Safety assurance: fact or fiction?

Many safety-related systems are also socio-technical systems and providing safety assurance for these systems is extremely challenging. Providing comprehensive safety assurance evidence for the technical elements of anything but the simplest of systems is impossible due to the complexity involved and these difficulties increase dramatically when the human and organizational factors have to be considered. Apart from the inherent complexity associated with the development of safe socio-technical systems, there are other reasons to believe that safety assurance claims can be overly optimistic and based more upon fiction than fact. This paper will examine where improvements could be made to the safety assurance process. The paper will first consider some of the reasons why safety assurance claims may be based too much upon 'self-fulfilling prophesies' appealing only to confirmatory and highly subjective evidence because of inherent methodological limitations with the safety assurance process and an overreliance on professional judgement. The paper will then examine a significant but common area of neglect for safety assurance claims; specifically, the widespread fixation on technology despite the prevalence of socio-technical issues for many safety-related systems. Finally, suggestions will be made regarding how to improve the validity of safety assurance claims through the use of metaevidence.