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Female Long Distance Specialists

Since we supposedly do statistics around here, the goal here will be to ‘statistically’ identify folks who specialize in longer distance races. By that I mean people who tend to ski better (relative to their own performance) in longer races. The fun part is to see whether the folks we single out match up with the people we would have thought of anyway. We’ll begin with the women.

The mechanics of this will largely mirror how I’ve identified technique specialists in the past, using mixed effects models. These are extremely handy modeling tools when you want to compare athlete specific effects. If you’re familiar with linear regression models, you can imagine doing a regression analysis on all skiers that investigates the effect of race length on performance. What we’d end up measuring is the average effect across all skiers. That’s not terribly interesting, or meaningful. Mixed effect models allow us to estimate a separate parameter for each skier that (hopefully) captures the effect of race length on performance for each individual skier.

Beyond that, I’ll spare you the nitty gritty, except to say that I included a handful of other variables in the model to attempt to control for some other differences in race types (technique, mass vs. interval, etc.).

Out of all the women with a reasonable number of major international distance races (at least 10), these are the ones with who have performed ‘significantly’ better in longer races:

The more negative the value, the stronger the preference for long races. One of the reasons I like this kind of analysis is that it doesn’t just pick out people who are good at long races; it picks out people who are better at long races than short races. This means you aren’t just picking out the fast folks over and over again. There are plenty of big names here, but also some folks who are not dominant WC skiers. I’ve never hear of Annmari Viljanmaa, for example.

Therese Johaug floating to the top here probably isn’t a surprise, although it’s not like I’d count her out completely in a 5k. And I’m also not surprised to see three Italians here; they seem to excel at the longer stuff a lot of the time.

Who are some folks at the opposite end of this list? Along with a lot of people I’ve never heard from you’d find the likes of Vesna Fabjan, Ida Ingermarsdotter, Astrid Oeyre Slind, Katrin Zeller, Wendy Wagner and Natalia Korosteleva, who would all apparently tend to do worse in longer races.

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Head to Head: Bente Skari vs Stefania Belmondo

I haven’t done one of these in a while, so just for fun…

This time let’s compare two great female skiers from the 90’s (and early 00’s), Norwegian Bente Skari and Italian Stefania Belmondo.  Unlike with Daehlie and Alsgaard, things are little more balanced for these two:

Continue reading ›

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Comparing 1st And 2nd Runs In Slalom and GS

Wait, what? Alpine skiing?

Yep. I’ve got 18 seasons of World Cup, Olympic and World Championship alpine results. Not nearly as extensive as my XC results, but it’s interesting data nonetheless.

As with any new set of data, you spend a bit of time just poking around looking at stuff. Today I’m going to share something that I thought was rather odd, but that could be because my experience with alpine racing is, shall we say, limited.

With slalom and GS races, since you have times for each run (at least, since ~2000; before that FIS didn’t seem to report both times) an obvious thing to look at is comparing performance across the first and second run. Strangely, I thought that the people who ski fast on their first run would tend to be the generally faster skiers, and so would be more likely to ski fast on their second run as well. (Using my patented “Fast skiers ski fast” analytical technique.)

So here’s what we see using all the data: Continue reading ›

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OPA + Scandinavian Cup FIS Points Follow-Up

I started writing an answer to a comment to Monday’s post, but it started getting long, so I thought I’d make it a short post, instead.

Basically, the question was how can the points be so different between OPA and Scandinavian Cup races when the penalty calculation methods is exactly the same. Recall that these were the estimated point differences between the FIS points of top ten finishers at OPA and Scandinavian Cups and their FIS points in WCs.

OPA Cups:

EstimatedDifference StandardError
Men Distance 27.04 2.23
Men Sprint 16.73 3.10
Women Distance 43.24 2.95
Women Sprint 21.16 3.91

Scandinavian Cups:

EstimatedDifference StandardError
Men Distance -6.03 2.25
Men Sprint -6.67 2.40
Women Distance 4.05 3.09
Women Sprint -0.88 3.57

So, the penalty calculation method doesn’t really have anything to do with this. Suppose that someone races in an OPA Cup and receives 20 FIS points. Supposedly, this should mean that they ought to get about the same result in a WC race. But in reality what we see is that they tend to do quite a bit worse than this. At least, as measured by FIS points.

