How PFF grades all positions

[fredtoast]

(07-16-2019, 03:28 PM)Synric Wrote: It's not that difficult to understand the harder the throw the higher the grade.

Then tell me the difference.  Where is the line drawn?  What exactly is the difference between a +1 throw and a +2 throw?

They are not talking about "a little better".  They are talking about 100% better.  Seems to me they should be able to tell me what makes the difference.  If I am watching a game how can I tell if a throw gets a +1 or a +2?