Citation

Aven t. Reliab. Eng. Syst. Safety 2016; 145: 215-220.

Copyright

(Copyright © 2016, Elsevier Publishing)

DOI

10.1016/j.ress.2015.08.012

PMID

unavailable

Abstract

In risk assessment we are typically faced with a huge number of potential scenarios and events, and in practise some of these are ignored, either because they are not identified or because of judged low probability. However, a scenario or an event may occur despite being extremely unlikely. Considering a large population of such scenarios and events, the occurrence probability is not necessarily negligible. In this paper we take a closer look at this challenge, the main aim being to clarify the issue and provide some recommendation on how to best handle it in practise. A main conclusion is that the risk assessment should be placed in a sufficiently broad framework, ensuring that the outcome and main event spaces are complete, and sufficient focus is placed on the hypotheses and assumptions supporting the detailed scenarios that are identified.