An unintended action, omission or decision by an individual or team that causes a deviation from intended procedures, system states or safety boundaries, occurring because of cognitive limitations, misperception, poor interface design, inadequate training, workload, stress or organizational factors.

Principle

Human error typically results from the interaction between human cognitive capabilities and the design of tasks, tools and systems: errors arise when system demands exceed attention, memory or decision capacity, or when affordances and feedback do not support correct action.

Demonstration

Situation: A plant operator reads a poorly labelled gauge during a high workload period and closes the wrong valve. Recognition: Post‑event review shows the valve labels were ambiguous and similar. Action: Management redesigns labels and control layout, automates interlocks for critical valve sequences and provides targeted training. Consequence: The combination of improved UI, procedural safeguards and automation reduces the probability of the same human error recurring.

Misapplication

Attributing incidents solely to 'operator error' without examining system design, procedures, ergonomic factors or latent organizational contributors; the semantic error is treating human actions as isolated causes rather than outcomes of socio‑technical context.

Consequence

Human errors can cause immediate incidents, near‑misses, reduced throughput or latent faults that later precipitate failure; analyzing errors systemically enables causal remediation (redesign, training, automation, procedure change) rather than only disciplining individuals, and can convert incidents into opportunities for resilience improvement.

Reversal

Some actions labelled as error are intentional violations made for operational reasons (workarounds) and should be treated as choices under constraints rather than cognitive slips; furthermore, highly automated systems can produce new classes of errors (automation complacency, mode confusion) where human involvement is reduced but still critical.

Boundary

Clearly within: A slip where an operator selects the wrong pre‑programmed mode due to similar control names. Boundary case: A lapse caused by fatigue that degrades memory for a rarely used safety step—diagnosis requires workload and duty‑cycle data. Clearly outside: Deliberate sabotage or malicious action is not human error, though initial effects may appear similar.

Semantic Tension

Individual accountability versus system design: organizations must balance holding individuals responsible with recognizing and correcting systemic factors that enable errors; overemphasis on blame can suppress reporting and impede learning, while ignoring individual responsibility can permit neglect of standards.

Synthesis

Human error is best understood as a symptom of system design and organizational context rather than solely personal failing: reducing error incidence requires modifying the environment—task design, interfaces, training, procedures and organizational practices—to align system demands with human capabilities and to make correct actions the easiest and most observable choice.