What Has Been Learned from the Deworming Replications: A Nonpartisan View

A heated discussion on the value of mass deworming campaigns followed the release by a team of epidemiologists (Aiken et al, 2015; Davey et al 2015) of a replication analysis of an influential study on the educational benefits of deworming in Western Kenya (Miguel and Kremer 2004). Despite strong critiques of a seminal paper, and many rounds of responses, neither side appeared to change their views much on the quality of the evidence in the paper. Here I go back to the data and the arguments on both sides. My conclusion is that the replication has raised (or in some cases, highlighted) important questions both over the strength of evidence for spillovers and for the strength of the direct effects of deworming on school attendance – at least insofar as these pass through a worms mechanism. There should have been learning here. I point to structural factors that may contribute to the polarization of this discussion, make it hard for authors to acknowledge errors, and inhibit learning from this kind of replication exercise.
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