I'm not sure. The definition of the rating is "The likelihood that a player gets of out of cold streak or gets on a hot streak". Not exactly that, but that's the meaning. I've often wondered, though.
I've been thinking about getting some of the roster edits together to talk about what different ratings and sliders REALLY do. For instance, I don't think Offensive Tempo determines how quickly the offense moves the ball around, I think it determines how likely they are to take the open shot. If you put this slider at 100, teams will shoot more often with a small amount of room. The lower you take it, the more space they require to take the open shot. At least this is one of the results I have seen. I'd like to know what other people have seen, also.