| I think you raise important points, that are useful more generally in understanding the process of science and scientific review of papers. However, the correct answer to a non-significant study is not to assume that there is no difference, rather that we have not been able to detect a difference. The results section: A total of 3030 participants were randomly assigned to the recommendation to wear masks, and 2994 were assigned to control; 4862 completed the study. Infection with SARS-CoV-2 occurred in 42 participants recommended masks (1.8%) and 53 control participants (2.1%). The between-group difference was −0.3 percentage point (95% CI, −1.2 to 0.4 percentage point; P = 0.38) (odds ratio, 0.82 [CI, 0.54 to 1.23]; P = 0.33). Multiple imputation accounting for loss to follow-up yielded similar results. Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection. So, overall there were 95 participants who got a Covid diagnosis, of the 6k enrolled, and the 4.8k who completed the study. This is basically noise. My personal prior is that had this study taken place in the US or Brazil, we would have been able to detect an effect. However, clearly I don't have any evidence for this. tl;dr that study gives us very little information, because the baseline prevalance of Covid was so low that we don't have enough power to detect a difference between the two groups. This is consistent with a finding of masks don't work, and masks work (but we can't detect the difference in this study). |
I completely agree (which might be why I didn't write that there is no difference:) In fact, we don't know if there's a difference, or if there is, what the difference is, and right now the evidence (as a whole) points to a negative difference for the outcome we're hoping for. It's essentially a (fairly) open question at this point (which again leads back to the religiosity on show from some "sides" in this debate).
The statement was:
> To say that cloth masks "haven't been shown to help do anything" is demonstrably false
I just want to cut down statements like that, statements that really are demonstrably false* in their certitude.