I have judged in the past and have always had a "form" to fill out (and these art shows were judged by more than one "judge" so scores were combined). I think as art teachers we automatically do the calculations in our heads when "judging" our own students' work, however when it comes to ribbons (which personally I abhor, but I digress) there is a need for an accountability to take the judgement from "subjective" to "objective".