Apr 25 2012

LTIFR – Measuring Achievement by Failure

LTIFRLook at almost any company’s annual report and you’ll find some comments about what the business is doing to improve their safety performance – usually measured by how many injuries they’ve had that year and more specifically how many of those injuries have required time off work for recovery. So, we get told what a good job they’re doing to prevent injuries and they measure they’re performance by how many times they’ve failed. Bizarre … definitely but not as bizarre as the wide-spread use of the Lost Time Injury Frequency Rate or LTIFR which is an almost universal statistic used to report on safety performance and comparing how one company or part of a company is performing in comparison with another.

What is the LTIFR?

The LTIFR is a measure of the how lost time injuries (LTI) occurred per so many hours worked. For example, a LTIFR of 3 may mean 3 LTIs for every million hours worked or it could be 10 000 or 50 000 hours. So what does that tell the reader or the business?

Think about it. If this years LTIFR is less than last year’s does this mean the company has a more effective safety program in place? Or, conversely, does a higher LTIFR indicate a less effective program? If one company has a LTIFR of 2.5 and another company a LTIFR of 5 does this mean that the latter company is less committed to safety or has a worse safety program?

What does the LTIFR Show?

Let’s break this down a little further. The almost universal definition of a LTI is a work related injury that results in the injured employee having at least one full shift off work – by definition this excludes the shift on which the injury happened. Converting this to a million hour LTIFR involves multiplying the number of LTIs by 1 000 000 and dividing the result by the number of hours worked. So the LTIFR is influenced not only by the number of LTIs that happened but also by the number of hours worked. So 2 companies with the same number of LTIs but substantially different hours will end up with totally different LTIFRs – the larger the number of hours the lower the LTIFR.

Have a look at the table below to see the calculation for different combination’s of hours and LTIs (hours across the top, LTIs on the left side):


100K 200K 300K 400K 500K 600K 700K 800K 900K 1000K
1 10 5 3.3 2.5 2 1.67 1.43 1.25 1.11 1
2 20 10 6.67 5 4 3.33 2.86 2.5 2.22 2


30 15 10 7.5 6 5 4.29 3.75 3.33 3


40 20 13.33 10 8 6.67 5.71 5 4.44 4


50 25 16.67 12.5 10 8.33 7.14 6.25 5.55 5

So if we return to our 2 companies, company A had a LTIFR of 2.5 and company B had 5. As you can see from the table, there are a number of combination’s that can produce these results and without knowing either the hours worked or the number of injuries, the LTIFR by itself doesn’t really say anything and reveals nothing about either company’s safety performance.

So, does the LTIFR reveal anything else? Not really. Since only one day off work is required for an injury to be classified as a LTI, the LTIFR doesn’t tell us how serious the injuries were or whether they resulted in a day, a week, a month or even a year off work. Since a fatality would not be considered a LTI they are similarly excluded from the calculation.

Why if the LTIFR So Commonly Used?

If the LTIFR reveals nothing of value why is it used so much? Quite simply because it’s easy. It’s easy to calculate and it’s easy to comprehend. As well, because it’s a frequency rate it provides an appearance of a standardised statistic that can be used to compare against other businesses or different parts of the same business. Generally, businesses that measure their safety performance using the LTIFR are businesses that have only a superficial commitment to improving safety performance. If they were serious they would quickly come to realise that this statistic provides them with nothing to check their safety performance and it would be quickly abandoned in favour of other more meaningful sources of information.

So the next time you hear someone bragging about their great safety performance because of their declining LTIFR think about what you’re being told and ask some questions to see what they’re doing, how they’re doing it and what (if any) other measurements they are using to assess performance.

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