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


  • Kevin Croke
  • Joan Hamory Hicks
  • Eric Hsu
  • Michael Kremer
  • Edward Miguel


The WHO has recently debated whether to reaffirm its long-standing recommendation of mass drug administration (MDA) in areas with more than 20% prevalence of soil-transmitted helminths (hookworm, whipworm, and roundworm). There is consensus that the relevant deworming drugs are safe and effective, so the key question facing policymakers is whether the expected benefits of MDA exceed the roughly $0.30 per treatment cost. The literature on long run educational and economic impacts of deworming suggests that this is the case. However, a recent meta-analysis by Taylor-Robinson et al. (2015) (hereafter TMSDG), disputes these findings. The authors conclude that while treatment of children known to be infected increases weight by 0.75 kg (95% CI: 0.24, 1.26; p=0.0038), there is substantial evidence that MDA has no impact on weight or other child outcomes. We update the TMSDG analysis by including studies omitted from that analysis and extracting additional data from included studies, such as deriving standard errors from p-values when the standard errors are not reported in the original article. The updated sample includes twice as many trials as analyzed by TMSDG, substantially improving statistical power. We find that the TMSDG analysis is underpowered: it would conclude that MDA has no effect even if the true effect were (1) large enough to be cost-effective relative to other interventions in similar populations, or (2) of a size that is consistent with results from studies of children known to be infected. The hypothesis of a common zero effect of multiple-dose MDA deworming on child weight at longest follow-up is rejected at the 10% level using the TMSDG dataset, and with a p-value

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  • Kevin Croke & Joan Hamory Hicks & Eric Hsu & Michael Kremer & Edward Miguel, 2016. "Does Mass Deworming Affect Child Nutrition? Meta-analysis, Cost-Effectiveness, and Statistical Power," NBER Working Papers 22382, National Bureau of Economic Research, Inc.
  • Handle: RePEc:nbr:nberwo:22382
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    References listed on IDEAS

    1. Eva Vivalt, 2015. "Heterogeneous Treatment Effects in Impact Evaluation," American Economic Review, American Economic Association, vol. 105(5), pages 467-470, May.
    2. Owen Ozier, 2018. "Exploiting Externalities to Estimate the Long-Term Effects of Early Childhood Deworming," American Economic Journal: Applied Economics, American Economic Association, vol. 10(3), pages 235-262, July.
    3. Willett, W.C. & Kilama, W.L. & Kihamia, C.M., 1979. "Ascaris and growth rates: A randomized trial of treatment," American Journal of Public Health, American Public Health Association, vol. 69(10), pages 987-991.
    4. Serene A Joseph & Martín Casapía & Antonio Montresor & Elham Rahme & Brian J Ward & Grace S Marquis & Lidsky Pezo & Brittany Blouin & Mathieu Maheu-Giroux & Theresa W Gyorkos, 2015. "The Effect of Deworming on Growth in One-Year-Old Children Living in a Soil-Transmitted Helminth-Endemic Area of Peru: A Randomized Controlled Trial," PLOS Neglected Tropical Diseases, Public Library of Science, vol. 9(10), pages 1-20, October.
    5. Edward Miguel & Michael Kremer, 2004. "Worms: Identifying Impacts on Education and Health in the Presence of Treatment Externalities," Econometrica, Econometric Society, vol. 72(1), pages 159-217, January.
    6. McKenzie, David, 2012. "Beyond baseline and follow-up: The case for more T in experiments," Journal of Development Economics, Elsevier, vol. 99(2), pages 210-221.
    7. Hoyt Bleakley, 2007. "Disease and Development: Evidence from Hookworm Eradication in the American South," The Quarterly Journal of Economics, Oxford University Press, vol. 122(1), pages 73-117.
    8. Antonio Montresor & David Addiss & Marco Albonico & Said Mohammed Ali & Steven K Ault & Albis-Francesco Gabrielli & Amadou Garba & Elkhan Gasimov & Theresa Gyorkos & Mohamed Ahmed Jamsheed & Bruno Lev, 2015. "Methodological Bias Can Lead the Cochrane Collaboration to Irrelevance in Public Health Decision-Making," PLOS Neglected Tropical Diseases, Public Library of Science, vol. 9(10), pages 1-4, October.
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    1. Does Mass Deworming Affect Child Nutrition? Meta-analysis, Cost-Effectiveness, and Statistical Power
      by maximorossi in NEP-LTV blog on 2016-09-07 22:03:51


