The GiveWell Blog

Answering some questions about water quality programs

On June 22, we held a virtual event on research into water quality interventions, featuring presentations from Michael Kremer of the University of Chicago’s Development Innovation Lab; Brett Sedgewick from Evidence Action, the parent organization of Dispensers for Safe Water; and Stephan Guyenet, Elie Hassenfeld, and Catherine Hollander of GiveWell. (If you weren’t able to attend, we’ve published a video recording, audio recording, and transcript here.)

We hosted the event to provide some additional background for our recommendation of up to $64.7 million to Dispensers for Safe Water, which installs chlorine dispensers to treat water at rural collection sites in Kenya, Malawi, and Uganda. This grant was the result of a lengthy investigation and a significant update in our views on the cost-effectiveness of water treatment, which we’ve written about here.

Several attendees wrote in with a range of thoughtful questions—about our analysis of the effects of chlorination interventions, about the particulars of Dispensers for Safe Water’s program, or more generally about our work. We covered as many as we could during the event and followed up on others by email. Below, we’re sharing a selection of the questions we responded to in writing, along with other questions we’ve gotten about this work outside of the event, in the hope that they’ll be of interest to a broader audience. Questions and answers have been anonymized; some have been edited slightly for brevity, or to fill in important context that was missing.

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How we evaluate a study

We previously wrote about our general principles for assessing evidence, where “evidence” is construed broadly (it may include awards/recognition/reputation, testimony, and broad trends in data as well as formal studies). Here we discuss our approach to a particular kind of evidence, what we call “micro data”: formal studies of the impact of a program on…

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Development experiments (randomized controlled trials) as a counterpoint to marketing materials

There’s been a minor flurry of recent blog posts about randomized controlled trials (RCTs) in international aid, including William Easterly’s take and responses by Chris Blattman and GiveWell Board member Tim Ogden. A central theme has been the difficulty of generalizing from one experiment to whether something “works in general.” There seems to be a…

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