A Research Square study of two adjacent North Dakota school districts, one of which mandated student masking and one of which did not, found “no significant difference” in Covid-19 case rates between the two. The researchers, who received funding from the University of Southern California, noted that “randomized data about the effectiveness of mask mandates in children is still entirely lacking.” Indeed, they wrote, “While observational studies of school mask mandates have had conflicting results, randomized studies have failed to detect an impact of masking on participants under 50 years of age.” These researchers, however, were fortunate enough to discover...