Dr.ReproEndo said:

There is a difference between no evidence and evidence of no effect, and this subject is one where the two get swapped freely in both directions.

There is a second half to this that has not been said yet. The distinction that resolves most of these threads is between what is true on average and what is true for one person. Both are real; they answer different questions and get quoted as if they were the same one.

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

The figures, for anyone assembling their own picture. If you are comparing against somebody else’s result, check that you are comparing the same measurement taken the same way. Most of the apparent contradictions in these threads dissolve at that step.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

Following on from Dr.ReproEndo — and this may be the naive question:

What did you change at the same time, and can you separate the two now?

NicoleRaleigh said:

If you are comparing against somebody else’s result, check that you are comparing the same measurement taken the same way.

Pushing back on NicoleRaleigh here. Filing an objection on the n=1 problem. Personal experience is genuine evidence about one person and very weak evidence about anybody else, and this thread keeps promoting the first into the second.

If somebody has the primary source to hand I would rather cite it than paraphrase it.

NicoleRaleigh said:

If you are comparing against somebody else’s result, check that you are comparing the same measurement taken the same way.

Fair, and it stops being fair at the extremes. The middle of the range is well understood; the ends are where the honest answer is that nobody knows.