Positive expected value (EV+) simply refer to situation where the potential payout from a bet is higher than the risk involved. Sharp bettors look for these scenarios since the bet is expected to be profitable in the long run as variances play out.

The Kelly Criterion is a mathematical formula that is used to determine the optimal amount of money to bet on a particular wager based on the perceived probability of winning and the potential return on investment.

The Kelly Percentage is used to calculate the size of the bet using the Kelly criterion. Simply multiply your bankroll by the Kelly percentage to determine recommended bet size. For example, if your bankroll is $100 and the Kelly percentage is 19%, your bet should be $100 x 19% = $19.

Bettors that feel the Kelly Criterion gambling is too risky in its purest form, may use a Kelly Multiplier to lower risk. For instance, instead of applying "Fully Kelly," bettors might apply "Half Kelly" (1/2) or "Quarter Kelly" (1/4) or even "Eighth Kelly" (1/8).

Vig is short for vigorish. It is more commonly known as juice. Every sportsbook builds vigorish into their betting lines, as it allows them to pay their overheads and generate a profit. It is similar to the house edge built into a casino game, such as roulette, blackjack or a video slot.

To calculate the expected value of a bookmaker's price for a specific outcome, bettors must first determine the probability of that outcome occurring. In order to reach an accurate set of probabilities, sportsbooks' vig must be removed through a process known as "devigging."

There are four popular methods for devigging, and choosing the right one depends on the specific market circumstances and your historical success rates. The method you select should align with your evolving EV betting strategy.

Devig odds are simply the odds the bettor decides to use as the to determine the fair value of a betting opportunity. They are usually sourced from a "sharp" book like Pinnacle, BetOnline, Circa, etc.

Fair Value Odds represent the bettor's chances of winning if the sportsbook didn’t add vig.

For example, standard point spreads are usually available at -110 odds. That extra -10 is the vig. Fair Value Odds is a representation of the odds without the 10 points of vig. So, on a truly 50/50 bet with the 10 points of vig removed, the odds would be +100. These are the Fair Value Odds.
​

Arbitrage in sports betting is when a bettor makes multiple bets on opposing sides of a gameline or prop to guarantee a profit no matter the result.

Arbitrage Percentage is the percentage return a bettor can expect to earn if they play the arbitrage.

For example, if Caesars is offering a market for D'Andre Swift's first rushing attempt O/U 9.5 yards (Over +325, Under -200), a bettor could lock in 10.87% profit (the Arbitrage Percentage) by staking $24 on the over (+325) and $68 on the under (-200), winning $10 (10.87% of their total wager) regardless of the result of Swift's first rushing attempt.

Middle Betting is a strategy where bettor place wagers on both sides of the same bet, exploiting the middle range of the bet, capping their potential losses, and giving themselves an opportunity for a big payout.

Implied Probability is simply the conversion of betting odds into a percentage. For example +100 odds imply that the event has a 50% chance of occuring.