Supposing they do use a threshold based on an absolute value, by what measure would they have chosen this value in the first place? How, when, and why would the

Supposing they do use a threshold based on an absolute value, by what measure would they have chosen this value in the first place? How, when, and why would they review this value? In the end, if their decision process is based purely on a number, it will eventually become a popularity contest or an excluder of outliers. It's turtles all the way down.