Assurance-driven design in Problem Oriented Engineering∗

The design of assurance cases is hampered by the positand-prove approach to software and systems engineering; it has been observed that, traditionally, a product is produced and then evidence from the development is looked for to build an assurance case. Although post-hoc assured development is possible, it often results in errors being uncovered late—leading to costly redevelopment—or to systems being over-engineered—which also escalates cost. As a consequence, there has been a recent move towards the proactive design of the assurance case. Assurance-driven design sees assurance as a driving force in design. Assurance-driven design is suggestive of how the design process should be shaped for assurance. It is not, however, a prescriptive method; rather it allows an organisation to assess their assurance needs according to their developmental needs, including their attitude to risk, and to adapt their processes accordingly. The work is situated within Problem Oriented Engineering, Hall and Rapanotti’s engineering design framework, with its root in software and systems engineering. In the paper we present the main elements of the approach and report on its application in real-world projects.