Michael Kremer, Gates Professor of Developing Societies in the Department of Economics at Harvard University
Kevin Croke, Economist, Development Research Group, World Bank
David Roodman, Senior Advisor, GiveWell
Justin Sandefur, Senior Fellow, Center for Global Development
The WHO has recently debated whether to reaffirm its long-standing recommendation to deliver deworming drugs en masse to children in places with high worm prevalence. While deworming drugs are safe and cheap, a recent Cochrane review concluded there is “substantial evidence” that mass deworming has no impact on weight or other child outcomes, leading some to question the WHO policy.
Croke, Kremer, and co-authors revisit the Cochrane review’s methods and conclusions, drawing both policy lessons for an ongoing public health debate and methodological lessons for evidence synthesis more broadly. They argue that the Cochrane review’s conclusions were too conservative, confusing an absence of evidence from a small sample of studies with evidence of absence of a deworming effect. Based on their own analysis of a larger set of studies, Croke et al. conclude deworming’s effect is robustly positive, with a weight gain per dollar spent more than 35 times greater than found in RCTs of school feeding programs.
*The CIRF series is an academic research seminar that brings some of the world's leading development scholars to discuss their new research and ideas. The presentations are at times technical, but retain a focus on a mixed audience of researchers and policymakers. There’s more about the series here.