Lost Time Injury Frequency RateLTIFR

The Lost Time Injury Frequency Rate is the metric the rest of the world uses where the US uses TRIR — lost-time injuries normalised to a fixed hours denominator so employers of different sizes can compare. The formula is the number of lost-time injuries multiplied by a million and divided by the hours worked, and it is the benchmarking currency in Australia, the UK, and global mining and construction, where a customer or a principal contractor asks for the LTIFR before they let a contractor on site. A lost-time injury is a work-related injury that keeps the worker off at least one full scheduled shift after the day of the incident, and the threshold is what makes the number comparable across employers.

The difference between LTIFR and the US TRIR is the denominator and, in practice, the population. TRIR normalises to 200,000 hours — 100 workers at 2,000 hours — and LTIFR to a million, so the two numbers are not directly comparable and a program that reports both has to label them clearly. The weakness of LTIFR is the same as every lagging indicator: it counts the failures that already happened, on a lag, and a small site can swing the number with a single event. The honest use is as the outcome the leading indicators — near-miss rate, overdue corrective actions, inspection closure — are trying to move. See LTIR, TRIR, and DART.