Haddon Matrix

The Haddon Matrix is a commonly used modeling tool in the safety/injury prevention field, developed by William Haddon in 1970. It consists of a grid with three rows and three or four columns.

The rows represent different phases of an accident or injury:

• Pre-event
• Event
• Post-event

The columns represent different influencing factors:

• Host
• Agent
• Environment (sometimes split into physical environment and social or socio-economic environment)

Here’s an example from Wikipedia on vehicle and road safety:

	Human Factors	Vehicles and Equipment Factors	Environmental Factors
Pre-crash	Information Attitudes Impairment Police	Road-worthiness Lighting Braking Speed management	Road design and road layout Speed limits Pedestrian facilities
Crash	Use of restraints Impairments	Occupant restraints Crash-protective design Other safety devices	Crash-protective roadside objects
Post-crash	First-aid skills Access to medics	Ease of access Fire risk	Rescue facilities Congestion

References

• Runyan CW, Using the Haddon matrix: introducing the third dimension. Injury Prevention, 1998;4:302-307.
• https://www.triaxiomsecurity.com/2020/09/29/what-is-the-haddon-matrix-and-how-does-it-relate-to-security/
• https://en.wikipedia.org/wiki/Haddon_Matrix