I think Mineur has a point in that there are advantages to a Bayesian approach to assessing the likelihood of a risk, especially in situations where we don’t have large data sets of incidents and near-misses to inform a determination of the scientific probability for each type of risk we want to assess.

His argument against the risk matrix as a whole, however, seems to rest on a straw man. The risk matrix does not exist solely as a 3x3 matrix with linear scaling. In fact, in the resources that the ACS provides for risk assessment (e.g. https://www.acs.org/content/acs/en/chemical-safety/hazard-assessment/fundamentals/risk-assessment.html) the use of a weighted scale is described, with the explanation that each institution should first define an appropriate scaling method.

While stumbling around the web with regard to thinking about the risk matrix, I came upon an article that questioned its value:

https://medium.com/**At_Symbol_Here**JornMineur/why-the-risk-matrix-must-die-620a7287e7c

The essence of the argument, I think, is that estimates of probability are very unreliable.   I’d appreciate the wisdom of the list regarding this essay and its conclusion.

Dave

David C. Finster
Professor Emeritus, Department of Chemistry
Wittenberg University

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