:: By Lydialyle Gibson

:: Graphic by Allen Carroll

Investigations ::

Hookworm and human capital

In 1909, when John D. Rockefeller gave $1 million to rid the South of hookworm, the parasite wasn’t
regarded as a plague. Yet its near-demise by 1914 had tremendous effects, say GSB researcher Hoyt Bleakley and Yale economist Fabian Lange, PhD’04. In a study to be published this year in the Review of Economics and Statistics, they argue that hookworm’s decline led to a significant rise in school attendance—children were particularly susceptible to infection—and the resulting increase in human capital led to falling fertility rates. Both boosted economic growth. The researchers calculate that an infection-rate drop from 40 to 20 percent accounted for 40 percent of the South’s entire fertility decline between 1910 and 1920.