A lagging indicator is a safety measure that counts harm after it has happened, such as recordable injuries, lost-time cases or fatalities, usually expressed as a rate per hours worked.
The standard US lagging indicator is the total recordable incident rate (TRIR), calculated the way BLS describes: recordable cases multiplied by 200,000 and divided by total hours worked, where 200,000 hours represents 100 full-time workers for a year. The DART rate uses the same formula for cases with days away, restricted work or job transfer.
Lagging indicators are needed for OSHA recordkeeping and for comparing a site with industry figures, but they have limits in forklift safety. Forklift fatalities and serious injuries are rare at any one site, so a site can go years with a clean injury rate while pedestrians and trucks still share uncontrolled crossings. A falling injury rate can also reflect under-reporting rather than lower risk. Pairing lagging rates with leading indicators and SIF classification gives a fuller picture. See leading vs lagging indicators.