Models to promote effective system change

Computing systems are complex, both in their composition and in the way that they evolve over time. To help manage this complexity, models can be used to highlight the significant elements and attributes of a system, and summarise key processes in its operation and evolution. The purpose of the paper is to present a set of such models for debate. Most of these are at the highest levels of system description and are therefore generally applicable across a range of development techniques. Consequently they provide a framework within which specific system development techniques can be described and assessed. The models are discussed with respect to an experimental methodology, BASE, being developed at the University of Ulster. Two significant aspects of this approach are: (i) placing the production or enhancement of computing systems in the context of `business improvement´; and (ii) emphasising the need to make change with respect to a `vision´ of where improvement is leading. The business analysis part of BASE is built on Soft Systems Methodology. The discussion is illustrated using examples from an IT system review undertaken within the Department of Education for Northern Ireland