The Haddon Matrix

Developed by William Haddon in 1970, his "phase-factor matrix" was developed to facilitate an assessment of the many things that contribute to injury occurrence and severity. Using this framework, one can then evaluate the relative importance of contributing factors and use that assessment to design prevention strategies.

Injury Definition

The term injury may be defined as damage to the body caused by exposure to environmental energy (kinetic, thermal, chemical, electrical, or radiation) in amounts that exceed the human body’s resilience. In epidemiological terms, the agent of injury is exposure to energy from an external source. However, poisoning, drowning, suffocation and exposure to extremes of ambient temperature are also considered injuries because normal body functions can be interrupted by these external exposures. To fit this definition of injury, the exposure should be acute – occurring in a fraction of a second, or at most within a few hours. Damage from longer exposures, such as to low levels of hazardous chemicals or ionizing radiation is usually classified as a disease.

The physical laws relevant to the behavior of energy have been known for hundreds of years. The laws of physics and knowledge of physiology, anatomy, and biomechanics may be used to predict the occurrence and severity of damage due to energy exposures.

Example: The Haddon Matrix For Motor Vehicle Occupant Safety

Factors → Phases ↓	Personal Factors	Equipment Factors	Physical Environmental Factors	Social Environmental Factors
Pre-event	Driver skills Driver attentiveness Sobriety	Maintenance of brakes, tires, etc. Windshield cleanliness	Roadway condition Darkness or glare	Attitudes to drink driving and speeding, Use of restraints
Event	Human tolerances to crash forces Wearing of seatbelts	Vehicle crashworthiness Energy absorbing design Airbags	Presence of fixed objects near roadway Unsecured objects within the vehicle	Enforcement of mandatory seatbelt and child restraint use
Post-event	Crash victims general health status	Petrol tanks designed to minimize likelihood of post-crash fire	Availability of effective emergency response	Public support for trauma care and rehabilitation

For More Information

• Haddon W Jr. (1968). "The changing approach to the epidemiology, prevention, and amelioration of trauma: the transition to approaches etiologically rather than descriptively based". Am. J. Public Health Nations Health 58 (8): 1431–1438. doi:10.2105/AJPH.58.8.1431. PMC 1228774. PMID 5691377.
• Haddon W Jr. (1974). "Editorial: Strategy in preventive medicine: passive vs. active approaches to reducing human wastage". J. Trauma 14 (4): 353–354. doi: 10.1097/00005373-197404000-00022. PMID 4819627.
• Baker SP, Haddon W Jr. (Fall 1974). "Reducing injuries and their results: the scientific approach". Milbank Mem. Fund Q. Health Soc. 52 (4): 377–389. doi:10.2307/3349509. JSTOR 3349509. PMID 4498200.
• Haddon W Jr. (December 1970). "On the escape of tigers: an ecologic note". Am. J. Public Health Nations Health 60 (12): 2229–2234. doi:10.2105/AJPH.60.12.2229-b. PMC 1349282. PMID 5530409.
• Haddon W Jr. (1980). "Advances in the epidemiology of injuries as a basis for public policy". Public Health Rep. 95 (5): 411–421. PMC 1422748. PMID 7422807.
• Christoffel, T, Gallagher SS (2006). Injury Prevention and Public Health Practical Knowledge, Skills and Strategies, 2nd Ed. Sudbury, Massachusetts: Jones and Bartlett Publishers; p. 157.