Robustness to Variability in Project Networks

Our aim in this paper is to highlight the relative impact of activity variability on the completion time of different project configurations. We show that there is, in general no categorical connection between the stage of a project in its life-cycle and the impact of increased activity variability on the expected remaining project duration. Thus investing resources to decrease activity variability is, in general, as important in the early stages of the project life-cycle as it is in the later stages. However, our analysis suggests that in projects with dominant critical paths, it pays to invest resources to reduce activity variability at an early stage rather than at a later stage in the project. We apply some of our analytical results to gain insights into the issue of structuring project activities into work packets and assigning the work packets to project teams. We extend our framework to examine different modes of subcontracting projects.