In reply to: You are slightly off the mark. Book could indeed take posted by btd
The throws were almost always immediate -- snap, catch and instantly throw. Check downs happen at a much slower rate.
You could also see the entire field from our upper deck seats -- which actually aren't bad for football games because of the ability to see the entire field every play.
Since we ran those 3 yard throws in an infinite loop, we began to focus heavily on your point -- is he checking down. The conclusion was no -- largely because of my first point, but also because of what the other players were doing. You could see the other routes being run, the attempts to block by other players, etc.
I'd say at least 90% of those crossing routes were designed calls.