First, we need to define where the midfield is. This is how I defined it, between 38 and 79 yards away from the goal in my advanced soccer graphics representation program. This was just my decision based on what looked right and there are probably other ways of defining it that might be more correct. Looking at the bottom of the graph.

Looking into the Analytical and Economical aspects of the beautiful game. what is Football Analytics and how can I get involved? A short introduction and further reading for getting involved in Football Analytics. PEP is a non-shots based Expected Goal model, which you can read more about.