ABSTRACT
In recent years increasing attention has been given to the black swan metaphor in the context of risk assessment. A number of interpretations of black swans in this context exist, some of which link black swans to low probability/high consequence type of events, while others link black swans to something unforeseen and hence not included in a preceding risk analysis. The question of completeness of a risk analysis can be seen as part of the epistemic uncertainty concept, which divides into parameter, model and completeness uncertainty. In the present paper we consider four different interpretations of black swan type of events and study these in relation to some common uncertainty classification systems, including the aleatory/epistemic uncertainty distinction. The underlying question is whether there is a need to address black swans as a separate concept, or if and how it can be addressed as part of existing concepts. The purpose of the paper is to strengthen the basis for the understanding and treatment of black swan type of events in risk analysis and risk management.
