This paper describes the application of the system dynamics method to the study of a conceptual military Command, Control, Communications and Information System (CIS) in the early phases of procurement. The work from which this paper was drawn constitutes one half of two parallel study streams to investigate the usefulness of the system dynamics technique in this area (the work did not attempt to assess the CIS itself). The conclusions from both streams are discussed in a separate paper (Gavine, 1990).