ABSTRACT This paper will present a discrete event simulation model of a spiral development lifecycle that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process. There is a need for simulation models of software development processes other than the waterfall due to new processes becoming more widely used in order to overcome the limitations of the traditional waterfall lifecycle. The use of a spiral process can make the inherently difficult job of cost and schedule estimation even more challenging due to its evolutionary nature, but this allows for a more flexible process that can better meet customers’ needs. Cost figures for the spiral process may initially appear higher but can ultimately prove to be much more realistic or even lower than the final cost for a waterfall process since the data on which they are based is continuously updated. The goal of this work is to present a preliminary model that provides insight into the impacts of selecting a spiral development approach and that demonstrates the usefulness of such a model in order to encourage the development of more detailed spiral development models.
