The cliché that tennis is a sport of matchups is probably right

ANGELIQUE KERBER’S (pictured, left) reign at the top of the world rankings for women’s tennis came to an end on July 10th, when Garbiñe Muguruza (right) of Spain knocked her out of Wimbledon in the fourth round. Although Ms Kerber had not yet won a title in 2017, the numbers suggested she was a modest favourite in the match: according to Elo, a statistical rating system that evaluates players based on their performances and the quality of their opponents, she was both the better player overall and was superior specifically on grass courts, the surface of Britain’s grand slam. A forecast based on the model put Ms Kerber’s chances of advancing at 66.9%.

Bettors, however, saw things differently. Entering the match, it was Ms Muguruza who was the bookmakers’ favourite, priced at an estimated probability of victory around 62.5%. Ms Kerber’s season-long slump surely played a part in how the wagering crowd valued her chances, but it can’t explain the entire discrepancy: Ms Muguruza’s season has been only slightly better. A more likely explanation for the market’s preference for the lower-ranked Spaniard was the history between the two players. In...Continue reading