I investigate whether a school-based deworming intervention in Kenya had long-term effects on young children. I exploit positive externalities from the program to estimate impacts on younger children who were not directly treated. Ten years after the intervention, I find large cognitive effects—comparable to between 0.5 and 0.8 years of schooling—for children who were less than one year old when their communities received school-based mass deworming treatment. I find no effect on child height or stunting. I also estimate effects among children whose older siblings received treatment directly; in this subpopulation, cognition effects are nearly twice as large.
Link to published paper in American Economic Journal: Applied Economics
Pre-print 2017 manuscript (pdf)
Earlier version appears as World Bank WPS 7052, October 2014, also available from SSRN
Data and analysis files: (hosted at ICPSR)
Featured in World Bank Development Research e-Newsletter May 2017, Deworming in early childhood can benefit younger siblings and the community
August 2015 VOX article: Mass deworming: (Still) a best buy for international development
July 2015 Center for Global Development blog post discussion: Mapping the Worm Wars: What the Public Should Take Away from the Scientific Debate about Mass Deworming
July 2015 GiveWell blog post discussion: New deworming reanalyses and Cochrane review
Featured in World Bank Development Research e-Newsletter November 2014
October 2014 blog post and video on Africa Can End Poverty: Deworming improves child cognition. Eventually.
September 2015 World Bank Evidence to Policy note: KENYA: Do Infants Benefit When Older Siblings are Dewormed? (also available in French)
Presentation at ASSA 2017
IPA project page
JEL codes: I10, O12, O15
Recommended citation: Ozier, Owen. "Exploiting externalities to estimate the long-term effects of early childhood deworming." American Economic Journal: Applied Economics 10, no. 3 (2018): 235-62