Trials. 2022 Sep 15;23(1):786. doi: 10.1186/s13063-022-06704-z.
ABSTRACT
A recent randomized trial evaluated the impact of mask promotion on COVID-19-related outcomes. We find that staff behavior in both unblinded and supposedly blinded steps caused large and statistically significant imbalances in population sizes. These denominator differences constitute the rate differences observed in the trial, complicating inferences of causality.
PMID:36109816 | DOI:10.1186/s13063-022-06704-z
