What is a SIF precursor?

Why counting minor incidents does not save anyone

Heinrich’s safety triangle holds that a fixed ratio of minor incidents underlies each serious one, so driving down the minor ones drives down the serious ones. The modern re-analysis of that claim found it is only half true — and the half that is false is the dangerous half.

Minor-incident data predicts minor incidents. Fatalities have their own distinct precursors, and they are about energy: work at height, lifting operations, energised systems, mobile plant. A site can drive its cut-finger rate to zero and still kill someone, because nothing it did went anywhere near the crane.

What to look for instead

The test has two parts, and both must be true. Was high energy present — a fall from height, a suspended load, live electricity, a moving machine? And was a control absent, defeated, or failed?

If both, you have a SIF precursor, and it deserves a full investigation regardless of whether anyone was hurt. Treating it as a minor event because the outcome was minor is how an organisation banks a run of good luck and calls it a safety record.

The reporting consequence

This is why the severity ladder needs a rung for the no-injury high-potential event — the “dangerous occurrence” — and why it must not be quietly filed alongside first-aid cases.

It is also why sophisticated clients now ask for SIF-potential rates alongside TRIR and DART. A falling TRIR tells you about cut fingers. It tells you nothing about whether the next lift will kill somebody.

Terms

• Near Miss
• SIF Precursor