Expanding the Uncertainty Toolkit for Risk Analysis

Uncertainty is an inherent part of risk: where there is no uncertainty, there is no risk. However, most international standards for risk analysis provide minimal guidance on the consideration of uncertainty. In particular, the relationship between uncertainty and risk remains disputed, resulting in the lack of an agreed definition and the absence of comprehensive methodologies for uncertainty analysis. To address this issue, a conceptual framework for uncertainty analysis in risk science is presented. This framework describes the intrinsic uncertainty of risk and is supplemented by a three-layered approach of first, second and third order uncertainty analysis. Somewhat surprisingly, first order uncertainty analysis is risk assessment itself. The definition of risk, according to ISO 31000:2018 is "the effect of uncertainty on objectives". By implication, risk assessment requires analysis of that uncertainty. Typically, the uncertainty in question relates to knowledge of the probability and consequences of risk. Second order uncertainty analysis within this context is thereby viewed as evaluation of the residual uncertainty that remains from the risk assessment but also includes consideration of other components of risk analysis, such as risk communication, risk management and risk governance. Finally, third order uncertainty analysis involves evaluation of higher order uncertainty of the risk paradigm and is described as metauncertainty. This comprehensive conceptual framework for uncertainty can assist in the identification and treatment of different types of uncertainty. Consideration of metauncertainty further enhances our uncertainty toolkit to advance risk science.

Keywords: Uncertainty, Risk, Risk analysis, Risk paradigm, Metauncertainty, Safety, Ambiguity, Ignorance.