On the assessment of uncertainty in risk diagrams

Risk matrices and risk diagrams are widely used tools for analyzing, assessing and visualizing risk in many industries, and are used extensively for risk management purposes. Despite their popularity and wide application, they have recently become the object of discussion and research in scientific environments, which can be seen as part of a wider focus on foundational issues in the risk analysis discipline. Identifying several serious limitations and problems with the risk matrix approach, various authors have proposed extensions, modifications and recommendations for their use. One issue which has been raised recently but has attracted relatively limited scientific attention is the consideration of uncertainty in risk diagrams, i.e. how to visually represent and communicate uncertainty. This paper first reviews the available proposals for this question. Subsequently, the strengths and weaknesses of these proposals are discussed. Finally, some new proposals are made on how to represent uncertainty in risk diagrams in practical applications.