https://www.cougarboard.com/board/message.html?id=33630891
So many reasons why the passer rating is higher, but PFF grading is lower.
1. The WR were so open that a bad throw doesn't matter. The passer rating sees 70 yards and a touchdown, while PFF sees a ball that was underthrown.
2. The WR makes a crazy catch. The passer rating sees 30 yards, while PFF sees the ball was overthrown.
3. An incompletion: The passer rating sees 0/1, while PFF sees the QB missed a wide open receiver.
4. A check down: The passer rating sees a 5 yard completion to a RB, while PFF sees the QB missed 2 wide open receivers, which would've given 25 and 15 yards respectively.
5. The list
6. goes on
7. and on...