Groupwork redux

With tongue firmly in cheek I'm trying to develop an equation to express the spirit, if not the precise nature, of group work in library school. Here's my first whack:
P = S^1/2Mt^1/7/N

Where
P = performance/quality of finished product
S = aggregate skill of group members
M = aggregate motivation of group members
t = time allowed for project
N = number of group members

We'll see if this goes over well in the "reflection paper" I'm writing in which I'm to describe the nature and process of our group's collaboration. It's totally subjective, I know, but what the hell.