title: Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a pure replication.
abstract: BACKGROUND
  Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits regarding worm infections and school attendance. Effects were seen among children treated with deworming drugs, untreated children in intervention schools and children in nearby non-intervention schools. Combining these effects, the intervention was reported to increase school attendance by 7.5% in treated children. Effects on other outcomes (worm infections, anaemia, nutritional status and examination performance) were also investigated.
  
  
  METHODS
  In this pure replication, we used data provided by the original authors to re-analyse the study according to their methods. We compared these results against those presented in the original paper.
  
  
  RESULTS
  Although most results were reproduced as originally reported, we identified discrepancies of several types between the original findings and re-analysis. For worm infections, re-analysis showed reductions similar to those originally reported. For anaemia prevalence, in contrast to the original findings, re-analysis found no evidence of benefit. For nutritional status, both original findings and re-analysis described modest evidence for a small improvement. For school attendance, re-analysis showed benefits similar to those originally found in intervention schools for both children who did and those who did not receive deworming drugs. However, after correction of coding errors, there was little evidence of an indirect effect on school attendance among children in schools close to intervention schools. Combining these effects gave a total increase in attendance of 3.9% among treated children, which was no longer statistically significant. As in the original results, re-analysis found no effect of the intervention on examination performance.
  
  
  CONCLUSIONS
  Re-applying analytical approaches originally used, but correcting various errors, we found little evidence for some previously-reported indirect effects of a deworming intervention. Effects on worm infections, nutritional status, examination performance and school attendance on children in intervention schools were largely unchanged.
authors.affiliation: Department of Social and Environmental Health Research, Faculty of Public Health and Policy, and alexander.aiken@lshtm.ac.uk.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Aiken
authors.affiliation: Department of Social and Environmental Health Research, Faculty of Public Health and Policy, and.
authors.forename: Calum
authors.initials: C
authors.lastname: Davey
authors.affiliation: Department of Social and Environmental Health Research, Faculty of Public Health and Policy, and.
authors.forename: James R
authors.initials: JR
authors.lastname: Hargreaves
authors.affiliation: Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Hayes
mesh_terms: D000041:Absenteeism; D000871:Anthelmintics / Q000627:therapeutic use*; D002648:Child; D002657:Child Development / Q000187:drug effects*; D005260:Female; D006266:Health Education; D006373:Helminthiasis / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D008297:Male; D009752:Nutritional Status; D012574:Schools; D016896:Treatment Outcome
chemical_list: D000871:Anthelmintics
keywords: Helminth; Kenya; primary schools; randomized control trial; worms parasitic