Lagging indicator

A lagging indicator measures what already happened — TRIR, LTIR, DART, the lost-time injury count, the fatality count, the citation count, the environmental release count. It is the metric a customer or a regulator asks for first because it is comparable across employers and because OSHA defines the numerator and the denominator. A lagging indicator is the bottom line of safety performance: it tells you whether harm happened, not whether it is about to.

The weakness of a lagging-only program is steering. A rate that counts recordable cases tells you the program failed after the failure, on a lag of weeks to months, and at a granularity where a single event swings the number at a small site. Programs that report only lagging indicators to leadership are flying blind between reviews, because the leading measures — near-miss rate, overdue corrective actions, inspection closure, training compliance — move before TRIR does. The honest use of a lagging indicator is as the outcome variable the leading indicators are trying to move, not as the day-to-day steering signal. See leading indicator, TRIR, and DART.