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Author	SHA1	Message	Date
gbanyan	51d15b32a5	Paper A v3.2: partner v4 feedback integration (threshold-independent benchmark validation) Partner v4 (signature_paper_draft_v4) proposed 3 substantive improvements; partner confirmed the 2013-2019 restriction was an error (sample stays 2013-2023). The remaining suggestions are adopted with our own data. ## New scripts - Script 22 (partner ranking): ranks all Big-4 auditor-years by mean max-cosine. Firm A occupies 95.9% of top-10% (base 27.8%), 3.5x concentration ratio. Stable across 2013-2023 (88-100% per year). - Script 23 (intra-report consistency): for each 2-signer report, classify both signatures and check agreement. Firm A agrees 89.9% vs 62-67% at other Big-4. 87.5% Firm A reports have BOTH signers non-hand-signed; only 4 reports (0.01%) both hand-signed. ## New methodology additions - III-G: explicit within-auditor-year no-mixing identification assumption (supported by Firm A interview evidence). - III-H: 4th Firm A validation line: threshold-independent evidence from partner ranking + intra-report consistency. ## New results section IV-H (threshold-independent validation) - IV-H.1: Firm A year-by-year cosine<0.95 rate. 2013-2019 mean=8.26%, 2020-2023 mean=6.96%, 2023 lowest (3.75%). Stability contradicts partner's hypothesis that 2020+ electronic systems increase heterogeneity -- data shows opposite (electronic systems more consistent than physical stamping). - IV-H.2: partner ranking top-K tables (pooled + year-by-year). - IV-H.3: intra-report consistency per-firm table. ## Renumbering - Section H (was Classification Results) -> I - Section I (was Ablation) -> J - Tables XIII-XVI new (yearly stability, top-K pooled, top-10% per-year, intra-report), XVII = classification (was XII), XVIII = ablation (was XIII). These threshold-independent analyses address the codex review concern about circular validation by providing benchmark evidence that does not depend on any threshold calibrated to Firm A itself. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>	2026-04-21 01:59:49 +08:00
gbanyan	9d19ca5a31	Paper A v3.1: apply codex peer-review fixes + add Scripts 20/21 Major fixes per codex (gpt-5.4) review: ## Structural fixes - Fixed three-method convergence overclaim: added Script 20 to run KDE antimode, BD/McCrary, and Beta mixture EM on accountant-level means. Accountant-level 1D convergence: KDE antimode=0.973, Beta-2=0.979, LogGMM-2=0.976 (within ~0.006). BD/McCrary finds no transition at accountant level (consistent with smooth clustering, not sharp discontinuity). - Disambiguated Method 1: KDE crossover (between two labeled distributions, used at signature all-pairs level) vs KDE antimode (single-distribution local minimum, used at accountant level). - Addressed Firm A circular validation: Script 21 adds CPA-level 70/30 held-out fold. Calibration thresholds derived from 70% only; heldout rates reported with Wilson 95% CIs (e.g. cos>0.95 heldout=93.61% [93.21%-93.98%]). - Fixed 139+32 vs 180: the split is 139/32 of 171 Firm A CPAs with >=10 signatures (9 CPAs excluded for insufficient sample). Reconciled across intro, results, discussion, conclusion. - Added document-level classification aggregation rule (worst-case signature label determines document label). ## Pixel-identity validation strengthened - Script 21: built ~50,000-pair inter-CPA random negative anchor (replaces the original n=35 same-CPA low-similarity negative which had untenable Wilson CIs). - Added Wilson 95% CI for every FAR in Table X. - Proper EER interpolation (FAR=FRR point) in Table X. - Softened "conservative recall" claim to "non-generalizable subset" language per codex feedback (byte-identical positives are a subset, not a representative positive class). - Added inter-CPA stats: mean=0.762, P95=0.884, P99=0.913. ## Terminology & sentence-level fixes - "statistically independent methods" -> "methodologically distinct methods" throughout (three diagnostics on the same sample are not independent). - "formal bimodality check" -> "unimodality test" (dip test tests H0 of unimodality; rejection is consistent with but not a direct test of bimodality). - "Firm A near-universally non-hand-signed" -> already corrected to "replication-dominated" in prior commit; this commit strengthens that framing with explicit held-out validation. - "discrete-behavior regimes" -> "clustered accountant-level heterogeneity" (BD/McCrary non-transition at accountant level rules out sharp discrete boundaries; the defensible claim is clustered-but-smooth). - Softened White 1982 quasi-MLE claim (no longer framed as a guarantee). - Fixed VLM 1.2% FP overclaim (now acknowledges the 1.2% could be VLM FP or YOLO FN). - Unified "310 byte-identical signatures" language across Abstract, Results, Discussion (previously alternated between pairs/signatures). - Defined min_dhash_independent explicitly in Section III-G. - Fixed table numbering (Table XI heldout added, classification moved to XII, ablation to XIII). - Explained 84,386 vs 85,042 gap (656 docs have only one signature, no pairwise stat). - Made Table IX explicitly a "consistency check" not "validation"; paired it with Table XI held-out rates as the genuine external check. - Defined 0.941 threshold (calibration-fold Firm A cosine P5). - Computed 0.945 Firm A rate exactly (94.52%) instead of interpolated. - Fixed Ref [24] Qwen2.5-VL to full IEEE format (arXiv:2502.13923). ## New artifacts - Script 20: accountant-level three-method threshold analysis - Script 21: expanded validation (inter-CPA anchor, held-out Firm A 70/30) - paper/codex_review_gpt54_v3.md: preserved review feedback Output: Paper_A_IEEE_Access_Draft_v3.docx (391 KB, rebuilt from v3.1 markdown sources). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>	2026-04-21 01:11:51 +08:00
gbanyan	9b11f03548	Paper A v3: full rewrite for IEEE Access with three-method convergence Major changes from v2: Terminology: - "digitally replicated" -> "non-hand-signed" throughout (per partner v3 feedback and to avoid implicit accusation) - "Firm A near-universal non-hand-signing" -> "replication-dominated" (per interview nuance: most but not all Firm A partners use replication) Target journal: IEEE TAI -> IEEE Access (per NCKU CSIE list) New methodological sections (III.G-III.L + IV.D-IV.G): - Three convergent threshold methods (KDE antimode + Hartigan dip test / Burgstahler-Dichev McCrary / EM-fitted Beta mixture + logit-GMM robustness check) - Explicit unit-of-analysis discussion (signature vs accountant) - Accountant-level 2D Gaussian mixture (BIC-best K=3 found empirically) - Pixel-identity validation anchor (no manual annotation needed) - Low-similarity negative anchor + Firm A replication-dominated anchor New empirical findings integrated: - Firm A signature cosine UNIMODAL (dip p=0.17) - long left tail = minority hand-signers - Full-sample cosine MULTIMODAL but not cleanly bimodal (BIC prefers 3-comp mixture) - signature-level is continuous quality spectrum - Accountant-level mixture trimodal (C1 Deloitte-heavy 139/141, C2 other Big-4, C3 smaller firms). 2-comp crossings cos=0.945, dh=8.10 - Pixel-identity anchor (310 pairs) gives perfect recall at all cosine thresholds - Firm A anchor rates: cos>0.95=92.5%, dual-rule cos>0.95 AND dh<=8=89.95% New discussion section V.B: "Continuous-quality spectrum vs discrete- behavior regimes" - the core interpretive contribution of v3. References added: Hartigan & Hartigan 1985, Burgstahler & Dichev 1997, McCrary 2008, Dempster-Laird-Rubin 1977, White 1982 (refs 37-41). export_v3.py builds Paper_A_IEEE_Access_Draft_v3.docx (462 KB, +40% vs v2 from expanded methodology + results sections). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>	2026-04-21 00:14:47 +08:00

