Why a low injury rate can hide a workplace that's one bad day from disaster
Lag indicators measure what has already happened — injuries, incidents, lost-time rates. They matter, but they look backwards and can stay low through luck. Lead indicators measure the activity that prevents harm — inspections done, hazards reported, actions closed, training completed. A balanced safety scorecard uses both: lag to know your outcomes, and lead to know whether you're actually managing risk before something goes wrong.
They tell you what already went wrong.
Lagging indicators are outcome measures: numbers of injuries, lost-time injury rates, incidents, notifiable events, ACC claims and days lost. They are important — you have to know your outcomes — and they are easy to count. But they share two weaknesses: they only move after someone has been harmed, and in smaller workplaces the numbers are so low that a clean record may reflect good fortune rather than good management. Relying on lag indicators alone is like driving by looking only in the rear-view mirror.
They tell you whether you're doing the things that prevent harm.
Leading indicators measure the activity and conditions that drive safety, before an incident occurs. Because they track effort and engagement rather than outcomes, they give you early warning and something you can act on now. They are a little harder to choose well — a poor leading indicator just measures box-ticking — but a good set tells you whether your system is actually working, not just whether you've been lucky.
| Lagging (outcomes) | Leading (activity) |
|---|---|
| Number of injuries / LTIs | Hazards and near misses reported |
| Lost-time injury frequency rate | Inspections and audits completed on time |
| Notifiable events | Corrective actions closed within target |
| ACC claims and days lost | Training and inductions completed |
| Incidents by type | Toolbox talks held; worker participation |
These are common examples; choose indicators that fit your real risks. Source: established H&S practice.
Measure what matters, not just what's easy to count.
General information, not legal advice. Metrics support good management but don't replace your legal duties. Check current WorkSafe NZ guidance for requirements that apply to you.
Report lead and lag together, and act on the gap.
The most useful safety reporting puts leading and lagging indicators side by side, so governance and leadership can see both the outcomes and the effort behind them. If lag is good but lead is weak, treat it as a warning, not a victory. If lead activity is strong and outcomes are improving, you have evidence your system is genuinely working. Review the measures periodically and drop any that have stopped telling you something useful.
Get a system that tracks the activity behind your outcomes. Book a demo and we'll show you how it works — free 30-day trial included.
Lagging indicators measure outcomes that have already happened, such as injuries and lost-time rates. Leading indicators measure the preventive activity that reduces risk before harm occurs, such as hazards reported, inspections completed and actions closed.
Because it looks backwards and can stay low through luck, especially in smaller workplaces with few incidents. A clean record might reflect good management — or simply that nothing has gone wrong yet. Leading indicators show whether you're actually managing risk.
Hazards and near misses reported, inspections and audits completed on time, corrective actions closed within target, training and inductions completed, and toolbox talks held with good participation — chosen to match your real risks.
Keep the set small and meaningful. A handful of indicators tied to your most serious risks, reviewed regularly, is far more useful than a large dashboard that nobody reads or acts on.
