Multiple schedules and measures of resource constrained float

Abstract

The conventional analysis of a resource constrained network produces a single schedule. A measure of float for each activity can be defined by examining the sequences of activities, incorporating the linkages implied by the sharing of resources in this particular schedule. However, the resultant floats are specific to one schedule and the analysis ignores the flexibility inherent in many resource constrained networks. It is often possible to employ alternative resource allocations resulting in schedules with identical overall durations but different timings for individual activities; in one schedule an activity may be critical but in another it may have significant float. A systematic exploration of alternative schedules reveals the flexibility of the network and the consequent variation in activities' floats. This paper defines new parameters describing these characteristics of activities in resource constrained networks. The practical value of the parameters is demonstrated in an example in which the measures of float guide the project planner to an alternative schedule, avoiding a critical dependency on a problematic activity and reducing the risk to the project at no additional cost.