Follow-up to Script 32 verdict C. Tests whether using the non-Firm-A
population (515 CPAs) as a "fully-replicated reference" recovers the
Paper A hand-signed signal through deviation analysis on Firm A.
Methodology:
* Robust 2D Gaussian fit (MCD, support_fraction=0.85) on
(cos_mean, dh_mean) of all_non_A CPAs. Reference center =
(cos=0.946, dh=8.29).
* Score Firm A CPAs by symmetric Mahalanobis distance, log-
likelihood, and directional cosine left-tail percentile.
* Cross-validate against Paper A's per-CPA hand_frac proxy
(signatures with cos<=0.95 OR dh>5).
Key findings:
* Directional metric (-cos_left_tail_pct) vs Paper A hand_frac:
Spearman rho = +0.744 (p < 1e-30) -- PAPER_C_STRONG.
* Symmetric Mahalanobis vs hand_frac: rho = -0.927 (p < 1e-73).
The negative sign is a feature, not a bug: Firm A bifurcates
into two anomaly directions from the non-Firm-A reference --
(a) ultra-replicated CPAs (cos>=0.985, dh~1) sitting beyond
the reference's high-cos tail, and (b) hand-signed CPAs
(cos~0.95, dh~6-7) sitting near or below the reference
center. Symmetric distance lumps both into a positive
magnitude; directional metrics distinguish them.
Implication: a "Paper C" reframing is statistically supported.
Use non-Firm-A as the replication reference, not Firm A as the
hand-signed anchor. This removes the "why is Firm A ground
truth?" reviewer attack and reveals the bifurcation structure
that Paper A's symmetric framing obscures.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
gbanyan
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