One billion people worldwide lack access to clean water (United Nations, 2008). Five thousand children die every day of diarrhoeal diseases caused by unsafe water and poor sanitation, such as cholera, typhoid and dysentery.

 

A 3ie-organized session at the recent Campbell Collaboration Colloquium presented new evidence on how better access to water and sanitation can save lives through better child health.

 

The consensus is that water treatment at point-of-use and hygiene interventions are necessarily the most effective and sustainable interventions to help reduce diarrhoea. However, new evidence from a forthcoming synthetic review funded by 3ie shows that sanitation interventions such as the promotion and installation of toilet are also highly effective – though the sanitation Millennium Development Goal is one of the most seriously off-track.  

 

A 3ie case study of Nepal supports this finding. Evidence from DHS surveys shows a 40 per cent reduction of diarrhoea cases attributable to sanitation coverage among children under 5 years (“The impact of Water Supply and Sanitation interventions on child health: evidence from DHS surveys” by Ron Bose).

 

In spite of this, the sustainability of these interventions remains an issue. The 3ie study showed that impact falls over time. An important aspect of sustainability is the willingness to pay for clean water, which is being explored in another 3ie-financed synthetic review (“A synthetic review of household valuations of water quality improvements in developing countries” by Michael Kremer, Robyn Meeks, Edward Miquel, Clair Null, and Alix Peterson Swane).The evidence collected so far suggests that people are sensitive to price in their use of water treatment.

 

A number of other 3ie funded reviews from developing countries were presented at the Colloquium. Overall, systematic review helps determine the gaps that need to be filled through primary research, and identify what works, what doesn't, and why, based on existing evidence.

 

The Campbell Collaboration is an international research network and partner of 3ie, which provides technical support to produce systematic reviews of social interventions and manage an emerging library of high quality reviews.