Person:

Kremer, Michael

Two billion people are infected with intestinal worms. In many areas, the majority of schoolchildren are infected, and the World Health Organization (WHO) has called for school-based mass deworming. The key area for debate is not whether deworming medicine works—in fact, the medical literature finds that treatment is highly effective, and thus the standard of care calls for treating any patient known to harbor an infection. As the authors of the Cochrane systematic review point out, a critical issue in evaluating current soil-transmitted helminth policies is whether the benefits of deworming exceed the costs or whether it would be more prudent to use the money for other purposes. While in general we think the Cochrane approach is very valuable, we argue below that many of the underlying studies of deworming suffer from three critical methodological problems: treatment externalities in dynamic infection systems, inadequate measurement of cognitive outcomes and school attendance, and sample attrition. We then argue that the currently available evidence from studies that address these issues is consistent with the consensus view expressed by other reviews and by policymakers that deworming is a very cost-effective way to increase school participation and has a high benefit to cost ratio.

Two articles published earlier this year in the International Journal of Epidemiology [1,2] have re-ignited the debate over the World Health Organization’s long-held recommendation of mass-treatment of intestinal helminths in endemic areas. In this note, we discuss the content and relevance of these articles to the policy debate, and review the broader research literature on the educational and economic impacts of deworming. We conclude that existing evidence still indicates that mass deworming is a cost-effective health investment for governments in low-income countries where worm infections are widespread.

Rather than provide development assistance indefinitely, foreign aid donors increasingly seek to help communities sustainably provide local public goods themselves. We examine various strategies for sustainably fighting intestinal worms through voluntary local mobilization. Intestinal worms affect one in four people worldwide, but can be controlled by taking medicine twice annually. Since much of the resulting treatment benefit comes through reduced disease transmission, standard public finance analysis provides a rationale for subsidized treatment. Randomized evaluations suggest several efforts to replace subsidies with sustainable worm control measures were ineffective. A drug cost recovery program reduced take-up by 80%. A mobilization intervention designed to boost drug take up failed. Health education did not affect behavior. People were less likely to take drugs if randomly exposed to more information through their social network. In this context, using external interventions to promote sustainable voluntary provision of local public goods (like worm control) appears unrealistic.

We report results from a randomized evaluation of a merit scholarship program for adolescent girls in Kenya. Girls who scored well on academic exams had their school fees paid and received a cash grant for school supplies. Girls eligible for the scholarship showed significant gains in academic exam scores (average gain 0.12-0.19 standard deviations) and these gains persisted following the competition. There is also evidence of positive program externalities on learning: boys, who were ineligible for the awards, also showed sizeable average test gains, as did girls with low pretest scores, who were unlikely to win. Both student and teacher school attendance increased in the program schools. We discuss implications both for understanding the nature of educational production functions and for the policy debate surrounding merit scholarships.

We study a randomized evaluation of a merit scholarship program in which Kenyan girls who scored well on academic exams had school fees paid and received a grant. Girls showed substantial exam score gains, and teacher attendance improved in program schools. There were positive externalities for girls with low pretest scores, who were unlikely to win a scholarship. We see no evidence for weakened intrinsic motivation. There were heterogeneous program effects. In one of the two districts, there were large exam gains and positive spillovers to boys. In the other, attrition complicates estimation, but we cannot reject the hypothesis of no program effect.