What is Positive EV?

What Does Expected Value Mean?

Expected value (EV) is a mathematical concept that measures the average outcome of a bet if it were repeated thousands of times. In sports betting, it tells you whether a wager is likely to be profitable over the long run. A positive expected value (+EV) bet means you stand to gain more than you risk on average, while a negative EV bet means the sportsbook has the edge.

The concept applies far beyond gambling. Investors use expected value to evaluate stocks, insurance companies use it to price policies, and poker players use it on every hand. The core idea is the same: weigh the potential outcomes by their probability, and see if the math works in your favor.

Why Positive EV Matters

Most bets offered by sportsbooks have a negative expected value for the bettor. The odds are set so the house has a built-in edge (the vig or juice). However, sportsbooks are not perfect. They sometimes misprice lines, especially in less popular markets or when new information emerges. When you find a bet where the true probability of winning is higher than what the odds imply, you have found a +EV opportunity.

Here is a simple analogy: imagine a coin flip where you get paid $120 when you win but only lose $100 when you lose. Each flip is a 50/50 shot, but the payout structure means you profit $10 on average per flip. That is positive expected value in action.

How to Calculate Expected Value

The formula is straightforward:

EV = (Win Probability x Profit if Win) - (Loss Probability x Amount Risked)

For example, say you find a bet at +150 odds that you believe has a true probability of 45% to hit. If you bet $100:

  • Profit if win: $150
  • EV = (0.45 x $150) - (0.55 x $100) = $67.50 - $55.00 = +$12.50

That means on average, every time you make this bet, you expect to profit $12.50. One individual bet might lose, but over hundreds of similar bets, the math will play out in your favor.

The Role of the Vig

Sportsbooks build their profit margin (the vig) into every line they offer. When you see -110 on both sides of a bet, the implied probability for each side is about 52.4%. Added together, that is 104.8%, and the extra 4.8% is the vig. To find +EV bets, you need to identify situations where the true probability differs enough from the implied probability to overcome this built-in house edge.

Strategies for Finding +EV Bets

  • Compare lines across sportsbooks: If most books have a team at -150 but one book offers +110 on the other side, that outlier may represent a +EV opportunity.
  • Focus on market width: Tight markets (where the two sides of a bet are close together) tend to be more accurately priced. Wide markets offer more room for mispricing.
  • Be cautious with player props: These markets have higher variance and wider lines. Only bet player props with a meaningful edge.
  • Track your results: Over a large sample size (250+ bets), your actual results should converge toward your expected profit if you are consistently finding +EV spots.

PowerPicks helps you identify +EV opportunities by analyzing odds across multiple sportsbooks and highlighting bets where the math is in your favor.