Effects of erroneous estimation of activity durations on scheduling and dispatching a single project

This research examines the effects of erroneous estimation of activity durations on two different approaches for executing a resource-constrained project. The two approaches are scheduling and dispatching. This research is conducted in two phases. Phase one examines the performance of scheduling and dispatching rules in a variety of project environments. These project environments are categorised by three different factors, namely, the order strength of the precedence relationship, the level of resource availability and the size of errors in estimating the activity durations. The results show that scheduling generally produces a shorter project completion time than the heuristic dispatching rules. The rules also indicate that project environment affects only the relative performance differences of the scheduling and dispatching rules but not their ranking. Phase two examines the effect of rescheduling. The results show that frequent rescheduling improves the project completion time, while the timing of rescheduling has little impact on the improvement in the project completion time. The results also identify the project environments where rescheduling is beneficial.