Providing Clean Water: Evidence from Randomized Evaluations

Diarrheal diseases kill 1.6 million children annually, and a key cause is unsafe drinking water. The limited existing evidence from randomized evaluations suggests that consumers are willing to pay for increased quantity and convenience of water, but does not yet demonstrate that increasing quantity without improving quality improves health. On the other hand, multiple randomized evaluations suggest that many consumers have low willingness to pay for investments in water quality, such as chlorination, but these can improve health very cost effectively. Salient information on the quality of existing sources, personal contact with promoters, public messages, and convenience can all modestly boost the demand for water quality. A free chlorine dispenser placed conveniently and saliently next to an existing water source, and with a local promoter generates takeup of more than 60% compared to less than 10% under existing retail distribution models at an estimated cost of less than $20 per disability adjusted life years (DALY). Randomized impact evaluations have also generated a number of methodological insights: they have demonstrated the importance of survey effects (as well as ways to limit that impact); helped generate revealed preference measures of clean water valuation; and allowed experimental estimation of parameters needed for structural policy simulations.