Bookmakers love Same Game Parlays (SGPs) because they are mathematically complex. Unlike standard parlays, where events are independent, SGP legs are often correlated (linked).
If you bet on “Kansas City to Win” AND “Mahomes to throw 3 TDs,” these events are highly correlated. The bookmaker will drastically reduce the odds to account for this. Our calculator helps you determine if they reduced the odds too much, or if there is still value in the bet.
How to Use the SGP Calculator
This tool uses a correlation coefficient to adjust the joint probability of two events.
- Individual Probabilities: Enter your estimated win chance (%) for Leg 1 and Leg 2 independently.
- Correlation Strength: Estimate how linked these events are.
- None (0): Independent events (e.g., Coin flip + Dice roll).
- Low (0.1): Slightly related (e.g., Over 2.5 Goals + Both Teams to Score).
- High (0.5): Strongly linked (e.g., Team Win + Star Player Goal).
- Bookie Odds: Enter the combined odds the sportsbook is offering for the SGP.
- Result: The tool calculates the Fair Odds. If the Bookie Odds are higher than the Fair Odds, you have found +EV (Positive Expected Value).
Example: The “Correlation Tax”
Scenario: You want to bet on Liverpool to Win (60% chance) AND Salah to Score (50% chance).
- Independent Math: 0.60 * 0.50 = 30% Probability (Fair Odds: 3.33).
- With Correlation: If Liverpool wins, Salah is more likely to score. Let’s apply a 25% correlation boost.
Adjusted Probability = ~37.5%.
True Fair Odds: 2.66.
The Bookie Offer: The sportsbook offers odds of 2.40.
Verdict: Even though the events are correlated, the bookie has slashed the odds below the true fair price (2.66). This bet has Negative EV. You are paying a “Correlation Tax.”
Frequently Asked Questions (FAQ)
Why are SGP odds lower than standard parlays?
Because the risk is lower. If Leg A happens, Leg B becomes more likely. To protect themselves, bookmakers use algorithms to reduce the payout, often taking a much larger margin than on standard bets.
Can I find +EV in Same Game Parlays?
Yes, typically in scenarios where the correlation is counter-intuitive (e.g., Underdog to Win + Game Total Over). Bookmaker algorithms are sometimes inefficient at pricing these “negative correlation” scripts.