Writers of Pro Football Prospectus 2008

08 Mar 2013

2012 Adjusted Games Lost

by Danny Tuccitto

Apparently, I've picked up whatever bug it was that made Aaron have to communicate via grunts (translated by Rivers) and scribbles for 90 percent of the MIT Sloan conference, so apologies in advance for this being shorter than you might expect. Promise I'll make it up to everyone in the second post, which will be arriving in this internet space next Tuesday.

With that bit of groveling out of the way, it's time to once again present Football Outsiders' Adjusted Games Lost (AGL) totals for the recently completed season. For any new readers out there, AGL is our metric that quantifies how much teams were affected by injuries, and is based on two fundamental ideas: (1) Injuries to starters, injury replacements, and important situational reserves impact a team more than injuries to bench warmers; and (2) Injury effects should be adjusted for whether or not a player was out, doubtful, questionable, or probable. Although this should go without saying, higher AGLs are worse than lower AGLs.

Below are the AGL totals and rankings for 2012. For comparison, I've also included the 2011 totals.

Team 2012 AGL 2012 Rank 2011 AGL 2011 Rank
SF 16.2 1 38.4 8
MIN 30.9 2 48.8 10
CHI 31.1 3 54.5 14
SEA 32.9 4 78.6 27
NO 35.1 5 24.6 3
STL 36.2 6 110.0 32
MIA 37.7 7 31.7 6
HOU 40.8 8 50.1 11
DEN 49.2 9 55.4 15
SD 49.4 10 72.6 23
ATL 52.9 11 48.6 9
TB 56.9 12 51.4 12
BAL 57.4 13 18.8 1
CIN 63.3 14 51.8 13
TEN 64.5 15 37.7 7
OAK 66.7 16 78.0 25
Team 2012 AGL 2012 Rank 2011 AGL 2011 Rank
ARI 72.3 17 86.8 29
PHI 73.3 18 21.9 2
NE 74.7 19 97.5 30
CAR 76.1 20 109.2 31
NYJ 78.7 21 30.4 5
KC 79.2 22 65.5 19
BUF 79.7 23 71.0 21
DET 81.5 24 28.0 4
NYG 82.7 25 78.3 26
PIT 83.3 26 60.5 17
CLE 83.4 27 71.8 22
DAL 86.5 28 62.5 18
WAS 89.4 29 67.5 20
IND 92.5 30 84.7 28
JAC 99.9 31 73.4 24
GB 108.1 32 58.7 16

The average team AGL this past season was 64.5, which was up slightly from 2011 (60.0), and therefore qualifies as the highest leaguewide average in our database. Put differently, an average NFL team these days suffers the injury equivalent of four important players missing the entire season. That's over one full season more than what the expectation was five years ago (45.5). However we interpret it, the bottom line is that 2012 continued an upward trend we discussed in last year's piece.

Another leaguewide trend that continued last season was the year-to-year AGL correlations, for which we're still trying to come up with a suitable explanation. From 2008 to 2012, team AGLs have been more consistent than they were from 2002 to 2007. During that earlier period, previous year AGL explained less than one percent of the variation in current year AGL; since then, it explains about 10 percent on average. Of course, this means that 90 percent of it doesn't carry over from one season to the next, so we shouldn't get carried away by that result. It does, however, seem reasonable to conclude that AGL totals have gotten more predictable of late.

Something else readers might find interesting from a predictive perspective is how well total AGL has correlated with wins and total DVOA over time. Here's a table for you:

Year r(Wins) r(DVOA) r(Win Diff) r(DVOA Diff)
2002 -.21 -.20 -- --
2003 -.30 -.37 -.35 -.51
2004 -.48 -.40 -.66 -.58
2005 -.36 -.37 -.64 -.58
2006 -.03 +.13 -.49 -.31
2007 -.26 -.16 -.30 -.21
2008 -.56 -.50 -.59 -.54
2009 -.21 -.31 -.29 -.43
2010 -.14 +.05 -.21 -.31
2011 -.39 -.49 -.13 +.05
2012 -.40 -.38 -.52 -.65
Total -.28 -.25 -.40 -.40

To situate ourselves, the first column of correlations is current-year AGL with current-year wins, and the second column is current-year AGL with current-year total DVOA. The final two columns involve correlations between year-to-year AGL change, year-to-year win change, and year-to-year total DVOA change.

Starting at the bottom of the table, we see that for the 2002-2012 period, the change in AGL from year to year does a better job of explaining why a team won (or lost) more games compared to the previous season than current-year AGL does explaining win totals in the current year. The same goes for the relationship between AGL and DVOA.

In that context, 2012 turned out to be a year in which injuries played a much larger statistical role than normal, especially with respect to how teams performed relative to 2011; case in point: the St. Louis Rams. Last year, we mused about reasons for St. Louis' consistently awful AGL, which averaged a ranking of 28th from 2007 to 2011. Enter Jeff Fisher, who had previously been associated with a Tennessee Titans team that was consistently healthy, ranking third on average from 2007 to his departure in 2010. Could there really be a Jeff Fisher effect? I highly doubt it, primarily because, in addition to hiring Fisher, St. Louis purged their roster last offseason. I'd guess that, as a general rule, if a team gets rid of a bunch of injury-prone guys, it's not going to be as injury-plagued.