Conversely, if someone gets 20 FIS points in a Scandinavian Cup race, it’s much more likely that this is close to how they’ll perform in a WC race. Again, close as measured by FIS points.

So what’s happening here is that the penalties at OPA Cups are likely artificially low, in that they are overestimating the field strength. Notice that the estimates for many of the Scandinavian Cup disciplines were actually negative, indicating that FIS points at these races are actually underestimating people’s performance in a WC race. How could this be? Well, remember that the penalty at these races can’t be any lower than 15, but Scandinavian Cups often have several Norwegian or Swedish national team members present, perhaps working their way back from an injury or something. This means that the penalty of 15 is likely too high.

 

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Accuracy of FIS Points In OPA Cups vs Scandinavian Cups

Some comments on a recent post got me curious about the FIS points awarded at OPA Cup races. Similarly to my commenters, I’d noticed that oftentimes the top skiers at an OPA Cup race would receive very low (i.e. good) points for that race, and that this often wouldn’t seem to match up well with how they actually ski against a real World Cup field.

Here’s what I’m interested in: are the FIS points of top skiers at OPA Cups a worse indicator of performance on the WC than the FIS points of top skiers in high-level Scandinavian races (i.e. Scandinavian Cups). I think we all would suspect that the answer is yes; but how big is the difference? Can we quantify it?

Let’s take all the skiers who finished in the top ten in an OPA Cup race over the past five season and compare their OPA Cup FIS points with their WC/WSC/OWG/TdS FIS points. In the process, we obviously going to filter out some folks who didn’t participate in both types of races. Normally I just make a pretty graph, but I was feeling fancy, so here are some estimates of the difference in FIS points obtained via some simple linear modeling:

EstimatedDifference StandardError
Men Distance 27.04 2.23
Men Sprint 16.73 3.10
Women Distance 43.24 2.95
Women Sprint 21.16 3.91

These values all indicate significantly higher FIS points against actual WC fields for these skiers. (Note: these models were fairly crude, but did attempt to account for the number of races of each type a skier did as well as general performance changes over time.) Note that generally speaking, OPA Cup FIS points are a worse predictor of WC FIS points in distance races; for the women, they are very bad, on average.

How about Scando races? Let’s do the exact same thing, but instead we’ll take the skiers who’ve finished in the top ten over the past five seasons in Scandinavian and even general FIS races held in Norway, Finland and Sweden. The estimates we get for this group of skiers are: Continue reading ›

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Good Young Finnish Women

A companion post to my previous entry looking at some of the Finnish men. I’m using a sort of cohort style plot. They compare each athlete’s FIS points (similar to, but not exactly, what FIS uses for their rankings) to those of athletes who have gone on to finish in the top ten in a WC, WSC or OWG event. There’s obviously a range of FIS points in that group, hence the varying shades of gray in the plot.

I just grabbed five (young-ish) Finnish women who had particularly good points last season, first looking at folks with good distance results( click through for full version):

No surprise to see Lahteenmaki there, and Kerttu Niskanen is another name I know fairly well. As for the sprinters: Continue reading ›

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Some Top Young Finnish Men

I can’t keep up on the enormous number of good young skiers from every nation. I have a hard enough time with just those in my own backyard, the US and Canada. So it’s fun to look at some folks from other countries that I’m not so familiar with. For instance, here are some graphs looking at some good young male skiers from Finland. I’m using ‘cohort’ style graphs; they compare an athletes FIS points at a particular age to the range of FIS points achieved by skiers in the past that have gone on to achieve top ten results at WC, WSC or OWG races. (Remember, of course, that FIS points have plenty of limitations, and I calculate them slightly differently that FIS. For instance, I select people’s best results from a season, not from a calendar year.)

First, here are five young Finnish men who had strong distance results last season (click for full version):

Obviously, one wants to be at or below the shaded region, ideally. But those shaded regions don’t represent everyone who was ever successful, so it’s certainly possible to buck the trend and be a late bloomer. It just happens less frequently. Perttu Hyvarinen certainly seems promising. Sami Lahdemaki does as well, despite a slight uptick in his results last season.

To go along with this, here are five good young Finnish sprinters; again, FIS points for sprinting are only measuring qualification speed: Continue reading ›

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