Six Decades of Utility

The Haddon Matrix, named by its originator Dr. William Haddon Jr., was introduced in 1968 in an article for the American Journal of Public Health, explaining the various factors in highway and traffic crashes. Dr. Haddon hoped it would spark discussion about ways to reduce risk and save lives.

Since that first introduction, it has become a staple in public health, injury prevention, and industrial accident prevention. It is a simple, easy-to-use tool that can be easily applied to every type of occupational safety and health issue.

Dr. Roger Jensen, a lawyer, professor and professional engineer at the University of Montana, wrote in his 2012 textbook, Risk Reduction Methods for Occupational Safety and Health, that the Haddon Matrix is crucial for safety professionals to use: “[it] is highly regarded as a fundamental tool for guiding injury risk-reduction programs” across multiple industries, occupations, and job tasks.

Entering The Matrix

The Haddon Matrix has stood the test of time. It can be modified and adapted as needed but basically contains space to identify the various factors that contribute to, or cause, safety issues. The matrix also includes three phases: pre-incident, the incident itself, and post-incident. Ideally, it can be done prior to, or in conjunction with, a job safety analysis, since that information will be essential to identifying the various factors that may lead to safety incidents. Other data, such as OSHA accident summaries, industry publications, litigation, and news articles may also be useful in preparing a Haddon Matrix.

The cells, according to Dr. Haddon’s original article, are where the true safety value lies and provide endless possibilities. Here, professionals can use their knowledge, creativity, observational assessments, research, analytical prowess, and technology to help generate “what-if” scenarios that can be used to identify control or mitigation tactics. Dr. Haddon wrote: “each cell contains a substantial number, breadth, and complexity of factors, categories of variables, and opportunities for influencing the end results,” which result in a safer work environment.

Figure 1. Simple Haddon Matrix

	Human (Behavioral) Factors	Equipment, Tools, or Device Factors	Environmental Factors
Pre-Incident
Incident
Post-Incident

Hammer Meet Nail

To illustrate its applicability, we will use a simple example of hammering a nail into a piece of lumber. To keep our fingers safe and free from the painful delivery of a hammerhead, we first identify the human/behavioral factors. These could include:

• Not knowing how to use the hammer
• Inability to properly center the nail
• Bad wrist motion
• Swinging too hard

For the device, equipment, or tool factors, components of unsafe hammering could be:

• Not selecting the correct nail for the job
• Wood that easily splinters or isn’t thick enough (e.g., balsa wood)
• Worn grip that slips

Environmental factors can include distractions, fatigue, weather conditions, inability to see (e.g., light conditions, eyesight, etc.) and many other elements that safety professionals know may be problematic.

As this example proves, elements may “float” between various categories; what ultimately matters is that safety professionals identify the major risks and connect them with controls or approaches to ensure safer work practices.

Countermeasures and Safety Strategies

Haddon described 10 methods for countering the effects of perils to safety, written in an article in December 1970, also for the American Journal of Public Health, and summarized for the journal Public Health Reports five years later. These 10 principles are remarkable for their similarity to the occupational health profession’s Hierarchy of Controls.

1. prevent the creation of the hazard in the first place.
2. reduce the amount of hazard created or used.
3. prevent the release of the hazard that already exists.
4. modify the amount, distribution, or timing of release of the hazard from its source.
5. separate the hazard through a material barrier.
6. create distance, shielding, time, or protective equipment to reduce exposure.
7. modify relevant basic qualities of the hazard (e.g., design and incorporating changes or modifications; essentially substitution controls).
8. increase the resilience of what is being protected against damage.
9. counter the damage already done through rescue, resuscitation, first aid, mental health counseling, etc.
10. stabilize, repair, and rehabilitate the object of the damage.

Hole in the Roof

Returning to Mario, who fell after stepping into an open roof hole on a construction site, we examine how a Haddon Matrix could be constructed for this situation. Luckily, with the advent of generative artificial intelligence (AI), this task may be greatly shortened — and enhanced — with technology. The author, using a commercially available AI platform, created the following prompt:

• Generate a Haddon Matrix to account for falling through an opening in a roof on a construction site.

The AI platform returned the Matrix below (figure 2). While safety professionals should embrace technology, they should also exercise due care in using generative AI, since it may not be accurate. As a metaphor, AI should be treated as a very smart, but inexperienced intern; everything it does must be checked. AI created a Matrix in a fraction of the time and is an excellent starting point for further discussions and deliberations.

It is also interesting to note that the platform separated Haddon’s original “Environmental Factors” column into two separate ones: physical and social/organizational; this represents the utility of this tool and why it can be so useful.

Figure 2. Haddon Matrix (AI Generated) for Roof Fall

Phase	Host (Worker)	Agent/Equipment (Roof Opening / Fall Hazard)	Physical Environment	Social / Organizational Environment
Pre-Event (Prevention)	• Fall protection training • Hazard awareness (recognizing openings) • Proper use of PPE (harness, lanyard) • Fitness for duty (no fatigue, impairment)	• Guardrails installed around openings • Secure covers over openings (labeled, load-rated) • Use of fall arrest systems • Warning lines or barriers	• Clearly marked openings (paint, signage) • Adequate lighting • Stable walking/working surfaces • Weather controls (ice, rain mitigation)	• Safety policies and procedures • OSHA-compliant fall protection program • Job hazard analysis (JHA) • Supervision and enforcement • Safety culture and communication
Event (During Fall)	• Proper use of personal fall arrest systems (PFAS) • Correct body positioning if fall occurs	• Fall arrest system activates (anchor, lifeline, harness) • Guardrails or covers fail or partially mitigate fall	• Presence of lower-level obstructions minimized • Safety nets below work area	• Emergency response readiness on site • Co-worker awareness and rapid response
Post-Event (Injury Mitigation & Recovery)	• Worker trained in self-rescue (if suspended) • Physical condition affects survivability	• Rescue equipment available (ladders, lifts) • Harness suspension trauma relief straps	• Access routes for rescue teams • Emergency medical access • Site layout allows quick evacuation	• Emergency action plan (EAP) • First aid and trained responders • Incident reporting and investigation • Post-incident review and corrective actions

Conclusion

As safety professionals, we have an obligation to think creatively and observe behaviors and attitudes, as well as mechanical or technical aspects, that could cause harm. Using the Haddon Matrix process — whether on paper or with technology — is an excellent way to start the process of managing risk, protecting people and businesses, and reducing damage, injuries, and deaths to employees, contractors, visitors, and the public.