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Posts tagged "Fun with Other Data"

A few weeks back, I discovered this list of all US junior and senior national team members dating back to 1983. I was primarily interested in testing out the narrative surrounding the growing number of clubs with gymnasts at the highest level, and you can read about that here. But basic summary statistics about the US national team are also intrinsically interesting, so since I have the data, I figured I’d share some more.

1. The senior national team has shrunk over time.

In the 1980s and 90s, the senior national team was almost always larger than twenty gymnasts. However, that hasn’t happened since 2004. Recent team sizes have been much smaller.

This might be related to the shrinking size of teams at international competition: if no more than five gymnasts will be needed to compete at any given competition, you don’t need as deep of a bench. Of course, it’s also worth noting that this data tells us nothing about who got funding. It’s possible that the changes in team size reflect changing norms around having unfunded athletes.

The junior national team was much smaller than the senior team in the 1980s and 90s, so we don’t see such a pronounced decline in its size. But from approximately 2000 onward, the junior team has been much closer in size to the senior national team. This may reflect an increasing emphasis on creating a pipeline of younger gymnasts who come up through the national team system.

To my surprise, we also don’t see much evidence of team sizes peaking during Olympic years. I was under the impression that the team grows as the Olympics approaches, both to let more athletes get closer to their dream and to maintain a large selection pool in case of injury. However, the data does not support this.

2. Most athletes don’t stay on the national team very long.

We know many gymnasts have short careers, but it’s really striking to see just how few athletes are able to hold on to a spot at the top in the US. The plot below shows the tenures of national team athletes.

The data begins in 1983, so I looked only at gymnasts who were on the team in 1990 or later for this analysis to ensure that I’m capturing athletes’ entire careers. For athletes who were on the team in 1990 or later, I do include all national team appearances going back to the 80s.

The mean national team athlete spends 2.74 years on the junior and senior national team combined. This is somewhat skewed by a few athletes with outstanding longevity: the median athlete is on the national team for just two years.

36.9% of athletes on the national team in this period — that is, 137 gymnasts — were only on the national team for a single year. 57.7% of athletes were only on the national team for one or two years. Put plainly, the vast majority of athletes who make it to the highest levels in US gymnastics do not stay there long.

There are, however, some very notable exceptions to this rule. Chellsie Memmel and Domique Dawes share the honor of spending a full decade on the national team. If Memmel succeeds in making the national team in 2021, she would become the single longest tenured member of the US national team in the modern era.

The full list of athletes with five years or more on the national team is below.

Chellsie Memmel10
Dominique Dawes10
Alicia Sacramone9
Nastia Liukin9
Amy Chow8
Ashley Postell8
Bridget Sloan8
Dominique Moceanu8
Jennie Thompson8
Mohini Bhardwaj8
Rebecca Bross8
Shannon Miller8
Tasha Schwikert8
Brenna Dowell7
Hollie Vise7
Jamie Dantzscher7
Jana Bieger7
Jordan Chiles7
Katie Heenan7
Kerri Strug7
Kristen Maloney7
Kyla Ross7
Melanie Sinclair7
Vanessa Atler7
Alexandra Raisman6
Amanda Borden6
Courtney Kupets6
Gabrielle Douglas6
Jeanette Antolin6
Jordyn Wieber6
Kassi Price6
Kim Zmeskal6
Kristen Stucky6
Kristy Powell6
Larrissa Fontaine6
Madison Kocian6
MyKayla Skinner6
Samantha Peszek6
Shayla Worley6
Simone Biles6
Tabitha Yim6
Terin Humphrey6
Amelia Hundley5
Andree Pickens5
Bailie Key5
Carrie Nagle5
Chelle Stack5
Christy Henrich5
Elise Ray5
Juliet Bangerter5
Katie Teft5
Kim Kelly5
Kristal Uzelac5
Kristin McDermott5
Lindsay Wing5
Mary-Beth Arnold5
Melinda Baimbridge5
Morgan White5
Ragan Smith5
Sabrina Vega5
Samantha Shapiro5
Shawn Johnson5
Stephanie Woods5
Summer Reid5

3. A small number clubs have absolutely dominated the national team over time.

Get ready to do some scrolling: here’s every single club that’s had a gymnast on the national team since 1983 in one plot.

