Using Human Factors, Human Error Prevention, and Mistake Proofing



Human error is a mistake made by a person that results in any unfavourable outcome. Humans are imperfect and our fallibility is universal. It is the nature of humans to misjudge and to make errors. Thus, it is necessary to recognize our human limitations and design our work and its tasks to provide error prevention and mistake proofing so that people can still do their work error-free.

Human error is very difficult to manage as people can do unexpected things, i.e. the failure types are unpredictable. Workplace activity is normal human endeavour in which errors and mistakes can occur. Human factors, the limitations of the human mind and body, are the foundations of human error. All of us are affected by human factors in diverse ways when doing our jobs and throughout our lives. One could reasonably argue that all failures are the fault of human design because we cannot stop them happening.

The chance of error increases when:

  • the mental stress on the person is excessive (“stressed out”), or inadequate (boredom);
  • the amount of information to process becomes greater or less than what is manageable;
  • decisions are made in haste;
  • inexperience, especially if combined with lack of supervision
  • unusual situations exist because a person is entrapped by their habits (task capture);
  • the mental understanding of the system is poor, or the system is ill-defined (poor training, ability/demand mismatch, poor feedback, or poor definition of roles and responsibilities);
  • the task is considered to be unnecessary, or it is thought that errors will be fixed by others.

For serious reduction in the number of human errors in your operation you need to include human factors engineering solutions that prevent the opportunity for your people to make mistakes. You require error prevention and mistake proofing solutions to be incorporated in your peoples’ work tasks as an output of the job design stage.

Solutions Uses for Human Error Prevention

Errors are classified as a slip, mistake, violation, or managerial error. A slip, or lapse in attention, arises when the intention is correct but the execution is faulty. For example, while thinking about the job you walk to where the workshop was 10 years ago.

A mistake happens when there is a faulty idea of what should be done, like thinking the lubricant was the correct one to use for the lubrication job, when in fact it was not. When there’s a mistake you’ll often hear people say, “How was I supposed to know that?”

Violation is a deliberate decision to ignore instructions. “I added a bit more just to be sure.” is a common excuse after a violation.

Managerial error arises from poor policy, and unwise decisions. Most errors can be traced back to this issue. Autocratic, demoralising styles such as, knee jerk reaction, policy on the run, “gung-ho” risk averse behaviour, and short-term planning are representative of management error scenarios.

The best human error solutions are those designed and built into the way of working. They make the task straight forward in a clear and practical way.

The job design protects against human error caused failures. The job design insures that there is only one way to do the task, the right way, and any other way is clearly wrong. Where the same human error in a job happens twice you need to install designed-in human error prevention and mistake-proofing solutions.

Human Error Proofing (Poka Yoke)

The goal of mistake-proofing or Poka Yoke is simple: to eliminate mistakes. Originally called ‘fool proofing’” in Japan, and later changed to ‘mistake proofing’ and ‘fail safe-ing’ so employees weren’t offended, poka yoke (pronounced “poh-kah yoh-kay”) translates into English as to avoid (yokeru) inadvertent errors (poka). The method uses small devices to either detect or prevent human error defects from occurring.

Current Methods of Human Error Detection

One branch of human error management strategy finds an error after it is made. Human errors are not stopped, but they are detected after they occur. The most common methods to detect human error are:

  1. Inspect and Check: Test samples against a standard for non-conformances.
  2. Work Process Audit: Inspect a work process and get information to better control the process (a feedback loop)
  3. Point-of-Origin Inspection: Assess the conditions are right for error-free outcomes before starting. Use the Poka Yoke concept of applying low cost devices and visual indicators to spot mistakes as the work progresses.

Current Methods of Human Error Prevention

The second type of human error management prevents human error. It recognises the effect of human factors and requires designing a system-of-work to remove or reduce the opportunity to make a mistake. Standard Operating Procedures, Fatigue Management, workplace ergonomics and Safety Management are examples of error prevention and mistake proofing practices and methods to help human do great work.

Human Factors Based Error Prevention and Mistake Proofing Solutions

In order to eliminate mistakes, we need to modify work processes so that it is impossible to make mistakes. This necessitates the inclusion of error prevention and mistake proofing in job design. With mistake-proofing solutions, many repetitive tasks that depend upon the memory of the worker are built into the work process itself. Mistake-proofing frees the time and minds of the workforce to pursue more creative and value-adding activities. Workers know they will still do the task accurately because that is the way the system-of-work was designed. Mistake-proofing also involves a change in the norms of the organisation. Organisations must establish a mistake-proofing mindset that promotes the belief that it is unacceptable to allow even a small number of product or work defects.

Experience and research has taught us that you need to apply human factors thinking to your work environment. Errors are inevitable – even for you! There are situations that can increase the likelihood of error and we need to recognize them for safety sake and for the success of the workplace. Close attention to human factors principles can lead to a reduction in error, or its consequences.

Human factors engineering is about designing the workplace and the equipment in it to accommodate for limitations of human performance. Add error prevention and mistake proofing into your work methods and you will help your people to:

  1. Avoid reliance on memory
  2. Make things visible
  3. Review and simplify processes
  4. Standardize common processes and procedures
  5. Routinely use checklists
  6. Decrease the reliance on vigilance

The best part of implementing human error prevention and doing mistake-proofing is that learning is never over. Continuous improvement through human factors analysis becomes an essential part in your safety and reliability plans to catch new opportunities for error proofing your workplace. Human factors analysis methods quickly identify the human error risks in your work processes. They spot the potential mistakes and errors in a job and design human factor solution that prevent the problems in the first place so you get right-first-time work.


Author: Mike Sondalini

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