A leading indicator is a measure of preventive activity or control performance used to help identify safety improvements before harm occurs. Examples include the timely completion of corrective actions, the quality of inspections, and verification that critical controls are functioning. Leading safety indicators is an alternative name for this concept.
An effective indicator has a defined scope, a consistent measurement method, and an action it can inform. Exposure and near-miss information can support forward-looking review, but counts also depend on reporting participation and detection coverage. A rise in reported hazards may reflect better reporting, so the measure should be interpreted with its collection method and alongside lagging outcomes.