Specific to QBs, I think a test that measures exactly how long it takes the brain to transfer, what they see into how quickly they act. If you know that routes and you've practiced the drops and the throws, which they all do, then they look better. However, in a real game, you don't know what you are going to see. You have to be able to read and throw in a split second and that's the key to a good QB. How long does it take the brain to transfer what it sees to a throw. I don't think they have any real good way of measuring that.