According to the Health and Safety Executive, human error can be defined as: "An action or decision which was not intended, which involved a deviation from an accepted standard, and which led to an undesirable outcome".

Human errors are generally caused either by skill-based errors or by mistakes.

Skill-based errors usually arise from slips of action or lapses of memory.

Mistakes can be categorised as rule-based mistakes or knowledge-based mistakes.

Human Factors | Human Error | Violations | HS(G)65