There are 178 teams on this list, which is a testament to the power of the semi-centralized system. It is incredibly impressive that 178 separate training programs have produced gymnasts capable of competing internationally. This is the true strength of American gymnastics: it is not reliant on a small number of individuals or vulnerable to the collapse of select programs. Elite gymnastics is widespread.

Of course, this plot above is highly skewed. Parkettes, Karolyis, CGA, and SCATS have all sent more than 30 athletes to the national team. (All of these clubs have been accused of abusive coaching practices.) On the other hand, most clubs — specifically, 59.4% of them — have only ever had one athlete on the national team. If you’d like to read more about measuring the extent to which the national team is dominated by just a few clubs, check out my last post!

Got any lingering questions that I can answer with this data? DM me on twitter or comment below!

Tags: Fun with Other Data

There’s a narrative I often encounter about the evolution of the national women’s gymnastics program in the United States. In the early days, there were a very small number of gymnastics clubs that could get you to the Olympics, creating a sort of "club of clubs." Gym hopping was rampant: adolescent girls regularly moved across the country to train, and coaches lived in fear that their top athletes would leave for someone with a bigger name.

But as the national team camps and the developmental program grew, so too did the number of top clubs. Camp served as a training opportunity for coaches as well as for athletes, and new coaches learned what it took to train a national team athlete.

So when I came across a list of former national team athletes and their clubs, I saw an opportunity to test the truth of this narrative. The data ranges from 1982 to 2019.

I found that the general trends hold up: national team athletes have become less concentrated at top gyms, and they tend to change clubs less frequently. But when we look more closely at the timing of these trends, we don’t see a sea change in the 2000s accompanying the onset of the current semi-centralized system. The trends are true, but the explanation isn’t.

Gymnasts on the National Team now come from more clubs.

I first calculated the average number of athletes on the national team per club in each year. If the number of athletes per club is high, then top gymnasts are clearly congregating at the same gym.The results are in the plot below.

This result is clear and unambiguous: over time, it’s become less common for a club to have multiple national team athletes. In 1982, there was an average of 2.53 athletes per club; in 2019, that number was just 1.35. The correlation between the year and the number of athletes per club is -0.81 and it’s statistically significant at alpha = 0.01.

I also measured the concentration of gymnasts at top clubs using the Herfindahl-Hirschman Index (HHI). This metric comes from economics, where it’s used to measure industry concentration: you calculate the market share of each firm in an industry, square it, and add up the results for each firm. Similarly, I calculated the share of national team athletes at each club in each year, squared those numbers, and added them up. The metric ranges from 0 to 1, with higher values indicating more concentration of gymnasts at a small number of clubs.

The HHI is a nice metric because it’s very sensitive to extremely large, dominant clubs. Consider two cases: 1) five clubs each send two athletes to the national team, and 2) one club sends six athletes to the national team, and four other clubs each send one athlete to the national team. In both cases, there are ten athletes and five clubs, giving us an average of two gymnast per club. However, in the second case, one club is much more dominant than the others. The HHI will reflect this fact: the first situation has an HHI of just 0.2, while the second situation has an HHI of 0.4.

The results are in the plot below. As we can see, the overall trend still exists: gymnasts were much more concentrated at top clubs in the early years of US gymnastics. In 1985, the year with the highest HHI on record, 8 of the 28 gymnasts on the national team came from SCATS, the gym of child abuser Don Peters.

However, we see that the HHI has remained relatively stable since around 2000, if not earlier. In other words, it seems as though the era of extremely high concentration of top gymnasts ended well before national team training camps and the developmental program became institutionalized.

