Parlay Correlation Lab
Parlays don't raise your win probability — each added leg lowers it and compounds the book's hold. Price your own slip below to see exactly what that costs. The one place value can hide is correlation: books price legs as independent, so when outcomes actually move together the parlay price is wrong. This lab measures that correlation on NBA markets and tests it honestly.
Showing NBA — correlation is measured per league, so “All Sports” resolves to the one in season. Pick a league above to change it.
Research and informational use only. Model outputs are probabilistic, not guarantees; historical performance does not guarantee future results.
What your parlay actually costs
Build a slip and we'll show you the hold — the share of your stake the book expects to keep. It's arithmetic on published prices, not a prediction, and it's the number that explains why parlays are the most profitable product on any sportsbook's menu.
market
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Pick a game above and add a leg to see the numbers.
Outcome correlation
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Independence mispricing
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Parlay backtest
Bets one fixed 2-leg same-game combo on every game in range — leak-free, it just reports what happened. Leg B is the game total.
Results
Pick a combo and hit run backtest. Most naive parlays lose — that's the point.