Sample-Selection Biases and the Historical Growth Pattern of Children

Abstract

Bodenhorn et al. (2017) have sparked considerable controversy by arguing that the fall in adult stature observed in military samples in the United States and Britain during industrialization was a figment of selection on unobservables in the samples. While subsequent papers have questioned the extent of the bias (Komlos and A’Hearn 2019; Zimran 2019), there is renewed concern about selection bias in historical anthropometric datasets. Therefore, this article extends Bodenhorn et al.’s discussion of selection bias on unobservables to sources of children’s growth, specifically focusing on biases that could distort the age pattern of growth. Understanding how the growth pattern of children has changed is important because these changes underpinned the secular increase in adult stature and are related to child stunting observed in developing countries today. However, there are significant sources of unobserved selection in historical datasets containing children’s and adolescents’ height and weight. This article highlights, among others, three common sources of bias: (1) positive selection of children into secondary school in the late nineteenth and early twentieth centuries; (2) distorted height by age profiles created by age thresholds for enlistment in the military; and (3) changing institutional ecology that determines to which institutions children are sent. Accounting for these biases adjusts the literature in two ways: evidence of a strong pubertal growth spurt in the nineteenth century is weaker than formerly acknowledged and some long-run analyses of changes in children’s growth are too biased to be informative, especially for Japan.

Stunting Rates in a Food-Rich Country: The Argentine Pampas from the 1850s to the 1950s

“…Later on, the 1927 Electoral Registry made into law a precept that was implicit from the late 19th century and became explicit in the 1912 electoral reform: only those who had made the military service were entitled to vote (and were listed in the electoral roster). For that reason, I do not think that our samples have the common selectivity problems some scholars attribute to military databases: truncation; different schooling; and social class [49,50].…”

Collider bias in economic history research

“…The recent debate sparked byBodenhorn et al (2017)'s critique of the anthropometric history literature has brought sample-selection bias back to the fore and prompted substantial new research on the topic including a special issue of Social Science History(Inwood and Maxwell-Stewart 2020;Komlos and A'Hearn 2019;Schneider 2020;Steckel and Ziebarth 2016;Zimran 2019). …”

Persistence of Natural Disasters on Children's Health: Evidence from the Great Kanto Earthquake of 1923

“…21 I do not use the height-for-age z-score of modern WHO standards to control for the age effects because the pubertal growth spurt of children in the early 20th century occurred at older ages than in modern healthy children. This leads to a distorted height-for-age profile for our sampled children (see Schneider, 2018). 22 The academic term runs from April to March in Japan.…”

“…This issue makes it difficult to identify whether the observed child stunting comes from fetal shocks or just the timing of child growth. See Schneider (2018) for a detailed explanation of this mechanism.…”