GiveWell’s latest webinar took a close look at a critical step in our research process: how we’re working to evaluate past grants to understand what happened, why, and how we can use what we learn to improve our grantmaking over time.
Our research spans the full lifecycle of grants. Before we approve funding for a grant, our research team reviews academic evidence, builds cost-effectiveness models, and consults with experts to estimate the program’s expected impact. When programs near the end of their funding, we investigate whether a grant achieved the impact we initially projected. In 2025, our growing research capacity enabled us to expand this final step for select grants and publish comprehensive evaluations that we call “lookbacks.”
During the webinar, GiveWell co-founder and CEO Elie Hassenfeld moderated a discussion with Program Directors Alex Cohen and Julie Faller and Senior Program Officer Adam Salisbury. They covered four examples of grant lookbacks—discussing what we’ve learned and how these lessons are informing our work—and answered questions from the audience live.
Elie, Alex, Julie, and Adam discussed:
Cash incentives that are more cost-effective than we estimated: New Incentives aims to increase coverage of routine childhood vaccinations in northern Nigeria by providing small cash incentives to caregivers who bring their children to health clinics for vaccinations. GiveWell has directed over $140 million in grants to support the program since it became a Top Charity in 2020. One of GiveWell’s first lookbacks was on our initial $17 million grant to New Incentives. We found the program was about twice as cost-effective as we initially estimated—saving around 8,000 lives. The program reached roughly twice as many children as expected, at about half the cost per enrolled child. This difference from our initial estimate illustrates the uncertainty in our cost-effectiveness estimates and the value of ongoing monitoring, reassessing our analysis, and collecting additional information beyond what’s included in our models—such as an implementer’s track record, conversations with experts and local officials, or qualitative reasons to think a program might outperform its initial estimate.
Following the data to a difficult decision on chlorine dispensers: In 2022, GiveWell made a grant of around $65 million to support Evidence Action’s Dispensers for Safe Water program, which installs chlorine dispensers for households to treat their drinking water. Our lookback found that roughly a third as many people were using the dispensers as we had estimated. This discrepancy was identified after a separate GiveWell-funded study in Kenya suggested chlorination rates were far lower than Evidence Action’s routine monitoring indicated, prompting GiveWell and Evidence Action to