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    Cited by:

    1. Fox, Jonathan & Grigoriadis, Theocharis, 2018. "A rural health supplement to the hookworm intervention in the American South," Discussion Papers 2018/5, Free University Berlin, School of Business & Economics.
    2. Garret Christensen & Edward Miguel, 2018. "Transparency, Reproducibility, and the Credibility of Economics Research," Journal of Economic Literature, American Economic Association, vol. 56(3), pages 920-980, September.
    3. Roodman, David, 2018. "The Impacts of Hookworm Eradication in the American South. A replication study of Bleakley (The Quarterly Journal of Economics, 2007)," International Journal for Re-Views in Empirical Economics (IREE), ZBW - Leibniz Information Centre for Economics, vol. 2(2018-3), pages 1-45.
    4. Vivian A. Welch & Elizabeth Ghogomu & Alomgir Hossain & Shally Awasthi & Zulfi Bhutta & Chisa Cumberbatch & Robert Fletcher & Jessie McGowan & Shari Krishnaratne & Elizabeth Kristjansson & Salim Sohan, 2016. "Deworming and adjuvant interventions for improving the developmental health and well‐being of children in low‐ and middle‐income countries: a systematic review and network meta‐analysis," Campbell Systematic Reviews, John Wiley & Sons, vol. 12(1), pages 1-383.
    5. Stanley, T. D. & Doucouliagos, Chris, 2019. "Practical Significance, Meta-Analysis and the Credibility of Economics," IZA Discussion Papers 12458, Institute of Labor Economics (IZA).
    6. Bloom, David E. & Kuhn, Michael & Prettner, Klaus, 2018. "Health and Economic Growth," IZA Discussion Papers 11939, Institute of Labor Economics (IZA).
    7. Isaiah Andrews & Maximilian Kasy, 2019. "Identification of and Correction for Publication Bias," American Economic Review, American Economic Association, vol. 109(8), pages 2766-2794, August.
    8. Eszter Czibor & David Jimenez‐Gomez & John A. List, 2019. "The Dozen Things Experimental Economists Should Do (More of)," Southern Economic Journal, John Wiley & Sons, vol. 86(2), pages 371-432, October.
    9. Isaiah Andrews & Jesse M. Shapiro, 2020. "A Model of Scientific Communication," NBER Working Papers 26824, National Bureau of Economic Research, Inc.
    10. Kevin Croke & Joan Hamory Hicks & Eric Hsu & Michael Kremer & Edward Miguel, 2017. "Should the WHO withdraw support for mass deworming?," PLOS Neglected Tropical Diseases, Public Library of Science, vol. 11(6), pages 1-3, June.
    11. Kumar, Tanu & Post, Alison E. & Ray, Isha, 2018. "Flows, leaks and blockages in informational interventions: A field experimental study of Bangalore's water sector," World Development, Elsevier, vol. 106(C), pages 149-160.

    More about this item

    JEL classification:

    • C49 - Mathematical and Quantitative Methods - - Econometric and Statistical Methods: Special Topics - - - Other
    • I15 - Health, Education, and Welfare - - Health - - - Health and Economic Development
    • I18 - Health, Education, and Welfare - - Health - - - Government Policy; Regulation; Public Health
    • O15 - Economic Development, Innovation, Technological Change, and Growth - - Economic Development - - - Economic Development: Human Resources; Human Development; Income Distribution; Migration

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