  References
Criticism Qualitative risk evaluations have been demonstratedWhat's wrong with risk matrices?, doi: 10.1111/j.1539-6924.2008.01030.x. URL to have significant limitations, chiefly: (a) Typical risk matrices can correctly and unambiguously compare only a small fraction of pairs of hazards, and they can assign identical ratings to quantitatively very different risks. (b) Risk matrices can mistakenly assign higher qualitative ratings to quantitatively smaller risks. (c) Effective allocation of resources to risk-reducing countermeasures cannot be based on the categories provided by risk matrices. (d) Categorizations of severity cannot be made objectively for uncertain consequences. Cox concluded "Inputs to risk matrices (e.g., frequency and severity categorizations) and resulting outputs (i.e., risk ratings) require subjective interpretation, and different users may obtain opposite ratings of the same quantitative risks. These limitations suggest that risk matrices should be used with caution, and only with careful explanations of embedded judgments." References
A
Criticism Qualitative risk evaluations have been demonstratedWhat's wrong with risk matrices?, doi: 10.1111/j.1539-6924.2008.01030.x. URL to have significant limitations, chiefly: (a) Typical risk matrices can correctly and unambiguously compare only a small fraction of pairs of hazards, and they can assign identical ratings to quantitatively very different risks. (b) Risk matrices can mistakenly assign higher qualitative ratings to quantitatively smaller risks. (c) Effective allocation of resources to risk-reducing countermeasures cannot be based on the categories provided by risk matrices. (d) Categorizations of severity cannot be made objectively for uncertain consequences.
A
Cox concluded "Inputs to risk matrices (e.g., frequency and severity categorizations) and resulting outputs (i.e., risk ratings) require subjective interpretation, and different users may obtain opposite ratings of the same quantitative risks. These limitations suggest that risk matrices should be used with caution, and only with careful explanations of embedded judgments."