Adjusted Games Lost (AGL), our injury metric at Football Outsiders, makes sense of the injury report by incorporating the historical likelihood of a player with a given status and role on the team missing a game.

As an example, from 2007 through 2009, a starter on a team who was listed as "Doubtful" on the injury report in a given week only played 3.7 percent of the time. As a result, each time a starter appears on the injury report as "Doubtful," AGL values him as having missed .963 games, regardless of whether he actually plays or not.

It gets a little more complex than that for the actual calculation of AGL -- we're incorporating a rolling baseline for the year in question (owing to holes in data for the 1996-1999 campaigns) and also adjusting for the position in question.

This does an effective job of encapsulating the impact of injuries on teams, but one of the factors it doesn't consider is how individual teams may game the injury report. It's easy to imagine one team listing every player with a minor nick as "Probable," while another team simply leaves those players off of the report. The difference in AGL wouldn't be very dramatic, even over the course of one season, but it could add up over the course of several seasons.

To figure out which teams have deviated furthest from their injury report expectations, I calculated an "expected" number of games missed using AGL. As an example, from 2007 through 2009, the mix of players the Cardinals listed on the injury report would have yielded an expected 249 games missed by their players over that three-year stretch. The Cardinals actually had their players miss 239 games over that timeframe, so Arizona has played the injured guys on their roster about four percent more frequently than league average. (Since 239 is less than 249, in the subsequent chart, this is reported as -4.0 percent.)

From 2007-2009, there was one team that manipulated the injury report far more than any other:

The issue of the Jets manipulating the injury report is nothing new. The linked article discusses Eric Mangini's affinity for playing games, though, and he's no longer the Jets coach. So did the Jets continue to mess around after Rex Ryan took over?

The answer is no. Under Mangini in 2007 and 2008, the Jets "reported" 181.1 games missed. Their players actually missed 153 games, for a difference of 28.1 games (15.5 percent). Last year, with Ryan running the show, the Jets reported 30.3 AGL worth of injuries and their players missed 30 games. Meanwhile, with Mangini in Cleveland, he reported 153.1 AGL worth of injuries and his players actually missed 141 games, a difference of 12.1 games (7.9 percent).

I was surprised to see teams like Kansas City and Indianapolis on the other side of the coin. Tennessee, which finished fourth, wasn't as surprising: At points during Jeff Fisher's tenure, the Titans have stopped listing players as "Probable" altogether. That's no longer the case, but it's a sign of how Fisher views the injury report. The real difference in how Fisher uses the report nowadays is when players are listed as "Questionable." The difference in expected games missed by "Probable" Titans players is pretty tiny (eight actual games missed vs. 6.4 expected games missed in 91 instances), but Titans players listed as "Questionable" have missed 69 games versus 59.2 expected misses (in 133 instances).

I suspect our readers in Nevada and outside of America may also find this data particularly interesting.

Posted by: Bill Barnwell on 28 Aug 2010

14 comments, Last at 30 Aug 2010, 9:21pm by mm