I've read a fair bit now, and I'm left with... questions. I haven't read it all yet, but nothing I've seen so far indicates that masks actually accomplish anything directly.

From the summary of results: "Medical masks were not effective, and cloth masks even less effective." I'm assuming that is referring to in hospital settings, but still... somehow they magically they work "in the community." Has anybody proposed or tested a reason for why they would work in one setting but not the other?

I saw no mention of controlling for how much time the participants (college students) spent with other people. Can we truly assume that wearing a mask had no other effect on the behavior of young people who are incredibly image-conscious and facing intense peer pressure to fit in? If I had to guess, the only thing they proved is that college students asked to wear masks will stay alone in their rooms more often than those not asked to wear masks. Of course, indirect benefits are still benefits. It is possible that something like this could happen when masks are mandated in public today. Meaning, mask mandates lead to people staying home more, which is obviously going to be effective. However, see next paragraph.

Another problem I saw immediately is that they were required to wear masks for long periods when in their dwelling, but not required outside of their dwelling. This, of course, is the opposite of what we are doing. What is the result of inverting the study practices?

They were studies on the flu. Can we assume the same effect on Coronaviruses?

From one study... "Generalizability limited to similar settings and age groups." Ok... so we're ignoring the paper's warnings about what we can learn from it?

In one study they were able to measure a decrease in flu-like-illnesses(ILI) with mask use, but it wasn't statistically significant, and it was only in the second half of the study (weeks 4-6). The summary ends with: "Neither face mask use and hand hygiene nor face mask use alone was associated with a significant reduction in the rate of ILI cumulatively." It then proceeds in the next sentence (the conclusion summary), to say, "These findings suggest that face masks and hand hygiene may reduce respiratory illnesses in shared living settings and mitigate the impact of the influenza A(H1N1) pandemic." Isn't this an example of a study what normally would be lampooned on this site? How exactly does the conclusion follow from the data?

Another study saw statistically significant reductions in ILI, but again, only in the second half of the study, and did not find statistically significant reduction in actual positive flu tests. It is summarized by: "Face masks and hand hygiene combined may reduce the rate of ILI and confirmed influenza in community settings. These non-pharmaceutical measures should be recommended in crowded settings at the start of an influenza pandemic." However, there was no control group that was just hand washing. Doesn't it seem much more reasonable to assume that the benefits are from hand-washing, rather than hand-washing and masks combined, since the mask-only group saw little to no benefit? And if so, why are we using this paper to prove that masks work?