We observed that safety arguments are prone to stay too abstract, e.g. solutions refer to large packages, argument strategies to complex reasoning steps, contexts and assumptions lack traceability. These issues can reduce the confidence we require of such arguments. In this paper, we investigate the construction of confident arguments from (i) hazard analysis (HA) results and (ii) the design of safety measures, i.e., both used for confidence evaluation. We present an argument pattern integrating three HA techniques, i.e., FTA, FMEA, and STPA, as well as the reactions on the results of these analyses, i.e., safety requirements and design increments. We provide an example of how our pattern can help in argument construction and discuss steps towards using our pattern in formal analysis and computerassisted construction of safety cases.Index Terms-FTA, FMEA, STPA, safety case, assurance case, hazard analysis, argument, pattern, scheme.• significantly reduce the confidence we are able to associate with such an argument and, consequently, • hinder systematic reuse of proven arguments. Related issues were recognized by, e.g. Yuan and Xu [18].
C. ContributionsIn this paper, we seek to reduce the mentioned issues and improve safety case methodology. Argument patterns based on evidence from FTA and FMEA have been discussed in [19],
