lack of concern on the project's performance during the currrent update period. It is not uncommon to see the schedule update process rush directly from progress reporting (left of the data date) to non-progress revisions (the right side of the data date) without any consideration of period performance.
Recognizing and measuring the project's performance during the most recent update period is key to change recognition, impacts and data collection for trends.
I would enjoy hearing your experience in this area of planning and scheduling?