EV (Expected Value)
Expected value — the average profit of an action over the long run
Definition
EV (Expected Value) is the mathematical expectation of profit or loss of a decision, calculated over a large number of repetitions in identical situations. An action is +EV if it profits on average, -EV if it loses money in the long run. The goal in poker isn't to win every hand, but to make +EV decisions. A decision can be +EV and lose in the short term (variance), or -EV but win occasionally (luck). That's the common confusion among beginners: judging their decisions by the result, not by the quality of the decision. The EV calculation factors in: the probability of winning, the pot size, potential future bets (implied odds), and the size of the bet to call. Maximizing EV on every decision is the very definition of good poker. All GTO strategies are built to maximize total EV across every situation.
Calling an all-in with 60% equity is +EV even if you lose that specific hand. Over 1000 repetitions, that decision is profitable despite the occasional losses caused by variance.