>The Centers for Disease Control in the U.S. have released multiple observational studies suggesting that school mask mandates significantly reduce case rates.

>The Centers for Disease Control in the U.S. have released multiple observational studies suggesting that school mask mandates significantly reduce case rates. >however, incorporating a larger sample and longer period showed no significant relationship between mask mandates and case rates. >Our study demonstrates that observational studies of interventions with small to moderate effect sizes are prone to bias caused by selection and omitted variables. Randomized studies can more reliably inform public health policy. I think the big story here is that the CDC is promoting bad science, while being treated as the gold standard by "fact checkers".