VendorMark said:

Practical: whatever you change, write down the date and the reason.

Agreed, and one caution: a single measurement is not a measurement. Anything that moves day to day needs a trend before it means anything at all.

VendorMark said:

Practical: whatever you change, write down the date and the reason.

This is exactly what I could not find anywhere else. I will report back once I have actually tried it.

Clinical perspective, offered as context rather than as advice. Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the correction. That is slower than asserting, and it is the only version that survives being wrong.

EndoResFellow said:

Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the…

This matches mine closely enough to be worth saying so out loud. I had assumed I was the exception until I read this.

EndoResFellow said:

Whatever the answer turns out to be, the method for getting there is the same: state the assumption, do the arithmetic in public, and invite the…

There is a second half to this that has not been said yet. Take it one variable at a time. Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent argument can untangle them after the fact.