Correlated parlay legs: the traps and the stacks
What are correlated parlay legs?
Legs are correlated when one result changes the chance of another. A quarterback's passing-yards over and the top receiver's receiving-yards over tend to move together; a running back's rushing over and the team falling far behind tend to work against each other. The trap is stacking legs that fight each other, which makes a ticket less likely than the multiplied odds suggest. Books price same-game parlays with correlation in mind.
Legs that move together
- A quarterback's passing yards and the main receiver's receiving yards.
- A game total over and a high-volume scorer's points over.
- A heavy favorite winning and its lead running back getting carries late.
Legs that fight each other
- A running back's rushing over with the team as a big underdog: teams that trail throw more.
- A game total under with overs on several players from the same game.
- Two players from the same team both going over on the same limited stat, like two receivers splitting the same targets.
Why same-game payouts look short
Because correlated legs hit together more often, books adjust same-game parlay prices for it. Expect the payout to be lower than multiplying the single-leg odds. Across different games, legs are usually close to independent, and the multiplication rule holds.
A quick check
For every pair of legs, ask: if this one hits, does the other get more likely, less likely, or neither? Drop the pairs that pull apart.