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Changelog

v20 submission-clean — May 23, 2026 (Current — JLEO)

Title: Cheap Signals, Costly Proof: Award-Layer Evidence Triage in Cartel Enforcement. Canonical source: work/v20-editor/submission_clean/ (full integral copy of the v18-editor build, last recompiled 2026-05-25). Headline: an 83% bid-microdata reduction recovering 131 of 193 adjudicated cobidders; firm-level discrimination AUC 0.864 under temporal holdout (0.924 in-sample).

2026-05-25 refresh.

  • D1 horse-race re-run completed (scripts/36_gate_d1_harmonized.R, FL14 = tenders_count ≥ 14). Continuous AUC 0.939 [0.932, 0.946] dominates binary FL14 0.924 [0.921, 0.926]; DeLong Z = −4.38, p = 1.2 × 10⁻⁵ — direction preserved, marginally tighter than the earlier (superseded) Z = −4.30 / p ≈ 2 × 10⁻⁵ that had been computed under the > 14 (FL15) cut. AN-011, AN-015, robustness, and the award-bid-complementarity hypothesis page updated; the "pending the D1 re-run" caveats are retired.
  • Site PDFs (paper.pdf, online_appendix.pdf) re-synced to the 2026-05-25 v20-editor build (intro / validation / forensics / price-scope section edits + macro corrections).

New result:

  • AN-041 — volume-matched cobidder audit. The "strongest remaining within-data audit": matching cobidders to non-cobidder FLs on tenders_count (standardized difference 0.49 → 0.00, PS nearest-neighbour
  • CEM), the within-FL profile distinctness is not a volume artifact — product HHI (d +0.47), winner-pair spread (−0.56), and median gap-to-winner (−0.25) hold or strengthen. Honest casualty: the AN-031 bid-dispersion elevation collapses (+0.05, n.s.) and is dropped. Script scripts/74_volume_matched_cobidder_audit.R.
  • AN-042 — volume-matched timing audit (null). Candidate second bid-conduct channel: pregão bid timing (revision intensity, inter-bid interval, last-bid position, engagement span) under the same matching. No dimension survives (all Wilcoxon p ≥ 0.23). Bid-conduct distinctness stays single-channel (gap-to-winner). Script scripts/75_volume_matched_timing_audit.R.
  • H5 promoted Mixed → Partial (strongly supported) (structural scope). The structural distinctness survives volume matching (AN-041); AN-021 / AN-032 re-labelled as scope limits on a causal-mechanism reading the hypothesis does not assert. Incorporated into the manuscript: §5 body + Appendix D.3 ("Volume-Matched Within-FL Profile") + \valVM* macros. Confirmed still blocked by the non-BEC replication constraint.

JLEO editorial optimization pass (main paper 42 → 40 pp):

  • Abstract microcorrection: "exposure audits" → "validation audits"; "procurement overlap" → "opportunity-set exposure".
  • Section 4 sharpened: the Three-Classifier Timing Battery and the Universe-Anchored Scope Matrix moved from the main text to Appendix D (D.6 and D.4); the full sham-FL distribution and the price-coefficient-under-sham moved to D.2. Main text keeps the compact Validation Architecture threat table.
  • Section 7 re-downgraded to scope/limits: the monetary-scope range (R$ figures / % of spending) and the full selection/within-cell decomposition table moved to Appendix E (E.3 and E.2); a bounded one-sentence pointer remains in the main text.
  • Mechanism-identification language softened throughout to descriptive scope evidence that does not identify a mechanism, a causal price effect, overcharges, or damages.

Site reconciliation (this version):

Note: the v18 entry below describes the Three-Classifier Timing Battery and Universe-Anchored Scope Matrix as main-text Tables 3/4; this pass moved both into Appendix D.

v18 — May 2026 (JLEO submission-clean)

Full hypothesis audit + manuscript integration:

  • All 8 hypotheses graduated to Partial (strongly supported) except H2 (Confirmed by structural design). Promotion to Confirmed for H1/H3/H4/H6/H7/H8 requires non-BEC replication; see the COMPRASNET_PATH_TO_CONFIRMED.md planning memo in the repo root.
  • 14 new AN pages added (AN-025 through AN-038) documenting the formal sham permutation, cutoff sweep, subsample robustness, universe-anchored stratum scope matrix, standardized differences battery, three-classifier timing battery, firm/market persistence, bid-level behavioral profile, matched-heterogeneity audit, formal Imhof incremental DeLong, sequential gatekeeping envelope, full architecture cost-of-evidence matrix, K-fold CV precision stability, sign-reversal decomposition, and item-group cell audit.
  • 38 total AN pages now with figures (19 from existing R outputs, 4 from PDF→PNG conversion, 19 generated via new scripts/gen_an_figures.py).
  • Manuscript integration: surgical inserts in §4.2, §4.3, §5.4, §7.2 bring the new audit-chain numbers into prose. Two new tables (Table 3 Three-Classifier Timing Battery and Table 4 Universe-Anchored Stratum Scope Matrix) added to §4. tab:price_scope_submission extended with broad-sample and overlap-cell-unweighted rows showing the full three-spec progression. Paper now 39 pages.
  • values.tex extended with ~95 new macros for the new audits; 6 macro names corrected (LaTeX names cannot contain digits).
  • Site sections updated: advanced.md rewritten from stub to substantive methodological reference; results.md extended with formal sham permutation + three-classifier + scope matrix below- random subsection; robustness.md extended with placebo / scope matrix / CV stability / cutoff sweep / subsample / matched-het audit subsections; extensions.md extended with architecture cost-of-evidence matrix and three-classifier battery.

