Game theoryFeb 13th 2019by J.S.twitter iconfacebook iconlinkedin iconmail iconprint iconON FEBRUARY 11th Lindsey Vonn, the most exciting racer to ever click on a pair of skis, competed one last time. Her curtain call at the World Ski Championships was not a triumphant one: she had to settle for bronze in the downhill time trial, the…
ON FEBRUARY 11th Lindsey Vonn, the most exciting racer to ever click on a pair of skis, competed one last time. Her curtain call at the World Ski Championships was not a triumphant one: she had to settle for bronze in the downhill time trial, the fastest of alpine skiing’s five disciplines and her signature event. But the fact that her final appearance on a podium came in Aare, a Swedish resort, was fitting. It was on those same slopes that Ms Vonn first hurtled onto the scene, with two silver medals at the World Championships in 2007.
Those results were just a hint of what was to come. Between 2008 and 2012, the American finished first in the cross-discipline end-of-season standings four times, a run that was marred only by a second-place showing in 2011. In those five years alone, she won 46 races at the World Cup (which is the circuit of elite races that take place between World Championships). Only three women have won more in their entire careers.
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Yet Ms Vonn’s triumphs came at great cost. After more than a decade of racing at the edge of human capacity, the 34-year-old American has suffered a lifetime’s worth of serious injuries, including repeated tears to her right knee, a broken ankle, and assorted fractures. On February 1st she announced her retirement, acknowledging that her body was “broken beyond repair”.
Retirement will give skiing aficionados plenty of time to ponder what might have been if Ms Vonn had spent more time holding her poles and less using her crutches. Her five-year stretch atop the sport was not ended by a loss of form. The reigning champion still finished first in the downhill rankings for the 2013 season, despite a crash that ended her campaign with only a month left to go. A related injury kept her out of much of the 2014 season, including the Sochi Olympics. When she finally resumed her full schedule in 2015, she won 17 more races in two seasons, finishing third and second in the 2015 and 2016 overall standings respectively.
There are only a few all-time records that Ms Vonn failed to surpass. It is easy to imagine an alternative, injury-free universe in which she also claimed those, such as the tally of 86 career World Cup events won by Ingemar Stenmark, a male Swedish star of the 1970s and 1980s. Ms Vonn has retired with a haul of 82, comfortably above Annemarie Moser-Pröll, the next most successful woman, who picked up 62 wins in the same era as Mr Stenmark.
At her peak, however, Ms Vonn towered above anyone else in her sport. To quantify a skier’s ability at any given point in time, we devised a new rating system for alpine skiing, using data for all professional races since 1967. We have called it “Ski-lo,” in homage to theElo methodoriginally used to rank chess players.
Existing leaderboards for skiing, such as the “super ranking”, are based on raw tallies of podium finishes and points associated with them. According to this system, Ms Vonn leads the women’s pack, outscores Mr Stenmark, and trails only Marcel Hirscher, an Austrian slalom master. But these rankings are not designed to predict future results, and take no account of the strength of the competition. By contrast, Ski-lo measures each skier’s performance in each race, increasing or decreasing her rating based on her finishing position and the quality of competition. The result is an estimate of each skier’s skill level before and after each race, for each of the sport’s five events.
Our calculations elevate Ms Vonn’s status from being merely one of the greats to the undisputed number one. At the end of the 2012 season, her Ski-lo rating for the downhill discipline was 3,168, some 700 points higher than that of her closest competitor at the time, Tina Weirather. A gap so substantial means that in a one-on-one race, Ms Vonn had a 98% chance of winning. Her all-time best downhill rating of 3,267, achieved early in the 2013 season, is nearly 400 points above that of any other female skier, a difference that translates to a 90% chance of victory (see chart). Male racers tend to be more specialised, but no man has come within 200 points of Ms Vonn’s downhill rating.
Furthermore, Ms Vonn excelled at all of the slalom events, unlike most other downhill champions. The American is one of only six women to have won races in all five alpine disciplines, and her peak Ski-lo of 2,420 in the giant slalom, her weakest of the bunch, still places her 43rd of all time in that event. Her average across all disciplines, at 2,929 points, puts her in first place among all skiers of both sexes, making her both the sport’s most dominant specialist and its finest all-rounder.
Nonetheless, her retirement comes at a time when her position as the greatest of all time is beginning to look threatened. Third on the World Cup roll of honour after Ms Pröll is Mikaela Shiffrin, an American slalom specialist who has won 56 events. At the tender age of 23, Ms Shiffrin is only just approaching the age at which Ms Vonn won her first overall World Cup title. Already the younger American has collected two Olympic gold medals: if there is one blemish on Ms Vonn’s career, it is that injuries only allowed her to win one. Ms Shiffrin has already recorded the highest ever Ski-lo rating in slalom, and the fourth-best in giant slalom. While she has yet to experience the success in her weaker events that Ms Vonn has enjoyed in hers, the 23-year-old could easily rack up a record-setting 87 World Cup races simply by sticking to her strongest categories.
Yet even if Ms Shiffrin ends up with pride of place on the all-time Ski-lo list, Ms Vonn will merit plenty of pages in the alpine history books. Her record in downhill races alone ensures that. She also established a new standard of excellence for American women in a sport that is dominated by Europeans. Her sole Olympic gold medal, in the downhill at the 2010 Vancouver games, was the first ever claimed by an American woman in the discipline, and her 2008 overall World Cup title ended a 25-year drought for the stars and stripes. Few women have worked harder to recover from injury. None has hurtled more thrillingly down a slope.