Frequently Asked Questions

What is the difference between a root cause analysis and a human factors analysis?

Root cause analysis is the systematic method of analysis to expose the foundational causes of failure, both material and human, because intervention is most effective there. Human factors analysis is the study within the RCA methodology to expose the root causes attributable to human performance.

What is the difference between Lean/Six Sigma and HFACS?

Lean/ Six Sigma is a methodology to improve efficiency, productivity and performance by systematically removing waste. Human factors is the discipline of studying human capabilities and limitations in order to design equipment, work environments, procedures, and policies that are compatible with human performance. The retrospective investigation of human error provides deep insight and intervention opportunities to achieve operational objectives.

How does HFACS support High Reliability?

High reliability is most often used to emphasize that high levels of operational risk and highly effective, incident free performance can co-exist. Some organizations must perform well under in very demanding environments, which requires intensive and deliberate effort to do so. Effective programs to investigate human factors have fundamentally shaped industries like commercial air transportation to achieve safety performance records near 1 in 10 million chances of a significant accident.

What is the HFACS process?

The HFACS process examines causes and causal relationships for human influence and then applies the proven taxonomy of human failures in order to determine why the error occurred. Once human root causes are revealed they are categorized into a database classification system that facilitates trend analysis and opportunities for strategic intervention.

What are the types of causes included in the human factors analysis?

The widely accepted human factors taxonomy categorizes human failure levels into four fundamental levels: individual actions, preconditions, supervisory influences and organizational influences.

What types of evidence is important to an investigation?

All types of evidence that help to uncover root causes will be helpful in determining human contributions to the causal relationships. Evidence such as statements and witness interviews, data on the physical and technological environment, standards and policies, training and maintenance records and planning and preparation events will be particularly useful in recreating the incident and untangling the causes. 

How are interviews conducted?

Conducting successful interviews is critical to an effective investigation. To be successful, interviewers must be trained and well prepared to guide an interview.

How quickly should an investigation be initiated?

Because of the perishability of human evidence, the HFACS investigation should be initiated as soon as it is safe for investigators to begin the process.

How is an HFACS investigation different than a legal investigation?

The objective of a legal investigation is to determine causes for the purpose of assigning liability and potential legal recourse. An HFACS investigation seeks to determine causes for the purpose of enhancing safety and productivity. At a philosophical level, these two aims are in competition. A legal investigation will promote protection and suppression of information, where a safety investigation promotes transparency, even non-attribution, in order to focus on prevention.

What will investigators learn in the training?

The HFACS investigator training trains investigators and safety managers in the theory and foundations of human factors including the four levels of failure, individual actions, preconditions, supervision and organizational influences. Sections of the training teach students how to conduct the investigation by gathering evidence, conducting the analysis, and identifying and tracking solutions.

Who should attend HFACS training?

HFACS training is designed for all organizational staff members assigned as investigators along with safety managers and supervisors with the responsibility for developing and implementing safety programs.

How will I know if it is working?

The most immediate measure of effectiveness will be observed in the quality of incident investigation reports and the associated corrective action. Over time as a result of improved investigations and interventions, organizations will see measurable improvements in safety and productivity measurements.

Who do I contact for more information?

Contact Chad Thacker at or 844-838-3749 (844-VETERGY).


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