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