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Quick summary
  • The default matrix rates hazards 1 to 5 from likelihood and severity, so multiplied spreadsheet scores won’t match.
  • From a residual rating of 3, you must fill in Residual Risk Justification and confirm whether the risk is ALARP.
  • Only count controls that are in place. An assessor will spot a residual rating that relies on planned ones.

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Likelihood

Likelihood is how often the harm happens.

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Severity

Severity is the possible consequences of the harm.

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How the rating is produced

Every workspace starts with this DCB0129 matrix. Where the likelihood’s column meets the severity’s row is your Overall Rating. A spreadsheet that multiplies likelihood by severity scores 1 to 25, which doesn’t map onto the matrix: likelihood 5 with severity 1 multiplies to 5, but the matrix gives 3.
If your organisation multiplies likelihood by severityOur team sets this up for you. Hazards then show a score from 1 to 25 in the same 5 bands (1 to 3, 4 to 6, 7 to 12, 13 to 16 and 17 to 25). The banner and required justification start at band 3, a score of 7, and the banner shows the score, such as “Undesirable level of risk: 9”.
With an organisation-specific scale, your bands and labels may differ from this page.

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What each rating means

On a risk stage, the info icon beside Overall Rating shows these definitions. A grey ? means no rating yet.

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What happens at 3 and above

  • Initial Risk: a line under Overall Rating always names the band, such as “Your initial risk rating is 2 which is acceptable. Adding further controls is optional.”
  • Residual Risk: from a rating of 3, a banner names the band and what you need to do:
    • at 3, “Undesirable level of risk” asks you to attempt to eliminate the hazard or add controls;
    • at 4 or 5, “Unacceptable level of risk” says eliminating the hazard or adding controls is mandatory.
From a residual rating of 3, Residual Risk Justification is required. Save & Exit shows “Please provide a justification for the residual risk rating” until you do. Its helper text asks whether the risk is :
“Residual risk rating is undesirable or unacceptable - confirm if ALARP, and if so provide a risk-benefit justification”
The residual risk stage showing an undesirable-risk banner and the required justification field filled in

The Residual Risk stage in a workspace that multiplies likelihood by severity. A score of 9 is undesirable, so the banner appears and the justification is required. It's filled in here.

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Score residual risk on the controls you’ve built

An assessor will spot residual ratings that assume controls you haven’t built. Keep Control Status accurate, and re-check the rating once a control is built.
A cause with two controls, both with Control Status Awaiting Evidence

A cause with 2 controls, both with Control Status set to Awaiting Evidence. Make sure each control is in place before the residual rating counts on it.

Create a hazard

Score the initial and residual risk as you add a hazard.

Hazard log overview

How the hazard log fits together, and how to read its table.