Back to basics: Risk matrices and ALARP

Abstract

Risk matrices are tools for comparing risks relative to one another (e.g. within a single system) and hence being able to 'rank' them relative to each other for the purposes of risk mitigation and the allocation of safety resources. Risk matrices are not tools for determining the tolerability, or otherwise, of individual or 'single risks'. However, the current trend of using risk matrices to determine whether individual risks are tolerable, and hence subject to ALARP arguments, stretches the risk matrix concept beyond its breaking point, and is thus leading to potentially misinformed decisions by senior managers regarding the true level of risk present, and hence whether risk reduction options are either needed or are reasonably practicable, across a range of projects for which they have responsibility. © Springer-Verlag London Limited 2009.