4 by 4 risk matrices use a scale of 1 to 4 to rate the likelihood of a risk occurring against the severity/impact of the risk. A high severity risk rated 4 may seem like something that must be managed, but if the likelihood of it occurring is low say 1, then it may not be cost effective to take action and the risk may be accepted. stakeholdermap.comThis risk matrix adds a number rating which combines the risk likelihood and risk severity on a scale of 1 to 4. A risk with the lowest likelihood and severity has a rating of 1. A risk with the highest has a rating of 16 (likelihood rating 4 multiplied by severity rating 4).
This matrix allows for a more nuanced assessment of risk than a 3 x 3 matrix, and identifies which risks need to be mitigated or avoided altogether. Risks with a rating between 1 and 3 are insignificant and don’t need any action. Risks with a rating of 8 or 9 need mitigation and those with 12 or 16 are show stoppers should be avoided.
Risk ratings
| Risk Rating | Description |
|---|---|
| Avoid | Find a way to avoid the risk. For example, by taking a different approach, not doing something, using different equipment etc. |
| Mitigate | Find a way to reduce the likelihood of the risk occurring or the severity of the impact if the risk does occur. |
| Allow | OK to proceed but aim to mitigate the risk if possible. |
| Accept | The risk is acceptable. The project can move forward, and mitigation of the risk is a low priority. |