I was looking at PFF's career section on data analysis jobs, and I though there was something very telling. On their job requirements, they specifically put "you never had to play or watch football." So, do I think someone can still provide some accurate stats without playing the game? Yes. But... to advertise it as such, breaks down what is wrong with their numbers and why they sometimes don't make sense. Football is not a solo sport like baseball where you can do the jockey math and come up with something fairly accurate. Complete, total team game, and I think if you're going to come up with a statistics system that grades these players correctly, you do need to have knowledge of the game. Every facet of the game depends on all 11 men doing their job right. They should be hiring ex-coaches to be on their stats team. Sometimes they get it right, but sometimes they get it wrong... very wrong.