anders_CPH said:

Keep the original post as written when you update it, and add the correction underneath.

Pushing back on anders_CPH here. This treats a plausible mechanism as a demonstrated one. Plausible is where you start looking, not where you stop.

anders_CPH said:

Keep the original post as written when you update it, and add the correction underneath.

That is right, and it stops being right at the edges. The general case is well behaved; the interesting cases in this thread are all at the boundary where the general case breaks.

Correct me if the detail matters more than I have assumed.

anders_CPH said:

Keep the original post as written when you update it, and add the correction underneath.

Bookmarking. The distinction being drawn above is the one nobody else makes. Taking it to my next appointment.

Adding the clinical framing, because it changes how the question reads. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

OP back with an update, since a thread like this is useless without one.

Late follow-up. I did not do what was suggested, I did something adjacent, and it worked; posting the difference in case it matters to somebody.