Author

SHA1

Message

Date

gbanyan

51d15b32a5

Paper A v3.2: partner v4 feedback integration (threshold-independent benchmark validation)

Partner v4 (signature_paper_draft_v4) proposed 3 substantive improvements;
partner confirmed the 2013-2019 restriction was an error (sample stays
2013-2023). The remaining suggestions are adopted with our own data.

## New scripts
- Script 22 (partner ranking): ranks all Big-4 auditor-years by mean
  max-cosine. Firm A occupies 95.9% of top-10% (base 27.8%), 3.5x
  concentration ratio. Stable across 2013-2023 (88-100% per year).
- Script 23 (intra-report consistency): for each 2-signer report,
  classify both signatures and check agreement. Firm A agrees 89.9%
  vs 62-67% at other Big-4. 87.5% Firm A reports have BOTH signers
  non-hand-signed; only 4 reports (0.01%) both hand-signed.

## New methodology additions
- III-G: explicit within-auditor-year no-mixing identification
  assumption (supported by Firm A interview evidence).
- III-H: 4th Firm A validation line: threshold-independent evidence
  from partner ranking + intra-report consistency.

## New results section IV-H (threshold-independent validation)
- IV-H.1: Firm A year-by-year cosine<0.95 rate. 2013-2019 mean=8.26%,
  2020-2023 mean=6.96%, 2023 lowest (3.75%). Stability contradicts
  partner's hypothesis that 2020+ electronic systems increase
  heterogeneity -- data shows opposite (electronic systems more
  consistent than physical stamping).
- IV-H.2: partner ranking top-K tables (pooled + year-by-year).
- IV-H.3: intra-report consistency per-firm table.

## Renumbering
- Section H (was Classification Results) -> I
- Section I (was Ablation) -> J
- Tables XIII-XVI new (yearly stability, top-K pooled, top-10% per-year,
  intra-report), XVII = classification (was XII), XVIII = ablation
  (was XIII).

These threshold-independent analyses address the codex review concern
about circular validation by providing benchmark evidence that does not
depend on any threshold calibrated to Firm A itself.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-04-21 01:59:49 +08:00

gbanyan

9d19ca5a31

Paper A v3.1: apply codex peer-review fixes + add Scripts 20/21

Major fixes per codex (gpt-5.4) review:

## Structural fixes
- Fixed three-method convergence overclaim: added Script 20 to run KDE
  antimode, BD/McCrary, and Beta mixture EM on accountant-level means.
  Accountant-level 1D convergence: KDE antimode=0.973, Beta-2=0.979,
  LogGMM-2=0.976 (within ~0.006). BD/McCrary finds no transition at
  accountant level (consistent with smooth clustering, not sharp
  discontinuity).
- Disambiguated Method 1: KDE crossover (between two labeled distributions,
  used at signature all-pairs level) vs KDE antimode (single-distribution
  local minimum, used at accountant level).
- Addressed Firm A circular validation: Script 21 adds CPA-level 70/30
  held-out fold. Calibration thresholds derived from 70% only; heldout
  rates reported with Wilson 95% CIs (e.g. cos>0.95 heldout=93.61%
  [93.21%-93.98%]).
- Fixed 139+32 vs 180: the split is 139/32 of 171 Firm A CPAs with >=10
  signatures (9 CPAs excluded for insufficient sample). Reconciled across
  intro, results, discussion, conclusion.
- Added document-level classification aggregation rule (worst-case signature
  label determines document label).

## Pixel-identity validation strengthened
- Script 21: built ~50,000-pair inter-CPA random negative anchor (replaces
  the original n=35 same-CPA low-similarity negative which had untenable
  Wilson CIs).
- Added Wilson 95% CI for every FAR in Table X.
- Proper EER interpolation (FAR=FRR point) in Table X.
- Softened "conservative recall" claim to "non-generalizable subset"
  language per codex feedback (byte-identical positives are a subset, not
  a representative positive class).
- Added inter-CPA stats: mean=0.762, P95=0.884, P99=0.913.

