How to Calculate TRIFR, LTIFR and Other Health and Safety Indicators

How to Calculate TRIFR, LTIFR and Other Workplace Health and Safety Indicators

Many inquiries around the world have identified that a focus on personal injury rates is not a good indicator of the effectiveness of the health and safety management system, and on occasions, the focus on personal injury rate management can distract an organisation from managing the critical health and safety risks in its business. (see Deepwater Horizon)

I know you feel uncomfortable about the validity of measuring safety this way but you probably don’t have a choice? Imagine, just for a moment, what workplace safety would look like if you didn’t have to “prove” safety? This is probably one of the best safety articles ever published: PROVING SAFETY

Worth a read:

Everything is Green: The delusion of health and safety reporting

Great article by WHS Lawyer Greg Smith. First published here Quotes from the article: “How do you know the or managers are not just wandering around practicing random acts of safety, reinforcing unsafe behaviors and generally just pissing everybody off?” “What is your health and safety reporting really telling you, as opposed to the assumptions you choose to make?  …… Enjoy the rest of the article >>>>>


This is a dangerous illusion!!

Download our Free Injury Data and Statistics Spreadsheet

First some other articles which perhaps you should read before worrying about calculating LTIFR to 5 decimal places:

Courage to Challenge the Great TRIFR and LTI Delusion
Courage to Challenge the Great TRIFR and LTI Delusion It was Marx (The German Ideology) who said ‘as individuals express their life, so they are’. At the heart of this aphorism is the idea that what is normalized in a culture comprises what the culture is. One of the things that have become normalized in the culture …… Enjoy the rest of the article >>>>>

LTIFR – A Measure of Safety Performance?

Bizarre… definitely but not quite as bizarre as the wide spread use of the Lost Time Injury Frequency Rate or LTIFR which is an almost …

Difficulties Calculating LTIFR and Other Safety Indicators • Safety Risk

The difficulties often encountered when calculating LTIFR, TRIFR and other safety indicators are not with the calculation itself but with the data.

Lost Time Injury Frequency Rate • Safety Risk

The Lost Time Injury Frequency Rate is the principal measure of safety performance in many companies in Australia. The definition of

More on 10 Sure Fire Ways To Stuff Up a Safety Management System

Some safety people cheat like hell with their L.T.I.F.R. statistics encouraged by managers with an eye to keep their key performance indicators …– management-system/

How to Calculate LTIFR, TRIFR and Other Health and Safety Indicators

Knowing how to calculate TRIFR, LTIFR and other safety indicators is an important skill to have if you work in the health and safety field. Despite the fact that these indicators don’t reveal a great deal of useful information managers love them and will insist on knowing what they are. They will use them to measure internal health and safety performance and to compare you’re company’s performance with other companies. These are not difficult to calculate and this can be made even easier if you use a spread sheet.

LTIFR, TRIFR and other Health and Safety Indicators

Broadly speaking, common health and safety indicators can be divided into two – frequency rates and incidence rates. So what’s the difference?

A frequency rate is an expression of how many events happened over a given period of time by a standardised number of hours worked. An incidence rate is the number of events that happened over a given period time by a standardised number of employees (usually lower than the standardised 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 over a period time per 1 000 000 or 100 000 or some other number of hours worked in that period. This could be over a month or a quarter or a year depending on the reporting requirements of your business. To convert this to an incidence rate just substitute the number of employees for the number of hours.

What deoes Total Recordable Injury Frequency Rate (TRIFR) mean?

The total recordable injury frequency rate (TRIFR), or total recordable injury rate, is the number of fatalities, lost time injuries, alternate work, and other injuries requiring medical treatment per million hours worked.

The TRIFR is not to be confused with the similarly named LTIFR (lost time injury frequency rate). This latter metric is limited to the number of fatalities and lost time injuries per million employees and does not include other types of injuries.

