[theredd]

+EV and -EV seem like important things, judging from the amount its mentioned in threads. So, can someone explain what it is? How is it calculated? How is it used?

[matreyt]

Expected value is your expected return on a wager. For example, suppose you made a bet with me on a coin flip. If it is heads, I give you $100. If it is tails, you give me $1. Should you theoretically take this bet (assuming that the coin is fair and has a fifty-fifty chance of landing on heads or tails)?

Definitely! There is a 50% chance of it landing on heads, meaning you win $100. Thus, your expected win is $50 (0.50 * $100). If it lands on tails, you lose $1. Thus, your expcted loss is $0.50 (0.50 * $1). Your expected profit is the expected win minus the expected loss. Thus, your expected profit is $49.50.

Obviously, you will not win $49.50. You will win $100 or lose $1. However, you should view the bet as "winning" $49.50. Outcomes in gambling are influenced by chance in the short run. However, in the long run, your outcomes will very closely reflect your expected value. If we did the coin flip example a million times, your final profit would be extremely close to $49.5 million.

something like that

[theredd]

Thank you for the explanation

And two related questions:

1) According to this explanation, eating chalk is as unprofitable in sports betting as it is in betting on horse racing. So why would anyone seeking a profit bet on favorites?

2) If I'm trying to calculate value, it seems that I would have to be able to calculate what I feel a team's probability of winning are, so that I can compare it to what the book feels the chances are. I can envision a couple (simpleminded) ways to do this, but Im wondering if many cappers actually do this, or am I thinking too much about it?

[suicidekings]

1) Any price put on a team can also be represented as an implied probability of winning. For example, a team that's -200 on the moneyline has an implied win percentage of 66.7% while a team that's +200 has an implied win percentage of 33.3% (discounting the juice). Learning this conversion is an important first step. The answer to your question is simply that favourites win more over the long term (however with respect to wagering on them, there are many more factors to consider for each game that can't be explained quickly. This is just a starting point).

2) It's very common to handicap matchups through a variety of methods and determine what you think a fair price is for the contest. Many bettors place huge emphasis on finding situations where, in their estimation, teams are undervalued by the market, and line shopping between books to get the best price available for a particular game, thereby maximizing their potential gains and minimizing their break-even win percentage.

[sideloaded]

All sharps use models to calculate value.

[theredd]

All sharps use models to calculate value.

Hmmm theres another mystery word that keeps appearing when I read posts on this board . . . models? Can someone explain what they are?