What prevents child diarrhoea? The impacts of water supply, toilets, and hand-washing in rural India*

The authors apply three matching methods to estimate the impacts of water supply, toilet, and hand-washing interventions on child diarrhoea in rural India. Although propensity-score matching generally retains sample size, it can be associated with imbalance in the variables used to estimate propensity scores between treated and control groups. In contrast, exact matching is balanced over observables between treated and control units, but can result in considerable loss of observations. The authors also apply a novel ‘coarsened exact matching’ method that can potentially address the problem of sample attrition when matching. Their main finding using each of these three methods is that hand-washing, after defecating or before eating, significantly reduces prevalence and duration of a measure of overall diarrhea as well as acute watery diarrhoea among children under age five but not acute dysentery. In contrast, there may also be an effect of piped water on acute dysentery but not acute watery diarrhoea. Effects of improved water supply or improved toilets on different diarrhoeal outcomes are not observed consistently across matching methods.