A table showing the risk scoring matrix. The severity or impact rating is measured on a scale of 1 to 5. 1 is insignificant, 2 is minor, 3 is moderate, 4 is major and 5 is catastrophic. Likelihood is measured on a scale of 1 to 5. 1 is rare (1 out of 100,000 chance), 2 is unlikely (1 out of 10,000 chance), 3 is possible (1 out of 1,000 chance), 4 is likely (1 out of 100 chance) and 5 is almost certain (1 out of 10 chance), The risk score is determined by multiplying the severity rating by the likelihood. 1 is the lowest possible risk score (insignificant severity of 1 multiplied by rare likelihood of 1). 25 is the highest possible risk score (catastrophic severity of 5 multiplied by almost certain likelihood of 5). A risk score of 1 to 5 is considered very low. A risk score of 6 to 8 is considered low. A risk score of 9 to 15 is considered moderate. A risk score of 16 to 25 is considered high.

	Severity/impact rating
Likelihood	1Insignificant	2Minor	3Moderate	4Major	5Catastrophic
5 – Almost Certain 1/10	5 – very low risk	10 – moderate risk	15 – moderate risk	20 – high risk	25 – high risk
4 – Likely 1/100	4 – very low risk	8 – low risk	12 – moderate risk	16 – high risk	20 – high risk
3 – Possible 1/1,000	3 – very low risk	6 – low risk	9 – moderate risk	12 – moderate risk	15 – moderate risk
2 – Unlikely 1/10,000	2 – very low risk	4 – very low risk	6 – low risk	8 – low risk	10 – moderate risk
1 – Rare 1/100,000	1 – very low risk	2 – very low risk	3 – very low risk	4 – very low risk	5 – very low risk