The risk matrix is broken into a grid. The grid is usually 5x5, though it can be larger or smaller depending on company needs – a 5x5 grid happens to be the ICAO default risk matrix. The grid is used to assign a calculated ―”number” to the risk, which is combination of Probability x Severity, and represents the risk priority.
Probability: It is how lightly the event has to occur
Severity: It is the extent to which a particular risk can create an impact.
The risk matrix grid:
• Usually increases in severity from left (low) to right (high);
• Usually increases in probability from bottom (low) to top (high); but
• A risk matrix can move in any direction, so it is common to see risk matrices that move from right to left and top to bottom, right to left and bottom to top, or left to right and top to bottom.
