Monday, March 7, 2011

Most Typical Person

There has been an infographic video floating around which was put together by National Geographic called "7 Billion: Are You Typical?" Frankly, it bugs me a bunch on a few points.


I think this video plays too fast and loose with exceedingly simplistic statistical notions, resulting in simplistic results.

To begin with, the video asserts that the most typical human is a 28 year old Han Chinese man. Now, I'm not sure what they mean by "typical human." My default assumption would be that the most typical human traits would be ones which are most evenly distributed across the world. In fact, National Geographic is treating the world as a large, uniformly mixed urn of people, and if you were to randomly draw from that urn, a 28 year old Han Chinese man has the highest expectation.

Except, that's probably not true either. I've turned to Wolfram Alpha to check some global stats. And it is true that the global median age is about 28, the largest ethnic group is Han Chinese, and that 50.3% of the world population is male. However, the median age for men in China is 33.5 years. This "most typical" person is actually not especially typical for his country, based on this age pyramid.


It looks like if you were to randomly sample China, someone in the 20-24 year old age bin would be more typical than a 28 year old.

At some point, the video also says the most typical person in the world owns a cell phone. That doesn't appear to be true for China (.48 cell phones per capita), nor does it appear to be true for the world at large (.32 cell phones per capita). Maybe this is just an issue with differing data sources, or maybe National Geographic was playing some complicated word games. The actual line is "The most typical person has a cell phone, but not a bank account." Maybe what they mean is that if you were to place the world population into this table:


Bank Account No Bank Account
Cell Phone A B
No Cell Phone C D

cell B has the most people in it. But, that would be a strange thing to mean, especially because most people would fall into cells A, C and D. In that case, it would probably be more accurate to say that the most typical person either has both a cell phone and a bank account, or neither.

(Edit: Thinking about it now, if A+B = 32% according to Wolfram Alpha, then C + D = 68%, and there's no way to distributed 68% between those two cells so that they're both less common than B.)

Maybe this is all quibbling over details, but what does any of this video matter of the facts it gives are all a little off? I too could create an infographic video with flashy animation and an inspiring sound track (well, let's say I could, for the sake of argument), but with completely fabricated numbers. That video would not count for anything, because it matters whether the facts are true, and accurate.

So what is the point of this video? They tip their hand at the end. First, they say "typical is always relative," which is true, but they seem to be trying to deconstruct the notion that statistical generalizations are possible or useful. They end with talking about individual choices, and that "our choices make a big difference." Really, they seem to be pushing the idea that we are all individually the authors of global society, a notion that I find only slightly more plausible than the structure of the universe being moulded by our consciousness.

I read this as being a very American conception, and looking at the video again, it seems to really be all about contemporary American anxiety about the economic development of China and India.

2 comments:

  1. Not only are they conflating a bunch of stats, but I'm bothered by the implication that median=typical. If there were 2 billion people who were 65, 2 billion people who were 10, and one person who was 28 you would still have a median of 28. Would you really call 28 "typical" in that case?
    Median is a useful measure, but the use of it as a synonym for "typical" really bugs me.

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  2. Not only are they conflating a bunch of stats, but I'm bothered by the implication that median=typical. If there were 2 billion people who were 65, 2 billion people who were 10, and one person who was 28 you would still have a median of 28. Would you really call 28 "typical" in that case?
    Median is a useful measure, but the use of it as a synonym for "typical" really bugs me.

    ReplyDelete

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