Safety Culture, Human Reliability, and Event Investigation
Core concepts
Safety culture includes reporting, just, flexible, learning, and informed cultures. Distinguish person-centred (blame) from system-centred views; a just culture separates honest error from reckless behaviour. Know safety climate versus safety culture and the role of leading indicators. Human reliability analysis methods (e.g., THERP, HEART, CREAM concepts) estimate error probability using performance-shaping factors; understand nominal human error probability and recovery factors.
Event investigation should be systematic: preserve evidence, establish timeline, identify causal and contributing factors, distinguish root causes from proximate causes, and avoid hindsight bias. Use barrier analysis, change analysis, and why-because techniques. Findings should lead to corrective actions addressing latent conditions, not just retraining.
Traps in questions
- Equating a just culture with no accountability.
- Confusing root cause with the last person in the chain.
- Ignoring hindsight bias when judging operator decisions.
- Assuming retraining alone fixes systemic problems.
- Treating near-misses as unimportant; they are free lessons.
Worked rule of thumb
Apply the substitution test: would a competent, similarly placed person likely have done the same? If yes, the cause is systemic. Example: an operator missed an alarm during a flood; substitution suggests any operator would struggle, pointing to alarm management, not individual failure.