Primary School Deworming Project (PSDP)

Project Overview:
This program provided free medical treatment for intestinal worms (helminths) and schistosomiasis, and worm prevention health education lessons to children in 75 primary schools in rural Busia district, Kenya during 1998-2002. In contrast to previous deworming evaluations, which did not consider spillover effects (effects on children who do not receive treatment yet benefit indirectly from the program), PSDP randomized over schools rather than students. Schools were randomly divided into three groups:

• 25 Group 1 schools began receiving treatment in 1998
• 25 Group 2 schools began receiving treatment in 1999
• 25 Group 3 schools began receiving treatment in 2000

By comparing outcomes in the three groups, researchers were able to isolate the impact of deworming on health, nutrition, and education.

Sample:
Over 30,000 primary school children, 6-18 years old

Main Results:

• Deworming treatment reduced serious worm infections in children by one half. In other words, the prevalence of moderate-to-heavy helminth infections was reduced by 25 percentage points in the treatment group.
• Pupils that received treatment reported being sick significantly less often, had lower rates of severe anaemia, and showed substantial height gains. The average height gain in treatment schools was roughly 0.5 centimetres.
• When younger children (Standards 1-4) were dewormed, they attended school 15 more days per year, while older children attended approximately 10 more school days per year.
• The entire community and those living up to 6 km from the treatment schools benefited from the "spillover" effects of deworming. Spillover effects occur because medical treatment reduces transmission of worm larvae (eggs) to other community members. Spillover effects allowed pupils of neighbouring schools to attend school an average of 3-4 additional days per year. Although we did not collect data on adults, it is likely that older community members were able to work more days as a result of spillovers.
• Including the spillover benefits of treatment, the cost of keeping a child in school one additional day is only US$0.02, which makes de-worming considerably less expensive than any alternative method of increasing primary school participation.

Principal Investigators:
Edward Miguel and Michael Kremer (Harvard)

Academic Publications:

Edward Miguel and Michael Kremer. 2004. Worms: Identifying Impacts on Education and Health in the Presence of Treatment Externalities. Econometrica 72(1): 159-217. This paper won the International Health Economics Association's 2005 Kenneth J. Arrow Award for Best Paper in Health Economics.

In the News:

New York Times article "World Bank Challenged: Are Poor Really Helped?, 28 July 2004

ICS Africa Press Release "National De-Worming Pilot Project

ICS Africa Press Release "ICS Sits On National School Health Committee