A few other teams seemed to benefit from year-to-year AGL improvements. The San Francisco 49ers avoided injuries for the second straight season under Jim Harbaugh, which might help explain why they weren't bitten by a projected regression to the mean in 2012 -- despite all statistical indicators to the contrary. San Francisco's primary NFC West rival for the foreseeable future, Seattle, rode a wave of improved health (27th AGL in 2011, fourth in 2012) to four additional wins and the second-largest DVOA improvement in the NFL (39.8 percentage points). Admittedly, Russell Wilson had something to do with it, too.

On the other end of the spectrum, several teams saw decreases in performance this past season track alongside changes in AGL. Green Bay was the most injury-riddled team in the NFL last season -- only the sixth 100+ AGL in our database by the way -- and that drop from 16th to 32nd coincided with four fewer wins. Green Bay's division-mate Detroit suffered a similar fate, as they won six fewer games in 2012, thanks in some part to a 20-spot drop in the AGL rankings. In the AFC, the New York Jets fell from fifth to 21st in AGL, and also saw their total DVOA drop 31.4 percentage points from 2011 to 2012.

There were a few trends worth mentioning related to the shenanigans of injury reporting. First, as we detailed last year, "questionable" is about as detached from the reality of injury reporting guidelines as "offensive pass interference" is detached from the NFL rulebook. Continuing a trend going back to 2008, 69.3 percent of players listed as questionable on the injury report actually played that week, which was nearly 20 percent more often than the 50 percent participation rate questionable is supposed to represent.

Speaking of questionable, the second bit of shenanigans we noticed was Bill Belichick's shift in diversion tactics this season. You'll recall that, for much of the previous decade, Tom Brady was listed as probable with a shoulder injury. Well, in 2012, Belichick didn't list him one time, instead opting for a game whereby seemingly the entire New England Patriots roster is questionable. Excluding New England, the average number of questionable designations for an NFL team over the course of the 2012 season was 21.6, with the Arizona Cardinals having the second most at 45. Bill Belichick listed a player as questionable 138 times.

One person in the league who refuses to be outdone by Belichick, however, is Rex Ryan, who apparently seemed content filling the "probable" void vacated by his arch-nemesis. In 2012, the New York Jets led the NFL with 164 probable designations when the average of the other 31 teams was 56.6.

To close, here's one final injury reporting anomaly -- to put it mildly -- that comes courtesy of the practice participation reports teams are now required to provide several times leading up to their games. If we only look at players who contribute to AGL (starters, injury replacements, and important situational reserves), and focus on those listed as doubtful on the injury report, we find the following. If the player did not participate in the final practice of the week, he had a 0.8 percent probability of playing. However, not a single doubtful player who fully participated in practice played that week. And what's more peculiar is that, if the doubtful player was "limited" in practice, he played that week 13.3 percent of the time.

That's all for now. Next Tuesday, I'll detail 2012 AGLs for team units.

Posted by: Danny Tuccitto on 08 Mar 2013

25 comments, Last at 21 Mar 2013, 9:36am by Dean


by BroncFan07 :: Fri, 03/08/2013 - 6:03pm

Hey Danny, just to be safe, we're gonna list you as Questionable (Bug) for that Tuesday column.

by Danny Tuccitto :: Fri, 03/08/2013 - 7:43pm

I LOL'ed.

by theslothook :: Fri, 03/08/2013 - 7:20pm

Nice to see even with a regime change...Indy maintains its clear ownership at the bottom of these rankings for yet another year.

by Bobman :: Wed, 03/13/2013 - 6:29pm

Must be the water.

What I like is the clear evidence that their 2-14 2011 record is connected to their horrid AGL ranking (mainly Manning, of course) and their 2012 11-5 playoff record is the direct result of a drastic improv.... oops, never mind.

by zenbitz :: Fri, 03/08/2013 - 8:08pm


by scl127 (not verified) :: Fri, 03/08/2013 - 11:44pm

Has the number of games lost per player gone down with less padded practices these past couple of years? I remember it being something the NFLPA fought hard to win as part of this current CBA.

by mgoetze (not verified) :: Sat, 03/09/2013 - 7:49am

"69.3 percent of players listed as questionable on the injury report actually played that week, which was nearly 20 percent more often than the 50 percent participation rate questionable is supposed to represent."

Actually, 69.3% is 38.6% more than 50%, significantly over the 20 percent mark.

by dbostedo :: Sat, 03/09/2013 - 1:21pm

Just some poor phrasing.... the participation rate WAS 20% higher... meaning almost 40% more players played than otherwise would have

by bucko (not verified) :: Sat, 03/09/2013 - 8:29am

Some job by Green Bay having the season it did with all the injuries.

by DisplacedPackerFan :: Sat, 03/09/2013 - 9:40am

It seems that is becoming standard operating procedure in Green Bay. I put together the little table for a post earlier in this season where my guess was they were going to be around 80 AGL (I was off there).

