Validity and validation of safety-related quantitative risk analysis: A review

- Scientific work on validity and validation of safety-related quantitative risk analysis is reviewed.
- Theoretical, methodological and empirical contributions are distinguished.
- Four generic methods for validation have been proposed.
- These are benchmark exercises, reality checks, independent peer review and quality control.
- More evidence is needed about the efficacy of these methods and about the cost-effective usefulness of QRA.

Quantitative risk analysis (QRA) is widely applied in several industries as a tool to improve safety, as part of design, licensing or operational processes. Nevertheless, there is much less academic research on the validity and validation of QRA, despite their importance both for the science of risk analysis and with respect to its practical implication for decision-making and improving system safety. In light of this, this paper presents a review focusing on the validity and validation of QRA in a safety context. Theoretical, methodological and empirical contributions in the scientific literature are reviewed, focusing on three questions. Which theoretical views on validity and validation of QRA can be found? Which features of QRA are useful to validate a particular QRA, and which frameworks are proposed to this effect? What kinds of claims are made about QRA, and what evidence is available for QRA being valid for the stated purposes? A discussion follows the review, focusing on the available evidence for the validity of QRA and the effectiveness of validation methods.