It's time to update the NFL Positive Impact Factor through four weeks of the 2012 NFL season. There was plenty of movement this past week, except at the very to where Matt Ryan still leads the pack. It is important to remember to think of these numbers as averages which will adjust as the season progresses. Here's the standings so far: 1. Matt Ryan, ATL, 69.7 2. Matt Schaub, HOU, 67.7 3. Robert Griffin III, WAS 64.8 4. Ben Roethlisberger, PIT, 64.4 5. Tom Brady, NE, 63.4 6. Peyton Manning, DEN, 60.3 7. Aaron Rodgers, GB, 57.3 8. Carson Palmer, OAK, 55.5 9. Alex Smith, SF, 54.3 10. Matthew Stafford, DET, 52.9 10. Eli Manning, NYG, 52.9 12. Christian Ponder, MIN, 49.2 13. Philip Rivers, SD, 47.8 14. Drew Brees, NO, 47.8 15. Kevin Kolb, ARI, 45.2 16. Blaine Gabbert, JAC, 43.9 17. Josh Freeman, TB, 42.9 18. Sam Bradford, STL, 42.8 19. Andy Dalton, CIN, 42.5 20. Joe Flacco, BAL, 41.1 21. Cam Newton, CAR, 39.4 22. Russell Wilson, SEA, 38.7 23. Mark Sanchez, NYJ, 38.4 24. Brandon Weeden, CLE, 34.6 25. Ryan Fitzpatrick, BUF, 30.4 26. Andrew Luck, IND, 30.3 27. Jay Cutler, CHI, 26.5 28. Michael Vick, PHI, 25.8 29. Ryan Tannehill, MIA, 25.4 30. Jake Locker, TEN, 19.2 31. Tony Romo, DAL, 14.6 32. Matt Cassel, KC, 6 The big movers this week were Matthew Stafford, Peyton Manning, Christian Ponder and Tony Romo. Stafford, Manning and Ponder all rose more than 10 places while Romo's Monday Night Football 5-interception meltdown sunk him to second to last. There are 6 QBs producing touchdowns on at least 5 percent of their touches. Ryan Fitzpatrick leads the way at 8.3 percent. Brandon Weeden is at the other end of the spectrum with just 1.7 percent of his touches going for TDs. Matt Ryan leads the QBs in lowest percentage of negative plays, with an incompletion, sack or fumble occurring on just 22.6 percent of his plays. Ryan has a nearly 8 percent lead on RGIII who is second in the category. Mark Sanchez is committing a negative play on 52.9% of his touches, which is the low mark through Week 4. Why are Romo and Cassel at the bottom? Romo has thrown 8 interceptions on a league-worst 16 percent of his incompletions and has also lost 2 fumbles. Cassel also has 10 turnovers (7 INT, 3 lost fumbles).