A Dialogue-based Safety Argument Review Tool

There has been increasing use of argument-based approaches in the development of safety critical systems. Within this approach a safety case plays a key role in the system development lifecycle. The key components in a safety case are safety arguments which are designated to demonstrate that the system is acceptable safe. Inappropriate reasoning in safety arguments could undermine a system’s safety claims which in turn contribute to safety-related failures of the system. The review of safety arguments is therefore a crucial step in the development of safety-critical systems. Reviews are conducted using dialogues where elements of the argument and their relations are proposed and scrutinised. This paper investigates an approach of conducting argument review using dialectic models. A new dialectic model specially designed to suit the requirements of argument review is proposed. An argument review prototype was then iteratively developed. It adopted the model and aims to conduct argument review dialogues in a structured manner. User-based evaluation of the system suggests the usefulness of the dialectics approach to safety argument review. The evaluation also sheds lights for the future development such an application.