GiveWell

GiveWell is an American charity evaluator. GiveWell was founded by Holden Karnofsky and Elie Hassenfeld, who aimed to rigorously assess the effectiveness of non-profits with the techniques they used while working at a hedge fund. Karnofsky and Hassenfeld initially promoted the project with sockpuppets on Internet forums and blogs, and they received early funding from the William and Flora Hewlett Foundation's Nonprofit Marketplace Initiative. GiveWell later partnered with Good Ventures to establish Coefficient Giving.

GiveWell has said that it has guided the donations of 150,000 donors and moved $2.6 billion to their recommended organizations. Under their cost-effectiveness estimates, this has averted 340,000 deaths. GiveWell has been criticized for insufficiently informing its readers of the risks and harms of the charities it recommends.