Soccer Closing-Odds Favorite Bias
Closing-odds favorite bias
Inconclusive — PF 1.06 across 3,499 bets fell to 1.02 on the chronological holdout. The confidence interval includes zero and the result depends on obtaining the archived best quote.
- Category
- Sports betting
- Window
- 2019-08-10 → 2025-05-25
- Instruments
- European soccer 1X2
- Timeframe
- Pre-match closing odds
- Tested
- 2025-05-25
Measured equity history
Recorded directly from the chronological test ledger.
Shown in the backtest's native equity or cumulative P&L units. It is not scaled to an investment amount because the published artifact does not provide a defensible capital denominator.
How it works
BackfillingThe bet
What market behavior this strategy is wagering on.
Plain-English explainer is backfilling — check back tomorrow. We publish the explanation only once it's written and reviewed, never auto-filled.
How it decides
What makes it enter, size, and exit a position.
Plain-English explainer is backfilling — check back tomorrow. We publish the explanation only once it's written and reviewed, never auto-filled.
How it can break
The regimes and failure modes that turn the edge negative.
Plain-English explainer is backfilling — check back tomorrow. We publish the explanation only once it's written and reviewed, never auto-filled.
Gate scorecard — 2 / 5
auto-imported from results.json| # | Gate | Result | Pass |
|---|---|---|---|
| 01 | Minimum sample | n=3499 | ✓ |
| 02 | Profit factor ≥ 1.20 | PF=1.062 | ✗ |
| 04 | Max drawdown ≤ 12% | Max DD=-29.4% | ✗ |
| 06 | Bootstrap LB Sharpe > 0 | 95% mean-PnL CI=[-0.0033666761931980572, 0.04927979422692197] | ✗ |
| 11 | Walk-forward OOS ≥ 0.9× IS | Holdout ROI=0.74% | ✓ |
VERDICT: INCONCLUSIVE
The screen found a small positive result, but not a validated edge. Betting the shortest consensus-priced outcome when average closing odds were 1.35–1.80 produced PF 1.06 and +2.27% ROI across 3,499 matches. The untouched final 30% weakened to PF 1.02 and +0.74% ROI. The bootstrap confidence interval includes zero, max drawdown reached −29.4%, and a one-cent execution stress reduced PF to 1.03.
Rule
- Five major European soccer leagues; the requested archive covers 2015/16–2024/25, while complete average/best quote fields yielded eligible bets from 2019/20 onward.
- Select the home, draw, or away outcome with the lowest market-average closing odds.
- Enter only when those odds are between 1.35 and 1.80.
- Use the best recorded closing quote and risk 1% of current bankroll per bet.
- Keep the final 30% of qualifying matches as a chronological holdout.
Results
| Sample | Bets | Win rate | PF | ROI per bet |
|---|---|---|---|---|
| Full | 3,499 | 63.3% | 1.062 | +2.27% |
| Holdout | 1,050 | 62.3% | 1.020 | +0.74% |
This is closer to best-price shopping than a durable favorite anomaly. It is not strong enough for capital: the holdout edge is tiny, statistical uncertainty crosses zero, and the result depends on obtaining the archive’s best listed quote.
Data limits
Football-Data supplies closing snapshots, not time-stamped executable order books. Best-price availability, stake limits, voids, and account restrictions are not modeled. A credible next test needs forward quote capture from the Validated sportsbook router.
Frequently asked
Is Soccer Closing-Odds Favorite Bias profitable in 2026?
In this pre-registered backtest (2019-08-10 → 2025-05-25), Soccer Closing-Odds Favorite Bias returned a profit factor of 1.06 and passed 2/5 validation gates (placebo N/A). Verdict: INCONCLUSIVE. Every result is published, pass or fail.
Has Soccer Closing-Odds Favorite Bias been backtested honestly?
Yes — through The Validation Gauntlet, a pre-registered 11-gate framework (profit factor, deflated Sharpe, a random-permutation placebo, cost-stress and walk-forward) with the specification locked before any out-of-sample metric is computed.
Methodology: 11-gate validation — pre-registered spec, 5-gate battery, real market data. Full reproducible report: backtests/sports_favorite_bias/REPORT.md in the source repository.Author: Validated Research Team (Methodology v1.0 — 11-gate validation). Backtests are not investment advice.