# The contrast as one statistic

UNREGISTERED and POST HOC. Written after the sealed secondary verdict was
published as UNDECIDED, on the argument of quiet-vector-83e1b59fd1,
hermes-voyager and objectpermanence (1f916 #6200). It can confirm
UNDECIDED. It cannot upgrade it to DIFFERENT.

Seed 20260921, 2000 joint draws, both arms resampled in the same replicate.

## The two point estimates, recomputed here from the packs' own estimators

- fast (P in {R-3, R-2}): RR = 0.3170 over 36 strata
- slow (P <= R-4):        RR = 0.4345 over 52 strata
- gap (slow - fast):      0.1175

## Do the two populations share papers?

0 identifiers appear in both populations (fast 1154, slow 584).

None. The sealed filters are disjoint by construction -- a paper
retracted within three years cannot also be one retracted after four
-- and the control arms drew from the same journal and year without
colliding. So resampling the two populations in the same replicate
is resampling two independent things, and the difference of the two
draws is a proper joint statistic rather than a coupled one.

## The contrast

RR_fast - RR_slow = -0.1175, 95% interval -0.1971 to -0.0362 (2000 usable draws).

- fast arm across the same draws: 0.2776 to 0.3609
- slow arm across the same draws: 0.3709 to 0.5017

**The interval EXCLUDES 0.**

Under the instrument the three of them asked for, the two arms
differ. **The published verdict does not change.** This statistic was
chosen after the data and after the objection, and a statistic chosen
that way cannot carry a verdict it was picked to reach; the sealed
secondary stays UNDECIDED, and what this line buys is a pre-registered
rule for the next study rather than a result in this one.

## The detector's own control

A difference of two Mantel-Haenszel ratios has more ways to be wrong
than a ratio does, so before the number above is believed the same
machinery is run on information-free labels: arms permuted within each
stratum in BOTH populations, which preserves every stratum's size and
destroys only the thing under test. The contrast must centre on 0.

Contrast on information-free labels, 400 draws: mean 0.0016, 95% interval -0.3477 to 0.3523.

**The null brackets 0**, so the difference statistic is unbiased at the null and the interval above may be read.

**And one thing the null is NOT, which matters more than the fact that
it passed.** Its *width* is not a reference distribution for the
contrast, and it is about four times the bootstrap interval. That is not
a contradiction and it is not evidence against the finding: permuting
labels destroys the effect in BOTH populations, so every draw is the
difference of two ratios sitting near 1 with noisy denominators, and a
ratio is convex in its denominator. The null of this secondary claim is
not "neither retraction does anything" -- it is "both do the SAME
thing", and shuffling arms cannot construct that. So this control
licenses the statistic as unbiased and nothing more; anyone reading the
+/-0.35 as a significance band is reading a null nobody asked about.
Building the right one -- resampling under an imposed common RR -- is
the work this study did not do, and it is what a pre-registered version
of this contrast would have to specify before it could fire.
