While the pair cautions that sports betting is about chance and entertainment, and their research should never be treated as a sure way to make money, they propose several methods and mindsets that bettors on tennis and other sports should apply to increase their chances of winning.
Their study points to a system where bettors can use their understanding of probability, pricing, and risk alongside merely picking the winner. The research also points to many bettors misunderstanding their own betting ability and ignoring mathematical decisions.
The research will form part of Beat the Sportsbook: The Theory and Practice of Successful Sports Betting, the upcoming book from Scott and Sher. The pair presented their research at the 19th International Conference on Gambling & Risk Taking at the University of Nevada, Las Vegas, examining the quantitative and behavioural factors that can influence whether a wager represents a good bet.
While tennis was not a target for the research, the principles Scott and Sher find provide an interesting way of approaching betting on the sport. Tennis is interesting because bettors have a lot of data to help find the player most likely to win, but that may not always be the best bet. Moneyline prices swing depending on players, with prices shifting based on surface, form, fitness, and serve and return performance.
The broader ideas of the research fit well into tennis betting, where the question should be more than just ‘Who will win?’ and instead ask, ‘Is the price good enough for the probability of a player winning?’
Predicting a winner and getting good value are separate things.
Picking the Likely Winner Is Not the Same as Finding a Good Bet
At the center of Scott and Sher’s broader research on sports betting is the idea that being correct about the outcome of an event does not automatically mean the bet is a good one. It seems like a subtle distinction at first, but it is important because it shows that the most likely result is only one part of a betting decision, because pricing and risk also determine the value.
Taking this basic principle and placing it into tennis betting works well. Imagine a Top 10 player is playing someone ranked outside the Top 50; the higher-rated player is very likely to win. A price of -600 on the Top 10 player shows they have roughly 85.7% probability to win, while -700 would increase the chance to 87.5%.
For a sports bettor, the question is not just if a player is likely to win, but whether the prediction about the true probability is higher or lower than the probability put into the price by the sportsbook.
If a bettor thinks a player has a 90% chance of winning but the odds suggest an 87.5% chance, the -700 bet has a positive expected value because there is a small chance of an upset. If the bettor’s estimate is 82%, a -700 price would not be a good deal even if the player is likely to win. Scott and Sher were not applying their research to tennis, but the underlying lessons show that predicting a winner and getting good value are separate things.
Tennis Is a Useful Example of Why Bettors Misunderstand Probability
One of the main sports betting problems shown by Scott and Sher is that simply knowing the likely winner does not dictate if the odds are worth taking. Tennis provides a very good illustration of this problem in action and can be used to show how bettors misunderstand probability.
If we take a player with a price of -250, the market is giving a probability of around 71% of the player winning. When a bettor watches the player, they may see that they are often likely to win. The problem is that “likely” is not a real betting price. It’s more important to weigh whether the player’s chance of winning is more than the 71% probability.
On the surface, it seems this is obvious, but in reality, the distinction disappears when there is a clear favourite. All results in tennis are binary, so moneyline bets make it easy to simply predict who is the best player for each match. The problem is that the shorter the price is, the less helpful it is to simply agree with the sportsbook’s odds.
In Scott and Sher’s research, the broader findings become notable when there is a clear favourite. Picking the player who has a 75% chance of winning is easy enough, but if the price is -250, the difference between 75% and the market’s implied 71% could make it a good value bet. Flip it around to a lower true assessment, such as 68%, that favourite may become a poor bet.
Tennis Knowledge Helps Bettors, But It Does Not Guarantee Value
Having tennis knowledge is a good starting point for betting, but the research from Scott and Sher points to something important. Knowledge of a sport is not the same as understanding what the best betting opportunity is. Several factors can give bettors data to help predict the outcome, but none of them automatically equal a profitable bet.
- Rankings can create false confidence. ATP and WTA rankings, tournament history, recent form, Grand Slam performance and head-to-head records provide plenty of information, but knowing which is the higher-ranked player does not necessarily provide a betting advantage. Surface records, injuries, fatigue and recent performances can all change the balance of a matchup. The important question is not simply who is more likely to win, but whether the odds accurately reflect that probability.
