Betting 101
What +EV Really Means
5 min read
TL;DR
Expected value is the long-run average of a bet — what you'd earn per bet if you could make it a thousand times. A +EV bet can lose tonight and still be the right bet. That distinction is what separates process from luck.
The math, without the pain
EV = (probability of winning × amount won) − (probability of losing × amount lost).
Say a prop pays -140 (bet $140 to win $100) and you believe it truly hits 65% of the time:
- Win: 65% × $100 = +$65
- Lose: 35% × $140 = −$49
- EV = +$16 per $140 staked ≈ +11%
That's what the green EV badge on our prop cards estimates: the model's probability vs. the book's price.
The hard part: losing +EV bets feel wrong
A 65% bet loses more than a third of the time. If you judge each bet by whether it cashed, you'll abandon good process during normal losing streaks and chase bad process during lucky ones.
The fix is to grade yourself on decisions, not outcomes. Did the bet have positive expected value with honest inputs when you made it? Then it was a good bet — including the ones that lost.
Where EV actually comes from
Books are very good at pricing. Real +EV comes from a few narrow places: information speed (lineups, weather before the line adjusts), soft markets (less-bet leagues where prices are looser), line shopping (same bet, better price — see that lesson), and selective disagreement (a model that beats the book on a specific subset, not everywhere). Anyone promising +EV on every game is selling something.
Keep these
- EV is the long-run average — judge decisions, not single outcomes
- +EV bets lose regularly; that's variance, not failure
- Edges are narrow and specific, never universal
Up next
The Vig: The House's Quiet Tax