Bird – using the findings of Heinrich – commissioned his own study to evaluate how true this mathematical ratio was. Bird analysed close to two million accidents in almost 300 companies wherein he found a similar ratio existed – this materialised in the one we have come to know and love today – 1-10-30.
Based on his findings, Bird found that for every major injury (resulting in death, disability, medical complications or lost time) there were likely to be 10 report minor injuries which required only first aid. This gives us our first two numbers, 1 & 10.
The meaning of 30 lies in property damage accidents – with approximately thirty of these occurring per major injury.