The schedule is a plan that outlines a path of completion through a series of way points or milestones by which we can measure progress. The schedule informs everyone of where we are and how we are doing and gives us a measure of control. Control for this purpose means, “knowing where we are now and where we need to be.”
In order to be a viable tool a plan needs to be adaptable and flexible to allow for or accommodate reality. If not is is strictly a waste of time and energy since no project proceeds as anticipated 100% of the time.