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(PS-2953) Extracting the Resource-Constrained Critical/Longest Path from a Resource-Leveled Schedule, Part II

This practical applications paper demonstrates a method to properly calculate total float, free float, float paths, and find the longest and critical paths for resource leveled schedules. Resource leveling can be a powerful tool, however, two issues have prevented it from gaining widespread acceptance: 1) Total float calculations are almost always incorrect in all of the major scheduling programs, and 2) Float paths, including the longest and critical paths, are not calculated correctly for the activities that have been delayed due to leveling.

The author has developed a simple tool in Microsoft Excel that infers a sequence of activities for a given leveled resource as finish-to-start links between activities. Furthermore, the tool can be used to load those inferred finish-to-start relationships into a similar but different “reporting” project schedule. Because the sequenced activities are now linked by relationships, the software can correctly calculate all of the float parameters. This allows standard reviews of the schedule to take place, without requiring special consideration of the leveling technique. The original project schedule is kept without the new links, so that resource leveling can be used again. The tool has been used on actual projects which used Primavera P6, and is simple enough to be retrofitted for other software programs such as MS Project.