Case Studies in Software Process Modeling with System Dynamics

Ray Madachy, Ph.D.
Denton Tarbet, Ph.D.
Litton Guidance and Control Systems

Litton's Guidance and Control Systems (GCS) Division has been using system dynamics to create small-scale models for investigating managerial process issues and supporting personnel training. The primary perspective of the investigative models has been at a multi-project or departmental level. These include models of resource contention among projects, Brooks' Law and hiring issues, domain learning, product-line reuse processes and a detailed walkthrough model. Insights provided by the models have supported decision-making at different levels and helped galvanize process improvement efforts.

The models encapsulate collective knowledge of modeling participants, and support organizational learning. By examining the models and simulated behavior, managers share a process vision and can discuss issues against the common models. The models have helped managers understand the key factors in complex scenarios. Knowledge of the interrelated technical and social factors coupled with simulation tools has enabled GCS to improve their planning and management processes.

Modeling is also used to support training of software managers and leads. Earned value techniques, requirements volatility effects and extrapolation of project tracking indicators have been presented with simulation models. Some of these are "flight training" scenarios that the students interact with.
Some of the models will be executed live for the audience to demonstrate lessons learned.