Human Factors Analysis and Classification System 8.0

The Human Factors Analysis and Classification System (HFACS) has been used by Department of Defense (DoD) safety investigators since 2011. Originally developed by Dr. Douglas Wiegmann and Dr. Scott Shappell for the Navy, the system was incorporated into the Air Force Safety Automated System (AFSAS) to provide a structured tool with a standardized set of definitions of human factors and system failures organized in a taxonomy. It focuses on analyzing flaws in the safety management system instead of individual failure. In this article, you will find updates to the latest version of HFACS, v8.0.

HFACS was founded on the “Swiss Cheese” model, a common investigation tool developed by James Reason in 1990 (Figure 1). Most people look at an incident scene and see the most recent actions that led to the event. The model calls these “unsafe acts,” and describes them as active failures. To find the root cause, Reason argued, one must look deeper into the preconditions that led to the unsafe acts. These unsafe acts could be active failures but could also include some latent failures—failures existing in the mental or physical environment that may have contributed to the incident. One should also examine supervisory influences—latent failures created by the supervisory chain that led to the preconditions. Finally, one should review organizational influences to find the latent failures present in the culture or the organization, such as regulations or informal guidance. Finding solutions at the higher levels that would have prevented the event in question could then prevent a broader rage of potential incidents.

What HFACS does is codify this model into specific terms, called “nanocodes.” A hierarchy was developed for each level, using standardized language, to define flaws in the safety management system instead of individual failure. This structure provides an easy-to-follow framework for analysis, helps investigators determine why something happened, aids in targeting the need for specific interventions, and can be useful in developing interview questions for mishap investigations and hazard inspections. Figure 2 shows an example of how HFACS is used.

Department of Defense Instruction (DoDI) 6055.07 requires the heads of the DoD components to “Collect, maintain, analyze, and report human error, human factors, and human performance data identified in safety investigations” and to use “a common human error categorization system that involves a human factors taxonomy accepted among the DoD Components.” Department of the Air Force Instruction (DAFI) 91-204, Safety Investigations and Reports, cites DoD Human Factors Analysis and Classification System codes in several places to enable tracking of human factors in the AFSAS database.

So, why revise HFACS? The previous version was heavily aviation-based and thus required “creative interpretation” to use for nonaviation mishaps. Also, the system needed to move from exclusive use by human factors experts to the broader safety investigator audience. Further, emotion-laden language was edited to push the system to focus on system inadequacies and mishap prevention. Here is a specific example:

• In v7.0, the definition for code SP006 read as follows—
  • SP006 Performed Inadequate Risk Assessment—Formal: Is a factor when supervision does not adequately evaluate the risks associated with a task or when pre-mission risk assessment tools/programs are inadequate.
• In v8.0, the definition for code SP006 reads—
  • SP006 Ineffective Deliberate Risk Assessment: Is when supervision/leadership did not effectively apply DoD risk management procedures (identify hazards, assess hazards, develop controls, implement controls, supervise and evaluate) during pre-mission activity, event planning, or a job hazard analysis (JHA) which resulted in hazardous conditions and/or unsafe acts. This [code] includes assessment of all hazards such as crew/team composition, etc.
    • (Examples include: Did not have enough trained, licensed, certified, or qualified personnel to safely operate the amount of vehicles or equipment available, or not enough personnel with specific occupational specialties required for the task or mission.)

Next are examples of changes by tier. In each tier, many existing sub-tier codes were recoded, and some new codes were added. For Organizational Influences, a new subtier called “Training Program Issues (OT)” was added. HFACS experts recognized that training-related information (to include currency and proficiency) was not being adequately captured, thus preventing implementation of more effective training practices (formal and informal). The new sub-tier reflects this new code.

For Supervision/Leadership, a new sub-tier was added called “Unit Safety Culture (SC),” which contains two new sub-codes: SC101 Unit Safety Culture and SC102 Pace of OPTEMPO (operations tempo)/Workload. Four new codes were added to the sub-tier Ineffective Planning and Coordination: SP008 Ineffective Pre-Mission Planning, SP009 Unit Failure to Provide Sufficient Operational Information Resources, SP010 Unit Failure to Provide Sufficient Manning/Staffing, and SP011 Unit Failure to Provide Sufficient Equipment or Supplies.

For Preconditions, the Sensory Misperception sub-tier was deleted, and its codes were recoded or combined with other codes. Several other codes were likewise combined. A new sub-tier, “Training (PT),” was added with four new codes and one revised code.

Unsafe Acts are now categorized as either Errors (performance/skill-based errors or judgment and decision-making errors), or Known Deviations (compared with the previous category named “Violations”).

For Air Force safety investigators, HFACS is built into AFSAS. Most reports will not allow submission of the final message unless an HFACS code is identified. More in-depth information can be located on the Air Force Safety Center public website at: https://www.safety.af.mil/Divisions/Human-Performance-Division/HFACS/.

Source: Update to the Department of Defense Human Factors Analysis and Classification System

(DoD HFACS) version 8.0, Author: Mr. Christopher R. Acord, Directorate of Analysis and Prevention, U.S. Army Combat Readiness Center. Presented at the Joint Professional Development Seminar, April 2023.

References
Reason, J. 1990. Human Error. New York, NY: Cambridge University Press.
U.S. Department of Defense Instruction (DoDI) 6055.07, Mishap Notification, Investigation, Reporting, and Record Keeping. June 6, 2011.
U.S. Department of the Air Force Instruction (DAFI) 91-204, Safety Investigations and Reports. 10 March 2021.
Wiegmann, Douglas A., and Scott A. Shappell. 2003. A Human Error Approach to Aviation Accident Analysis: The Human Factors Analysis and Classification System. London, UK: Ashgate Publishing Company.