The problems of eligibility and endogenous confounders when assessing the mortality impact of a nationwide disease-prevention programme: the case of insecticide-treated nets in Togo

Evaluation of the mortality impact of nationwide disease-prevention efforts is complicated by potential endogeneity: programme recipients may have unobserved characteristics that simultaneously make them both more likely to become recipients and more likely to survive as a result of other health practices. This population-based study assesses the mortality impact of a nationwide programme that distributed insecticide-treated nets (ITNs) to mothers of children aged 9-59 months in Togo. By comparing mortality rates before and after the programme according to households' eligibility status, we demonstrate that a one-time programme that restricts eligibility to households with a surviving child excludes some households with a high risk of child mortality. We then apply simultaneous estimation models to untangle the mortality impact of ITNs from the effects of unobserved confounders and show that among eligible households, living in a household with ITNs significantly reduces mortality for children aged 20-59 months, even after controlling for endogeneity.