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Anthropometric versus income measures of the standard of living:
Issues of theoretical consistency
Mary Eschelbach Hansen
Department of Economics, American University
4400 Mass. Ave. NW
Washington DC 20016
202-885-3973 (voice) 202-885-3770 (fax)
Department of Economics, University of Delaware
Background: Secular changes in anthropometric measures, such as height, are regularly used to infer
secular changes in the economic well-being. The existence of a positive correlation between change in height and change in historical real incomes has enabled the use of change in average height as a proxy for economic growth and decline. However, the correlation is not universal. In some historical circumstances, average height fell when real income rose. This paradox calls for careful examination of the relationship between measures of economic well-being.
Aim: The essay uses the fundamentals of utility theory to articulate the theoretical relationship between anthropometric measures and income measures of economic well-being, and to identify areas where additional theoretical work would be beneficial.
Conclusion: In order to be consistent with utility theory, a measure of overall economic well-being must capture any increase in new options available to people, including new options that arise from changes in relative prices. Anthropometric measures do not meet this criterion. When inputs into net nutrition of children become more expensive relative to other goods, lower levels of net nutrition for children may be consistent with higher levels of overall economic well-being. While anthropometric measures remain important measures of the health outcomes for populations, they cannot be interpreted as measures of overall economic well-being for all populations in history.
Anthropometric versus income measures of the standard of living:
Issues of theoretical consistency Mary Eschelbach Hansen Department of Economics, American University and Farley Grubb Department of Economics, University of Delaware I. Prologue Time magazine summarized the position of scholars studying anthropometrics or auxology thus: ‘The evidence of auxologists - who cross the disciplines of economic history, pediatrics, biology and sociology - is that average height reflects how well, or badly, a population is doing - its diet, wealth, quality of housing, levels of population, disease and stress - and is a far better measure of a nation's standard of living than such conventional indicators as gross national product or per capita income.’ A paragraph later the author stated, ‘There is no suggestion [in the anthropometric literature] that big is beautiful or better or that smart Davids won't continue to outdo lumbering Goliaths (Usher 1996, 64).’1 The author seemed unaware that he had reported a contradiction, namely that height both was and was not a superior measure of the standard of living. We believe that this contradictory assessment is indicative of a more general state of confusion over how height and other anthropometric measures relate to the standard of living. In this essay we point to areas where work is needed to articulate the relationship more clearly.
Over the last three decades, the study of human height has become prominent research agenda in economic history. Its thrust has been to use changes in anthropometric measures as an alternative to conventional economic measures of the standard of living, such as a substitute for changes in per capita real income (Floud 1992, 1994, Floud and Wachter 1982, Floud, Wachter, and Gregory 1990, Fogel 1986, 1989, 1993, Fogel, Engerman, and Trussell 1982, Fogel, et al. 1983; Komlos 1987, 1989, 1992, 1994b, Margo and Steckel 1982, Steckel 1979, 1983, 1986, 1992, 1994, 1995, Tanner, Whitehouse, and Takaishi 1966). Because data on human height exist for populations and periods where data on real income are lacking or unreliable, anthropometric research promises to allow comparisons of the standard of living over longer periods of time and across more disparate populations than has been possible up to now.
We argue that this promise has been prematurely made. It is not clear that the anthropometric measure is either superior to or a consistent proxy for the economic measure. We make an exploratory examination of the conditions under which an anthropometric measure might proxy the economic measure of the standard of living. We suggest some empirical tests of these conditions in order to refine our understanding of the circumstances under which anthropometric measures might be used to gauge the standard of living.
Our concerns are theoretical and interpretive rather than empirical. The collection of data by anthropometric researchers has been a success. Anthropometrics is a well-established research strategy for measuring an important aspect of the human condition - specifically health, the determinants of health, and the impact of health on society. While measurement, sampling, and estimation techniques have been debated, these debates are relatively minor.2 The proliferation of studies over the last two decades has allowed scholars to construct a nearly continuous series of heights from the present to 1710 for Americans of European and African descent, to the mid-eighteenth century for Britons and east-central Europeans, and to the late eighteenth century for several other European nationalities (Coclanis and Komlos 1995, Dye 1995, Floud and Wachter 1982, Floud, Wachter, and Gregory 1990; Fogel 1986, 1993, Fogel, Engerman, and Trussell 1982, Friedman 1982, Grubb 1999, Harris 1994, Johnson and Nicholas 1995, Kirby 1995, Komlos 1987, 1989, 1994a, 1994b, Mokyr and O'Grada 1994, 1996, Murray 1993, Nicholas and Oxley 1993, Nicholas and Steckel 1991, Riggs 1994, Sokoloff and Villaflor 1982, Steckel 1979, 1983, 1986, 1992, 1994, 1995. Recent work on skeletal evidence promises to extend the anthropometric records even further back in time (Steckel 2002, Steckel, Sciulli, and Rose 2002, Steegmann 1986). In short, the anthropometric literature has done an admirable job of charting how the human body has changed over time.
How changes in the human body relate to changes in the standard of living has received less critical scrutiny. The rhetoric presumes a clear and direct connection between how the body performs and the standard of living. The presumption grew out of work in biological science. Biologists demonstrated that the terminal height, the age at which terminal height is reached, and the age-specific velocity of growth in height measure the impact during childhood of the absorption of nutrients minus the energy claims made by metabolism, exertion, climatic conditions, and disease. Differences in height, therefore, can be used to measure differences over time and across populations in the nutritionexertion-climate-disease environments of children (the NECDEC). Clearly, such anthropometric measures can have economic determinants. But the NECDEC is not the same as the standard of living, as we will show. Nor is there an obvious or direct correspondence between secular changes in the NECDEC and secular changes in the standard of living.
