Python 56.2%
TeX 43.7%
1# REVIEW REPORT — editorial board (microstructure, prediction markets, financial economics, time-series econometrics), 2026-10-1723**WP 8 — Prediction Markets as Arrow–Debreu Securities: Evidence from Polymarket.** Version reviewed: 1.0 (May 2026, 58 p., never audited). Version produced: 1.1 (October 2026, 44 p.). Audit trail: `docs/CHANGELOG-REVISION.md`. Reference PDF: `docs/main_pre-revision-20261017.pdf`.45## 1. Overall diagnosis67The v1.0 manuscript had a sound idea — negative-risk groups on Polymarket are complete sets of state claims and their prices can be confronted with Arrow–Debreu pricing restrictions — but the execution did not support the text. The board found (a) a systematic one-day misalignment between Polymarket closes and U.S. market data and announcement dates; (b) a lag-selection procedure that minimised the p-value; (c) an abstract and conclusion describing analyses that were never run (Hasbrouck information shares, Treasury futures, "15–45 minutes" lead, Amihud ratios); (d) a robustness section reporting numerical results that no code produced; (e) factual errors about the data (federal funds rate 4.25–4.50 %, "post-election convergence to 0.58", 17 contracts "over 307 trading days"); (f) a Table 1 listing twenty unrelated markets; (g) a VAR table containing only intercepts; (h) event-study text whose contract labels did not match the table. The conceptual framing also conflated spanning (true by construction) with a test of completeness, and attributed a positive overround to the time value of money, which has the opposite sign.89The revised paper keeps the author's genuine contribution — the Arrow–Debreu lens on negative-risk groups, the two markets, the pricing and announcement questions — and rebuilds the empirical work from the raw snapshot with corrected calendars, honest inference, and a reconciliation appendix. Several v1.0 "findings" do not survive; the paper now says so.1011## 2. Section-by-section diagnosis1213**Abstract / Introduction (v1.0).** Strengths: clear motivation, correct identification of the neg-risk structure as the object of interest. Weaknesses: claims not supported by any analysis (information shares, Treasury futures, intraday lead, Amihud); "first formal test of completeness" when completeness is by construction; promotional tone ("comprehensive framework", "novel", "establish"). Rewritten around three results actually obtained; the misalignment and lag-search artefacts are disclosed.1415**Literature (v1.0, 8 subsections).** Serviceable but generic textbook summaries (GARCH history, Kyle, O'Hara) with no link to the hypotheses; key prediction-market references missing (Wolfers–Zitzewitz 2006 "Interpreting…", Ottaviani–Sørensen 2015, Page–Clemen 2013, Rothschild 2009, Rhode–Strumpf 2004); no monetary-policy-expectations literature (Kuttner, GSS, Bernanke–Kuttner, Piazzesi–Swanson, Nakamura–Steinsson); no discussion of why Hasbrouck shares require cointegration (Yan–Zivot, Baillie et al.); no Polymarket-specific work (Ng et al. 2025, Chernov et al. 2025, Reichenbach–Walther 2025); 8 bib entries never cited; bib errors. Rewritten as "Institutional Setting and Related Literature" with the neg-risk mechanics, UMA resolution, fee status, and five focused strands; 62 verified references.1617**Theory (v1.0).** Correct definitions, but the hypothesis "Σ ≈ 1 ⇒ completeness" is a category error; positivity is mechanically ensured by the price grid; "transaction costs and time value explain Σ > 1" is wrong in sign. Rewritten: spanning by construction; the testable content is the law of one price for the complete set with **executable, asymmetric bounds** e^{−rτ} − c ≤ Σ ≤ 1 + c derived from split/convert mechanics; E^Q[Δr] defined; three falsifiable hypotheses.1819**Data (v1.0).** Wrong frequency description (minute-level in README, daily in fact), wrong rate level, wrong day counts, "log returns" vs `pct_change` in code, calendar vs trading days, election "post-resolution" misreading. Rewritten with the alignment subsection, listing-day treatment, event dates and their mapping.2021**Methodology (v1.0).** Event study with K = 2–3 and 60-day estimation windows that excluded half the events; Granger lag "selected by AIC" but coded as min-p; HAR components mis-described; Amihud described but not computable. Rewritten; design choices justified; limitations of daily data stated.2223**Results (v1.0).** Table/text label mismatches; interpretation of γ₁ ("30 % more") mathematically wrong given α₁ = 0; "strong evidence" from an AIC gap with robust SE 0.37–0.72; Granger results artefactual; liquidity figure mislabelled ("Daily Trading Volume" panel was the price). Rewritten around Tables 3–7 and Figures 1–8; all numbers from `revision_stats.json`.2425**Robustness (v1.0).** Almost entirely unsupported (see CHANGELOG #11). Replaced by the election market as a second state space (with Σ over 17 contracts) and by executed sensitivity checks; a "Checks not performed" subsection lists honest recommendations.2627**Conclusion (v1.0).