Bow-Tie Risk Analysis

Bow-tie risk analysis is a barrier-centred technique that places a single top event — the moment control over a hazard is lost — at the knot of a diagram, branches its possible causes to the left and its possible consequences to the right, and arrays along each pathway the barriers meant to prevent or mitigate it. The shape gives the method its name: the fanning threats and consequences form the two halves of a bow tie around the central event. de Ruijter and Guldenmund's 2016 review in Safety Science documents how the approach grew popular precisely because it combines, in one readable picture, the cause logic of a fault tree and the consequence logic of an event tree while foregrounding the controls that managers actually own. ISO/IEC 31010 lists bow-tie analysis among standard risk-assessment techniques, used both qualitatively to communicate risk and barrier coverage and quantitatively to estimate consequence likelihoods.