Key Takeaways: Betting Market Analysis
One-Page Reference
The Three Primary Markets
| Market | What It Means | Example |
|---|---|---|
| Spread | Points given/taken | Chiefs -7 |
| Moneyline | Straight win/loss | Chiefs -280, Bills +230 |
| Total | Combined points | O/U 51.5 |
Odds Conversion
American to Probability:
Positive: P = 100 / (odds + 100)
Negative: P = |odds| / (|odds| + 100)
Example: -150 → 150/250 = 60%
Example: +200 → 100/300 = 33%
Spread to Probability:
P(cover) ≈ 1 / (1 + 10^(spread/8))
Each point ≈ 3% probability
The Vig (Vigorish)
Standard -110 both sides: - Risk $110 to win $100 - Implied probability: 52.38% - Vig ≈ 4.76%
Break-even at -110: 52.38%
To profit long-term, must exceed 52.38% win rate.
Market Efficiency
NFL Betting Markets Are: - Highly efficient (near 50/50 ATS) - Information-incorporating - Difficult to beat consistently
Historical Spread Accuracy: - ~50.5% home/favorite cover rates - Nearly perfectly calibrated
Closing Line Value (CLV)
The gold standard metric:
CLV = Line when bet - Closing line
Example: Bet Chiefs -6, closes -7.5
CLV = -6 - (-7.5) = +1.5 points
Why CLV matters: - Results are noisy (luck) - CLV is signal (skill) - Positive CLV → long-term profit
ATS Evaluation
| Record | Win Rate | vs Break-Even | Verdict |
|---|---|---|---|
| 55-45 | 55.0% | +2.6% | Promising |
| 53-47 | 53.0% | +0.6% | Marginal |
| 52-48 | 52.0% | -0.4% | Losing |
| 50-50 | 50.0% | -2.4% | Losing |
Need ~500+ bets for statistical significance
Line Movement Interpretation
| Movement | Interpretation |
|---|---|
| <0.5 pts | No significant info |
| 0.5-1.5 pts | Some sharp action |
| 1.5-3 pts | Significant money |
| >3 pts | Major news/injury |
Reverse line movement: Line moves opposite to public betting % → sharp money
Sharp vs Public Money
Public Biases: - Bet favorites - Bet home teams - Bet popular teams (Cowboys, Patriots) - Bet overs - Overweight recent performance
Sharp Characteristics: - Large bet sizes - Early week action - Move lines with their bets - Positive CLV track record
Model Comparison to Market
If |Model - Market| < 1.5: No edge
If Model - Market > 1.5: Value on away
If Model - Market < -1.5: Value on home
Warning: Market is usually right. Disagree cautiously.
Key Numbers in NFL
| Spread | Frequency | Cover Probability |
|---|---|---|
| 3 | ~15% of games | ~50.2% |
| 7 | ~10% of games | ~50.1% |
| 6 | Common | ~50.0% |
| 10 | Less common | ~50.0% |
These are "key numbers" - games land here often.
Practical Applications
For Analysts (not betting): 1. Use market as prediction benchmark 2. Compare model to closing lines 3. Track CLV as skill metric 4. Incorporate market wisdom
Market as Data Source: - Implied team ratings - Injury/news impact - Information flow timing
Quick Formulas
Expected Value:
EV = (Win% × Win$) - (Loss% × Lose$)
ROI at -110:
ROI = (Win% × 1.909 - 1) × 100
Required Win Rate for X% ROI:
Win% = (1 + ROI/100) / 1.909
Key Insight
If your model can consistently beat the closing line, you've built something valuable. If it can't, the market remains the best available prediction. Respect market efficiency while seeking to understand it.