** Overstated ("the experiment is succeeding", "reliable sources of information", "rival established financial markets"). Rewritten; adds manipulation/oracle/wash-trading risks with documented episodes (2024 election whale; March 2025 UMA dispute) cited to platform documentation and press via footnote-level description, not as academic claims.2829## 3. Methodology verdicts (master prompt §3)3031| Point | Verdict |32|---|---|33| Specification justified | Now yes: LOP bounds from mechanics; variance-based announcement identification (Ederington–Lee) appropriate for martingale prices; Granger in differences on a common grid. |34| Estimation assumptions explicit | Yes (HAC lags, Brown–Forsythe centring, AIC on system, QML). |35| Variables correctly defined | Yes (Appendix B; code and text now agree: Δp in pp, ΔE^Q in bps, log changes in %). |36| Fixed effects | n/a. |37| Temporal dependence | HAC everywhere; AR(1)/ADF for Σ − 1; lag orders by IC. |38| Standard errors | HAC/QML; v1.0 used unadjusted F with searched lags. |39| Sample construction transparent | Yes: listing day, gaps (18 days), 13 of 14 releases, 110 trading days, 304 election days. |40| Robustness addresses genuine threats | Yes for what is feasible; the main threats that remain (intraday timing, executable quotes over time) are explicitly deferred. |41| Coefficient interpretation | Corrected (γ₁; overround sign; VR not "30 % more"). |42| Statistical vs economic significance | Overround significant (t = 3.8) but economically within spreads — stated. |43| Causal language | None; Granger results read as absence of daily predictability. |4445## 4. Literature (verified / added / removed)4647All 62 entries verified through Crossref (`api.crossref.org/works?query.bibliographic=…` or `/works/<DOI>`) or the publisher page (IJCB). 29 added, 11 removed, 23 DOIs added to existing entries, 2 entry types corrected. Full list with DOIs in CHANGELOG §3. Not added for lack of a verifiable record: Gjerstad (2005); Forsythe et al. (1992).4849## 5. Results: inconsistencies found and resolved5051Listed in CHANGELOG §1 (#2–#14). Reproduction check: v1.0's 1.0205 / 0.0527 / 0.570 are reproduced exactly when the listing day is included; v1.0's Granger statistics are reproduced by the min-p procedure on misaligned data (not re-run with the old labelling, but the mechanism is demonstrated: with correct alignment the same procedure gives p = 0.064 / 0.370 / 0.258).5253## 6. Recommended analyses NOT executed (data not available locally; no network calls to Polymarket made)54551. Intraday price histories (CLOB `fidelity=1` or `60`) around the 13 releases, compared with Treasury futures (ZN/ZF or fed funds futures) — the only way to assess price discovery across venues; daily data cannot.562. Fed funds futures / OIS-implied expected change for the June 2026 meeting vs E^Q[Δr] — measures the risk-premium wedge (Piazzesi–Swanson).573. Historical order books to test executable bounds day by day (the public API gives only the current book).584. Cross-section of FOMC neg-risk groups (Dec 2025, Jan/Mar 2026 closed markets exist in `FED_CLOSED_MARKETS`) — term structure of the overround vs depth; calibration of resolved markets.595. Within-group price discovery: Hasbrouck shares between the direct "No change" price and its synthetic counterpart 1 − Σ(other four), which are cointegrated by construction.606. Trade-level data to separate flow from information around the 2024 whale episode.6162## 7. Remaining limitations6364Two groups, daily frequency, 13 releases, 110 common trading days; last-price Σ vs executable quotes; one order-book snapshot; 3–4-hour residual window between closes; risk-neutral vs physical probabilities unidentified; fee status at the snapshot (metadata `fee: None`) may have changed since; UMA resolution risk unpriced; reported volumes possibly inflated.6566## 8. Publication maturity6768- **Status**: a coherent, honest, modest working paper. Contribution: executable no-arbitrage bounds for neg-risk groups, term structure of the overround, announcement-day behaviour of a Polymarket-implied FOMC expectation, and a methodological warning on blockchain time stamps and lag search.69- **Target journals**: *Journal of Prediction Markets* (fit, feasible); *Journal of Financial Markets* or *Finance Research Letters* (possible after extension 1–2 above); *JBF / Management Science* unlikely without intraday and futures data and a larger cross-section.70- **Rejection risks**: small sample and absence of a positive price-discovery result; descriptive nature of the pricing evidence (one order-book snapshot); daily frequency; reliance on one platform's reported prices. The reconciliation appendix is an asset for credibility but also signals that the earlier version circulated with errors — it should remain.71- **Verdict**: not yet submittable to a top-field journal; suitable as a UQO working paper and, with extension 1 (intraday + futures), a credible JFM/JPM submission.72