Evidence-based development - coupling structured argumentation with requirements development

This paper reports on an assurance process that is being applied on a large nuclear defence project in the UK. Christened Evidence-based Development (EbD), the approach draws together requirements development and structured argumentation into a unified assurance framework. Part of the discipline of requirements management is to document which design artefacts contribute to the satisfaction of which requirements by tracing individual statements of requirement through the layers of design. Evidence-based Development recognises that the systematic collection of “decomposition arguments” for each step in the requirements development, along with supporting evidence provided by design validation and verification activities, amounts to a structured argument for the design. The theoretical advantages of this approach are that assurance is coupled tightly to the design process, and that assurance is applied uniformly to all aspects of the design. However, it is too early in the life-cycle of the project to make definite claims for the approach. This far, the major barrier to the implementation of this approach has been the education of engineers across multiple disciplines in how to write the arguments entailed is each design step.