Tuesday, July 17, 2007

I Smell A Rat

With this popularization piece in the New York Times "If You're So Rich, Why Aren't You Tall?", but I'm too pressed for time to do research in it. The gist of the piece is this:

From the days of the founding fathers right on through the industrial revolution and two world wars, Americans towered over other nations. In a land of boundless open spaces and limitless natural abundance, the young nation transformed its increasing wealth into human growth.

But just as it has in so many other arenas, America's predominance in height has faded. Americans reached a height plateau after World War II, gradually falling behind the rest of the world as it continued growing taller.

By the time the baby boomers reached adulthood in the 1960s, most northern and western European countries had caught up with and surpassed the United States. Young adults in Japan and other prosperous Asian countries now stand nearly as tall as Americans do.

Even residents of the formerly communist East Germany are taller than Americans today. In Holland, the tallest country in the world, the typical man now measures 6 feet, a good two inches more than his average American counterpart.

Compare that to 1850, when the situation was reversed. Not just the Dutch but all the nations of western Europe stood 2 1/2 inches shorter than their American brethren.

Does it really matter? Does being taller give the Dutch any advantage over say, the Chinese (men 5 feet, 4.9 inches; women 5 feet, 0.8 inches) or the Brazilians (men 5 feet, 6.5 inches; women 5 feet, 3 inches)?

Many economists would argue that it does matter, because height is correlated with numerous measures of a population's well-being. Tall people are healthier, wealthier and live longer than short people. Some researchers have even suggested that tall people are more intelligent.

The article goes on to argue that all races have the same potential to be tall. It then states that something is happening in the United States which is making people shorter and this "something" is bad:

In another recent paper, Komlos and Lauderdale also found height inequality between American urbanites and residents of suburbs and rural areas. In Kansas, for example, white males are about as tall as their European peers; it's big cities like New York, where men are about 1.75 inches shorter than that, that drag America's average down.

Now Komlos has started comparing the heights of children to determine at what age Americans begin falling behind their peers across the Atlantic. Not surprisingly, he sees a difference from birth, an observation that suggests prenatal care may be significant contributor factor to the height gap.

All those sweeping and simple-minded theories make me suspicious. For instance, why doesn't the piece point out that the racial mix of people is pretty different in the rural Midwest from New York city and that New York city has many more immigrants than the rural Midwest, immigrants who may have grown up in poor areas with diminished nutrition? Or is Komlos only comparing white or Anglo males to each other?

I'm also not so sure about that argument that all races have about the same likelihood of growing tall and that good nutrition and so on will help you to get there. What research is that based on?

If that is true we should observe the ruling classes of the past in countries such as China to have been six feet tall while the ordinary people were quite short. Is that the case? I would have thought that some history book would have discussed this astonishing finding.

The piece also confuses the use of relative height as a health indicator within a community and the use of height as some kind of a general measure of excellence. The former can be useful, the latter not so much. Taken to its absurd extreme the latter idea means that we are supposed to find a twelve foot tall person the very picture of good health, never mind all the health problems that person would have.

Who knows what the research really says, of course. But I don't think the world is as simple as this story and other similar stories suggest.