Effect of resource constraints on float calculations in project networks

The authors show how the standard method for calculating total float and free float in project schedules might produce misleading results when activities require common resources that are available in limited quantities. They propose new float definitions that retain the original meaning while accounting for the effect of resource availability on the schedule. The computational approach presented here is a refinement of the critical path method. It provides more precise information by explicitly taking into account time dependencies induced by aggregate resource requirements that exceed resource availability and force some activities to be delayed. The method presented in this paper avoids overstating the extent of flexibility available and generates more realistic schedules.