The Heinrich pyramid made waves in the EHS industry.


Let’s face it: the Heinrich pyramid is ubiquitous with workplace safety.

Since its creation in 1931 by William Heinrich, the Heinrich pyramid – also known as the Heinrich triangle – infiltrated health and safety procedures.

Now, all safety pros are familiar with the Heinrich pyramid. However, is it still the best way to tackle safety issues?

This blog post explains the Heinrich pyramid, and discusses whether it should still be used for workplace safety. Let’s go!

The history of the Heinrich pyramid

Heinrich’s pyramid was first released in his book Industrial Accident Prevention: A Scientific Approach.

Fundamentally, the pyramid claims that focussing on near misses and first aid incidents (bottom of the pyramid) leads to a reduction of fatalities and lost time injuries (top of the pyramid).

Heinrich wrote in Industrial Prevention: A Scientific Approach that the root of 88% of incidents is ‘unsafe acts of persons’. According to the pyramid, for every 300 accidents, 300 are no injury, 30 are minor injury and one is a major injury.

A diagram of the Heinrich pyramid.

Years after Heinrich put forward the pyramid, Frank E Bird developed it into the accident triangle commonly seen today.

In the 1970s, drawing data from the large insurance company he worked for, Bird concluded the relationship between workplace fatalities, serious injuries, minor accidents and near misses is ratio of 1:10:30:600.

In other words, there is one workplace fatality for every 600 minor incidents.

Why the Heinrich pyramid doesn’t work

Arguably, the conclusions drawn from the Heinrich pyramid are misleading. Furthermore, it amplifies the ideology of zero-harm and preventable injuries in the workplace.

For example, the Deepwater Horizon disaster. On the same day BP celebrated seven years without a lost time injury or fatality, the explosion killed 11 people, injured 16, and caused a 87 day oil spill.

A review by the Chemical Safety Board recommended focus on risk reduction policies and the human and organizational factors in workplace safety.

Furthermore, today’s EHS data proves that Heinrich’s pyramid theory does not exist. In fact, injuries and illnesses have decreased over the past five years, and fatalities have increased.

However, there is an alternative to the Heinrich pyramid: Social Amplification of Risk Framework (SARF).

What is Social Amplification of Risk Framework (SARF)?

Risk perception is complex, subjective and depends on multiple processes. SARF uses research from sociology, psychology and anthropology.

Essentially, SARF is an overview of risk event communication. It goes from the sender, through intermediate stations, and then finally to the receiver.

Interacting it hazards either amplifies or attenuates risk perception, in turn changing our behavioural response to risk.

Nevertheless, SARF is largely not utilised for risk assessment. In other words, the EHS industry does not consider risk in its full social complexity.

SARF vs Heinrich pyramid

The Heinrich pyramid focuses on event probability and their consequences. However, biases play a part in risk perception; most people understand risk, but many factors influence it.

The Heinrich pyramid encourages blames, punishment and dehumanization. The trajectory created by ‘all injuries are preventable’ results in near misses and mis-attributed first aid injuries.

❗ Alternative view: Are near misses important? →

On the other hand, SARF looks at risk communication. For example, a cut finger (the sender) is investigated with a root cause analysis (intermediate stations), resulting in new regulations (receiver).

Behavior based safety

The ripple effect of SARF is behaviour based safety, used to control and manage issues at the bottom of the pyramid.

Company management typically believe that identifying risks results in uniform behaviour from worker. But since risk is subjective, so are our reactions.

Safety metrics and data

Further evidence of the Heinrich pyramid’s failure is its approach to safety metrics. Typically, a company is considered safe if their safety metrics are at or below a certain level.

However, certain safety metrics can cause under-reporting. Plus, time is spent tracking, collecting and analyzing injury data rather than educating employees on safe work practices.

To clarify, as much as the Heinrich pyramid would like you to believe, numbers are not a true representation of a safe work culture.

The Heinrich pyramid blames workers for accidents. Framing workplace accidents as conscious behaviours from workers, like stupidity or laziness, the workplace safety culture is distorted. As a result, perfectionism and eliminating human error are strived after.

The good news

There are alternatives to the Heinrich pyramid. Importantly, recognise the impact of certain language on the safety culture.

Replacing the Heinrich pyramid with a learning environment moves towards critical thinking and self-reflection. Not easy task, but the Heinrich pyramid did not happen overnight either.

Are near misses important?

Get an alternative view on the value of encouraging near misses to be reported.

Why are near misses important? Read more →

Dave is a USA based student at The Centre for Leadership and Learning in Risk online program.

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