GiveWell is a nonprofit charity evaluator based in San Francisco. They conduct and publish research into the most cost-effective giving opportunities in global health and development (GiveWell 2017).
GiveWell was started by Holden Karnofsky and Elie Hassenfeld in 2007 (GiveWell 2018). GiveWell also helped incubate Open Philanthropy, which was spun off as a separate entity in 2017 (GiveWell 2018).
GiveWell annually publishes a list of "top charities" on the basis of cost-effectiveness and evidentiary basis (GiveWell 2020). As of November 2020, the top GiveWell charities were, in order:...