Of course, teaching comes to mind. There are all sorts of people weighing in on various sides of whether you can measure what a teacher does. There are bad teachers that sometimes certain metrics may find and sometimes they may not. There are plenty of things that a good teacher does that cannot be measured.
Seth's list of characteristics of what makes art:
Of course, if we try too hard, we'll end up trying to make a rubric to measure whether or not someone's teaching or other works are "artistic enough" which then actually completely misses the point in the first place.
But, think of the good and bad teachers you've had (or that you've been), and consider the 5 factors above. Are they realistic? Do they give more than they ask in return? Do they sometimes try things that don't work but still end up being just as much (or more) of a learning experience as the the lesson plans that were executed to perfection? Do they instill real change (for the better)? Is there a real personal touch present, even if but for a moment?