Betting glossary

American odds express a price as a number above or below zero, where a positive number is the profit on a 100 stake and a negative number is the stake required to profit 100.

Decimal odds express a price as the total return per unit staked, including the stake itself.

Implied probability is the chance of an outcome that a given price corresponds to, calculated as one divided by the decimal odds.

Break-even probability is the win rate at which a given price produces neither profit nor loss over the long run.

The price is the odds offered on an outcome at a particular venue at a particular moment.

The line is the handicap or threshold a market is set at, such as a point spread or a total.

A moneyline bet is a wager on which side wins outright, with no handicap applied.

A spread is a handicap applied to one side so that both sides of a market carry roughly equal chances.

A total is a market on the combined score of both teams, bet as over or under a stated number.

A push is a tie against the line, where the stake is returned and the bet counts as neither a win nor a loss.

Vig is the margin a sportsbook builds into its prices, which is why the implied probabilities of both sides of a market add up to more than 100 percent.

A no-vig probability is a market price with the sportsbook margin mathematically removed, so the two sides sum to 100 percent.

Expected value is the average result a bet would produce if it were repeated many times at the same price.

A bet is positive EV when the price on offer pays more than the true chance of the outcome warrants.

The closing line is the final price and line a market offers before an event begins.

Closing line value measures whether a bet was placed at a better price than the market offered at close.

Line movement is any change in the line or price of a market between opening and close.

A stale price is one that has not been updated to reflect current information and no longer represents what a venue would actually offer.

A minimum acceptable price is the worst price at which a stated recommendation still stands.

An actionable price is one currently available at a venue you can actually bet, on the terms stated.

Expiry is the point after which a price-conditional recommendation no longer applies.

A Certified Pick is an official V8 Predicts recommendation that met the published publication standard and carries a pre-event verification record.

The V8 Watchlist is a set of matchups V8 is monitoring that are not official recommendations.

A PASS records that V8 evaluated an event and issued no official recommendation on it.

A qualified opportunity is an evaluated event that met the published standard required to become a Certified Pick.

Verification is an independent record that a specific prediction existed in a specific form before the event started.

The Decision Ledger is the public record of what V8 evaluated and what it decided, including every event it passed on.

A pre-event commitment is a record created before an event that fixes what was predicted, so it cannot be changed once the result is known.

Settlement is the process of determining the official result of a bet from the final outcome of the event.

ROI is profit divided by total amount staked, expressed as a percentage.

Flat staking means risking the same amount on every bet regardless of how attractive it looks.

A unit is a standard stake size used to express results independently of currency.

Win rate is the share of settled bets that won, usually excluding pushes and voids.

Sample size is the number of settled results a performance figure is based on.

Variance is the natural spread of outcomes around a long-run average.

A drawdown is the decline from a peak in a running results total to the lowest point that follows it.

Calibration measures whether stated probabilities match observed frequencies over many predictions.

A confidence interval is a range that plausibly contains a true value, given the data observed so far.

A model version is a label identifying which iteration of a forecasting method produced a given prediction.

A bankroll is the total amount of money set aside for betting and treated as separate from everything else.

Unit size is the fraction of a bankroll risked on one standard bet.

Concentration is the share of a bankroll exposed to a single outcome or a single event at one time.

Correlation is the tendency of two bets to win or lose together rather than independently.

Risk of ruin is the probability of losing a bankroll entirely before any long-run edge can be realised.

The Kelly Criterion is a staking formula that sizes a bet in proportion to the edge and the price, in order to maximise long-run growth.

Fractional Kelly means staking a fixed fraction of the amount the Kelly formula suggests, such as a half or a quarter.