v5.1 --- April 2026

Referee-report edits (mr-frequent review):

  • Fixed combined AUC (0.502 → 0.608): included omitted z_skew component in combined score
  • Added "Why combination degrades" paragraph explaining AUC = 0.61 as empirical signature of Regime 2
  • "nearly orthogonal" → "largely non-overlapping" with theoretical ceiling note (corr/max ≈ 1/5)
  • "lower bound" → "conservative estimate" for cross-fit
  • Sample size clarified: body reports 1,654,447 (full sample) with footnote explaining 1,654,401 (prices) and 1,653,156 (non-FL firms)
  • AUC interpretation: added sentences clarifying AUC reflects high-participation proximity, not conditional discrimination
  • Measurement error: "Classical binary ME" → explicit assumption that FP > FN justifies attenuation direction
  • Bajari--Ye tender FE: acknowledged ambiguity ("suggestive but not definitive")
  • Fixed pre-existing LaTeX bug in tab_fl_crossfit.tex (unescaped underscores)
  • Updated MkDocs site to reflect all changes

v5 --- April 2026

JLE repositioning and institutional framing:

  • Repositioned for Journal of Law and Economics (institutional framing throughout)
  • Abstract leads with minimum-bidder rules giving cartels a reason to deploy cover bidders
  • Price range narrowed to 3.6--7.7% (cross-fit, OLS, matching), replacing 4--21% from v4
  • IV (19.4%) reframed as measurement-error diagnostic, not a primary estimate
  • Finding now Regime 2 (coordinated), not Regime 1 (complementary): \(\sigma_c / \sigma_g = 0.72\)
  • \(\gamma > 0\): strategic complementarity (more cover bidders in MORE competitive tenders)
  • Convite 3.8% vs pregao 9.3% --- larger where voluntary, signal dilution in convite
  • AUC = 0.94 against CADE convictions (primary validation)
  • Horse-race: correlation 0.06 with Imhof-style CV proxy; FL rises to 0.084 when CV added

New content:

  • Three new figures: corner solution, dispersion paradox, enforcement flowchart
  • Five JLE-relevant references added (Posner 1970, Caoui 2022, Ghosal & Sokol 2014, Harrington 2015, Baranek & Titl 2024)
  • Lei 14.133/2021 discussion with two testable predictions
  • Three-stage enforcement pathway (screen, triage, investigate)
  • Welfare reframed as cost-benefit of screening deployment
  • 12.5x gradient in oversight heterogeneity across PBU size quartiles
  • Minimum-bidder constraint variation: 7.6% voluntary premium vs. \(-0.160\) forced interaction
  • Five supporting diagnostics (M1--M5) with joint assessment
  • Non-claims paragraph and explicit limitations section

Tables and figures:

  • 35+ tables, 26 figures
  • ~56 pages, natbib/bibtex compilation

Pipeline:

  • 24 R scripts (22 numbered + figures_new.R + 00_setup.R), full pipeline in ~8 minutes
  • New scripts: 14_quality_checks.R through 22_threshold_heatmap.R plus figures_new.R

v4 --- March 2026

Manuscript:

  • Rewrote contributions paragraph with explicit H1/H2 structure and scope limitation
  • Softened over-claims throughout (9 instances: "establish" to "show", "confirming" to "indicating")
  • Expanded IV section: preferred spec declaration, lambda interpretation, LATE discussion
  • Bajari--Ye restructured around 3 sequential claims with magnitude hedge
  • DiD shrunk to 2 paragraphs (complementary, underpowered)
  • Mechanisms: added connective sentences and bridge paragraph
  • Heterogeneity: relabeled "high/low-suspicion" to "concentrated/competitive-market FL"
  • Added robustness roadmap paragraph (6 groups)
  • Added implementation blueprint (Flag, Triage, Investigate, Monitor)
  • Added enforcement integration and legal boundary sentences
  • Abstract trimmed to 136 words with policy contribution sentence
  • Broader implications paragraph added to conclusion
  • Float numbering fixed: appendix counters reset (A.1, B.1, etc.)
  • Added missing cross-references for 3 main-body floats

Tables and figures:

  • 35 tables (12 main body, 23 appendix)
  • 14 figures (6 main body, 8 appendix)
  • 59 pages, 0 errors, 0 undefined references

Pipeline:

  • 13 R scripts, full pipeline in ~8 minutes
  • New tables: IV balance, IV Panel C, Bajari--Ye tender FE, network interactions, homogeneous CV, welfare bounds (updated)

v3 --- February 2026

  • CADE validation section with CNPJ enrichment (3 FL firms matched)
  • Network-split IV regressions
  • Bajari--Ye tender fixed effects specification
  • Homogeneous sub-samples via price-CV approach
  • Welfare analysis with cross-fit bounds
  • Staggered DiD with MDE and Rambachan--Roth sensitivity

v2 --- January 2026

  • Bajari--Ye exchangeability and conditional independence tests
  • Network-based FL classification (winner HHI, repeat partners)
  • Regime test: complementary vs. coordinated cover bidding
  • Sensitivity analysis (Cinelli & Hazlett, 2020)
  • Matching estimators (CEM and IPW)
  • Year-by-year coefficient stability

v1 --- December 2025

  • Initial manuscript with OLS and IV regressions
  • FL definition (always-losers + IQR threshold)
  • Leave-one-out instrumental variable
  • 18 tables, 6 figures
  • Threshold sensitivity and cross-fitting robustness