In many cases, it becomes necessary to accommodate the schedule to fit a fixed, limited manpower pool. This calls for "balancing" or "leveling" manpower.

This can be accomplished by first planning and scheduling as usual and without any manpower considerations until the schedule is satisfactory. At this point, manpower utilization graphs should be printed. In ATC Professional™, these reports show both the actual manpower required by the schedule and the leveled manpower of the schedule based upon available float or slack time for all activities. The peak of the leveled manpower for a given resource should be the minimum allotment of that resource required to achieve the schedule. With these reports, manpower requirements for the scheduled resources are obvious.

Sometimes, there is a tendency to schedule and reschedule activities to force the actual manpower requirements to correspond to the leveled requirements. Care should be taken not to overdo this, as is frequently the case when using automatic resource leveling with some project scheduling software, because they produce undesirable results such as:

• Making most activities critical; therefore hiding or masking the true critical path. Managing the turnaround then becomes impossible, the schedule becoming meaningless because of the confusion being created when trying to set/change priorities.
• Leveling the work, instead of leveling the manpower. All too often the available work is "leveled", with the consequence that too much work is removed from the daily schedule. This results in wasted time when scheduled activities cannot be worked on for a variety of reasons (availability of tools or equipment, spare parts, safety, etc.). Supervisors must then either return to the planner’s office for re-scheduling while their crew waits (wasting time/money) or abandon the schedule.
• Loss of confidence in the schedule as well as the planner in charge, for the above reasons.

Automatic resource leveling is a tool that is applicable to projects with a static scope. Turnarounds are too dynamic and fluid to be managed effectively with automatic resource leveling.