To say that accidents and quality problems happen due to operator error is like saying falling is due to gravity. The fall has a starting point (loss of footing), allowing gravity to do its part. The term “Operator Error” is used universally in Root Cause Analysis (RCA) and Failure Mode and Effects Analysis (FMEA) development. This is an unacceptable cause of failure! Stating the cause as Operator or Human Error does not lead to the root of the problem. To clarify, operator error is a real thing and often present. However, quality problems are not due to an operator error, rather it is the condition the operator has been inserted into which is the source of the error.

Operator Error is not permitted as a response to a root cause because it does not provide a direction to discover the condition affecting the operator which existed at the time of the error. It also does not clearly define the path of action to prevent a similar future event.

The inevitability of Human Error dictates that designs must include an analysis of how humans can influence failure. This approach is expanded into product design, machine design interfaces and process design and methodology.

Human Error does not always result in failure. But errors occur all the time. For example, if an operator of an automobile did not see a stop sign, there are three possible effects:

• Accident / Injury
• Ticket or Violation
• No Effect, as the vehicle glides through unscathed

When analysing Human Factors, one should consider the worst-case scenario to determine the level of study and commitment to Error Proofing, Reduction of Variation or Mistake Proofing.

What is Human Factors Engineering

Human Factors is the study of all factors related to the human interface with the machinery, process and environment to make work easier to do the correct way. Human Factors is often associated with ergonomics but is much broader than ergonomics alone and includes the physiology and psychology of the operator expected to perform a task. When applied to a problem, HFE is the study of factors which contributed to the operator not completing the task correctly. Operator Error is studied in RCA, when the human is indicated as the centre of the problem being studied. When applied in machine or process design, HFE prevents failures by eliminating or making aware of process conditions which could result in human error. Quality-One recommends the inclusion of Human Factor Engineering in Advanced Product Quality Planning (APQP).

Why Implement Human Factors Engineering

The human is one link of a failure chain but not always the decisive factor. When applying Human Factors to process design, risk is used to determine both the consequence of failure and the probability of each human error identified. Risk reduction techniques, like FMEA and Fault Tree Analysis (FTA), must include the impact of people on the successful deployment of a product or process. We are all affected every day by thoughtful Human Factors Engineering. Most people are aware of HFE through the newest automotive safety features such as:

• Standardized icons for identification
• Cockpit ergonomic design
• Automatic braking
• Lane departure warnings
• Passive road rumble strips
• Active rest warnings and alarms

This design philosophy extends beyond just automobiles into many products that we use daily. Each human error identified and eliminated has the benefits of:

• Fewer defects being produced
• Fewer injuries on the job
• Increased interest in the job
• Reduced equipment downtime

Types of Errors

There are three main categories of errors that people can make:

• Lapse state
• Mistake.
• Violation.

When identifying the type of error that people can make, the potential improvement or solution can be selected from five categories:

• Work Station Design.
• Ergonomics.
• Training and Documentation.
• Tooling Design
• Cognition and Concentration.