[frumiousirc]

> the mask group were only told to wear a mask

They were asked if and how they followed instructions and the 7% that said they did not were removed from the analysis. Only half of the remaining said they followed instructions. I also doubt the veracity of the replies. This is a weak point of the procedure.

[happytoexplain]

I'm confused as to why they removed that 7%. Are they or are they not trying to test the effect of advisement? If that really was the goal, then the veracity of replies wouldn't matter, and the study would make sense - but then they also wouldn't have omitted that 7%.