Choosing the Right Risk Matrix: Hidden Biases and How to Overcome Them

Risk matrices are popular tools in risk management. They help teams assess and prioritize risks by rating two essential factors:

• Impact: How severe would the consequences be?

• Probability: How likely is the risk to happen?

Multiplying these two factors gives a simple risk score (Impact × Probability).

This score guides your decision-making about which risks need immediate attention.

There risk matrices typically come in many different sizes (resolutions):

• 3×3 – Simple, quick, but sometimes overly basic.

• 5×5 – Most common, offering clarity with enough detail for practical use.

• 6×6 or larger – Highly detailed, but often creates confusion or unnecessary complexity.

While they seem objective, each of these formats comes with hidden biases.

Let’s explore what these biases are, how they might be impacting your risk assessments, and practical ways to overcome them.

1. Subjectivity in Risk Scoring

Even with a clearly defined matrix, different people can assign different scores to the same risk. Why? Risk ratings are inherently subjective. Personal experience, expertise, and even mood at the time of scoring can influence the outcome.

This inconsistency can make your risk matrix unreliable, impacting everything from decision-making to your compliance with frameworks and regulations like NIS 2, DORA or ISO 27001 and SOC 2.

What you can do to reduce subjectivity in risk scoring:

• Define crystal-clear criteria for each level of impact and probability. Replace vague terms like “Medium” with measurable benchmarks.
  
  Example: “High” impact might mean “losses over €50,000” or “service downtime exceeding 4 hours.”

• Provide real-world examples tied directly to your organization’s context or past incidents.
• Regular calibration meetings: Periodically ask your team to rate the same sample risks and openly discuss discrepancies to keep everyone aligned.

2. Decision Fatigue Due to Excessive Granularity

More detail in your matrix (such as a 6×6 or even larger grid) doesn’t always mean more accurate risk assessments. Instead, too many choices can create confusion, slow down decisions, and cause decision fatigue among team members.

In practice, excessive granularity often leads teams to cluster their ratings around certain categories, leaving the extra complexity unused.

What you can do to reduce decision fatigue in risk scoring:

• Evaluate actual usage: Review recent assessments. If your team consistently uses only 3–4 categories, simplify your matrix.
• Keep it lean: Use the simplest resolution (usually 3×3 or 5×5) that meets your compliance and documentation needs.
• Regularly revisit the matrix size based on team feedback, compliance requirements, and practical usability.

3. Analysis Paralysis

When teams spend excessive time debating whether a risk should be a “3” or “4,” valuable time and resources are wasted—time better spent actually managing or mitigating the risk.

Analysis paralysis slows down your ability to take decisive action, impacting critical business processes and making compliance audits (ISO 27001, NIS 2, or DORA) more stressful and drawn-out.

What you can do to reduce analysis paralysis in risk scoring:

• Set strict time limits for risk scoring discussions (for example, 5–10 minutes per risk). If no consensus emerges quickly, document the range (e.g., “Moderate to High”) and immediately move on to mitigation planning.
• Prioritize actions over perfection: Remember, risk assessment is a means to an end. The ultimate goal is effective risk treatment.

tl; dr

Key Questions to Evaluate Your Current Risk Matrix:

• Are you consistently seeing large discrepancies in risk scoring between team members?
• Does your team regularly use all available risk levels effectively?
• Do your auditors explicitly require more detailed documentation than you’re providing?
• Are lengthy debates about minor rating differences frequently delaying decisions?

If you answer “yes” to any of these questions, revisit your current matrix approach and

Consider applying these tweaks:

• Clearly define each rating level with real, measurable criteria.
• Regularly calibrate understanding among team members.
• Simplify your matrix if the extra detail isn’t actively used.
• Focus team discussions on risk treatments rather than precise ratings.
• Regularly review and adjust your matrix based on team and auditor feedback.