TinaHashiRN 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.

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.

wanda_boise said:

Agreed, with the usual condition: that holds for the average and this board is a collection of individuals.

Genuinely useful, thank you. I had the facts and not the framework. I will report back once I have actually tried it.

TinaHashiRN 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.

Careful with the causal language. Two things moving together in a period when five things changed is not a mechanism, and stating it as one makes the thread less useful to somebody reading it later.

One concrete data point for the thread. The boring version of this is the one that works, and the boring version is: measure a baseline, change one variable, wait, measure again under the same conditions. Nobody wants that answer and it is still the answer.

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

Moderator note: the sourcing question belongs in the vendor section and has been split out. No action needed from anybody.