Packing Method for Resource Leveling (Pack)

TLDR

The study develops a new heuristic for resource leveling based on the critical path method. The heuristic constructs the resource histogram by iteratively assigning activities to days that minimize the sum of incremental moments and penalties, thereby shaping the histogram toward a rectangle while respecting CPM or PERT constraints. The resulting leveled histogram matches or closely approximates those from other optimization methods, and the approach is clear, logical, and computationally efficient, as demonstrated by a solved example.

Abstract

A new heuristic for resource leveling based upon the critical path method is developed. The minimum moment of the resource histogram is used to measure the level of resources. The heuristic assigns project activities to specific days so that the final resource histogram approaches a rectangle and its moment approaches a minimum value. Activities are listed in a priority order and all possible assignments for each are determined. Incremental moments contributed by the activity's resource rate and penalties that recognize network interactions are calculated. Each activity is positioned in the time span where the sum of these quantities is a minimum. The histogram is thereby built step‐by‐step until all activities have been positioned within the constraints of a CPM or PERT network. The resulting leveled histogram is the same as, or very close to, that produced by other optimization or heuristic methods. The method is clear, logical, and computationally efficient whether the leveling is done manually or by computer. An example is solved to show the method's details and an appendix provides a concise outline of the process.