Inline chlorination: the problem and solution

GiveWell is often thought of for its Top Charities, but over the last several years, we’ve been substantially broadening our work. We’ve developed new ways to identify potential grantees, funded research to fill gaps in our understanding, and explored new program areas where we believe cost-effective opportunities exist but other funders aren’t investing. This increased breadth isn’t a goal in itself—we’ve been laying the groundwork to deliver more impact, now and in the future.

In this episode GiveWell CEO and co-founder Elie Hassenfeld speaks with Senior Program Officer Julie Faller about how our research approach has evolved and what it means for the future of our grantmaking.

Elie and Julie discuss:

• Launching new approaches for finding grantees: In the past, we primarily found grantees through our existing networks. We’ve recently started running requests for proposals for programs like in-line chlorination (a water treatment program) and vaccine outreach, which has allowed us to learn about and fund organizations we hadn’t previously worked with. As our research team has grown, we’ve gained expertise and the ability to articulate a clearer perspective on the kinds of programs we believe are likely to be cost-effective.
• Using a grant portfolio approach to learn more: From the hundreds of proposals we received for in-line chlorination pilot programs, we funded a portfolio of pilots across a number of African countries. Because we funded a wide range of organizations working in varying contexts with diverse program models, we’ll learn a lot very quickly and be able to apply those lessons to future funding decisions. We’re incorporating intensive monitoring and evaluation, as well as technical assistance to increase the likelihood that the pilots succeed and to maximize what we learn.  
• Broadening our research funding: While GiveWell has funded research for many years, we’re now taking a broader view of the research questions and research designs we might support. For example, we recently funded a study to better understand how hemoglobin levels among anemic individuals are associated with particular health outcomes, which could improve global anemia guidelines and our funding decisions for iron fortification and supplementation programs.

This work reflects some of the outcomes of a shift several years in the making. By strategically growing and diversifying our research team, we’re building the capabilities needed to direct more donations to highly cost-effective programs and help more people in need. 

Visit our All Grants Fund page to learn more about how you can support this work, and listen or subscribe to our podcast for our latest updates.

This episode was recorded on January 13, 2026 and represents our best understanding at that time.