Episode 92 - 3 x 3 Risk Assessment Matrix

Dr. Ayers introduces the 3×3 Risk Assessment Matrix, the simplest of the common matrix formats. The episode emphasizes that reducing the scoring options forces teams to focus on meaningful discussion, credible severity, and practical controls, rather than getting lost in numerical precision.

The 3×3 matrix is ideal for quick field-level assessments, dynamic work environments, and frontline decision-making.

 

1. Structure of the 3×3 Matrix

The matrix evaluates hazards using Severity and Likelihood, each scored from 1 to 3.

Severity (1–3)

• 1 – Minor: First aid or negligible harm

• 2 – Moderate: Recordable injury or medical treatment

• 3 – Severe: Permanent disability or fatality

Likelihood (1–3)

• 1 – Unlikely: Not expected to occur

• 2 – Possible: Could occur under the right conditions

• 3 – Likely: Expected to occur or occurs regularly

Risk Score = Severity × Likelihood Range: 1 to 9, typically grouped into low, medium, and high.

 

2. Why Use a 3×3 Matrix?

Dr. Ayers highlights several advantages of the simplified format:

• Reduces overthinking Fewer choices mean faster, more consistent scoring.

• Ideal for dynamic risk assessments Great for pre‑task briefings, JHAs, and field-level hazard checks.

• Minimizes false precision You can’t pretend the difference between a “2 vs. 3 likelihood” is scientific.

• Improves team agreement Workers tend to align more easily when the scale is simple.

• Keeps the focus on controls The conversation becomes: “What can we do about this hazard right now?”

 

3. Common Pitfalls

Even with a simple matrix, leaders can misuse it:

• Treating the score as a justification to proceed A “3” doesn’t mean the hazard is acceptable.

• Ignoring credible worst-case severity Severity must reflect what could happen, not what usually happens.

• Not considering exposure frequency Likelihood must reflect how often workers interact with the hazard.

• Failing to reassess after controls Controls should reduce likelihood, and the matrix should show that.

 

4. How to Use the 3×3 Matrix Effectively

A. Use it for quick, real-time decisions

Perfect for crews starting a task or adjusting to changing conditions.

B. Score hazards as a group

Frontline workers often see risks leaders miss.

C. Document the reasoning

Even a simple matrix needs context behind the numbers.

D. Re-score after controls

Shows whether risk was actually reduced.

E. Prioritize severity

A severity of 3 always deserves attention, even if likelihood is low.

 

5. Leadership Takeaways

Strong safety leaders:

• Use the matrix to drive action, not to justify continuing work

• Encourage open hazard conversations

• Treat risk scoring as dynamic and situational

• Focus on engineering and administrative controls

• Use the matrix as a communication tool, not a compliance form

 

6. Example (in the spirit of the episode)

Working near a pinch point on a conveyor:

• Severity: 3 (severe)

• Likelihood: 2 (possible)

• Risk Score: 6 (medium/high depending on scale)

After installing a guard and adding a lockout procedure:

• Severity: 3 (unchanged)

• Likelihood: 1 (unlikely)

• New Score: 3 (low)

Again reinforcing the principle: controls reduce likelihood, not severity.