Soft systems and use-case modelling: mutually supportive or mutually exclusive?

Checkland´s Soft Systems Methodology (SSM) can be used to support strategic planning for business improvement. This involves the development of system models to identify the activities that an organisation must perform to meet its goals. Jacobson´s use-case modelling in the Unified Modelling Language (UML) is a requirements engineering technique that similarly lends to the identification of system activities, but driven by the needs of the system´s ´users´, rather than those of the system itself. This paper considers the potential gain from using these techniques in combination, examining each through the same car-park example. It is concluded that SSM is a better starting point for the analysis of a business. It can therefore be used to enhance UML, but requires careful integration of the techniques and associated models involved.