by Aaron Schatz

Two years ago, we introduced a new metric on FO called "adjusted interceptions." The basic idea:

We add in plays where the quarterback only escaped an interception because the defender couldn't hold onto the ball (dropped interceptions, which we've been tracking in game charting since 2007).

We subtract plays where the interception is tipped to the defender by a receiver who should have caught the pass.

We subtract Hail Mary interceptions as well as interceptions thrown in desperation on fourth down in the final 2:00 of a game.

Obviously, there's going to be a little bit of subjectivity here, but our game charters do their best. If the defender has to dive for a ball only to have it bounce off his fingertips, that's not a dropped interception.

This year, we made one change to how we charted interceptions and near-interceptions. Unlike in past years, we also charted passes that would qualify as "dropped interceptions" except that the defender's catch was broken up by the receiver. These "defensed interceptions" count against the quarterback but will not be included in the dropped interception count for defenders.

Interceptions are notoriously hard to forecast from year to year, because there's so much random chance and statistical noise involved. However, we did find that this new metric, adjusted interceptions, had a higher year-to-year correlation than standard interception totals and was a better predictor of future interceptions. But something very strange happened in 2012. The year-to-year correlation of adjusted interception rate was very high (.37), but the year-to-year correlation of actual interception rate was even higher (.52). I'm guessing this is a one-year fluke, and in the long run, adjusted interceptions are still a better predictor of the future than standard interception counts.

Andrew Luck led the league in dropped interceptions in 2012; in fact, dropped interceptions show that the efficiency gap between Luck and fellow rookies Robert Griffin and Russell Wilson was even larger than shown by stats like DVOA. Obviously, this is partly due to the fact that Luck was throwing the ball deeper and in harder situations than Griffin or Wilson, but the difference is still dramatic. Luck had 18 interceptions, the second-highest total in the NFL, and also had 14 dropped picks. Wilson had just 10 picks and five dropped picks, while Griffin had five of each. Luck's total of 14 dropped interceptions is the second-highest season total since 2007, behind only Mark Sanchez's 15 for 2010.

No quarterback threw more than one Hail Mary interception this year, but Chad Henne did throw three fairly meaningless interceptions: a Hail Mary at the end of the Week 16 game against New England, a pick on fourth-and-1 with 1:59 left and the Jaguars losing to the Colts by 17 in Week 10, and a first-down pick that came with 0:38 left and the Jaguars losing to the Bills by 16 in Week 13.

Alex Smith once again did a fabulous job of taking care of the ball, at least until losing his job. He had no dropped interceptions. Neither did Sam Bradford, even though he had 13 actual interceptions. Other quarterbacks who were underrated by conventional interception totals included Brady Quinn, Matt Cassel, Blaine Gabbert, and Kevin Kolb.

Matt Hasselbeck and Nick Foles actually managed to have more dropped interceptions than they did actual interceptions. Other quarterbacks who were overrated by conventional interception totals included Luck, Brandon Weeden, and Eli Manning.

The following table lists adjusted interceptions for all quarterbacks with at least 200 pass attempts. Note that the average quarterback's adjusted interception rate is 0.8 percent higher than his actual interception rate.