Towards a Minimal Realisable System Dynamics Project Model

Abstract

This paper looks at the established Systems Dynamics (SD) methods applied to Software projects in order to simplify them. These methods are highly non-linear and contain large numbers of variables and built in decisions. A SIMULINK version of an SD model is used here and conclusions are made with respect to the initial main controlling factors, compared to a NASA project. The eigenvalues of the linearised system indicate that the important factors are the hiring delay time, the assimilation time and the employment time. This illustrates how the initial state of the system is at best neutrally stable with control only being achieved with complex non-linear decisions. The purpose is to show the minimum level of complexity required for “good” simulation of project behaviour considering the Abdel-Hamid software project model and three simpler versions. These models give clues to the decision structures that are necessary for good agreement with reality.