Risk Assessment and Risk Acceptance
This domain examines how risk is characterized, compared with criteria, and formally accepted. Expect questions on matrix interpretation, residual risk, acceptance authority, and the difference between tolerable and zero risk.
Core concepts
Risk is commonly expressed as a combination of severity and probability, using a qualitative matrix, a semi-quantitative score, or a quantitative model. Individual risk applies to a person; societal risk applies to a population and is often shown on an F-N curve. ALARP means reducing risk until further reduction is grossly disproportionate to the benefit. Residual risk is what remains after controls.
Acceptance mechanics
- The program defines risk acceptance criteria and an authority matrix before hazards are scored.
- An acceptance record identifies the hazard, risk level, controls, residual risk, justification, time limit, and signature.
- Acceptance is not permanent: re-evaluate after design change, new information, a near miss, or an incident.
- Where risk is high, prefer further reduction or redesign before acceptance; use monitoring and compensating measures only with justification.
Worked example
A hazard is scored Catastrophic severity and Improbable probability, giving “Medium” on the matrix. A project engineer signs acceptance because it is only Medium. The better answer is that the matrix level does not by itself grant authority; the program’s acceptance matrix assigns Medium to a specific role, and catastrophic severity commonly triggers higher review even at low probability. The record must state residual risk and monitoring. Reasoning: authority follows both level and severity, and the acceptance must be traceable.
Traps that cost marks
- Accepting risk at a level below the designated authority.
- Treating “tolerable” as “zero” or “no action required.”
- Ignoring cumulative and societal risk when each hazard looks small.
- Accepting without a time limit or re-evaluation trigger.