Risk Heat Maps: Likelihood, Impact, and Their Limits
Explains how 5x5 risk heat maps are built, what the scoring means, and why the visual should support rather than replace underlying probability thinking.
This extension page exists to support specific long-tail queries with formula-first explanations. It is intentionally narrow, deliberately opinion-free, and designed to lead into the relevant calculator rather than replace it.
Plain Figures does not recommend products, wrappers, or financial actions here. The goal is to make the arithmetic and the assumptions visible.
Core Formula
- Likelihood bands convert rough frequency into a shared scale
- Impact bands convert severity into a shared scale
- Controls and velocity often sit outside the basic score
Why heat maps stay popular
Heat maps compress a complex risk register into something leaders can scan quickly. That is why they remain common even though they are not pure quantitative models.
A good explainer needs to show what the matrix is doing and what it is not doing.
Why the score is not magic
A score of 20 is not automatically twice as risky as a score of 10 in a mathematically rigorous sense. The grid is a prioritisation tool, not a full loss model.
That distinction makes the page useful because it helps teams use the visual without over-reading it.
FAQ
Does a heat map calculate expected loss?
Not directly. It ranks risks on a likelihood-impact scale rather than producing a monetary expectation.
Why do teams score the same risk differently?
Because the bands are partly judgment-based unless the organisation defines them tightly.
Disclaimer
Open the matching calculator to apply the guide to your own numbers.
Keep moving through the same topical cluster with nearby explainers that support the calculator.