Cover Probability is simply the likelihood that a bet will be a winner. It does not factor a bet’s vig (i.e. juice) into the equation. Therefore bets with vigs of -250 and +150 could have the same Cover Probability.

In the example above, the +150 bet would clearly be more desirable for a sports bettor. Valuing this piece is where the Expected Value metric comes into play. Unlike Cover Probability, the Expected Value calculation *does* factor in each bet’s vig. With comparable Cover Probabilities, a +150 bet will have a considerably better Expected Value than a -250 bet. Furthermore, a bet could have a worse Cover Probability than another bet, yet still have a higher Expected Value. Take a bet with a 65% Cover Probability and a -200 vig. This heavily juiced bet would have a worse Expected Value than a bet with a 55% Cover Probability and a +150 vig. This is because, on average, the +150 vig is going to be more profitable and produce a better ROI even if it hits less often.