A lot of things are presented in this manner. As well as lost time injuries there are Medical Treatment Injuries (MTI) another is significant injuries which are often categorized as LTIs plus MTIs. A slight variation is the severity rate which is usually a measure of the amount of time lost due to work related injury by some standardised figure that is used to indicate the severity of injuries.

Calculating Frequency Rates

The formula to calculate these indicators is really very simple. Let’s say we want the number of lost time injuries per 1 000 000 hours worked for the last year. You need to get two pieces of information – the number of TRI’s or LTIs that happened in the last year and the number of hours worked in the last year. You could probably get the number of LTIs from your workers compensation claims manager or insurance company and your payroll section should be able to tell you the number of hours worked over the period.

Multiply the number of LTIs 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. Say there were 7 LTIs in the past 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 – go on, grab your calculator and try for yourself.

What does that mean? It means that this business experienced 2.86 LTIs for every 1 000 000 hours worked over the past year.

Calculating Incidence Rates

Now, to calculate the LTIIR (Lost Time Injury Incidence Rate) which is the number of LTIs per 100 (or whatever figure you want) employees we just substitute the number of employees for the number of hours and multiply the number of LTIs by the standardizing factor which is 100.

So 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 firm experienced 0.88 LTIs.

Calculating Severity Rates

Finally the severity rate. Depending on how this is expressed you will need at least the information from above and the number of work days lost over the year. Say its 73. Most often the severity rate is expressed as an average by simply dividing the number of days lost by the number of LTIs. So, using the figures we have we get 73 divided by 7 which gives 10.43. That is, on average each LTI will result in 10.5 days off work. It can be converted to a frequency or incidence rate by multiplying the result by a standardizing factor. This, of course will 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. Not very hard and if you know even a little bit about spreadsheets you can easily insert the formulas into specific cells to calculate these indicators automatically.

This article explains more of the difficulties of calculating these injury rates:

Barry Spud

Barry Spud

Safety Crusader, Zero Harm Zealot, Compliance Controller and Global Pandemic Expert at Everything Safety
Barry Spud

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Barry Spud
What is a Safety Spud? Lets look at a few more spud head activities in risk and safety: 1. Coming on to site saying there is a safety issue when in fact there’s no such thing, it’s a political issue. 2. ‘Falling apart’ when people make choices that we think are stupid because they won’t do as we ‘tell’ them. Then we put on the angry face and think that overpowering others creates ownership. 3. Putting on the zero harm face, presenting statistics, knowing it has nothing to do with culture, risk or safety. 4. Putting on the superman (hazardman) suit and pretending to be the saviour of everything, this is good spud head cynic stuff. 5. Thinking that everyone else is a spud head except me. 6. Thinking there’s such a thing as ‘common’ sense and using such mythology to blame and label others. 7. Accepting safety policies and processes that dehumanize others. 8. Blaming, ego-seeking, grandstanding and territory protecting behind the mask of safety. 9. Thinking that risk and safety is simple when in fact it is a wicked problem. Denying complexity and putting your spud head in the sand. 10. Continually repeating the nonsense language and discourse of risk aversion that misdirect people about risk, safety, learning and imagination.

7 Replies to “How to Calculate TRIFR, LTIFR and Other Health and Safety Indicators”

  1. THIS INFO IS EXCELLENT…THE BEST AND SIMPLEST EXPLANATIONS I HAVE SEEN TO DATE….I FIRMLY BELIEVE IN THE K.I.S.S. PRINCIPLE SO WELL DONE TO THE AUTHOR(S). Please keep up the good work…you’re efforts have/are probably saved/saving a life somewhere…..

    1. Thanks but not so sure that safety people should think of themselves as lifesavers – that’s very different from telling someone to be careful and counting injuries……

  2. Dave, such language is counterproductive and discredits the activity of ‘helping’ others tackle risk. It sets up safety people as an elite class and this mitigates any chance of ‘helping’.

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