A Risk Matrix is a standard tool used in risk management to define the level of risk associated with a specific hazard. It helps you prioritise which risks need immediate attention and which are acceptable to monitor.
The matrix works by combining two factors: Likelihood and Consequence.
1. Likelihood (How likely is it to happen?)
You must estimate the probability of the incident occurring.
- Rare: May occur only in exceptional circumstances.
- Unlikely: Could occur at some time.
- Possible: Might occur at some time.
- Likely: Will probably occur in most circumstances.
- Almost Certain: Is expected to occur in most circumstances.
2. Consequence (How bad would it be?)
Estimate the severity of the harm if the incident did occur.
- Insignificant: No injuries, low financial loss.
- Minor: First aid treatment required.
- Moderate: Medical treatment required.
- Major: Extensive injuries, loss of production capability.
- Catastrophic: Death or permanent disability.
3. The Risk Score (L x C)
By cross-referencing Likelihood and Consequence on the grid (usually 5x5), you get a Risk Rating: Low (L), Medium (M), High (H), or Extreme (E).
- Example: A worker working on a roof without rails.
- Likelihood: Possible (slips happen).
- Consequence: Catastrophic (death from fall).
- Result: Extreme Risk.
What the Ratings Mean
- Extreme Risk: STOP WORK IMMEDIATELY. The risk is intolerable. Work cannot proceed until controls are implemented to lower the risk.
- High Risk: Urgent action required. Senior management attention needed. Controls must be implemented before work starts.
- Medium Risk: Manage by specific monitoring or audit procedures. Responsibility must be specified.
- Low Risk: Manage by routine procedures.
Residual Risk
When you perform a risk assessment, you usually score the risk twice:
- Inherent Risk: The risk level before any controls are applied. (e.g., Working on roof = Extreme).
- Residual Risk: The risk level after controls are applied. (e.g., Harness + Guard rails installed = Low).
The goal of your WHS system is to ensure that the Residual Risk for all tasks is reduced to a level that is "As Low As Reasonably Practicable" (ALARP).
Using the Matrix in Your Business
Every SWMS and Risk Assessment should utilise a risk matrix to justify the controls you have chosen. It provides a logical, defensible method for your safety decisions.
Need templates with matrices built in? Get a risk management plan or risk assessment templates.