A neat article on the use of randomized trials in economics research into poverty reduction: The Hyper-Efficient, Highly Scientific Scheme to Help the World’s Poor. "Hyper-efficient" is probably hyperbole, considering how some of the insights and solutions needed several years of hard field work.
... One of the most cost-effective ways to boost attendance came as a big surprise: treatment for intestinal worms, which caused absenteeism to drop by one-quarter. And it wasn’t only the schools receiving treatment that benefited. Attendance also rose at nearby schools as the overall transmission rate in the region dropped. The researchers calculated that, on average, deworming “buys” one extra year of school attendance for just $3.50, less expensive than any other intervention tested. This unexpected finding has led researchers to found an initiative called Deworm the World, which has worked in partnership with governments and NGOs to treat 37 million children.