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

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

anders_CPH said:

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…

I read this differently from anders_CPH, on substance rather than tone. 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.

Moderator note: a couple of off-topic posts removed. Thread quality here is what the rules are for. Keep it up.

anders_CPH said:

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…

Bookmarking. The distinction being drawn above is the one nobody else makes.

From the other side of the consultation, briefly. The version of this that has an answer is narrower than the version being asked. Narrow it and it becomes tractable; leave it broad and the thread will produce nine confident and incompatible replies.