Opinion: Do masks work? Randomized controlled trials are the worst way to answer the question
Early in the Covid-19 pandemic, before we had vaccines and effective medical procedures, the only ways to prevent transmission of the virus were behavioral measures like face masks and social distancing. There was (and continues to be) a desperate hunger for definitive studies telling us how well specific measures would work, with specific publics, in specific settings, for specific strains of the novel and changing virus. Although the scientific community mobilized at record speeds, it could not produce studies with the desired surety.
Indeed, the resulting studies could not, on their own, produce the evidence that public policy demanded. The virus was too new, and there were too many questions to answer all at once. As a result, unless researchers took extraordinary care to ensure that their necessarily ambiguous results were not misinterpreted, these studies led to incorrect conclusions — especially in a politicized environment.
