Sex Ratios in LDCs: Amartya Sen 1, Freakonomics 0

♠ Posted by Emmanuel in ,,, at 6/05/2008 12:32:00 AM
I am somewhat late to this story (apologies), but I do believe that it warrants additional commentary. In the past, I have covered the increasingly lopsided gender imbalances in China and India [1, 2, 3]. Conventional wisdom holds that traditional preferences in these societies for male offspring--continuing the family name, receiving and not paying dowry in marriage, having better economic return potential, etc.--have been exacerbated by the widespread availability of ultrasound techniques in LDCs. Sex selective abortion has been identified as a culprit. Also, women are not given as much attention as their male counterparts after they are born. China's so-called one-child policy may have further exacerbated matters. Nobel Laureate Amartya Sen garnered widespread notice for estimating that there are 100 million missing women if normal sex ratios held instead of the lopsided ones observed in LDCs:
In view of the enormity of the problems of women's survival in large parts of Asia and Africa, it is surprising that these disadvantages have received such inadequate attention. The numbers of "missing women" in relation to the numbers that could be expected if men and women received similar care in health, medicine, and nutrition, are remarkably large. A great many more than a hundred million women are simply not there because women are neglected compared with men. If this situation is to be corrected by political action and public policy, the reasons why there are so many "missing" women must first be better understood. We confront here what is clearly one of the more momentous, and neglected, problems facing the world today.
You should be familiar with the popularity of Freakonomics that currently grips the economics profession. It has spawned a very popular book and blog. While some in the economics profession and beyond have disparaged the Freakonomics phenomenon and there has been a back-and-forth on it already, I tend to be indifferent to the controversy. As long as it produces worthwhile research output, then I would welcome it. Freakonomics owes a good measure of its popularity either to tackling offbeat topics and/or to offering non-intuitive explanations. A few years ago, Emily Oster, an economist who was then completing her PhD at Harvard, offered an explanation of lopsided sex ratios in LDCs which was indeed non-intuitive in the Freakonomics sense. She attributed a considerable part of the "missing women" phenomenon to to parents carrying Hepatitis B as suggested by Baruch Blumberg, a Nobel Prize winner in Medicine. Hepatitis B is said to promote lopsided sex ratios alongside more unsavoury factors alluded to above. Here is the abstract of her academic paper:
In many Asian countries the ratio of male to female population is higher than in the West: as high as 1.07 in China and India, and even higher in Pakistan. A number of authors (most notably Amartya Sen) have suggested that this imbalance reflects excess female mortality and have argued that as many as 100 million women are “missing.” This paper proposes an explanation for some of the observed overrepresentation of men: the hepatitis B virus. I present new evidence, consistent with an existing scientific literature, that carriers of the hepatitis B virus have offspring sex ratios around 1.50 boys for each girl. This evidence includes both cross-country analyses and a natural experiment based on recent vaccination campaigns. Hepatitis B is common in many Asian countries, especially China, where some 10–15 percent of the population is infected. Using data on prevalence of the virus by country and estimates of the effect of hepatitis on the sex ratio, I argue that hepatitis B can account for about 45 percent of the “missing women”: around 75 percent in China, between 20 and 50 percent in Egypt and western Asia, and under 20 percent in India, Bangladesh, Pakistan, and Nepal.
As with pretty much everything else, academia is very much a marketing-driven endeavour, and I do not think many would bother to argue with this point. Novelty is treasured, and I recall reading advice given to would-be academics that soliciting a "gee, that's interesting" response increases one's chances of being published in respected academic journals. (To no small degree, the appeal of Freakonomics due to its novelty has also spilled into the commercial realm.) Now, the Journal of Political Economy is among the major titles in the economics oeuvre, and therefore landing a publication there was a coup for Emily Oster. During that time, author Steven Levitt of Freakonomics fame was the editor for the JPE based at the University of Chicago. He wrote a laudatory piece on Oster's work in Slate as well. Subsequently, she took up a post at Chicago.

As you would expect, many have come forward to contest the explanation offered by Oster. It now turns out that she was wrong, and she has admitted so herself for reasons you can read about in what is, in effect, her mea culpa: "Together, the data suggests that the interaction between hepatitis B and offspring is more complicated than that posited in the original papers from the1970s and 1980s, and in Oster (2005)." In the meantime, Levitt has lauded her academic honesty. The whole episode raises questions on a number of fronts. While I am again indifferent to the Freakonomics phenomenon, these are things which should be asked:

(1) Editors of academic journals are supposed to act as impartial arbiters. Should Levitt have trumpeted the now-discredited findings of Oster in Slate in his capacity as a JPE editor?
(2) If Emily Oster's PhD was granted on the basis of research on Hepatitis B and the missing women which she now has cast doubts on, should the degree now be rescinded?
(3) In light of this episode, should academia--particularly in the social sciences--place less value on novelty?

These are important questions, and the reputations of the persons involved have probably been affected already. From the point of a political science major such as yours truly, however, more helpful research would have gone towards investigating more meaningful things with policy implications than searching for esoteric explanations for the missing women. These may be not be "freaky," but may have more practical utility in the long run. These include:

(1) To what extent have the attitudes of families in China and India shifted over time on gender issues? Have these attitudes been affected by the rapid economic growth in these countries?
(2) China and India have instituted policies aimed at discouraging sex-selective abortion. Have these been effective?

There are many meaningful questions to ask regarding this touchy topic--some of whose responses can probably benefit from the use of advanced econometrics that the Freakonomics gang is proud of using. However, asking the right questions may be more important than coming up with novel explanations in helping reduce these unfortunate occurrences. There are indeed limits to the value of novelty and number-crunching unique data sets. (If you are further interested, the Wall Street Journal has a story and a pair of blog posts [1, 2] on the subject here.)