Adding the clinical framing, because it changes how the question reads. 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.

Ask again with the specifics and you will get a better answer than this one.

stefan_berlin said:

If you are going to change something, change one thing and give it long enough to express itself.

Coming at stefan_berlin’s question from a different direction. If two explanations both fit, the useful question is which one predicts something the other does not. That is answerable; arguing about which sounds more plausible is not.

Adding the numbers, since they settle part of this. 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.

One thing that is still open after stefan_berlin’s answer:

What would you measure differently if you were starting again?

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. No action needed from anybody.