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Human error

Human error is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Human error rather than just read about it. In short: Human error is an action that has been done but that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits". Human error has been cited as a primary cause and contributing factor in disasters and accidents in industries as diverse as nuclear power (e.g., the Three Mile Island accident), aviation (e.g., United Airlines Fligh…

Human error — main illustration
Human error — illustration

Key takeaways

  • Human error belongs to engineering; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Human error to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Human error from memory before moving on to harder problems.

Reference excerpt

Human error is an action that has been done but that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits". Human error has been cited as a primary cause and contributing factor in disasters and accidents in industries as diverse as nuclear power (e.g., the Three Mile Island accident), aviation (e.g., United Airlines Flight 173), space exploration (e.g., the Space Shuttle Challenger disaster and Space Shuttle Columbia disaster), and medicine. Prevention of human error is generally seen as a major contributor to reliability and safety of (complex) systems. Human error is one of the many contributing causes of risk events.

Definition

Human error refers to something having been done that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits". In short, it is a deviation from intention, expectation or desirability. Logically, human actions can fail to achieve their goal in two different ways: the actions can go as planned, but the plan can be inadequate (leading to mistakes); or, the plan can be satisfactory, but the performance can be deficient (leading to slips and lapses). However, a mere failure is not an error if there had been no plan to accomplish something in particular.

Performance

Human error and performance are two sides of the same coin: "human error" mechanisms are the same as "human performance" mechanisms; performance later categorized as 'error' is done so in hindsight: therefore actions later termed "human error" are actually part of the ordinary spectrum of human behaviour. The study of absent-mindedness in everyday life provides ample documentation and categorization of such aspects of behavior. Having a sense of awareness is needed to understand when dealing with a potential danger, thus being able to correct it. While human error is firmly entrenched in the classical approaches to accident investigation and risk assessment, it has no role in newer approaches such as resilience engineering.

Categories There are many ways to categorize human error:

exogenous versus endogenous error (i.e., originating outside versus inside the individual) situation assessment versus response planning and related distinctions in error in problem detection (also see signal detection theory) error in problem diagnosis (also see problem solving) error in action planning and execution (for example: slips or errors of execution versus mistakes or errors of intention) by level of analysis; for example, perceptual (e.g., optical illusions) versus cognitive versus communication versus organizational physical manipulation error 'slips' occurring when the physical action fails to achieve the immediate objective 'lapses' involve a failure of one's memory or recall active error - observable, physical action that changes equipment, system, or facility state, resulting in immediate undesired consequences latent human error resulting in hidden organization-related weaknesses or equipment flaws that lie dormant; such errors can go unnoticed at the time they occur, having no immediate apparent outcome equipment dependency error – lack of vigilance due to the assumption that hardware controls or physical safety devices will always work team error – lack of vigilance created by the social (interpersonal) interaction between two or more people working together personal dependencies error – unsafe attitudes and traps of human nature leading to complacency and overconfidence

Sources The cognitive study of human error is a very active research field, including work related to limits of memory and attention and also to decision making strategies such as the availability heuristic and other cognitive biases. Such heuristics and biases are strategies that are useful and often correct, but can lead to systematic patterns of error. Misunderstandings as a topic in human communication have been studied in conversation analysis, such as the examination of violations of the cooperative principle and Gricean maxims. Organizational studies of error or dysfunction have included studies of safety culture. One technique for analyzing complex systems failure that incorporates organizational analysis is management oversight risk tree analysis.

Controversies

Some researchers have argued that the dichotomy of human actions as "correct" or "incorrect" is a harmful oversimplification of a complex phenomenon. A focus on the variability of human performance and how human operators (and organizations) can manage that variability, may be a more fruitful approach. Newer approaches, such as resilience engineering mentioned above, highlight the positive roles that humans can play in complex systems. In resilience engineering, successes (things that go right) and failures (things that go wrong) are seen as having the same basis, namely human performance variability. A specific account of that is the efficiency–thoroughness trade-off principle, which can be found on all levels of human activity, in individuals as well as in groups.

See also Action slip Behavior-shaping constraint Error-tolerant design Human reliability Poka-yoke SHELL model User error Technique for human error-rate prediction Fallacy To err is human Ukraine International Airlines Flight 752

References

External links Autrey, T.D. (2015). 6-Hour Safety Culture: How to Sustainably Reduce Human Error and Risk (and do what training alone can't possibly do). Human Performance Association. Archived from the original on 2021-04-11. Retrieved 2020-08-21.

Illustrations

Human error: The Custom House in Dublin, which was built the wrong way around (the side facing the Liffey was intended to be the side facing Gardiner Street)[citation needed].
The Custom House in Dublin, which was built the wrong way around (the side facing the Liffey was intended to be the side facing Gardiner Street)[citation needed].
Human error: The "Hartlepool monkey" statue in Hartlepool, England, commemorating a monkey who was mistaken by locals to be a French soldier and killed.
The "Hartlepool monkey" statue in Hartlepool, England, commemorating a monkey who was mistaken by locals to be a French soldier and killed.

Worked examples

Example 1 — a first encounter with Human error

Start with the simplest possible case. Write down what Human error claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Human error before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Human error ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Human error

In research
Human error appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Human error in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Human error is common in secondary-school and first-year university syllabi. It links to neighbouring topics Error, Human reliability, Reliability engineering, so understanding it makes those chapters shorter.
In everyday life
Look for Human error outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Human error in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Human error means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Human error out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Human error in simple terms?

Human error is an action that has been done but that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits". Human error has been cited as a primary cause and contributing factor in disasters and accidents…

Why does Human error matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Human error?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Human error.

Tags

  • Error
  • Human reliability
  • Reliability engineering

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