Before 2020, based on the available evidence, we didn’t believe that water quality interventions had a large enough effect on mortality to make them a competitive target for funding. We’ve since seen new evidence that has led us to significantly increase our estimate of the mortality reduction in young children that’s attributable to these interventions: a 14% reduction in mortality from any cause, up from around 3%.
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Where we previously found that Evidence Action’s Dispensers for Safe Water program was about as cost-effective as unconditional cash transfers, we now believe it’s about four to eight times as cost-effective, depending on the location. That was a primary factor in our decision to recommend a grant of up to $64.7 million to Dispensers for Safe Water in January 2022.
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In low-income settings, contaminated water is a major cause of diarrhea, a leading cause of death in children under five years old. Several interventions exist to either purify water or protect it from contamination in the first place, but chlorination has a number of features that made it an attractive intervention for us to explore: it is inexpensive and widely used, several charities are already set up to implement it, and the technology behind it is well established.
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Pooling studies allowed Kremer’s team to obtain statistically significant results from studies that weren’t individually large enough to produce such results on their own. These results suggest that water treatments have a significant effect on mortality from any cause (“all-cause mortality”) in children under five—Kremer et al. currently estimate a roughly 25% reduction.
Their finding is especially noteworthy because it comes from an analysis of direct evidence on mortality, and it is eight times larger than an indirect estimate that extrapolates from diarrhea morbidity. This implies that water treatment yields a mortality benefit that cannot be fully explained by reduction in diarrhea alone.
From the article:
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