Human error

A human error (hereinafter, the Error) is any unintentional action or inaction of a human being working on a system that can potentially degrade this system. In other words, the Error can be defined as an individual's deviation from acceptable or desirable practice which culminates in undesirable or unexpected results.

Those actions or inactions that can potentially degrade the system that shouldn't be degraded and are made intentionally are called violations. The residual Errors and those violations that have not made on the purpose to degrade the system are mutually known as unsafe behaviors.

Classification

Dr. Jens Rasmussen developed a scientific classification of the Errors. This classification claims that a human being is making the Error while performing either:

1. An incorrect task. This type of the Error has been categorized as a mistake, which J. Rasmussen further classified as either a rule-based or knowledge-based; OR
2. A correct task incorrectly. Commonly, this type of the Error is categorized as a slip or lapse.

Mistakes

Main wikipage: Planned mistake

Slips

Main wikipage: Slip error

Slip of action error, slip of action

Lapses

Main wikipage: Memory lapse

Other groupings

Similarly to human performance, the Errors can be grouped in many ways.

Well-adjusted vs residual

Errors tend to be inevitable; the Roman Philosopher Cicero stated: “It is the nature of man to err”.

The most of Errors may possibly be corrected. A well-adjusted Errors cannot harm the system. At the same time, the Error that hasn't been corrected timely within the same set of enterprise efforts can be called residual and should be considered as an unsafe behavior.

Dirty Dozen

Main wikipage: Dirty Dozen in Aviation

Originally developed by Transport Canada, Dirty Dozen in Aviation is a highly popular grouping of the Errors that is used in aviation.

Unsafe behaviors

Main wikipage: Unsafe behavior

The residual Errors and those violations that have not made on the purpose to degrade the system are mutually known as unsafe behaviors or unsafe acts. J.T. Reason, as expressed in the CAA Flight-crew human factors handbook CAP737, developed the classification of unsafe acts that distinguishes between two types of the Errors:

1. Active failures, whose effects are felt immediately in a system. Active failures are usually the result of actions taken (or not taken) by front-line operators such as pilots, air traffic controllers, or anyone else with direct access to the dynamics of a system.
2. Latent failures, whose effects may lie dormant until triggered later, usually by other mitigating factors. Latent failures, on the other hand, are caused by those separated by time and space from the consequences of their actions in the dynamics of the system. Personnel working in vocations such as architectural design, hardware design and equipment maintenance are more prone to cause latent failures than active failures. On another hand, consider the case of a mechanic who assembled a component incorrectly which eventually led to a plane crash days or even weeks later. The defenses that should have normally caught this mistake were not in place. These defenses include proper training (the mechanic was taught to fix this particular component very informally and on-the-job), good situational awareness (the mechanic was tired from a double shift the night before), and independent inspection (the job was "pencil-whipped" to save time).

Prevention

The Error is one of the many contributing causes of risk events and a significant cause of disasters and accidents in industries such as aviation, nuclear power, space exploration, and medicine. Prevention of the Errors and/or their impact is a major contributor to reliability and safety of complex systems.

Pyramids

Main wikipage: Accident pyramid

Unsafe behaviors may lead to incidents, and those may cause accidents, including fatal accidents. Proportions for those unsafe acts that led to the catastrophes are known as accident pyramids such as:

Type	Description	Number
Unsafe act	Those Errors that haven't been corrected properly	300
Incidents	Those unsafe events that lead to minor failures	29
Accidents	Those incidents that lead to fatal accidents or catastrophes	1

Employee resource management

Main wikipage: Employee resource management

Studies of human factors and ergonomics that allow for reduction of the Errors are the focus of several disciplines such as crew resource management (CRM) and maintenance resource management (MRM).

Safety culture

Main wikipage: Safety culture

See also

• https://www.iwolm.com/en/do-you-know-the-3-types-of-human-errors-learn-from-them/
• https://www.nopsema.gov.au/resources/human-factors/human-error/
• https://www.safetyandhealthmagazine.com/articles/print/6368-
• https://www.isnetworld.com/events/ugm/osha2016/Sessions/Micah%20Backlund%20-%20Comparing%20the%20Heinrich%20Triangle%20Theory.pdf
• https://risk-engineering.org/concept/Heinrich-Bird-accident-pyramid