We are still in the early stages of the COVID-19 pandemic, and there is considerable uncertainty about both basic facts about the disease, and potential interventions for reducing the pandemic's impact. Professor Nicholas B. King will discuss the roles of evidence, expertise, and uncertainty in decision-making during a pandemic, addressing questions including: what kind of evidence do we need? What do we need evidence for? How do we - decision-makers and the lay public - deal with uncertainty? What are the challenges to making good policy decisions under conditions of uncertainty?