Which of the following are lagging indicators of process safety performance you might track?

• A. Frequency of near-miss reporting
• B. Number and severity of process safety incidents
• C. Maintenance backlog
• D. Hours of safety training completed

Answer: (B)

Lagging indicators are measures of what has already happened—outcomes that reflect past performance of the process safety system. The number and severity of process safety incidents fit this idea best because they are actual events that occurred, with real consequences, and they reveal how well protection layers worked in practice over a given period. They provide a clear record of past failures and their impact, which is exactly what lagging indicators are meant to capture.

By contrast, a higher frequency of near-miss reporting signals safety activity and culture that can help prevent incidents in the future, so it’s a leading indicator. A maintenance backlog points to potential risk building up and the likelihood of future failures, also considered leading risk indicators. Hours of safety training completed reflects the inputs put into readiness and capability, another leading indicator focused on preparation rather than actual outcomes.