Most bettors don't even blink when it comes to laying $110 to win $100. "It doesn't matter if I'm paying an extra $10 because my team is going to cover this bet easily." But that extra $10 is serious business to those who are serious about winning in the long term. For bookmakers, that 10% is their cut—or vigorish (vig)—for posting odds, collecting legal bets, and paying out the winners. The extra 10% makes it harder for serious players to turn a profit.
Bettors need to win 52.4% of the time to break even. Handicappers like me and sharps view a 54% to 55% success rate as the goal. The percentage differences may seem tiny, but they're not when it comes to losing and winning money long-term betting on sports. The percentages can appear even smaller when identifying positive expected value (+EV) on games, but it adds up over the medium to long haul.
+EV Betting Explained
A positive expected value is when the probability of cashing is higher than the odds implied by the price of that wager. Think of it as tilting the percentages slightly in your favor. If you think the Packers should be a 10-point favorite and they're only 3, that's outstanding value. You'd rush to the window to make a big play on Green Bay at -3. However, that line differential of seven extra points doesn't happen very often, as the oddsmakers aren't dummies. But if you find seven games that are off by just one point in your estimation, which is common for good handicappers, that's seven extra points on your side and could increase your chance of winning.
Moneyline Positive Expected Value Betting
The above calculation works the same with moneyline odds. Since the odds of a coin flip are 50/50 on heads or tails, the true odds are +100 (even). Moneyline odds are listed as -110 on the favorite and +110 on the underdog, or -140 and +130, etc. Expected value is a way to measure the probability differential between the sportsbook's expectations and those of sports bettors.
Let's say the Giants are even-money on the moneyline (+100) against the rival Cowboys. A sports bettor has concluded that New York has several edges in its favor, should win the game, and should be a slight favorite. The posted odds are out of whack with the handicapper's expectations, creating Positive Expected Value. I’m always honing my systems to help me identify the matchups with positive expected value.
Minus-EV
The worst Super Bowl bet is the coin toss. While the true odds are +100 on heads or tails (50/50), the actual odds are -110 or even -115. The sportsbooks love it when people gamble on the opening coin toss because it’s the equivalent of throwing away money while hoping to get a win before the game even starts. The books are charging 52.38% at -110 for that +100 coin toss bet —a perfect example of negative expected value. which can increase your probability of losing.
Expected Value Importance for Bettors
Not every sporting event is a coin toss. There are plenty of underdogs where matchups by serious handicappers find they're capable of winning the game or should even be favored. It's that kind of positive expected value that I’m on the lookout for. Serious sports bettors are also known as EV bettors for this reason. Most bettors bet for the thrill but with strategies unfit for winning and growing a bankroll. Wagering by feel is great if you just want to throw a few bucks into the pot to add some excitement to a game, but if you really want to win, line shopping, finding edges, and channeling your emotion into the excitement of finding a positive EV bet is a more surefire strategy
Overvalued and Undervalued
Sportsbooks calculate the implied probability of the final score. The odds they post, however, are often tweaked. Money can move a line, as can public hype and media coverage. Adjusting the line from the true odds, even slightly, makes numbers overvalued or undervalued. A football team coming off a 40-3 blowout win gets the attention of fans and the media. Fans overreact to that one performance and can be in a hurry to bet on them the following week, no matter the number. Instead of opening as a 4-point favorite, they might open at -6 and get bet up to -7. Overreaction means overvaluation. The underdog in that example has a positive expected value of +7 when the line should be closer to +4 or +5. Scenarios like then are when I’m looking for matchup reasons to back the +7, recognizing there's +EV.
Why Overvaluation or Undervaluation Occurs
Sportsbooks aren't in business to predict winners. Their goal is balance, to lessen liability. Books adjust odds based on betting volume to ensure some profit, no matter the final score. They have no problem overvaluing or undervaluing an opening line because they're anticipating what the large pool of bettors, primarily casual players, are thinking. That pool of unsophisticated bettors is where they ultimately collect their small profit margin. That's the advantage of getting picks from someone like me putting in the time to study matchups and shifting odds to identify positive expected value and find you the best bets.
Super Bowl Defense
A good example of overestimation is Super Bowl offenses versus defenses. The average bettor flocks to high-scoring teams. On Super Bowl Sunday, they figure the better offensive team with the better quarterback will win. However, pro bettors put a higher premium on defensive capabilities first. When Peyton Manning led the record-setting Denver Broncos offense in Super Bowl XLVIII, they were favored due to the public perception of their unstoppable offense. The public was on Denver, while sharp bettors recognized the No. 1 defense of the Seattle Seahawks was undervalued. It wasn't even close as the Seattle defense was the "unstoppable force" in a 43-8 rout. A similar thing happened when the No. 1-ranked Oakland Raiders offense faced the No. 1 defense of Tampa Bay in the Super Bowl. The Raiders were a 4-point favorite, but the superior defense dominated in a 48-21 Buccaneers blowout. Savvy bettors saw positive EV in the underdog with the dominant 'D'.
Timing the Betting Market
Pro Tip: Waiting a few minutes before the game starts is more likely to get you a negative expected value than a positive one and possibly limit your probability of winning.
So, when is the best time for line shopping? It depends on the sport. With baseball, basketball, hockey, and soccer action taking place 24 to 48 hours after the previous game, that's the window for opening lines and variable movement. Many serious handicappers have their projections ready the instant odds are posted and can lock in expected positive value as they have a good idea which way the odds will shift. Football odds are posted six days before kickoff and sometimes longer. The best college and pro football bettors identify value early in the week. By Thursday, oddsmakers have made adjustments, and opportunities to find value bets diminish.
Think Critically About +EV
Understanding positive and negative expected value increases your odds of collecting more profit from sports betting. It's a similar principle to what the best stock market players utilize: buy low, sell high. Begin with handicapping basics, such as analyzing matchups, stats, and situations. Then, make your own numbers based on critical thinking, more than "feel" or with your heart. The difference between winning, losing, and breaking even is slight. Before placing a wager, calculate when the best time is likely to make that bet to maximize positive expected value. There will be overvalued and undervalued lines, so getting the timing right is essential for winning handicappers. Most bettors lose, while the most successful bettors take advantage of everything to try and outsmart the sportsbooks. Or, you can always get my advice and start winning more without the effort.
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