Thanks Josh and Adam.
In my revenue model, a "Qualified Lead" is triggered by a lead score change with the new score >90
However, since I scored my leads for several years before I built my model, I have lots of people (probably far too many) whose score already exceeds 90. I don't want to call all of them qualified, as they may have been inactive for some time, or for other reasons. Therefore, I wanted to make a positive action trigger a "return to qualified". That's way using a "Previous stage = not qualified" or "Previous score is at least Y" won't work.
Could I make my Qualified Lead stage change trigger be "Lead score change", "New score >90" and "Score change is not -10" ? Then my alert will be triggering off of the right thing.
(The "lots of people with high lead scores" is why I've implemented the inactivity based negative scoring)