Date Tuesday 9 February 2016
Venue Room 116, Sir Llew Edwards Building (#14)
Time 10:00 am

Ariell Zimran

Northwestern University


It is widely believed that the antebellum puzzle—a simultaneous decline in average stature and rise in GDP per capita, coupled with lower average stature in richer regions, in the antebellum United States— reveals a welfare cost of economic development that is hidden by conventional indicators; but it has been argued that the puzzle may be an artifact of sample-selection bias, stemming from a reliance on data from military volunteers to construct height samples. In this paper I provide the first empirical test of whether sample-selection bias explains the antebellum puzzle by using a two-step semi-parametric sample-selection model to estimate trends and patterns in average stature in the antebellum United States that are corrected for selection into military service on the basis of both observable and unobservable characteristics. This estimation is based on a new data set of my construction, consisting of military data from US Army enlistment records—including stature—for the birth cohorts of 1832–1860, linked to US census data and combined with similar data from the Union Army project. Identification is based on the incorporation of voting data from the presidential elections of 1856 and 1860, which measure political motives for military enlistment, and on differences in the nature of the military enlistment decision depending on whether an individual was old enough to serve in the Civil War. I find that the antebellum puzzle is robust to these corrections, and therefore is not an artifact of sample-selection bias. A net decrease in average stature of approximately 0.6 to 0.7 inches between 1832 and 1860 is present despite the correction, as is a gap of about 0.5 to 0.6 inches in favor of Southerners relative to Northeasterners. These results, however, do not imply that sample-selection bias can be disregarded in studies of historical heights. On the contrary, the degree of sample-selection bias is shown to vary over birth cohorts and across regions and sectors, and accounting for sample selection meaningfully and statistically significantly alters patterns in average stature across birth cohorts, regions, and sectors.