When our finds robust and meaningful differences between charities, it plays a large role in our recommendations (more on the role it plays in this ).
But while our cost-effectiveness analysis represent our best guess, it's also subject to substantial uncertainty; some of its results are a function of highly debatable, difficult to estimate inputs.
Sometimes these inputs are largely subjective, such as the moral weight we assign to charities achieving different good outcomes (e.g. improving health vs increasing income). But even objective inputs are uncertain; a key input for anti-malaria interventions is malaria mortality, but the Institute for Health Metrics and Evaluation estimates 1.6 times more people died in Africa from malaria in 2016 () than the World Health Organization does ().((Differences in their methodology have been discussed, with older figures, in a by the Center for Global Development.))
Before we finalized the recommendations we released in November, we determined how sensitive our results were to some of our most uncertain parameters.