We identify several problems of interpretation of anthropometric measures. First, while pointing out and constantly cautioning that height measures net nutrition and not gross nutrition, scholars proceed to the conclusion that differences in nutrition are the source of measured differences in height.3 Additionally, anthropometric research has only recently begun to address the exertion-climate-disease part of the NECDEC; in the main the published literature treats exclusively nutrition. The difficulty of measuring the exertion-climate-disease part of the NECDEC and directly incorporating it into anthropometric analysis does not explain the nutrition-centric conclusions. We argue that the need to assert a connection between economic and anthropometric measures of the standard of living has led scholars to focus on adult nutrition because the food intake of adults has a direct connection to the decisions of individuals in the market place. By contrast, the connection between economic decisions of adults and disease, climate, and the food intake of children is not so direct.
Early anthropometric studies showed a coincidence of trends between anthropometric measures and real income.4 The coincidence gave scholars confidence that anthropometric measures could be substituted for real income measures in time periods and economies where data on real income was lacking or unreliable. The initial coincidence of trends also left little need to develop a theoretical connection between anthropometric and economic measures of value. This confidence was shaken by the anthropometric evidence for nineteenth-century populations, which revealed substantial divergence between the anthropometric and real income measures of the standard of living. These findings cannot be explained away as isolated incidents or as anomalous events, because divergence occurred in a number of countries in Europe as well as in America, and in different decades in different countries (Floud, Wachter, and Gregory 1990, Fogel 1986, 1989, Fogel et al. 1983, Johnson and Nicholas 1995, Komlos 1987, 1989, 1993a, Nicholas and Steckel 1991, Steckel 1992, 1994, 1995, Steckel and Haurin 1994).5 The phenomenon of the divergence between anthropometric and real income measures of the standard of living during the nineteenth century has not been satisfactorily resolved. Empirical research has proceeded, while the validity of a key assumption of anthropometrics has been ignored. Without the assumption that height (or the NECDEC) is a positive, monotonic function of real income, anthropometric measures cannot be substituted for real income measures. If the assumption is set aside, anthropometricians must demonstrate that their measures are theoretically superior to real income measures of the standard of living. As it stands, scholars appear to hold a dualistic belief that anthropometric measures are the same as, but also fundamentally different from and superior to, real income measures of the standard of living. The following assessment of the British standard of living during the early nineteenth century seems a typical defense of anthropometric measures, A striking feature, to me, of the recent contributions to the debate is the juxtaposition of the evidence of rising real wages after 1820 beside the lack of evidence for what workers and their families were getting out of the increased wages before midcentury: no increase in food consumption, no increase in longevity or nutritional status, no improvement in housing. The infant mortality results presented here for the sample parishes in the heartland of the Industrial Revolution provide support for the view that clear evidence of significant improvement in the daily lives of English workers and their families is lacking before the middle of the century (Huck 1995, 547).
The author appears to be arguing that workers suffered no increase in consumption as their real wages rose, thus consuming under their budget constraints.6 The contrast between anthropometric and economic measures of the standard of living has been shaped, in part, by the subtle mischaracterization of the economic measure of the standard of living. The economic standard is not per capita real GNP, wages, or income, as a reading of the literature or popular press would lead one to believe. Real income, however measured, is merely an empirical tool for gauging the change in the true standard of living. The true standard of living is utility, or happiness, gained from consumption. Consumption, in turn, is defined broadly as any good, activity, or state of being that humans can acquire. Economic theory establishes the conditions under which observable changes in real income can be used to infer changes (increases or decreases) in utility. It should be noted that economic theory recognizes the necessity of establishing only one ‘standard’ of living. The fundamental attraction of utility theory is that it allows for the possibility that people may make utilityenhancing trade-offs across any goods, activities, or states over which they have the ability to choose.
Anthropometrics has not shown under what conditions changes in anthropometric measures can be used to infer changes (increases or decreases) in utility.
We address the following question: Can anthropometric and economic measures of the standard of living be made theoretically consistent with each other regardless of whether or not their competing estimates of the standard of living track each other or diverge? We begin by exploring the connection between how the body performs, the NECDEC, and the standard of living as presented in the literature.
There are two general ways to conceive of the NECDEC's connection to the standard of living.
It can be treated as just another good in the consumption basket used to calculate real income indices, that is, treated in the same way as art, alcohol, fruit, tobacco, toilets, and so on. Alternatively, the NECDEC can be treated as fundamentally different from the goods in the consumption basket that comprise real income indices. The anthropometric literature in recent years has been moving toward the latter treatment. The literature uses the term 'biological standard of living' (BSL) to suggest that the NECDEC is fundamentally different from the conventional economic measure of the standard of living.7 If the NECDEC is treated as one of many goods in the consumption basket, then living standards could always be driven by the consumption of other goods. But if we adopt the BSL interpretation of the NECDEC, the divergence between economic and anthropometric measures of the standard of living during the nineteenth century is not a source of contradiction because the two measures are fundamentally different. But the BSL cannot simultaneously be incomparable and superior to the conventional economic measure of the standard of living. Moreover, how the BSL fundamentally differs from the economic measure of the standard of living, and how it is connected to happiness or utility, is unclear.