bet is a wager in which a sportsbook
will predict a number for a statistic in a given game (usually the combined score of the two teams), and bettors wager that the actual number in the game will be either higher or lower than that number. For example, in Super Bowl XXXIX
, most Las Vegas casinos
set the over-under for the score of the game at 46.0
. A bettor could wager that the combined score of the two teams would be either more than or less than that number (as it happened, the combined score was 45, so anyone who had bet the under won).
The goal of a sportsbook manager is to have an equal number of bets on both sides of the over-under. In theory, this means that the manager could set the value at zero and then readjust based on either the number of incoming bets and/or events that influence the potential outcome. In practice, the initial value is based on both quantitative (e.g. win-loss record, average points per game, etc) and subjective information (e.g. media reports, injury status of players, etc).
Adjustment of Value
In Las Vegas over-under bets, the value changes automatically by half a point based on each $1,000 bet.
For example, if the current over-under is 5 and a bet for $1,000 over comes in, the value is adjusted to 5.5.
As another example, if the current over-under is 6 and an over bet for $20,000 comes in and an under bet for $18,000 comes in, the value would move to 7 ($20,000 - $18,000 = $2,000).
Though this bet is most commonly made with the combined score of the two teams, many other statistics can be used, including:
- A team's win-loss record for the season
- In American football, a player's or team's total rushing yards or attempts, down conversions (first or third), interceptions, completions, etc.
- In basketball, a player's or team's total assists, blocks, turnovers, steals, field goal percentage, etc.
- In baseball, a player's or team's total number of home runs, RBI, etc.
- ESPN talk show Pardon the Interruption commonly features a segment called Over/Under in which the hosts, Tony Kornheiser and Michael Wilbon will debate the over-under for certain statistics, some of them being particularly obscure and off-beat (such as the duration of a particular celebrity marriage).