All posts

The Haddon matrix and drowning: twelve places to stop it

Injury scientists use one grid to find every point where an injury can be prevented. Here it is applied to toddlers and water at home, cell by cell.

In 2024–25, 15 Australian children under 5 drowned, and half of them drowned in home pools. Around 300 children a year are hospitalised after a drowning incident, 179 of them aged 1–4. Most of the advice parents hear is one line: watch them. Injury science offers a wider view, and it comes from the same thinking that runs workplace safety.

Injury is energy, not bad luck

In 1980 the injury scientist William Haddon Jr set out a simple idea. Injuries "cannot occur without the action of specific agents", Haddon wrote, and those agents are forms of energy: heat, motion, electricity, chemicals. The agent acts on a host (the person) in an environment. Injuries follow patterns, not luck, and every part of the agent, host or environment we can change is a place to break the pattern.

Workplace safety uses the same model. A mine's register of fatal hazards is a list of energies that can kill: moving vehicles, falling rock, electricity. The child injury tables on this site are the same list in a house.

The grid

Haddon laid the idea out as a matrix. The rows split time into three phases:

The columns are the host, the agent, the physical environment and the social environment (rules, laws, habits and norms). Carol Runyan's 1998 paper in Injury Prevention set out this layout and added a third dimension for choosing between options. Each of the twelve cells asks one question: what could we change here?

Drowning, cell by cell

Pre-event: stop the child reaching water

  1. Host. Toddlers are mobile, curious and drawn to water. Water familiarisation lessons build comfort, but no lesson makes a toddler drown-proof.
  2. Agent. Remove the water. Tip out baths, buckets, paddling pools and eskies straight after use.
  3. Physical environment. A four-sided fence with a self-closing, self-latching gate, and nothing climbable near it. Queensland's rules ask for a barrier at least 1200 mm high, gaps no wider than 100 mm, and gates that close and latch from every position.
  4. Social environment. A named adult watches the water at every gathering. Pool barrier laws, and inspectors to enforce them.

Event: limit the harm while the child is in water

  1. Host. A small child can't lift out of water and goes under silently.
  2. Agent. Less depth means a faster rescue. Shallow bath water, no standing water in the yard.
  3. Physical environment. An adult within arm's reach in the bath. A clear line of sight from the house to the pool.
  4. Social environment. A family rule: the bath never pauses for the phone or the door. Take the child with you.

Post-event: survive and recover

  1. Host. Time without oxygen decides the outcome.
  2. Agent. Get the child out of the water first.
  3. Physical environment. A CPR chart on the fence, a phone kept near the pool, the house number visible from the street for the ambulance.
  4. Social environment. Every carer, grandparents included, trained in child CPR and ready to call 000.

What the grid shows

Fill in all twelve cells and two things stand out.

First, "watch them" appears in only a few cells. The grid pushes us toward the physical environment, where controls work even when an adult is distracted. That matches the workplace hierarchy of controls, which ranks barriers above rules and supervision.

Second, the cells depend on each other. In the Queensland study of 46 children under 5 who drowned in home pools between 2005 and 2015, the most common way in was a gate propped open (28.3%), then a fence in disrepair (19.6%), then no fence at all (13.0%). The physical barrier existed in most of those homes. A social control, the habit of never propping the gate and checking it works, had failed. The same study reports earlier research finding four-sided fencing twice as effective as three-sided fencing.

Use it for any hazard

The grid works for scalds too. The host is a toddler's thin skin. The agent is heat: a hot drink, bath water, a kettle. The physical environment is the bench edge, the tablecloth and the bathroom tempering valve. The post-event cells hold first aid: 20 minutes of cool running water. Scalds cause 52% of child burns, and the typical child burned is 3.

Print a blank grid, pick one hazard, and fill it in as a family. Then choose the two or three cells that would do the most good, and do those this week.

The full guide, Run your home like a work site, has the matrix as a table, plus the risk matrix, critical controls and a printable checklist.

Sources