TrialNerd_Beth said:

Start from the measurement rather than the conclusion.

Correct as far as it goes. The part it does not cover is what to do when the honest answer is "not enough data", which is more often than anyone likes.

Dr.SleepRoch said:

Agreed, with a caveat about community reputation: it is a lagging indicator.

Genuinely useful, thank you. I had the facts and not the framework. Sending this to two other people who asked me the same thing last week.

TrialNerd_Beth said:

Start from the measurement rather than the conclusion.

Pushing back on TrialNerd_Beth 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.

Adding the numbers, since they settle part of this. Give anything pharmacological four weeks before you judge it, and give anything measured weekly a four-point rolling average before you call it a trend.

Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful.