What is a value bet?
In sports betting, "value" gets thrown around constantly. Pundits and handicappers are always touting the day's "best value bets." But what does it actually mean for a bet to have value?
In the simplest terms, a value bet is a wager where you believe the chances of winning are greater than the probability implied by the bookmaker's odds. Put another way, it's a bet that has a positive expected value (+EV), meaning that if you placed the same wager many times over, you would expect to turn a profit in the long run. Our daily picks are graded by expected value to help you identify these opportunities.
But how do you figure out whether a bet has value? That's what separates sharp bettors from the rest.
How to assess betting value
Sharp bettors look at three main factors when sizing up a potential wager:
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True Win Probability: What are the real chances of each outcome occurring, based on a complete analysis of relevant quantitative and qualitative factors? This is the foundation of successful handicapping.
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Implied Probability: What probability of each outcome occurring is implied by the current betting odds? This can be mathematically derived from the odds offered.
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Market Discrepancy: Is there a meaningful difference between your estimated true probability and the bookmaker's implied probability? If so, there may be betting value on one side of the wager.
Here's a closer look at each factor and how sharp bettors use them to find value in the betting markets.
Estimating true win probability
The bedrock of value betting is the ability to accurately predict the likelihood of each possible outcome in a sporting event. This is where domain expertise, statistical modeling, and qualitative research come together.
To arrive at a true win probability, sharp bettors consider factors like:
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Team quality: How do the competitors compare in terms of advanced performance metrics, adjusted for strength of schedule?
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Player matchups: Which side has the edge in important one-on-one matchups, such as a star quarterback facing a stingy pass defense?
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Game situation: How might factors like home field advantage, travel, rest, and motivation levels impact each team's chances of success?
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Betting trends: How have the teams performed in similar spots in the past, both in terms of straight up wins and losses and against the spread?
The goal is to synthesize all relevant information into a single probability estimate for each potential outcome. Many bettors use mathematical models or computer simulations to assist in this process, but there's always an element of qualitative judgment involved.
Calculating implied probability
Once you have a true win probability estimate, the next step is to compare it to the probability implied by the sportsbook's odds. This implied probability can be derived with a simple formula:
- For decimal odds: Implied Probability = 1 / Decimal Odds
- For moneyline odds: Implied Probability = Risk / (Risk + Win Amount) for a favorite, or Win Amount / (Risk + Win Amount) for an underdog
For example, if a team is listed at 2.50 decimal odds to win, the implied probability is 1 / 2.50 = 0.40, or 40%. If they're a -150 moneyline favorite, the implied probability is 150 / (150 + 100) = 0.60, or 60%.
It's important to understand that the sum of the implied probabilities for all outcomes in a market will always exceed 100%. That's because of the sportsbook's built-in profit margin, or "vig." For a bet to have positive expected value, your estimated probability needs to be higher than the implied probability by enough to overcome this vig.
Spotting market discrepancies
The final step in the value betting process is comparing your true probability estimate to the sportsbook's implied probability. If your estimated chance of winning is significantly higher than the implied odds, that's a strong indication of a value betting opportunity.
Of course, be humble here. The sports betting markets are highly efficient, with thousands of sharp bettors and advanced models constantly hunting for mispriced lines. If your probability estimate differs drastically from the market, double-check your assumptions first.
That said, betting markets aren't perfectly efficient. Biases and inefficiencies do exist, especially in the short term. Some common situations where value-minded bettors look to capitalize include:
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Overreaction to recent results: Bettors, and even oddsmakers, tend to give too much weight to a team's last game or two, creating value on squads that are better than their recent scores suggest.
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Underreaction to key absences: If a star player is ruled out shortly before game time, the betting market may not fully adjust to his absence, creating value on the other side.
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Public bias towards favorites: Casual bettors prefer betting on the better team, especially popular squads like the Cowboys or Lakers. This can inflate the odds on underdogs, making them valuable in spots where they have a decent shot at an upset.
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Scheduling and travel spots: Oddsmakers may underestimate the impact of situational factors like a team playing its third road game in four nights or coming off an emotional rivalry win.
Spotting these discrepancies takes analytical chops and awareness of the betting markets. You need to monitor line movement, understand public betting patterns, and stay on top of injury news and locker room rumblings. Our NBA player props page surfaces these signals with hit rates and confidence scores to speed up the process. For the most committed advantage bettors, it's close to a full-time job.
The Kelly criterion for bet sizing
Finding value is only half the battle in long-term betting success. Equally important is sizing your bets correctly to grow your bankroll over time while managing risk. Many sharp bettors use a formula called the Kelly Criterion to optimize their bet sizing