DanielChem_CHI 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 DanielChem_CHI, on substance rather than tone. Not convinced. The evidence being cited is consistent with the conclusion and also consistent with two other conclusions nobody has ruled out.

Reporting back.

Closing this out. What actually changed my mind was the point about waiting for a trend instead of reading a single measurement, which is embarrassing in hindsight and worth saying anyway.

DanielChem_CHI 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…

Thank you — that is the clearest version of this I have read, and I have read a lot of them. Taking it to my next appointment.

Adding the clinical framing, because it changes how the question reads. Order of operations matters more than any single choice here: establish a baseline, change one thing, wait long enough for it to express itself, then measure again under the same conditions.

Old thread, but it comes up first when you search for this, so it is worth updating. One habit that pays for itself: post the method alongside the number. A figure without its method cannot be checked, and an unchecked figure is how this community accumulates folklore.