Dear Friends,
Simply stated your answer is noted below.
The injury frequency rates and severity rates are based on standard formulas set forth in ANSI Z 16.1. It specifies to use 1 million. We are just following it.
However I will not be happy with the above answer.
Explanation follows as below:-
Accident statistics should be comparable not only from year to year but also from industry to industry, region to region and, so far as practicable, country to country.
Accident statistics should be compiled on the basis of uniform definition of industrial accidents, framed for the purpose of prevention in general and the measurement of the importance of risk rates in particular. All accidents as thus defined should be reported and tabulated uniformly.
Frequency and severity should be compiled on the basis of uniform methods.
In place of 1 million one industry uses 100 and yet another industry uses 1000 and so on comparison between industries become impossible. Same way accident rates of two countries cannot be compared in the absence of uniformity in the formula.
Take the case of frequency rate. A rate of 20 means the disabling injuries were incurred at the rate of 20 for each 1,000,000 employee-hours worked. Occasionally, this interpretation may be difficult to understand, particularly when a company does not work 1,000,000 employee- hours during the period for which the rate is determined. However, as with a vehicle which can travel 60 kilometers per hour without being operated for an entire hour, a plant can have a rate of 20 injuries per 1,000,000 employee hours without actually working this number of hours.
If you are anyway involved in safety job, I am sure you will be able to get the doubts cleared with the above explanation.
Regards.
Kesava Pillai