Resource Critical Path Ambiguity

A prior article demonstrated that for an unleveled project schedule, there could be multiple, non-delay  resource-feasible schedules of varying durations.  The range, distribution and mean of this set of durations could be estimated using simulation.  Further, it was demonstrated that for any particular resource-feasible project duration in the set of non-delay schedules, there could be multiple, unique resource-feasible schedules that would yield that particular project duration.

A different article showed how to identify resource critical paths and remove phantom float errors in resource-leveled schedules.  In the simple example used in that article, the capacity of each resource type was limited to one unit.  That simplified the identification of resource paths and constraints.  However, projects usually have more than one resource type and more than one unit of each type.  This complicates the identification of the resource paths and constraints required to identify resource critical paths.  Since there can be multiple sequences describing how a unit resource is assigned to tasks, there can be more than one set of resource constraints derived from a unique resource-feasible schedule. And, there can be more than one combination of resource critical paths for that unique resource-feasible schedule.

In this article, we will explore this ambiguity using simulation.  First, we will generate sets of resource paths that can be used to define sets of resource constraints for a unique resource-feasible schedule.  Then, using these sets of resource constraints, we will identify the combinations of resource critical paths that are derived from these sets of resource constraints.   Continue reading “Resource Critical Path Ambiguity”