Incident Investigation Flashcards
6 cards from real NEBOSH practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Incident Investigation flashcards as text
What does Heinrich's domino theory of accident causation propose?
Answer: Accidents result from a chain of sequential factors (social environment, fault of person, unsafe act/condition, accident, injury) and removing one 'domino' can prevent the injury
Heinrich's domino theory (1931) proposes that accidents result from a sequence of five factors like a row of dominoes: social environment/ancestry, fault of person, unsafe act or mechanical/physical hazard, the accident event, and injury. Removing any one domino — particularly the middle one (unsafe act/condition) — breaks the chain and prevents injury.
What is the 'Swiss cheese' model of accident causation?
Answer: Reason's model showing that accidents occur when hazards pass through aligned holes (weaknesses) in multiple defensive layers — each layer has gaps, and an accident happens when the gaps line up
James Reason's Swiss cheese model shows that organisations have multiple layers of defence (procedures, training, engineering controls, supervision). Each layer has weaknesses ('holes') that may allow hazards through. An accident occurs when the holes in several layers momentarily align, allowing a hazard to pass through all defences.
What is the '5 Whys' technique used for in incident investigation?
Answer: Repeatedly asking 'why' to drill down through symptom-level causes to identify the root cause of an incident
The 5 Whys technique involves asking 'why?' repeatedly (typically around five times, though it may be more or fewer) to move beyond the immediate or obvious cause of an incident to identify its root cause. Each answer becomes the basis for the next 'why', progressively uncovering deeper systemic issues.
Under RIDDOR 2013, which of the following events must be reported to the relevant enforcing authority?
Answer: A fracture of any bone other than fingers, thumbs, or toes suffered by a worker as a result of a work-related accident
RIDDOR 2013 requires reporting of specified injuries including fractures other than to fingers, thumbs or toes. Other reportable injuries include amputations, permanent loss of sight, crush injuries, burns requiring hospital admission, scalping, and any injury leading to loss of consciousness or requiring resuscitation.
What is a fishbone (Ishikawa) diagram used for in root cause analysis?
Answer: To visually organise potential causes of an incident into categories (such as People, Methods, Materials, Machinery, Environment, Management) to systematically identify root causes
The fishbone or Ishikawa diagram organises potential causes of an incident into main categories branching off a central spine. Common categories include People, Methods, Materials, Machinery/Equipment, Environment, and Management. This structured approach ensures all potential contributing factors are systematically considered rather than jumping to obvious conclusions.
Why is near-miss reporting considered important in incident investigation and prevention?
Answer: Near-misses share the same root causes as actual incidents — investigating them provides an opportunity to identify and fix hazards before someone is actually harmed
Near-misses are essentially accidents where the outcome was fortunately not harmful. They share the same causal factors as actual injuries and occur much more frequently. Investigating near-misses is a proactive opportunity — identifying and addressing the underlying hazards and system failures before they result in actual harm to people.