## Terminology & sentence-level fixes
- "statistically independent methods" -> "methodologically distinct methods"
  throughout (three diagnostics on the same sample are not independent).
- "formal bimodality check" -> "unimodality test" (dip test tests H0 of
  unimodality; rejection is consistent with but not a direct test of
  bimodality).
- "Firm A near-universally non-hand-signed" -> already corrected to
  "replication-dominated" in prior commit; this commit strengthens that
  framing with explicit held-out validation.
- "discrete-behavior regimes" -> "clustered accountant-level heterogeneity"
  (BD/McCrary non-transition at accountant level rules out sharp discrete
  boundaries; the defensible claim is clustered-but-smooth).
- Softened White 1982 quasi-MLE claim (no longer framed as a guarantee).
- Fixed VLM 1.2% FP overclaim (now acknowledges the 1.2% could be VLM FP
  or YOLO FN).
- Unified "310 byte-identical signatures" language across Abstract,
  Results, Discussion (previously alternated between pairs/signatures).
- Defined min_dhash_independent explicitly in Section III-G.
- Fixed table numbering (Table XI heldout added, classification moved to
  XII, ablation to XIII).
- Explained 84,386 vs 85,042 gap (656 docs have only one signature, no
  pairwise stat).
- Made Table IX explicitly a "consistency check" not "validation"; paired
  it with Table XI held-out rates as the genuine external check.
- Defined 0.941 threshold (calibration-fold Firm A cosine P5).
- Computed 0.945 Firm A rate exactly (94.52%) instead of interpolated.
- Fixed Ref [24] Qwen2.5-VL to full IEEE format (arXiv:2502.13923).

## New artifacts
- Script 20: accountant-level three-method threshold analysis
- Script 21: expanded validation (inter-CPA anchor, held-out Firm A 70/30)
- paper/codex_review_gpt54_v3.md: preserved review feedback

Output: Paper_A_IEEE_Access_Draft_v3.docx (391 KB, rebuilt from v3.1
markdown sources).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-04-21 01:11:51 +08:00

gbanyan

9b11f03548

Paper A v3: full rewrite for IEEE Access with three-method convergence

Major changes from v2:

Terminology:
- "digitally replicated" -> "non-hand-signed" throughout (per partner v3
  feedback and to avoid implicit accusation)
- "Firm A near-universal non-hand-signing" -> "replication-dominated"
  (per interview nuance: most but not all Firm A partners use replication)

Target journal: IEEE TAI -> IEEE Access (per NCKU CSIE list)

New methodological sections (III.G-III.L + IV.D-IV.G):
- Three convergent threshold methods (KDE antimode + Hartigan dip test /
  Burgstahler-Dichev McCrary / EM-fitted Beta mixture + logit-GMM
  robustness check)
- Explicit unit-of-analysis discussion (signature vs accountant)
- Accountant-level 2D Gaussian mixture (BIC-best K=3 found empirically)
- Pixel-identity validation anchor (no manual annotation needed)
- Low-similarity negative anchor + Firm A replication-dominated anchor

New empirical findings integrated:
- Firm A signature cosine UNIMODAL (dip p=0.17) - long left tail = minority
  hand-signers
- Full-sample cosine MULTIMODAL but not cleanly bimodal (BIC prefers 3-comp
  mixture) - signature-level is continuous quality spectrum
- Accountant-level mixture trimodal (C1 Deloitte-heavy 139/141,
  C2 other Big-4, C3 smaller firms). 2-comp crossings cos=0.945, dh=8.10
- Pixel-identity anchor (310 pairs) gives perfect recall at all cosine
  thresholds
- Firm A anchor rates: cos>0.95=92.5%, dual-rule cos>0.95 AND dh<=8=89.95%

New discussion section V.B: "Continuous-quality spectrum vs discrete-
behavior regimes" - the core interpretive contribution of v3.

References added: Hartigan & Hartigan 1985, Burgstahler & Dichev 1997,
McCrary 2008, Dempster-Laird-Rubin 1977, White 1982 (refs 37-41).

export_v3.py builds Paper_A_IEEE_Access_Draft_v3.docx (462 KB, +40% vs v2
from expanded methodology + results sections).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

2026-04-21 00:14:47 +08:00

3 Commits