Does Mass Deworming Affect Child Nutrition? Meta-Analysis, Cost-Effectiveness, and Statistical Power

Abstract

for helpful comments. Michael Kremer declares that he is a former board member of Deworm theWorld, a US non-profit organization. He has received no funding from Deworm the World. He is also a part-time employee of USAID, which financially supports deworming activities. This paper was written in his academic capacity and USAID had no influence over the writing of this paper. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

Identification of and Correction for Publication Bias

“…Fitting this model yields the estimates reported in Table 4. The point estimates here suggest that statistically significant results are less likely to be included in the meta-study of Croke et al (2016) However, the standard errors are quite large, and the difference in publication (inclusion) probabilities between significant and insignificant results is itself not significant at conventional levels, so there is no basis for drawing a firm conclusion here. Likewise, the estimated θ suggests a positive average effect in the population, but is not significantly different from zero at conventional levels.…”

“…Second, we consider the literature on the impact of mass deworming on child body weight. Estimates based on data from the meta-study by Croke et al (2016) find that results appear more likely to be included in this meta-study when they do not find a significant impact of deworming, though the standard errors are large and we cannot reject the null hypothesis of no selectivity.…”

“…Our final application uses data from the recent meta-study Croke et al (2016) on the effect of mass drug administration for deworming on child body weight. They collect results from randomized controlled trials which report child body weight as an outcome, and focus on intent-to-treat estimates from the longest follow-up reported in each study.…”

“…They include all studies identified by the previous review of Taylor-Robinson et al (2015), as well as additional trials identified by Welch et al (2017). They then extract estimates as described in Croke et al (2016) and obtain a final sample of 22 estimates drawn from 20 studies, which we take as the basis for our analysis. For further discussion of sample construction, see Taylor-Robinson et al (2015), Croke et al (2016), and Welch et al (2017).…”

“…They then extract estimates as described in Croke et al (2016) and obtain a final sample of 22 estimates drawn from 20 studies, which we take as the basis for our analysis. For further discussion of sample construction, see Taylor-Robinson et al (2015), Croke et al (2016), and Welch et al (2017). To account for the presence of multiple estimates in some studies, we again cluster by study.…”