KevinCompounds said:

It is worth asking what the claim would look like if it were false.

True, with the qualification that this is a self-selected group. The people for whom it did not work post less, and that shapes everything we think we know.

CarlaRPh_TPA said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

This answered a question I did not know how to ask.

KevinCompounds said:

It is worth asking what the claim would look like if it were false.

This is where I part company with the consensus forming above. Not convinced. The evidence being cited is consistent with the conclusion and also consistent with two other conclusions nobody has ruled out.

The figures, for anyone assembling their own picture. Say what you would expect to see if you were wrong, before you look. It is a small discipline and it changes what you notice.

Moderator note: the sourcing question belongs in the vendor section and has been split out. Report rather than reply if it drifts again.