IOSH Human Factors in Safety 4 — Questions and Answers
Question 1: What is the 'Swiss Cheese Model' and how does it relate to human factors?
- A model for food safety in cheese production
- James Reason's model showing how accidents result from the alignment of failures (holes) across multiple defensive layers, with human factors influencing each layer (Correct answer)
- A model for selecting PPE
- A model for prioritising risk assessments
Correct answer: James Reason's model showing how accidents result from the alignment of failures (holes) across multiple defensive layers, with human factors influencing each layer
Reason's Swiss Cheese Model shows that organisations have multiple layers of defence against accidents. Each layer has weaknesses (holes) — from organisational culture and management decisions down to individual errors. An accident occurs when holes in multiple layers align, allowing a hazard to pass through all defences.
Question 2: How can task design reduce human error?
- By making tasks more complex to keep workers alert
- By simplifying procedures, reducing cognitive demands, providing clear feedback, standardising processes, and matching tasks to human capabilities (Correct answer)
- By increasing the number of steps in each task
- By removing all decision-making from workers
Correct answer: By simplifying procedures, reducing cognitive demands, providing clear feedback, standardising processes, and matching tasks to human capabilities
Good task design reduces error by: simplifying procedures (reducing unnecessary steps), standardising processes, providing clear and immediate feedback, designing tasks that match human capabilities and limitations, reducing reliance on memory, and building in checks and verification at critical points.
Question 3: What is 'perception of risk' and why does it matter?
- It is the same as actual risk
- How people subjectively assess the level of risk, which can differ significantly from the objective risk level and influence their behaviour (Correct answer)
- A mathematical calculation of risk probability
- The official risk rating from a risk assessment
Correct answer: How people subjectively assess the level of risk, which can differ significantly from the objective risk level and influence their behaviour
Risk perception is how individuals subjectively judge the level of risk. It can differ significantly from objective risk assessments due to: familiarity (familiar risks seem less dangerous), personal experience, perceived control, dread factors, and media influence. When perception is wrong, behaviour may be inappropriately safe or unsafe.
Question 4: What is 'normalisation of deviance'?
- A statistical technique for analysing accident data
- The gradual process by which unacceptable practices or standards become acceptable over time as people get used to them (Correct answer)
- The process of making all work procedures standard
- A technique for integrating new workers into the team
Correct answer: The gradual process by which unacceptable practices or standards become acceptable over time as people get used to them
Normalisation of deviance (coined by Diane Vaughan studying the Challenger disaster) is when shortcuts, rule violations, or degraded standards gradually become accepted as normal because 'nothing bad has happened'. Over time, the boundary of acceptable practice shifts until a serious incident occurs.
Question 5: How does worker wellbeing influence safety performance?
- Wellbeing has no connection to safety
- Physical and mental wellbeing directly affect concentration, decision-making, physical capability, risk perception, and engagement with safety practices (Correct answer)
- Only physical fitness matters for safety
- Wellbeing is a personal matter outside the employer's responsibility
Correct answer: Physical and mental wellbeing directly affect concentration, decision-making, physical capability, risk perception, and engagement with safety practices
Worker wellbeing directly influences safety through: concentration and alertness, quality of decision-making, physical capability and coordination, willingness to follow procedures, engagement with safety practices, reporting behaviour, and team dynamics. Poor wellbeing (stress, fatigue, illness) impairs all of these.
Question 6: What is 'procedural drift' and how can it be prevented?
- The process of updating procedures regularly
- The gradual deviation from established procedures over time, often due to perceived inefficiency, which can be prevented through monitoring, reinforcement and procedure review (Correct answer)
- Moving procedures from one department to another
- A method for writing new procedures
Correct answer: The gradual deviation from established procedures over time, often due to perceived inefficiency, which can be prevented through monitoring, reinforcement and procedure review
Procedural drift occurs when workers gradually deviate from established procedures, often because the procedure seems unnecessarily cumbersome, or shortcuts are taken without immediate consequence. Prevention includes: regular monitoring and observation, reinforcing the importance of procedures, updating procedures to ensure they're practical, and addressing the root causes of drift.
IOSH Human Factors in Safety 4
What is the 'Swiss Cheese Model' and how does it relate to human factors?