Letter from America - American shortcomings: the highs and lows of publication

In his latest letter from America Angus Deaton shows how difficult it can be to ensure a serious discussion of research findings, especially when they touch on sensitive issues.

Americans always used to be the tallest people in the world. Some have argued that this was true even before Europeans set foot on North America. But the new Americans were taller too, and they established the advantage as early as the late 18th century. The wide-open, fertile, and healthy prairies were better places to grow up than the polluted European cities of the industrial revolution, not to mention the marginal agricultural land from which many immigrants came. But no longer. Mean heights of Americans are now less than mean heights in several European countries, not only in the Netherlands, which leads the world, but even in such apparently unpromising places as the erstwhile East Germany. After the birth cohort of 1960, it seems that Americans stopped growing, at least upwards. Why this should have happened is not understood. Nor is it clear whether anyone should be concerned. Governments are not held accountable for the heights of their populations, there is no international competition in mean height, nor has the United Nations added height to its human development index.

Taller is better?
Perhaps they should, according to a recent working paper by my Princeton colleagues Anne Case and Christina Paxson. Although their paper does not say so in so many words, the basic argument is that, at least on average, taller people are smarter. The paper, under the not obviously inflammatory title, ‘Stature and status: height, ability, and labor market outcomes’, was posted on the National Bureau of Economic Research’s website in mid-August. Much of the argument is about long-known regularities: taller children do better on cognitive tests; taller adults earn higher wages-about 2.5 percent per additional inch on average-and taller children become taller adults-height at age three explains about 75 percent of the variance in adult height. The new argument is that there is a plausible link. The labor market premium to adult height is eliminated once we control for the results of cognitive tests taken in childhood. And taller people select not into jobs and occupations that require brawn, but into those that require brains. Case and Paxson also outline a reasonable mechanism. Nutrition and health in utero and in childhood affect both cognitive and physical development, so that those who do not fulfill their genetic potential in one dimension may not fulfill it in the other. As they emphasize, this does not imply that men are smarter than women, and indeed there is no difference in their average scores on cognitive tests. Their paper is silent on national or historical differences, but if we suppose that the inhabitants of the eighteenth century were nutritionally deprived relative to their potential, they were possibly also short of their full cognitive potential, and the same may be true of people in poor countries today. And perhaps Americans should indeed be concerned about their recent shortcomings relative to the Dutch, the Swedes, or even the Germans, not to mention the Indians and Chinese roaring up behind them. There is also a worldwide secular upward trend in IQ scores that might, or might not, have something to do with the worldwide secular improvement in nutrition and the associated trend in stature.

Getting a fair reading
If I am misinterpreting, that is nothing compared to the reaction of some readers. The NBER Working Paper was picked up by Reuters news service under the title ‘Taller people are smarter’, and, in some versions, over a photograph of Peter Crouch. Reuters has a link to Yahoo News, from which the item was the top download among all news stories for several consecutive days. The paper was downloaded from the NBER website two thousand times in the next week. Discussions appeared in many blogs, and reasonable and well-informed comments have appeared or are planned in publications as diverse as The New Yorker, Scientific American, and Men’s Health. But the Washington Post presented the statement ‘Taller people are smarter’ as a direct quote, having excised the words ‘on average,’ turning it into a truly inflammatory challenge. And then there were the hate mail and phone calls. Apart from the perhaps surprising fact that substantial numbers of people will send obscene email (from their own accounts) to people they do not know, notable were the ‘comments’ from self-proclaimed short men, who seemed mostly upset that such views should have come from academics who were women, (aka ‘elitist bitches’) and whose suggestions for correction and redress were frequently in explicitly sexual terms. Americans may or may not have reason to be concerned about their diminishing relative height, but they certainly are sensitive on the subject.

There are other, quite different issues raised by this story. Case and Paxson, like the rest of the profession, will now submit their paper to an academic journal in economics. If they are lucky enough to find a home for it in one of the leading journals, the results will be published in perhaps the spring of 2009. But what does ‘published’ mean exactly, for a paper that has already been downloaded thousands of times, whose summarized contents have been read by many more thousands, and when the entry case+paxson+height+princeton returns 15,900 hits on Google? Whatever the economics journals are doing, ‘publishing’ is hardly an accurate description. It has long been the case in the medical sciences that not only the public, but also many professionals, gain their new knowledge from often ill-informed and always incomplete press reports, but medical papers have been (at least minimally) reviewed prior to press exposure. Indeed medical (and most science) journals will not publish papers that have been previously circulated or posted on the web. Perhaps economics journals need to move in this direction, promising rapid review in exchange for eliminating unreviewed dissemination. Presumably at least some of the newer electronic journals will speed things up, as will perhaps the brood of new journals that is currently being hatched by the American Economic Association. In the meantime, and as this story makes clear once again, the most important ‘journal’ in economics is the NBER working paper series. It provides a window through which the world watches economics, and where new work that catches the public imagination can be given wide coverage. The National Institutes of Health, which currently funds a great deal of economic research, including Case and Paxson’s study, has officially classified the NBER papers, which are not refereed prior to ‘publication’, as publications for purposes of monitoring old grants and obtaining new ones. For the doctors and scientists who dominate NIH, the idea that publication might take years is too bizarre to credit, and they are relieved to know that the way economists ‘really’ publish is through the NBER. All of which is splendid for the NBER and for the researchers who are associated with it. Others, not fortunate enough to have the connection, have no ‘write access’, to this important publication, which is determined entirely ad hominem, or in this case, ad feminam. Elitist indeed. We must surely find some way of doing better.

Disclosure Note: The Case (5' 8") and Paxson (5' 9") paper is available, and freely downloadable, at https://www.wws.princeton.edu/rpds/downloads/Case_Paxson_Stature_Status_8312006.pdf. Anne Case is married to Angus Deaton (6' 4").

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