Single consolidated draft of Section III sub-sections G through L,
replacing the v3.20.0 §III-G..L block with the Big-4 reframe.
Sub-sections (note: G/H/I/J/K/L written together to keep cross-
references coherent; user originally requested G/I/J/L only but
H rewrite and new K were required for cohesion):
G Unit of Analysis and Scope
-- accountant unit defined; Big-4 scope justified by
within-pool homogeneity, dip-test multimodality,
LOOO feasibility.
H Reference Populations
-- Firm A pivots from "calibration anchor" to "templated-end
case study"; non-Big-4 added as reverse-anchor reference.
I Distributional Characterisation
-- dip-test multimodality at Big-4 level (p < 1e-4 both axes);
BD/McCrary null as honest density-smoothness diagnostic.
J Mixture Model and Operational Threshold Derivation
-- K=2 vs K=3 fits reported; K=3 selected with rationale
deferred to §III-K LOOO evidence.
K Convergent Validation (NEW in v4.0)
-- three-lens Spearman convergence (rho >= 0.879);
per-signature K=3 fit (kappa = 0.870 vs per-CPA);
K=2 LOOO UNSTABLE / K=3 LOOO PARTIAL;
pixel-identity FAR 0% on 262 ground-truth signatures.
L Per-Document Classification
-- inherits v3.x five-way box rule for continuity;
K=3 alternative output documented.
Includes: cross-reference index, script-to-section evidence map
(linking each empirical claim to the spike Script 32-40 commit),
and 5 open questions flagged at the end for partner / reviewer
review of this draft.
Output: paper/v4/paper_a_methodology_v4_section_iii.md (single
file replacing the v3.20.0 §III-G..L block on this branch only;
v3.20.0 paper/paper_a_methodology_v3.md left untouched).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
