Sports Betting and the Sportsbook

A sportsbook is a gambling establishment that accepts bets on sporting events. Depending on jurisdiction, it may also be known as a bookmaker, oddsmaker, or book.

The basic type of wager is a straight bet, which is placing money on a single outcome. For example, if you believe that the Toronto Raptors will beat the Boston Celtics in an NBA game, then you would place a straight bet on the Raptors. Another popular option is a spread bet, which involves betting on the margin of victory. This is usually expressed as a number that represents the expected difference in points, goals, or runs. The numbers are adjusted by the sportsbook based on the amount of action it receives for each side.

In order to maximize their profits, sportsbooks try to balance the number of bettors on each side of a wager. This is done by pricing each bet so that it reflects the true exact probability of a given event occurring. If this is done correctly, then bettors will win a proportional share of point-spread and moneyline bets while the sportsbook collects its 4.5% profit margin (vig).

The article explains how this is accomplished by modeling the relevant outcome variable as a random variable with a probability distribution. It then uses this distribution to derive propositions that answer key questions facing the astute sports bettor. In particular, it identifies games that are shaded by the public’s “betting percentages,” and shows how to select the subset of bets that yield positive expected returns.