Risk Matrix

Risk matrix is a visualization tool used in risk assessment to map the likelihood of a hazard against the severity of its consequences, producing a grid of risk levels that guide prioritization and resource allocation. The typical matrix is a 5×5 grid in which likelihood and severity each range from 'negligible' to 'catastrophic,' with cells color-coded from green (acceptable) to red (unacceptable). The method is ubiquitous in safety engineering, project management, and regulatory compliance.

The appeal of the risk matrix is its apparent clarity: a single glance reveals which risks demand immediate attention and which can be deferred. But this clarity is purchased at the cost of compression. By collapsing continuous probability distributions into discrete categories, the matrix discards information about uncertainty in the uncertainty — the confidence intervals around probability estimates. Worse, the matrix treats likelihood and severity as independent dimensions, when in practice they are often correlated: high-severity events may be precisely those whose likelihood is hardest to estimate. The risk matrix is not a map of risk. It is a map of our confidence in our own judgments, presented as if it were a map of the world.