Jack Dahlgren suggests that we should treat The Schedule as a Symptom at his Project blog:
The more I think about it the more I am convinced that many people see the schedule as the problem rather than a symptom of some other problem. Schedules even in the best case are an abstraction of the work to be done.
This is in line with what I've heard elsewhere that the schedule as a picture of how you hope the project will go. Reality always changes that picture. If you treat the schedule as written-in-stone, then it will always look like the problem.
A schedule should represent the sequence of activities and the resources required to achieve a goal. It is the goal of the project that is interesting to the organization, not the individual activities. In my mind, it is the health of the goal that needs to be monitored, rather than the individual task level. The way most schedules are built and handled almost forces people to focus on the tasks and their prescribed start/stop times. This task focus guarantees the project will be late - or at least never early. Project management needs to treat the schedule fluidly, since reality always throws in surprises.