Changelog¶

v5.1 --- April 2026 (Current)¶

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

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:

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

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:

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)