Practical error management for any workplace

What is human error?

The human element is the most flexible, adaptable and valuable part of the … system, but it is also the most vulnerable to influences which can adversely affect its performance’.

(ICAO circular 216-AN/131, 1989)

Error is an ever-present and natural part of life and it is generally accepted that we will all make errors on a daily basis. Each of us already have an intuitive understanding of the term human error, but it is useful to define it in order to better understand its nature and to develop mechanisms for effective error management.

Human error is a generic term that involves all those instances where a planned activity fails to achieve its intended outcome.[1] For example, forgetting to set your park brake in your car or misapplying your vehicle brakes in wet and slippery road conditions.

In any organisation, human error is a regular occurrence. The good news is that most of the time, these errors are self-corrected and they have little consequence. Other interesting facts about error include:

  • Average rate of error is constant at 1-3 per hour whatever the expertise (except for beginners).
  • Errors tend to decrease in more demanding situations (due to cognitive control) but the recovery rate collapses (due to insufficient mental capacity).
  • Errors change with the nature of expertise. Routine based errors (slips & lapses) increase with expertise, knowledge base (mistakes) decrease.
  • Motor skill errors (learning) are more frequent for beginners but decrease with experience.
  • Experts are characterised by their ability to recover from error (anticipation).

[1]  Reason, J. (1990). Human error. New York: Cambridge University Press.

What causes human error?

‘To err is human; to blame it on the other guy is even more human.’

Bob Goddard, rocket scientist

There are many reasons why human error occurs; it is not typically just one single factor. A summary of the main reasons found across a range of different industries can be grouped according to the following four broad areas:

  1. Human performance limitations (information processing capability, memory, fatigue, stress).
  2. Task or Environmental demands (time pressure, adverse weather).
  3. Organisational/Systemic factors (equipment design, poor management oversight, poor planning).
  4. Social and Cultural factors (peer pressure, group conformity, safety culture).

Errors are not random events. Rather, they are a consequence of what normally goes on in our mind, arising because of inattention, incomplete knowledge, sparse sensory data, mis-perceptions, forgetting something, problems in our relationships with colleagues, friends and family, and so on (see below Panel: Errors are consequences – not causes).

Figure 1. Consequences vs. causes

In turn, many of these factors are shaped by the operational context in which we work, including the social climate, the management culture, our working conditions and the fitness for purpose of the tools we work with.

Different types of errors

Professor James Reason, formerly of the University of Manchester, has studied human error and its involvement in accidents for many years. His model distinguishes between intended and unintended actions, and between errors and violations.

Figure 2. Error types

Unintended Actions

These are the slips and lapses and are referred to as skill based errors which occur during highly routine or familiar activities, when attention is diverted from a task, either by thoughts or external factors. Generally when these errors occur, the individual has the right knowledge, skills, and experience to do the task properly. The task has probably been performed correctly many times before. Even the most skilled and experienced people are susceptible to slips and lapses. As tasks become more routine and less novel, they can be performed with less conscious attention; the more familiar a task, the easier it is for the mind to wander. This means that highly experienced people may be more likely to encounter this type of error than those with less experience. Additionally, re-training and disciplinary action are not appropriate or useful responses for skill based errors.

The following table distinguishes between slips and lapses, typical reasons why they occur and provides examples of different types of errors.

Table 1. Unintended Actions – Slips and Lapses
Intended Actions – Mistakes

‘Making mistakes simply means you are learning faster.’

Weston H. Agor, Professor of Public Administration

Mistakes occur when we plan to do something, and carry out our plan accordingly, but it doesn’t produce the outcome we wanted (we find that this shop doesn’t sell the item we are looking for). This is often because our knowledge was inadequate, or the rules we applied in deciding what to do were inappropriate.

The following table distinguishes between rule and knowledge based mistakes, typical reasons why they occur and provides examples of different types of mistakes.

Table 2. Intended Actions – Mistakes
Intended Actions – Violations

Violations involve deliberate departures from established rules, procedures or values (speeding on the way to the shop to get there quicker). The following table distinguishes between different types of violations, providing typical examples, and describes their main causes.

Checklist for identifying the risk of workplace rule breaking

Sometimes people break a rule because they don’t know it exists, or they don’t understand it well enough, or they fail to recognise that a situation demands it. Or perhaps they simply forget that the rule exists. In all of these cases, rule breaking falls into one or another of the categories of human error discussed previously as either slips, lapses or mistakes.

However, sometimes people break a rule deliberately. This means that the rule-breaking is not really an error, but a violation. Research on rule breaking in high risk industries like rail and offshore oil and gas indicates that people do not tend to break rules maliciously, but for entirely rational reasons. In general, violations result from the conflict between an organisation that is attempting to control the behaviour of the workforce, and the individual who is attempting to carry out their task as easily as possible.

Use the following check questions to assess whether a given workplace is effectively managing the ever present risk of a rule breaking culture being developed.

Table 4. Workplace rule breaking checklist

How can error be reduced?

Error management should be tailored to suit specific contexts in particular organisations. The challenge for organisations is to create environments in which people can make mistakes without harmful consequences. This means using the most cost-effective combination of techniques across a range of human factors issues explored in this workbook, as follows:

  • Design – is used either to ensure that people cannot make certain kinds of mistake (e.g. installation of interlocks or cut out safety switches), or to help users review their decisions before enacting them (e.g. a dialogue box that asks ‘Are you sure you want to delete the selected file?’). While automation may seem attractive because it designs the human out; at best, it does not eliminate error but simply changes the problem to one of how to create the best possible interface between people and the automated component. At worst, it creates even more problems when the automation fails in front of a bored, de-skilled user..
  • Training – is used to ensure that people are rehearsed in their skills and knowledge and therefore less likely to make mistakes, or be better able to recover from mistakes when they do make them. However, considered thought needs to be given to the type of training required. More training on skills, rules and knowledge is of little benefit to people who commit deliberate violations. Violations are better dealt with by showing people the consequences of their actions.
  • Resourcing – is used to ensure that the right people are placed in the right jobs. More importantly, it ensures that people are recruited who can be trained in the skills and responsibilities to the level that will be required of them.
  • Culture – is developed by the organisation, through its leadership and management so that people work in a supportive and transparent environment. As a result, everyone develops a responsible approach to managing the detection and correction of mistakes, reducing their consequences and preventing their re-occurrence.
  • Workplace Conditions – are considered with the aim of identifying and reducing the error producing consequences of motivation, morale, stress, workload and fatigue. This reduction is achieved mostly through effective design, training and management (including self-management) of Error Producing Conditions (EPC’s) that increase the likelihood of errors occurring.

Want to know more?

For more in depth information on practical error management strategies based on different error types, attend our highly practical 5-Day program on Human Factors and Error Management for Safety Critical Industries . Presented by highly qualified and experienced human factors experts, a comprehensive suite of practical error management tools, templates and resources will be provided for you to take back and apply in your own workplace.

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