VendorMark 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…

Coming at VendorMark’s question from a different direction. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

Adding the numbers, since they settle part of this. One practical note: write down what you did and when, before you need it. Reconstructing a timeline from memory three months later is how people end up unable to answer the one question that would have resolved it.

I would rather be corrected than agreed with, if it comes to it.

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

How long did you give it before you decided it was working?

PharmacoVig_BOS said:

One practical note: write down what you did and when, before you need it.

This is where I part company with the consensus forming above. Not convinced. The evidence being cited is consistent with the conclusion and also consistent with two other conclusions nobody has ruled out.

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

PharmacoVig_BOS said:

One practical note: write down what you did and when, before you need it.

True, and it depends on a baseline nobody has stated. Without knowing where someone started, the same number can be an excellent result or a disappointing one.