[BostonCard]

Likewise, I'm just as cynical against studies that find nothing is good enough.  They mix studies together like apples & oranges and say that orange cider isn't very good, even though one did apple cider and the other did orange juice.  I'm sure it will be quoted by those supporting not using masks, not washing hands, not coughing into elbows, or not washing surfaces.  This was out in early release in March at the CDC when I was looking at evidence about face masks back when the CDC was insisting that there was no reason to wear masks unless you're taking care of a sick person.

Your points are well taken.  I think if you look at the figure I linked in, you can see that almost none of the individual studies that make up the meta analysis showed an effect; the confidence intervals for most of the studies include 1.  Also, if you look, the meta analysis reports a measure of heterogeneity; I2 is roughly a measure of how much variability there is between studies.  A value of 30% is fairly low, and a statistical test for heterogeneity (do you see more heterogeneity between studies than you would based on chance alone) was non-significant.

Now, none of this is to say that any of this proves that masks are harmful or even that it proves they aren't helpful.  If they make even a small difference, the cost (a few dollars and some mild discomfort) will be well worth it, because this is a very low cost intervention.  And theoretically, they should be helpful.  The bottom line is that I do use a mask when other social distancing measures like staying at home can't be pursued.  My pushback comes against those people who say it is self-evident that masks work, and especially, those who believe that masks are a substitute for other measures.

BC

[BostonCard]

Likewise, I'm just as cynical against studies that find nothing is good enough.  They mix studies together like apples & oranges and say that orange cider isn't very good, even though one did apple cider and the other did orange juice.  I'm sure it will be quoted by those supporting not using masks, not washing hands, not coughing into elbows, or not washing surfaces.  This was out in early release in March at the CDC when I was looking at evidence about face masks back when the CDC was insisting that there was no reason to wear masks unless you're taking care of a sick person.

Your points are well taken.  I think if you look at the figure I linked in, you can see that almost none of the individual studies that make up the meta analysis showed an effect; the confidence intervals for most of the studies include 1.  Also, if you look, the meta analysis reports a measure of heterogeneity; I2 is roughly a measure of how much variability there is between studies.  A value of 30% is fairly low, and a statistical test for heterogeneity (do you see more heterogeneity between studies than you would based on chance alone) was non-significant.

Now, none of this is to say that any of this proves that masks are harmful or even that it proves they aren't helpful.  If they make even a small difference, the cost (a few dollars and some mild discomfort) will be well worth it, because this is a very low cost intervention.  And theoretically, they should be helpful.  The bottom line is that I do use a mask when other social distancing measures like staying at home can't be pursued.  My pushback comes against those people who say it is self-evident that masks work, and especially, those who believe that masks are a substitute for other measures.

BC