There has been endless speculation during the Beijing Olympics as to whether the Chinese gymnasts are old enough to compete under Olympic rules, which require participants to turn 16 in the year that they compete.
Blog reader Chris Bourdon decided to stop talking about it and actually do some interesting data analysis.
Here is the e-mail message that Chris sent me:
I thought it would be interesting, in the wake of the controversy over the ages of the female Chinese gymnasts, to see if the numbers would say anything about their ages. So, putting “looks” and official government age documentation aside, how do the sizes of the Chinese gymnasts in question compare to the general Chinese population? And how do Olympic gymnasts compare to their countrymen in other countries?
Attached, find charts for the Chinese and U.S. 2008 women’s gymnastics teams. The charts show [statistics for] each gymnast’s height, weight, and officially reported age [along with] overlaying growth data from each respective country. The Chinese growth charts are from 1965 and can be found here.
Fwcc.org has links to more recent charts but [they] lack underlying data points, which makes graphing inaccurate. Suffice to say that Chinese women have gotten bigger across each percentile over the last 40-plus years.
The U.S. charts are from 2000 and can be found at the Centers for Disease Control and Prevention web site.
The statistics for each gymnast come from the official Chinese Olympic web site.
A few notable observations:
• All the U.S. gymnasts are at the 3 percent mark or above in each category, except Shawn Johnson, who is significantly below the 3 percent mark in height and slightly below in weight.
• Four of the six Chinese gymnasts are below the 3 percent mark in height, and three of the six are below the weight [of the average Chinese person] in 1965.
• The smallest Chinese gymnast is the same height and weight as an average 11 1/2-year-old Chinese girl was in 1965.
The charts Chris made do an excellent job of reinforcing what commentators are saying: these Chinese gymnasts are incredibly tiny.
All this discussion and analysis raises the question of why there should be any minimum age requirement at the Olympics in the first place.
I suspect one justification for banning 13-year-old gymnasts is that perhaps they are thought to have an unfair advantage because they are smaller and more flexible.
I can’t really believe that is true, however. I challenge you to name any activity other than gymnastics (excluding obvious things that depend purely on being small in stature) in which someone who practices regularly between the age of 13 and the age of 16 wouldn’t be a whole lot better by the age of 16 than they were three years earlier.