A definition for an accidents is: “…an unexpected event that may result in property damage, and does result in an injury or illness to an employee.”

We say: “Ouch”, we hurt, gets infected or bleed.

Incidents are defined as: “… an unexpected event that may result in property damage, but does not result in an injury or illness”. Incidents are also called, “near misses, near hits, close calls” or “good catches.”

We say: “Whew, THAT was close!”

Both events are unplanned, both can present damage to places or things, but only accidents result in illness or injury to a person. Basically, by definition, all accidents are incidents, but not all incidents are accidents.

There is a proven statistical relationship between accident, incidents and unsafe actions. There are more incidents than accidents, and there are more unsafe acts than incidents. In 1931 Herbert W. Heimlich, a pioneering occupational health and safety researcher, suggested the following relationship: 1:30:300.

In the 1970s Frank E. Bird who worked for the Insurance Company of North America modified the ratio to 1:10: 30: 600. Bird analyzed more than 1.7 million accidents reported by 297 cooperating companies. These companies represented 21 different industrial groups, employing 1.7 million employees who worked over 3 billion hours during the exposure period analyzed. Bird, like Heinrich, claimed that the majority of accidents could be predicted and prevented by acting on minor incidents and the behavior of employees.

The safety pyramid has been called a cornerstone of health and safety for the last 80 or more years. Many safety systems include the premise that reporting and dealing with near miss incidents and their behavioral causes can nearly eliminate major accidents.

The ratio can be used as a guide for how many Unsafe Acts versus Near Misses versus Incidents and Accidents an organization should expect to get reported – if the reporting system is comprehensive and full proof.

In reality it does not matter what the exact ratio is, we can use the incidents and unsafe actions as cues or indicators for where accidents might happen, and we can use these cues to clean up our behavior in time. That is IF we monitor and document the incidents and unsafe actions. While an accident most likely will be discovered by management or colleagues, incidents and unsafe actions might not. Often it is associated with some shame or embarrassment, as most incidents happen when cutting corners, deviating from procedures or simply not considering the consequences of a certain act. For the system to work it must rest on trust and mutual respect. Punitive actions, repercussions, blame or ridiculing will be an immediate game stopper. Some organizations finds it natural and easy to abide by this, other organizations need a little help to get started on the right foot.

H. W Heinrich was born on October 6, 1886.
He was an Assistant Superintendent of the Engineering and Inspection Division of Travelers Insurance Company. He published his book Industrial Accident Prevention, A Scientific Approach in 1931. One empirical finding from his 1931 book became known as Heinrich’s Law: that in a workplace, for every accident that causes a major injury, there are 29 accidents that cause minor injuries and 300 accidents that cause no injuries.


Whenever we do a root cause analysis, it is because something already went wrong. An accident or incident occurred. This is NOT the ideal way to drive an institution forward in a safe and secure manner; however, there can be good lessons to learn from reflection.

Looking through the rear view mirror.