Knowing how to calculate LTIFR and other safety indicators is an important skill if you work in the health and safety field. Although these indicators do not reveal much useful information, managers love them and insist on knowing what they are. They will use them to measure internal health and safety performance and to compare their company’s performance with that of other companies. These are not difficult to calculate and this can be made even easier if you use a spreadsheet.
Health and Safety Indicators
In general terms, common health and safety indicators can be divided into two: frequency rates and incidence rates. So what is the difference?
A frequency rate is an expression of how many events occurred during a given time period for a standardized number of hours worked. An incidence rate is the number of events that occurred during a given period for a standardized number of employees (usually less than the standardized number of hours). For example, an LTIFR, which stands for Lost Time Injury Frequency Rate, is the number of Lost Time Injuries (LTI) that occurred during a time period per 1,000,000 or 100,000 or some other number of hours worked in that period. This could be more than a month, a quarter, or a year, depending on your company’s reporting requirements. To convert this to an incidence rate, simply substitute the number of employees for the number of hours.
Many things are presented this way. In addition to lost time injuries, there are medically treated injuries (MTIs), others are significant injuries that are often classified as LTIs plus MTIs. A slight variation is the severity rate, which is typically a measure of the amount of time lost due to a work-related injury using some standardized figure used to indicate the severity of injuries.
Calculation of frequency rates
The formula for calculating these indicators is really very simple. Let’s say we want the number of lost-time injuries per 1,000,000 hours worked in the last year. You need to get two pieces of information: the number of LTIs that occurred in the last year and the number of hours worked in the last year. You could probably get the LTI amount from your workers’ compensation claims administrator or insurance company, and your payroll section should be able to tell you the number of hours worked during the period.
Multiply the LTI number by 1,000,000 and divide the result by the number of hours worked and there you have it: the LTIFR. To show it using numbers. Let’s say there were 7 LTIs in the last year and 2,451,679 hours worked. So 7 X 1,000,000 = 7,000,000. Divide that by 2,451,679 and you get 2.86.
What does that mean? It means that this company experienced 2.86 LTIs per 1,000,000 hours worked during the past year.
Calculation of incidence rates
Now, to calculate the LTIIR (Lost Time Injury Incidence Rate), which is the number of LTIs per 100 (or whatever number you want) employees, we simply substitute the number of employees for the number of hours and multiply the number of LTI for standardization. factor that is 100.
So let’s say this mythical business had 791 employees, we get 7 X 100 = 700. Divide this by the number of employees, 791, and we get 0.88. So for every 100 employees, this company experienced 0.88 LTI.
Calculation of severity rates
Finally the severity index. Depending on how you phrase it, you will need at least the above information and the number of work days missed during the year. Let’s say it’s 73. Most of the time, the severity rate is expressed as an average by simply dividing the number of days lost by the number of LTIs. So using the numbers we have, we get 73 divided by 7, which is 10.43. In other words, on average each LTI will translate into 10.5 days off work. It can be converted to a frequency or incidence rate by multiplying the result by a standardization factor. This will, of course, increase the result, which is why you don’t see it very often. Who wants a severity rate of 104 days off per 100 LTIs?
So there you have it. It’s not very difficult, and if you know a little about spreadsheets, you can easily insert the formulas into specific cells to calculate these metrics automatically.
