Why are Africans getting shorter?

South Asia still posts the lowest average height for adults in the world (see image below). But a remarkable finding of a recent study is that adult Africans (among other low income regions of the world) have gotten shorter, on average, since the 1970s.

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.

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What explains deceleration in average adult heights on the Continent?

One obvious explanation is a decline in nutrition amid rising populations and declining agricultural productivity (Africa barely registered a green revolution). Another major culprit is the economic disaster that visited the Continent from the late 1970s to the early 1990s — which resulted in poor nutrition and an unchecked disease burden. Lastly, there is the issue of water and sanitation, especially in the context of a rapidly urbanizing population, which has direct implications for the realized disease burden.

Education and Human Capital Externalities (in Benin)

Wantchekon, Klasnja and Novta have a really cool paper (forthcoming in QJE) investigating the relationship between human capital and development:

Using a unique dataset on students from the first regional schools in colonial Benin, we investigate the effect of education on living standards, occupation and political participation. Since both school locations and student cohorts were selected with very little information, treatment and control groups are balanced on observables. We can therefore estimate the effect of education by comparing the treated to the untreated living in the same village, as well as those living in villages where no schools were set up. We find a significant positive treatment effect of education for the first generation of students, as well as their descendants: they have higher living standards, are less likely to be farmers, and are more likely to be politically active. We find large village-level externalities – descendants of the uneducated in villages with schools do better than those in control villages. We also find extended family externalities – nephews and nieces directly benefit from their uncle’s education – and we show that this represents a “family-tax,” as educated uncles transfer resources to the extended family.

The amazing finding is that having just one educated person in an extended family makes a significant difference, not only for the educated person’s offspring, but also for their nieces and nephews:

These descendants have better education at all levels than descendants (either children on nieces and nephews) in families where no progenitor was educated. These effects are statistically significant and substantial  – such descendants are 20% more likely to have primary school education, 19% more likely to have secondary school education and 11% more likely to go to university..

The main takeaway of the paper is that investment in human capital has a positive effect on long-term development that is independent of (colonial) institutions.