The news is awash today with a new study suggesting that schools with mask mandates have a 3.5x higher rate of "Covid outbreaks" than those with no such requirements. For example:  Newsweek  and  USNews . At this point it's pretty unclear why researchers are even willing to put their names on studies like this. I can think of a couple explanations: It's just a way of getting in front of more academic readers to burnish their credentials, or They believe that masks "should" work, so they want to encourage people by whatever means necessary to wear them in as many situations as possible. The study at hand is superficially compelling. A 350% increase in outbreaks is very significant, and that's such a large number that it's pretty unlikely to happen as a result of pieces of bad data or  P Hacking . When I read the popular news reports on it, I wondered whether I'd have to change my stance that the data on school masking is very shaky. Here are some ...