DIAG-7 · Diagnosis · Invariant — holds by construction, no expiry

A zero identifies nothing

The law

A zero reading assigns near-equal likelihood to no-demand, no-exposure, and event-dropping measurement failure; alone it identifies no cause. Silence becomes evidence of absence only after exposure and instrument health are independently verified, with strength scaling with expected volume.

Scope

Count/event metrics whose failure modes suppress rather than inflate.

What this licenses you to do

Before any verdict on a zero metric, confirm spend/impressions in the same window and a prior non-zero baseline from the same source; alert on worked-then-stopped, never on absolute zeros.

Evidence

Observed at scale in production health-monitoring systems: a detector tuned for sensitivity over precision can raise the overwhelming majority of its incidents as false positives, teaching operators to distrust and eventually ignore the entire alert class, the exact failure this law predicts.