USST 2011-2012 Preview
Another season is just around the corner! While the USST saw some changes over the off season, the folks we are most likely to see top results from are still the Big Three: Kikkan Randall, Andy Newell and Kris Freeman.
My expectations and questions for Freeman are summed up in this graph:
This shows his median (and 10th/90th percentile – errorbars) WC results by month, using standardized percent behind the median skier. Freeman has tended to see a big dropoff in January and has had inconsistent results mid-season. The differences between the months may not seem huge, since the y axis units are not something you’re used to thinking in. But keep in mind that a difference of 0.5 can easily mean the difference between 10th and 30th (or more).
So I won’t be surprised if Freeman comes out of the gate skiing fast in November, but I’ll be very curious what happens when we hit January.
As for Kikkan Randall, I think there’s probably a lot of excitement surrounding her, considering the breakthrough season she had last year. I’ve spoken before on this blog about her chances for contending for the WC sprint title, and I think she certainly will be a podium contender in every freestyle sprint she enters. But here’s a minor note of caution: Read more
How’d We Do? USA/CAN Season Review 3
This week it’s the sprinter’s turn in the limelight, starting with the men. As you might imagine, there are quite a few more cheery topics when talking about North American sprinters. As before we’ll begin with a simple plot showing the number of results per race over time:
The American men have seen a steady decline in top thirty sprint performances, mostly due to the recent struggles of Torin Koos. For about three seasons, the US men had two skiers regularly qualifying for the heats, but Koos’s results have dropped off, leaving only Andrew Newell as the top performer. Simi Hamilton, while surely talented, hasn’t yet made up the difference created by Koos’s absence. Hamilton only did five major sprint races this season and qualified twice, but was well back of 30th the other three times. It has sounded from the news reports like he has struggled a bit with injury and illness this season, so perhaps he can show that he can be a regular in the heats next year if he stays healthy.
Outside of Newell, the US men have seemed inconsistent. Of the top thirty performances from someone other than Newell since 2002, 27 belong to Koos, and another 11 to Chris Cook and Garrot Kuzzy. All three either didn’t ski particularly well, or in Kuzzy’s case didn’t ski well enough to get a real chance at any big starts. As for Newell himself, his results were actually fairly similar to what he’s done over the past 3-4 years: Read more
Andrew Newell Sprint Qualification Redux
So there was this post a while back where I looked at the oft repeated CW that Andrew Newell tends to qualify rather fast and then slip back a bit in the heats. My goal was just to see whether and to what degree this actually happens. It turns out that my attempt to tackle this topic is slightly cursed because I keep messing it up.
The first time around I mistakenly mixed sprint races with 16 and 30 people moving on into the heats. More recently, Nat Herz reminded me of something that should have been obvious from the start: people who qualify well are more likely to move backwards simply because there are only so many spots available to them to move up.
For example, if you qualify 3rd, in some respects you more likely to do worse in the heat simply because there’s more room behind you than in front of you. To give you a sense for how right Nat was about this effect, check out this plot:
As you can see, it’s much more common for people who qualify well (i.e. top 5-10) to end up losing places, and vice versa for people who qualify slowly. However, the blue trend lines probably aren’t as steep as you might expect. This is because there’s another general trend working in the opposite direction. Skiers who qualify well do actually tend, on average, to be faster skiers. So it’s quite common for them to do as well or better in the finals. You can see this tendency in the plot by looking at the size of the points, which indicate how often a particular combination occurred.
How do we fix this? Simple: rather than looking at the difference between each skier’s qualification and final places, we instead look at how that difference compares to the median difference over all skiers who qualified at that rank. For instance, say I qualified 5th and then ended up in 9th after the heats. That’s a change of 5-9 = -4. We then look at all the people who qualified 5th and calculate the median change across all these skiers, suppose it’s -2. That means that I moved back two more places than is “typical” for people who qualified 5th.
Here are plots focusing on the men and women who’ve done at least 15 WC sprint races over the past 4 years or so, complete with error bars: Read more
Tour de Ski: Leaders & North Americans
Once again, not much commentary here, just some graphs showing some notable individuals progress through the tour. I haven’t highlighted all the leaders, per se, just some of the top people and some other interesting ones.
No one’s likely to touch Kowalczyk for the overall, although there’s a lot of racing left to be done. But the race for second and third is definitely going to be interesting for the women.
As for the North Americans:
TdS Classic Sprint: North Americans
Just a few short notes focusing on the North Americans in the classic sprint yesterday. First the men:
One thing that stands out to me is that Harvey was actually skiing slightly faster than Kershaw all day. Of course, the differences are very small (~1 second), but it highlights how large an impact the make-up of your quarterfinal and semifinal can have on your result.
The corresponding women’s graph is obviously pretty boring: Read more
Top 10 Qualification vs. Making The Final
This is a follow-up post to an earlier entry where I noted an off-hand comment by US coach Chris Grover that when Kikkan Randall qualifies in the top ten in a sprint race, that this is a good sign that she has a good chance of making it to the finals.
I looked at some data and concluded that it mostly supported his claim, but that the sample sizes were small enough to not mean much, from a statistical point of view. It was suggested in the comments that I look at this overall, for all skiers and see what, if any, relationship there might be.
Generally speaking, I think we shouldn’t be terribly surprised about a correlation between one’s performance in qualification and one’s performance in the heats. It just makes sense that, on average, the faster sprinters will do better in qualification.
What we’re interested in here is in quantifying this somewhat arbitrary, but interesting, cutoff of finishing in the top ten in qualification. First up is a modified version of the plots I made for Kikkan Randall and Andrew Newell in the previous post: Read more
Is Qualifying In The Top Ten A Good Sign For Kikkan?
So US coach Chris Grover mentioned to FasterSkier.com that he thought that when Kikkan Randall qualifies in the top ten that’s a really good sign that she has a good chance to make the finals.
I did this once before with an interesting quote of his, and I feel kind of bad. I’m not trying to pick on him, but this is such an obvious thing to check with some actual data, I just can’t pass it up.
Here’s Randall’s qualification and final ranks for WC, WSC and OWG sprint races:
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