How good the other unit is, field position, and strength of schedule, none of which are relevant to how good the unit is.
For example, UCF (16) and Utah State (7) and top 20 in total offense. Any stag that purports to have them in the top 20 I don’t think is that useful at all. An offense can move the ball really well, but have fewer possessions, get good field position, and play really tough teams and end up pretty low in total offense