Combining Safety and HCI Arguments to Increase Confidence in Information-Only Systems

Whilst the argument for equivalent levels of rigour being applied to Safety and Human Computer Interaction (HCI) in defence, is generally well recognised, it is the authors opinion and experience that this is rarely the case and this could be due to the lack of guidance and collaboration between HCI and Safety guidance and communities. This paper will compare the confidence levels defined in Def Stan 00-56, Issue 4 [3] along with the equivalent Safety Integrity Levels (SILs) in IEC 61508 [2] and discuss the need for the consideration of HCI issues within the confidence levels commensurate with the level of safety risk within the defence domain.