Market bias report
Favourite-longshot bias in football odds
Blindly backing every price in a bucket is not a betting system. It is a diagnostic. This report checks where the historical market has punished long 1X2 selections, draws and totals using imported Football-Data history at recorded maximum prices.
What The Report Says
- Long 1X2 prices are dangerous. The bigger away-win and draw prices carry the clearest negative bias.
- Away wins need a stronger edge threshold than home wins because the poor buckets are wide and persistent.
- Over/under 2.5 behaves more cleanly than 1X2, which is why the current public automation is totals-first.
- Asian handicap is the next serious research lane because it gives a cleaner two-way expression of team-strength, injury and motivation signals.
- A rough patch from a strong-name side is not a longshot catalyst by itself. The model needs systemic evidence or news confirmation before fading them.
Longshot Catalyst Gate
A long draw or away outsider now needs a named reason beyond the screen price. Acceptable catalysts include verified team-news shocks, manager disruption, fixture congestion, rotation risk, market movement from the opener, or repeated underlying decline across several matches.
- Price gap alone: reject.
- Strong team in a short rough patch: reject.
- Weak favourite plus confirmed injury cluster or major market move: research-only candidate.
- Favourite vulnerability without a clean longshot catalyst: express through Asian handicap, draw-no-bet or totals instead.
1X2
ROI below is from backing every selection in each bucket at the recorded maximum price.
| Selection | Odds bucket | Bets | Strike | Avg odds | ROI |
|---|---|---|---|---|---|
| AWAY_WIN | <1.50 | 820 | 74.0% | 1.36 | 0.0% |
| AWAY_WIN | 1.50-1.99 | 2,665 | 57.1% | 1.77 | 0.7% |
| AWAY_WIN | 2.00-2.99 | 10,459 | 40.3% | 2.52 | 0.3% |
| AWAY_WIN | 3.00-3.99 | 9,783 | 27.8% | 3.43 | -5.1% |
| AWAY_WIN | 4.00-5.99 | 8,303 | 20.3% | 4.73 | -5.2% |
| AWAY_WIN | 6.00+ | 5,180 | 11.4% | 9.55 | -6.7% |
| DRAW | 2.00-2.99 | 322 | 34.5% | 2.91 | -0.2% |
| DRAW | 3.00-3.99 | 27,016 | 28.7% | 3.50 | 0.1% |
| DRAW | 4.00-5.99 | 8,218 | 22.1% | 4.53 | -1.2% |
| DRAW | 6.00+ | 1,749 | 12.8% | 7.97 | -5.4% |
| HOME_WIN | <1.50 | 2,840 | 76.5% | 1.33 | 1.3% |
| HOME_WIN | 1.50-1.99 | 8,493 | 57.3% | 1.76 | 0.2% |
| HOME_WIN | 2.00-2.99 | 16,515 | 40.8% | 2.42 | -2.8% |
| HOME_WIN | 3.00-3.99 | 5,497 | 29.1% | 3.37 | -2.8% |
| HOME_WIN | 4.00-5.99 | 2,574 | 21.0% | 4.69 | -2.3% |
| HOME_WIN | 6.00+ | 1,382 | 10.8% | 9.06 | -6.2% |
Over/Under 2.5
Totals are not magic, but the buckets are less distorted than long 1X2 prices.
| Selection | Odds bucket | Bets | Strike | Avg odds | ROI |
|---|---|---|---|---|---|
| OVER | <1.70 | 6,304 | 64.5% | 1.54 | -0.9% |
| OVER | 1.70-1.89 | 6,809 | 56.5% | 1.80 | 1.5% |
| OVER | 1.90-2.09 | 8,318 | 49.3% | 1.99 | -1.7% |
| OVER | 2.10-2.39 | 10,492 | 43.4% | 2.22 | -3.8% |
| OVER | 2.40+ | 5,381 | 37.3% | 2.62 | -2.6% |
| UNDER | <1.70 | 7,290 | 61.6% | 1.59 | -2.1% |
| UNDER | 1.70-1.89 | 10,609 | 55.5% | 1.79 | -0.6% |
| UNDER | 1.90-2.09 | 7,714 | 49.4% | 1.98 | -2.2% |
| UNDER | 2.10-2.39 | 6,339 | 42.4% | 2.22 | -5.7% |
| UNDER | 2.40+ | 5,352 | 34.6% | 2.84 | -4.2% |
Operating Rule
- Treat long 1X2 prices as contaminated by favourite-longshot bias and bookmaker outlier noise.
- Block automatic away-win publication above the model guardrail unless later live backtesting proves otherwise.
- Require a longshot catalyst before any draw or outsider is even considered for public paper trading.
- Prefer two-way markets such as over/under 2.5 for public automation while Asian handicap is being built into the paper-trading record.
- Keep every public tip in the record, including bad early picks. The record is the point.
The raw report is still available as market-bias-report.md. The Asian handicap follow-up is available as Asian handicap research notes.