Odds and Ends after Otepää

After all the hype, particularly last season, regarding the major (though seemingly friendly) rivalry between Petter Northug and Marcus Hellner, it’s been interesting to have it all sort of fizzle out this year. Northug’s been struggling with getting back into form after being sick, and Hellner also struggled somewhat during the Tour de Ski.

However, Daniel Rickardsson has really stepped up and provided the Swedes with some quality results so far. Here’s a comparison of the two Swedes distance results, using the percent behind the median skier in each race:

This past weekend’s race is in red. While Hellner’s trend line is pushing upwards this season, I wouldn’t panic much. See how his results this season are fairly cleanly divided into two groups, good and bad? Well four of those bad races are from the Tour, which makes me suspicious about whether they are really indicative of his form or whether they’re specific to him struggling with that particular multi-day event.

In any case, Hellner’s good races are right in line with his better performances last year, so I think he’ll be a significant threat as the season goes on.

Finally, one thing that’s becoming apparent is how much more movement there is on the men’s podium than the women’s this season. Mostly that’s due to Marit Björgen winning nearly everything in sight, but here are some numbers to chew on.

Including the Tour de Ski, 13 different men have won various events versus only 7 different women. If we remove the Tour, where Björgen didn’t race, these numbers drop down to 10 for the men and 5 for the women. In regular WC races, there are twice as many men with wins than women.

Of the 12 total distance events so far this season (including the Tour) Björgen and Kowalczyk have won 9 of them. On the men’s side, only Dario Cologna has 3 wins, followed by Hellner with 2. In fact, the first five men’s distance events had five different winners!

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Comparing Variability In Men’s & Women’s Sprinting

I was listening to FasterSkier’s podcast the other day and was a bit startled to here one of the participants mention me by name!1

The topic was whether we tend to see the same few skiers at the top in women’s sprint races more than in men’s races.  In other words, are we more likely to see “random” skiers make the A-final or even the top three in a men’s sprint race?  I actually posted something related to this a while back that was more geared towards the question of competitiveness.  I did some fancy math and concocted something to measure this idea that I called “churn”.  Basically it measures the degree to which we see the same group of people in the top 3, or top 5 or whichever group we’d like to look at.  But the graph in that post isn’t very useful for comparing men and women directly.

Let’s start really simple.  For sprinting, I’d say we’re most interested in the top 3 (podium) and the top 6 (the A-final).  Last season we saw 15 different women on the podium versus 19 for the men.  There were 32 different women women reached the A-final (top 6) at least once, versus 34 for the men.  On a basic level, this supports the notion that there’s more “churn” in men’s sprinting, while we’re more likely to see the same women in the top 3 or 6 in sprint races.

But the differences are pretty small, of course.  So keep in mind that often we’re talking about an extra 3-4 skiers rotating into the podium spots or the A-final.

I’m not going to rehash my derivation of how I defined churn.  You can go reread the above link if you’d like.  Let’s just say that the result is a number between 0 and 1.  A churn of 0 would mean that the exact same set of skiers is on the podium (in a possibly different oder) every single race.  A churn of 1 would mean that every race we get a totally new set of skiers on the podium.  Here’s two bar charts comparing men and women for several seasons:

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  1. By the way, Christopher, it’s pronounced JOR-an; like “Jordan” but with no “d”.  My parents gave me the Scandinavian name, but not the Scandinavian pronunciation.  And shame on you, Colin, for not correcting him.  You know how to say my name!

Measuring Competitiveness Using Churn

In one of the articles I wrote for FasterSkier.com, someone asked a question in the comments that I thought was interesting, so I dashed off a quick answer.  Sadly, as is common when I do something quickly, I made a mistake.  So I need to correct the record.

Commenter triguy mentioned that it would be interesting to look at the number of different skiers who land on the podium during each season.  I hacked out something really quick in SQL and slapped it up in a comment.  I had meant to return to that idea and look at turnover among top 10 finishers, top 30, etc.

When I did, I discovered a small error in the numbers I posted in that comment.  The general trend is roughly the same, but the ratios should all be shifted slightly.  So, my bad.  But now I get to elaborate on that idea with actual graphs! Read more