The "methodology" of bow-tie is that the diagrams are used to identify controls and show how they map on to hazards (often one control is applicable to several

The "methodology" of bow-tie is that the diagrams are used to identify controls and show how they map on to hazards (often one control is applicable to several hazards). Once you have this mapping you can demonstrate that you have sufficient controls for the various risks, make trade-offs between controls, identify nugatory controls etc. And finally you can track the controls as requirements for the system to make sure that they all get implemented. Its true that the diagram on its own is not a method, but once you have the diagram the rest of the method is pretty straightforward. The great thing about bow tie diagrams is that they capture the information you need for a high-level safety analysis without getting bogged down in the details. Bow tie diagrams are also excellent for stakeholder communication. They are simple, intuitive, and don't require any training (imagine presenting a UML state chart to non-technical audience). Product plug: The Diametric Safety Case Manager does bow-tie diagrams, amongst other things. The diagrams are part of a model, so the tables of controls, hazards etc can be extracted from the model rather than maintained separately (i.e. the Don't Repeat Yourself principle). See https://diametricsoftware.com https://diametricsoftware.com