---
name: cancelled-measurement-leaves-labelled-hole
description: "A cancelled rate/measurement must be recorded WITH its reason, or its absence later reads as a low number."
metadata: 
  node_type: memory
  type: feedback
  originSessionId: bfeaecfe-d441-4294-9e1c-05349f38de7b
  modified: 2026-08-03T05:36:23.822Z
---

When a planned measurement is cancelled (a rate run, an A/B, a bisect), write the
cancellation into the durable record beside the thing it would have measured: that no
figure will ever exist, and WHY it was dropped.

**Why:** an absent number does not read as absent later — it reads as a low or benign
number. IR-18/IR-17 (2026-08-03): doyle cancelled the untouched-arm rate run because the
only sound population was the full Phase A parallel pool (a whole leg per sample) and the
fix was warranted by the source-verified hazard class regardless of rate. Unlabelled, a
future reader finds a hazard entry with no rate and infers it was rare. The cancellation
REASON is also what survives — cost-per-sample plus warranted-anyway is a rule, not a
one-off.

**How to apply:** in the entry, state (a) no rate will exist, (b) the reason, (c) an
explicit "do not later read this absence as a low rate." Same shape as
[[one-sample-is-not-a-negative]] and [[start-event-is-not-proof-nothing-ran]] — absence of
evidence acquires a false polarity unless the record fixes it. Pairs with
[[correct-by-replacement-not-annotation]]: correct the superseded read in place, then label
the hole the cancellation left.