Statistical Skier

Doogiski over at NordicXplained has a good post up regarding the rivalry (such as it is) between Marit Bjørgen and Justyna Kowlaczyk. The issue between the fans of these two great skiers is the question of which one is better. Shocker, I know.

Doogiski gives a good rundown of some of the limitations of comparing skiers using only World Cup points and does some adjustments for the number of races each skier did, plus a few other factors. I think this is a reasonable way to look at World Cup points, but ultimately I agree with one of his commenters that this is really fairly simple. In the specific case of two athletes who have actually raced against each other a fair amount, the least ambiguous way to measure who was better is simply to look at these specific head-to-head matchups.

In this case, they raced against each other in 7 sprint races and 14 distance races. (I’m not including the overall standings for the stage races both ladies competed in at Kuusamo and in Falun, just each individual race.) Kowalczyk beat Bjørgen in only one sprint race (Otepaa) and in only two distance races (handicap pursuit in Kuusamo and the regular pursuit in Lahti). That’s a record of 6-1 (Sprint) and 12-2 (Distance) for Bjørgen, and with numbers like that it’s very hard for me to take seriously claims that Kowalczyk was the better skier this season. And one of those wins for Kowalczyk was a somewhat unusual race, with Bjørgen holding the overall lead in the Kuusamo mini-tour and most likely not really trying to win the stage, but simply hold on to the overall lead.

In fact, if you extend this back to the previous two seasons, Bjørgen’s record is 11-3 (Sprint) and 20-5 (Distance). Kowalczyk can, and does, beat her on occasion, but it’s not exactly a back-and-forth rivalry lately.

Obviously, Kowalczyk skied very well at the Tour de Ski, and I think in doing so proved that she was (on average) better than everyone other than Bjørgen this season. (Although one could possibly argue that Johaug deserves that title.) Bjørgen didn’t do the Tour, but probably will next year, which I predict will lead to either an epic battle between the two, or a really boring Tour as Bjørgen crushes everyone.

Let’s kick things up a notch, though, focusing in on the times they’ve raced against each other in distance events overall: Continue reading ›

I promised a separate post on Leif Nordgren earlier, so here it goes. I don’t really have any fancy analysis to present, but here’s his results in major international competitions (WC, WBC and OWG):

Obviously, the guy is young and this is his first season skiing on the WC circuit “full time” or mostly so. His two fantastic races at World Championships certainly attracted some attention, and rightly so. But I’d also note just how different those two races were from the rest of his results. Now, that’s not uncommon in biathlon, where a few more shots made here and there can easily move you up or down 15-20 places. I just wouldn’t expect him to pump out that kind of race on a regular basis, even next season.

However, you’ll also note that (if you look carefully) his result from just this season were steadily improving throughout the season it seemed. Not by a huge amount, perhaps, but it’s noticeable. That’s exactly what you want to see from a young guy getting used to international competitions. I would think that the best case scenario for him next season would be to have his results spending most of their time in the ‘Good’ section of these graphs, with occasional forays in ‘Elite’. He’s certainly an interesting guy to watch, though.

This got me wondering though about young skiers in biathlon in general. My age data for biathletes is much less complete than for cross country, since that information is harder to obtain in large chunks. I did my best to identify a few men under the age of 22 who raced in WC or WBC races this season. There were only a few people who appeared to do this more than a handful of times: Continue reading ›

Thanks to some help from Jan at WorldOfXC.com, I’ve been slowly gathering the split time data for World Cup races from this season. Analyzing them is tricky, though, for a variety of reasons.

First, the data quality is poor. There are numerous instances where the live timing data is obviously wrong in a way that I can’t fix by hand, and so a certain number of split times need to be omitted completely. Second, the live timing data itself doesn’t say exactly how far into the race each timing instance is, so I have to infer that from the times and the length of the race. It works pretty well, but I’m sure it’s only accurate to +/- 500 meters or so. Lastly, handicap start races have to be dealt with separately, since the live timing tracks the time from when the first racer starts, not from when each racer starts.

Still, I’m beginning to find some interesting stuff. A little later I’ll show you some graphs on individual skiers that can shed some light on tactics and performance that I think are kind of interesting. For now, though, the obvious: Continue reading ›