OK thank you for expressing your issues with the paper in a much more useful fashion that your first take, it's greatly appreciated.
I would note, however, that your strong point that self-reported data is garbage would lead you to disbelieve in the existence of pain, which seems like an unlikely interpretation.
That French study is interesting, I need to dig into it a little more.
That being said, do you think that people lied about being in hospital/on ventilator. That seems unlikely to me, and the cognitive outcomes seem to respond in a dose-dependent fashion to each step of Covid infection, which is not something that I would have expected to see if there were response biases going on.
Like, the only real explanation I can come up with here is that maybe a bunch of people were still sick, and this correlation drives the observed responses with cognitive function.
Looking at the methods, the Covid stuff comes after the cognitive test, so could not have impacted the cognitive test results. Additionally the actual webform (linked from the paper) shows nothing about Covid. Again, I think the biggest bias in this sample is likely to be their TV-watching status.
That being said, they did a complete cases analysis, which can often throw away lots of useful data, but it doesn't appear that many people quit halfway through (which is weird, given my experience of doing survey research).
> As the French CONSTANCES study (a much better study) I linked showed: when people are allowed to self-report even just their covid status, they mess up the results.
This comes under the headings of different disciplines are different I guess. If this study had been done under the aegis of a medical department, then we'd have laboratory confirmed Covid but they'd have messed up the cognitive test part. Science is difficult, and messy and often not satisfying to anyone, and personally I think we can learn things from this paper.
You disagree, I guess we'll find out when the systematic reviews/meta-analyses happen ;)