R-280: the band replaced by the test it was standing in for

MEASURABLE = [15,85] proxied for "can this fight move at all". The direct form,
in the units the guard already uses: the spread rate must stand clear of both
ends by more than its own noise. Deliberately blind to the gain -- admitting the
sizes where focus fire clears its noise would make the guard's claim true by
construction. Size is still picked on nearest-an-even-fight.

31 measurable became 38. the_arrears returns at 6.3, and switchboard arrives at
8.1 -- the second largest gain in the artifact, thrown away for being one point
past a round number. Four of the eight carry effects larger than most rows the
band already admitted.

Two of them do not clear their own noise: the_choir has 0.7 points of headroom
and used 0.2, the_stanchion has six and used 0.2. Above-noise falls 31/31 to
36/38 and the bestiary prints 36. That is two measurements reporting no
detectable effect, which the band suppressed by refusing to take them.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/REVIEW_LOG.md

@@ -6492,3 +6492,50 @@ unasked.
 
 **Nothing published quoted the lost row.** The bestiary prints the above-noise count from
 the artifact, so it moved 31 to 30 on its own and says nothing that is now false.
+
+## R-280 — the band replaced by the test it was standing in for
+
+`MEASURABLE = [15, 85]` was a proxy. The question it answered is *can this fight move at
+all* — a rate pinned at 0 or 100 cannot show an effect of any size — and it answered with
+two round numbers. R-279 found it excluding the_arrears by three tenths of a point while
+that row carried a gain of 6.2 at 2.4x its own noise.
+
+**The direct form, in the units this guard already uses:** a fight is measurable if its
+spread-fire rate stands clear of both ends by more than its own seed-to-seed noise.
+
+**It deliberately does not look at the gain.** Admitting the sizes where focus fire happens
+to clear its noise would make this guard's own claim true by construction, which is the
+worst thing a guard can be. Size is still chosen on nearest-an-even-fight, and admission is
+still decided without reference to the effect being measured. The order changed — the row
+is measured first and admitted second, because the noise the test needs is a product of the
+measurement rather than of the scan.
+
+**31 measurable became 38.** the_arrears is back at gain 6.3, and seven others arrive:
+
+| | n | spread | gain | noise |
+|---|---|---|---|---|
+| switchboard | 6 | 86.3% | **8.1** | 1.4 |
+| the_arrears | 2 | 14.7% | **6.3** | 1.5 |
+| nuckelavee | 2 | 8.2% | **5.9** | 0.5 |
+| hollow_man | 6 | 92.2% | **4.6** | 0.8 |
+| supporter | 2 | 4.5% | 2.6 | 0.8 |
+| hedley_kow | 6 | 97.7% | 1.6 | 0.6 |
+| the_stanchion | 2 | 6.0% | 0.2 | 0.9 |
+| the_choir | 6 | 99.3% | 0.2 | 0.4 |
+
+Four of the eight were carrying effects larger than most of the rows the band already
+admitted. **switchboard at 8.1 is the second largest gain in the artifact and the band was
+throwing it away**, because an 86.3% fight is one point past a round number.
+
+**And the honest part: the last two do not clear their own noise.** the_choir has 0.7 points
+of headroom at 99.3% and used 0.2 of it; the_stanchion has six points of room and used 0.2.
+The above-noise count falls 31 of 31 to 36 of 38, and the bestiary now prints 36. That is
+not a regression — it is two measurements saying *no detectable effect*, which is a result
+the band suppressed by refusing to take it. A guard that only records the cases where
+something happens is not measuring, it is confirming.
+
+**What is now weaker, and worth watching.** The hard claim — focus fire helps in every
+measurable pack — is satisfied by gains of 0.2, so it is a weaker sentence than it was when
+the band admitted only contested fights. If it should be a stronger claim, the place to
+strengthen it is the claim, not the admission rule; tightening admission to protect a claim
+is how the band got here.