The increasing complexity of systems being designed in the 21st century has resulted in the increasing use of specifications and models to control that complexity. Models are used in the specification, simulation, test, design, and implementation of the systems that are being produced by both government and industry today. Un-fortunately, the relationship between these various models is not only formally undefined, but conceptually unclear. This paper will explore the relationship between test specifications and the system specification, simulation, design specification, and implementation of a complex system.