What +EV actually means
The one idea the whole thing rests on, in five minutes.
You took the Under at -108. It missed by four points. Evergreen still says that was an excellent bet.
Both of those are true at once, and the reason is the only thing this lesson is about.
Expected value is what a bet returns on average if you could place it a thousand times. A +3% EV bet returns about $3 per $100 staked over the long run. Take enough prices like that and the arithmetic does the rest — not because you predicted anything, but because you were paid more than the outcome was worth.
A real example
A total sits at Under 239.5. One recreational book has it at -108. Two sharp books have it at -134 and -136. Strip the margin out of those sharp numbers and the honest price is about -123. The book offering -108 is paying you meaningfully more than the market thinks it is worth. That gap is your edge, and it exists whether the under hits tonight or not.
Fair price is -123 (55.2%). At -108 you're being paid as though it were rarer than it is.
The formula, if you want it
EV = (chance you win × what you win) − (chance you lose × what you stake). Bet $50 on a true coin flip at even money and it comes to zero — you break even forever. Every bet you will ever be offered is a version of that sum, and the only question is whether the price makes it positive.
The grades on the feed
Nothing above required an opinion on the teams. The edge came from two books disagreeing about a price, which is a thing you can see rather than a thing you have to predict.
Every card carries the same four numbers. The price you can get, the price it should be, the gap between them, and a letter so you don't have to do the comparison in your head.
1 of 3
You take a +3% EV bet and it loses. What does that tell you about the bet?
2 of 3
A book offers -108 and the fair price is -123. Who is getting the better of it?
3 of 3
What grade does this app give a 3.5% edge?
The goal isn't to predict games. It's to buy probabilities for less than they're worth.
Terms from this lesson
Education, not betting advice. 21+. Gambling problem? Call or text 1-800-GAMBLER.