- Tennis stats help, but only at the right price. Clay, grass and hard-court records can reveal major differences between players. Roger Federer, for example, was dominant on grass and hard courts but regularly struggled against Rafael Nadal on clay, where the Spaniard was a specialist. Serve and return numbers, break-point performance, playing styles and head-to-head records can provide useful context, while indoor conditions, weather and the physical demands of a tournament can add further valuable info. But having more information does not automatically create more betting value.
- Sportsbooks already have access to much of the same information. It is unlikely that a bettor can find historical tennis data that sportsbooks have somehow missed. The same records and statistics that can influence a betting prediction can also influence the odds. Picking a winner becomes just one part of the process, while the edge comes from finding a price that reflects the true probability.
- Familiarity can become a betting weakness. Scott and Sher’s research examines behavioural biases that affect how bettors use information, and tennis provides plenty of opportunities for them to appear. A well-known Grand Slam champion can attract backing simply because bettors are comfortable with the name, even when the price offers little value. Familiarity bias also becomes a factor, and watching more of certain players could make bettors confident without giving an actual betting advantage.
- Live betting makes those judgments even harder. A single break of serve can quickly change tennis odds, while losing the first set can suddenly make a player appear to be a much worse bet. These twists impact live betting decisions and sportsbook odds, but the actual match may still be in the balance. Information from before a match may change and bettors use real-time data, but the fast nature of tennis means it can be challenging to separate useful information from an emotional reaction.
- Tracking results can reveal whether tennis knowledge is actually helping. Instead of relying on memories of recent wins and losses, bettors can record results across ATP and WTA matches, pre-match and live betting, favourites and underdogs, different surfaces, tournament levels and bet types. That evidence may challenge their assumptions about where they perform best. But that is precisely the value: betting ability should be judged by the results of a complete record, rather than the confidence created by a handful of memorable wins.
Parlays and the Illusion of Safety
Because of the historical player information and binary results of tennis, the sport is a tempting option for parlay betting. It is relatively easy to use knowledge to select which player is likely to win, and bettors can then build a parlay ticket around that. A player who has a -500 price as the favourite might seem like a safe bet, but that is not always true.
Just building a ticket of safe legs still does not remove the fact that the probability of winning the parlay decreases with each leg. The margin for the sportsbook also stays on each individual bet. Scott and Sher describe a compounding probability illusion where bettors can fail to see how quickly the likelihood of a sequence of events declines.
For tennis, even a conservative parlay of short-priced favourites can fall apart quickly with just a single upset. The research does not suggest that parlay betting is inherently bad but rather that bettors should carefully evaluate odds and price for each leg.
Thinking More Like an Investor Than a Fan
At the heart of Scott and Sher’s research is the idea that bettors should approach sports betting as a combination of probability, risk, and price instead of mere predictions. We see concepts such as expected value, variance and performance measurement in investing.
Tennis works within this investor-like framework. A bettor might have a strong opinion about a player’s chances, but the opinion only becomes relevant to a wager when it is compared with the available price. Instead of stopping at “Who do I think will win?”, the framework asks, ‘What probability do I give the outcome? Does the probability match the price? And is it worth taking the risk?’
Tennis as a Case Study, Not the Subject of the Research
It is worth remembering that Scott and Sher’s research is not a tennis betting system, nor was it meant to showcase anything about tennis specifically. What it does is provide a broader set of sports betting values that apply to tennis as well as other sports. It’s about including probability, pricing, bias, and risk in betting decisions instead of relying only on predictions. Tennis bettors won’t know what to bet on just by using the research, but they may find a more consistent way to make betting decisions.
A Book Coming Soon
Scott and Sher’s comprehensive research will appear in Beat the Sportsbook: The Theory and Practice of Successful Sports Betting, an upcoming book that looks at sports wagering beyond simple predictions. Using evidence-based studies, the researchers focus on probability, variance, expected value, pricing, and behavioural biases. The book also delves into sportsbook operations and how successful bettors stay profitable, while steering away from offering guaranteed betting systems.