Supporting software process decisions using Bi-Directional simulation

In this paper, we present a "forward-looking" decision support framework that integrates timely metrics data with a simulation based defect model of the software development process in order to support software project management decisions regarding product quality. These predictions are evaluated using Outcome Based Control Limits (OBCLs) and Bi-Directional (both forward and reverse) simulation models of the software development process. The Bi-Directional models provide useful guidance to the program manager when evaluating possible corrective actions on a project that has gone outside the OBCLs. The forward model predicts the potential performance impacts of the proposed corrective actions. The reverse simulation models are new and take the desired system outcome as the starting point and represent the system as it evolves backward in time to identify the necessary starting point to achieve the desired outcome. The approach is presented using an illustrative example.