Scales For Risk Assessment

What are Risk Assessment Scales?

Risk assessment scales help you assess, evaluate, and prioritize risks based on their probability and impact. By using these scales, you can determine the degree of impact and likelihood for each individual risk. These levels are also used as the axes of the risk matrix, which helps visualize the risk's value.

• Grades for Impact Level
• Degrees for Probability Level
• Overall Risk Level: Typically calculated as Impact * Probability

Commonly Used Scales for Risk Assessment

Popular scales for risk assessment o evaluate the severity and likelihood and level of risks use 3, 4 or 5 steps. These scales help in systematically assessing and prioritizing risks based on their potential impact and probability, and evaluate and then prioritize risk level:

• 3-point scale: Low, Medium, High
• 4-point scale: Negligible, Minor, Major, Critical/ Catastrophic
• 5-point scale: Insignificant, Minor, Moderate, Major, Critical/Catastrophic

These scales help to systematically assess and prioritize risks based on their potential impact and likelihood, and to evaluate and then prioritize the level of risk. Which scale you use is purely up to your methodology. In our experience, the 4-point scale that is set as the default in the risk register is the best.

Default 4-Point Risk Rating Scale

Probability:

1. Low: Extremely unlikely, very low chance that the risk will occur.
2. Medium: Normally possible.
3. High: Highly likely, the risk is likely to occur.
4. Almost Certain: Bordering on certainty, the risk will almost certainly occur.

Impact:

1. Negligible: Minimal or no impact.
2. Minor: Small impact that can be easily handled.
3. Significant: Significant impact that requires management.
4. Critical: Severe impact that can be catastrophic.

Risk Level:

The level of risk is calculated by combining probability and impact. Here is a common range:

• 1-4: Negligible, Low Risk - Acceptable, no action required.
• 5-8: Moderate Risk - Monitor and manage.
• 9-12: High Risk - Requires immediate attention.
• 13-16: Extreme, Catastrophic Risk - Immediate and significant action required.

Example of a 3-Level Risk Assessment Scale

Probability:

1. Low
2. Medium
3. High

Impact:

1. Small
2. Medium
3. High

Risk Levels:

1. Low
2. Moderate
3. High

Example of a 5-Point Risk Assessment Scale

Probability:

1. Almost Impossible, Rare: Very unlikely to happen.
2. Unlikely: Possible but not expected to happen.
3. Moderate: May happen occasionally.
4. Probable: Expected to occur under many circumstances.
5. Almost Certain: Very likely to happen.

Impact:

1. Insignificant: Minimal or no impact.
2. Minor: Low impact, easy to control.
3. Moderate Noticeable impact, requires management.
4. Major: Significant impact, requires thorough management.
5. Severe: Critical impact, can be catastrophic.

Risk Levels:

1. 1-4: Tolerable, Low Risk – Acceptable, no action required.
2. 5-9: Moderate Risk – Monitor and manage.
3. 10-16: High Risk – Requires attention.
4. 17-20: Very High Risk – Requires immediate attention, significant action needed.
5. 21-25: Extreme Risk – Immediate action or termination of activity required.

How to Change Impact Levels and Risk Probabilities

• See how you can adapt the risk levels or their names to your methodology