Predicting the 2015 Wimbledon Men's Tournament
The upcoming Wimbledon showdown promises to be a high stakes game amongst men’s tennis elites. Roger Federer looks to win a record 8th Wimbledon title on his strongest surface. Novak Djokovic seeks to defend his title after winning his 5th Australian Open title this year. Rafael Nadal, seeded 10th, has a lot to prove and now must do it on his least reliable surface. Murray comes fresh off of a win at the Aegon Championships and will look to capitalize on his hometown support. Finally, we cannot rule out Stanislas Wawrinka, the "other" Swiss that recently won the French Open crown.
But who is the favorite to win the most prestigious tournament in tennis in 2015? Inspired by FiveThirtyEight’s World Cup Prediction model, we apply similar principles to men’s tennis to calculate the odds of each player advancing to different stages of the tournament.
What do our results say? Djokovic is a clear favorite to clinch his 3rd Wimbledon Crown.
In fact, we are more optimistic about this claim than what the betting odds suggest. Our model claims that Djokovic has a 55.6% chance of winning, while Bet365 implies a win probability of 44.4%. We also believe that Federer has a higher chance of winning Wimbledon than Murray, due to his strong head-to-head record against the British favorite. Finally, we think Bet365 overvalues Nadal’s prospect; given his recent form, we think other Top 10 players such as Berdych, Raonic and Nishikori have higher chances of winning the title.
Our model also shows the probability of each player reaching a given round of Wimbledon (below). This helps us determine who we should bet on at latter stages of the tournament. For instance, Kei Nishikori is quite a reasonable bet if he makes it to the semifinals. While he only has a 11% chance of making it to this stage (lower than many other top 10 players), he has the 5th highest chance of winning the grand slam, suggesting that Nishikori will only become stronger in the latter stages. (He is also projected to meet Djokovic in the semifinals, which explains his low probabilities)
We will continue to update these two figures after each round - stay tuned for more of our Wimbledon analysis. The details of our model are described below:
Details of Our Model
FiveThirtyEight uses ESPN’s Soccer Power Index (SPI) to rate a team at a given time. Similarly, we created an Elo-rating style system that tracks a tennis player’s rating at a given point in the tournament. Our system uses current ATP Rankings as a baseline and adjusts player ratings based on matches they have played in the past year. How much matches affect a player’s ratings are based on the following factors:
- Quality of Opponents - An upset (i.e. beating a higher-rated or losing to a lower-rated opponent) causes a player’s rating to fluctuate more
- Recency - Matches that happened recently are weighted higher than matches further back in time
- Surface - Since we are predicting the Wimbledon tournament, grass court matches matter more than clay and hard court ones
- Tournament Level - Grand slam matches, Masters 1000 matches and ATP 250 and 500 level matches are given different weightings.
- Set-Level Scoring - Players are given more credit for straight-set wins than more drawn-out affairs.
Using these ratings, we simulated 5,000 tournaments and with that predicted the odds of players reaching different rounds. In calculating the odds of one player beating another, we also took into account their head-to-head record. Like in the player’s rating, recency, surface, tournament level, and scoring matter.
Update for Ferrer's Withdrawal:
