Sports Betting
Understand odds, implied probability, sportsbook margin, line movement and the difference between predicting outcomes and finding value.
Sports betting is not just picking winners. A wager is a price on an outcome, and whether that price is favorable matters as much as the prediction itself.
Odds are prices
Decimal, American and fractional odds express the same underlying concept: the payout associated with a probability estimate.
The vig matters
Sportsbook prices usually imply probabilities that add to more than 100%. That excess is a pricing margin, not a guarantee of sportsbook profit on every event.
Results and decision quality differ
A good bet can lose and a poor bet can win. Evaluating a wager requires separating the quality of the price from the short-term result.
Separate observable price from estimated probability
The sportsbook price is observable. A no-vig probability is a model derived from those prices. Your own probability estimate is a separate judgment. Keeping those three objects separate prevents a common error: calling a margin-removed market estimate “the true probability.”
Market definition comes before calculation
Overround only makes sense when every mutually exclusive outcome in the same settlement-defined market is included. A soccer 1X2 market cannot be analyzed using only home and away prices because the draw is part of the market.
Use worked markets
The Sportsbook Pricing Dataset preserves exact example prices, raw implied probabilities, book percentage, overround and proportional no-vig outputs so the calculations can be checked independently.