Taken together, these two metrics confirm that the national team now represents a wider range of clubs than it did in the last — but they don’t prove that the USAG pipeline for younger gymnasts is the cause.

More clubs started breaking in before the camp system began.

The narrative gives us a specific explanation for this fall in concentration: the developmental program has supported new coaches, enabling new clubs to bring athletes to the elite ranks. To test this, I looked at the number of clubs who sent an athlete to the national team for the first time in each year, from 1992 onward.1

It’s simply not the case that an unprecedented number of new clubs have sent athletes to the national team since the onset of the developmental pipeline in the early 2000s. In fact, 1997 and 1998 were peak years for clubs to have their first athlete make the national team, with clubs like WOGA, Gym Max,Bart Connor Gymnastics, Gym Cats, and more reaching that milestone in that period.

What happened the late 1990s? Well, for one thing, the flood of young girls who signed up at their local gymnastics clubs after seeing Mary Lou Retton atop the podium in 1984 were becoming old enough to make the national team. My best guess is that the increasing variety of clubs at the highest level has as much to do with the rising popularity of the sport as it does with institutional factors within USAG. There was simply a greater chance that a girl with world-class potential would sign up at her local gym -- even if that gym wasn't already nationally renowned. Of course, this is just a hypothesis: I can’t say for sure if this explains the trends in the graph above. If anyone has historical data on gymnastics participation in the United States going back to the 1980s, send it my way — I’d love to test it out.

The plot shows that a healthy number of clubs are still having their first athlete make the national team — it’s not like the doors have closed. For example, World Champions, First State, ENA Paramus, IGN, and many more have all had their first athlete on the national team in recent years. It’s just not true that drastically more clubs have achieved this goal since the early 2000s.

Club hopping is less common now than it was in the past.

Finally, I counted the percent of national team athletes who changed clubs in each year. Specifically, I counted a gymnast as changing clubs if she represented a different club on the national team in the previous year.

I should note that this only measures club hopping at the highest level — that is, club hopping amongst gymnasts who have already been on the national team. The trend is more often described as young gymnasts who change clubs as soon as their potential becomes clear, hoping for a better shot at “making it.” It also counts gymnasts as club hopping when their club changes names, or when they follow their same coach to a new club. Nevertheless, the trends are informative:

It’s clear that club hopping now is less common than it used to be. In any given year, a smaller share of national team athletes are training a new gym that they weren’t at in the previous year. The correlation between the year and the percent of gymnast who changed clubs is -0.48, and it’s statistically significant at alpha = 0.01.

This trend might be related to the falling concentration of athletes at a small number of gyms. Anecdotally, much of the club hopping of the 1990s and early 2000s occurred when a promising athlete felt she wasn’t getting enough attention due the presence of other top elites in her training group. For example, Kerri Strugg temporarily left the Karolyis after feeling overlooked, and the Rybackis famously played Vanessa Atler and Jamie Dantzscher off each other.

Of course, club hopping isn’t necessarily a bad thing — athletes should feel empowered to change coaches when a training situation isn’t working for them. But if the fall in club hopping is a sign that more athletes feel like they can achieve their goals at the local gym where they grew up, so much the better.

In Conclusion

The general narrative is true: national team athletes are no longer so concentrated at a few top clubs, and they’re less likely to hop around during their tenure on the national team. The era of the "club of clubs" is gone. But the common explanation for these trends doesn’t hold up. The data simply doesn’t support the claim that these changes occurred due to the rise of the national team training camps or the developmental pipeline that became institutionalized in the 2000s.

So what does explain the trends? My best guess is that it has to do with the rising widespread popularity of the sport, but I can’t be sure. If you’ve got another idea, drop me a comment or let me know on Twitter!

1These results might contain some errors because my data only goes back to 1982 — it’s possible that some clubs had athletes competing internationally before 1982 but not in the decade between 1982 and 1991. My method would count those as “new” clubs on the scene.

Tags: Fun with Other Data