Occupational Safety

The accident triangle explained

How to use this statistical tool to evaluate and improve occupational safety

7 minutes10/14/2021

How important are near-miss reports in occupational safety? As part of the Safety Management Trend Report 2021, we surveyed over 600 European specialists who deal with occupational health and safety daily – and 55% of them told us they regard near misses as an integral part of their set of KPIs. So, why is it so important to examine and engage with near misses? One clear illustration comes from the accident triangle, which depicts the relationship between accident severity and accident frequency. Sometimes known as the ‘safety triangle’, it visualizes the connections and normal distributions between fatal or severe accidents, minor accidents and near misses. It is an emphatic demonstration of how important a holistic approach to incident management can be. Why? Because the triangle shape is no coincidence: In most cases, a severe accident is just the tip of the iceberg. Looking at the full picture – that is, taking near misses and unsafe behavior into account – makes it possible to identify potential optimizations with far-reaching impacts. In this article, we’ll present the different accident triangles, explain how they can help you evaluate your accident KPIs more effectively, and show how you can define targets for better occupational safety.

Heinrich’s Law and the first accident triangle

When trying to understand how the accident triangle works and what exactly it represents, it can be useful to look back at its origins. In the 1930s, Herbert W. Heinrich conducted empirical research into occupational safety. In his analysis of 550,000 accidents in industrial settings in the USA, he identified an almost constant ratio of severe accidents, minor accidents and near misses. For every severe accident (with serious injury/fatality), there were 29 minor accidents and 300 near misses. This “1-29-300” ratio became known in academic journals as Heinrich’s Law, often depicted in the form of a triangle, which serves as a visual representation of the relative frequency of different accident types.

Updates for modern occupational safety

Occupational health and safety has evolved in every respect in the 90 years since Heinrich’s analysis – and so too has the accident triangle. One of the most noted additions came from Frank E. Bird, who added a fourth level to the triangle. Bird drew a distinction between fatal accidents and accidents with serious injury that result in lost working time to provide a more nuanced view of the severity of accidents at the tip of the triangle.

A further accident triangle was produced in 2003 on behalf of ConocoPhillips, with at-risk behavior added as an additional level at the base of the triangle.

How to apply the accident triangle ratio in practice

All three pyramids clearly demonstrate that reducing the frequency of minor accidents and near misses has a direct impact on the frequency of severe accidents. We can reduce the probability of a fatal or severe accident by examining figures from lower levels of the pyramid and using the insights gained to improve overall health and safety. This also underscores the importance of an active culture of failure and feedback. However, a low number of reported near misses does not necessarily indicate that few incidents have occurred. This is because, when we look at the statistical probability illustrated in the accident triangle, near misses and safety incidents are often simply not reported.

When deciding on a set of incident management KPIs, you should focus not only on severe accidents at the tip of the triangle but also the ratio of near misses and minor accidents in your company. To what extent do your company’s figures correspond to the accident triangle? What can you deduce from this? As a rule, the “flatter” the pyramid, the better. This means that reports and instances of unsafe behavior or near misses should be far more prevalent than serious or fatal accidents. Not only does this reflect very safe work processes, it is also indicative of a positive corporate culture.

Fresh perspectives on accidents and safety culture

A growing number of experts point to the safety triangle as evidence that the frequency of accidents and problematic situations is too simplistic and short-sighted as a safety measurement concept. Learn about more contemporary concepts and find out how you can establish an effective safety culture by combining traditional occupational safety with the following modern approaches:

  • Behavior Based Safety: Relying on teamwork, behavioral analysis and positive reinforcement to promote safe behavior.

  • Safety II: For every accident, there are 9,999 instances of safety behavior. Broaden your perspective and maximize safety by understanding what’s working well and supporting it.

  • Psychological Safety: A safety culture is the key to success. Motivate employees to report incidents and learning from mistakes together.

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Practical tips to increase near-miss reports

The accident triangle makes clear that safety managers rely on a large proportion of near misses being reported. However, in a recent LinkedIn survey, 56% of respondents said it was “very challenging” to get employees to report near misses openly. So, how can you overcome this challenge and obtain more data on near misses?

Make it as easy as possible for employees to submit reports. Remove hurdles and barriers by introducing simple, smooth technology that requires little to no training. You can then switch your focus to motivating your employees to use the new reporting system.

70% more near-miss reports

An app-assisted safety culture: By adopting digital tools, the Head of EHSQ at Veltec GmbH und Co. KG revolutionized the company’s occupational safety and used QR codes to generate more near-miss reports.


Find out more

You should provide personal incentives, but also make clear that you can only reach your target of more near-miss reports if everyone works together. This places a degree of pressure on more passive employees. Introduce rewards for employees who are particularly active in reporting their observations. Communicate using a number of different channels, such as email, your EHSQ software, noticeboards, your intranet and your company’s social networks. Make sure to communicate your messages consistently and put them on the agenda at relevant meetings.

When it comes to measuring the success of near-miss reporting, positive KPIs are generally more insightful than negative KPIs. For example, you might start by looking at the total number of near-miss reports per person per year. To begin with, a realistic target could be between 1 and 10 reports per person per year, depending on your company’s current safety culture.

If your initiative gathers pace and you receive a high number of reports, you need to be ready to respond quickly. You don’t necessarily need to be the person who provides feedback – but you need to ensure that feedback is being given. The easiest way to do this is to introduce an EHSQ software solution that automates both the feedback processes and follow-up tasks. If employees get involved and you achieve your targets together, it’s important to communicate and celebrate this. And finally, don’t forget to set the bar higher with more ambitious goals for the following year. After all, every finishing line is the start of a new race.

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