Rank is most to least injured (the AGL articles sometimes sorted that way or sometimes sorted least to most)

YEAR - AGL (rank) record DVOA Pt Diff
2008 - 48.2 (16th) 6-10 09.2% +39
2009 - 37.0 (25th) 11-5 29.1% +164
2010 - 86.3 (3rd ) 10-6 23.0% +148
2011 - 58.7 (17th) 15-1 27.0% +201
2012 - 108.1 (1st) 11-5 26.6% +97

I think it should be noted that a substantial amount of the AGL from 2010 onwards has been from the MLB position for them. That is a spot where the best players they have put out there in that period are league average at best and the players who replaced them may have been as good or better than the injured player (Bishop replacing Barnett in 2010, DJ Smith replacing Hawk for part of 2011, etc).

That being said they were also "lucky" in that many of the injuries were at deep positions. They lost a lot of WR games, Jones was the only starter who didn't miss time to injury and they only had something like 3 games where all 4 of their WR were healthy at the same time (Jennings, Cobb, Nelson, and Jones) and for this team that matters with how they want to run the offense. The injuries to the secondary were also handled well in large part because the succession plan for Woodson managed to work a year early and Casey Hayward turned out to be well worth trading up to get.

They also played games missing a good starter at every level of the defense in the same game. By good I'm talking BJ Raji, Clay Matthews, Sam Shields level; not CJ Wilson, Erik Walden, Davon House level that they also had to play without.

So in some ways the injuries were "better" than the ones they dealt with in 2010, in some ways they were "worse". This year the offense had way more key injuries than in previous years. That was part of the reason Rodgers was on the ground so much, and part of the reason the offense seemed off to many people (see post 140 of this thread http://www.footballoutsiders.com/dvoa-ratings/2012/week-16-dvoa-ratings if you want more of my thoughts on that).

I think recent history is enough to suggest a trend with injuries on the Packers. They have given some off season lip service to looking at the potential issues, which I hope is more than that. Injuries do have a large random component. Planning on having players not be available needs to happen, but even if only 10% of team injuries is "controllable" the Packers look to be candidates for being awful at controlling what they can. I'm hoping they find and fix something so they don't have to do so much "next man up".

by bucko (not verified) :: Sat, 03/09/2013 - 5:22pm

It's also true that GB seems very cautious with injuries. So guys sit out plenty before returning full time.

by RickD :: Sat, 03/09/2013 - 6:11pm

Couldn't you do this, but only look at who actually misses time rather than reading the injury lists? Trying to infer anything from the Patriots' injury list is like trying to predict troop movements by reading the comics.

by Jerry :: Sat, 03/09/2013 - 8:04pm

The advantage of using injury lists (Patriots shenanigans aside) is that it does help to capture guys playing at less than 100%. Nothing's going to be perfect, of course.

by Anonymous13 (not verified) :: Sun, 03/10/2013 - 3:46am

It might be better to call this statistics Adjusted Games Missed, instead of Lost. If the players are healthy, they still might not Win the game.

by Puddin Patterson (not verified) :: Sun, 03/10/2013 - 1:15pm

I also found the title a bit confusing.

by nat :: Sun, 03/10/2013 - 2:29pm

I'd be curious to see how teams stack up in how their injury reports match who actually plays. For example, having 20 players listed as questionable is a lot. But on average, that indicates that six will not actually play, with a fair amount of swing both directions. Is it shenanigans if just four sit out the whole game? If so, how many teams played shenanigans by that percentage in a game?

That's the Patriots on week 17, which I think is their high water mark for using the questionable designation in 2012.

It's fun to take shots at Belichick. It's better to dig a little deeper into the stats to find the real story. If he overuses "questionable" what does he underuse? Ditto for other teams. Who overuses the injury report as a whole? Who hides injuries from the fans?

by Jerry :: Sun, 03/10/2013 - 6:44pm

"Shenanigans" was in response to your fellow Patriot fan RickD, who pointed out that New England's, er, idiosyncratic use of injury designations makes it harder to derive useful information. It wasn't a potshot at Belichick.

by nat :: Sun, 03/10/2013 - 10:07pm

Oh, I wasn't replying to your post. The article itself jumps from "there were a lot of questionables" to "it was shenanigans" without doing the interesting checks. It's a missed opportunity, or just taking the easy road to simply assert "shenanigans" rather than digging a little deeper into how the injury report relates to who actually played, how much, and who practiced.

by Danny Tuccitto :: Mon, 03/11/2013 - 2:05am

Since you're being persistent about this, I'll respond. At the beginning of the article, I said I was sick, and so the column would be shorter than one might expect. If I had another 1,000 words in me, I would have gone deeper into a whole host of things, including the NE anomaly. Not sure why you're ascribing some "lack of due diligence" reason when I laid out that explanation in advance.

With that said, now that I've left the ranks of the walking dead, here are some answers: 85% of NE's questionables played, which is 16 percentage points more (or, to be accurate for comment 6, 23% more) than the 69% average leaguewide last year. In terms of "using the injury report," the average NFL team had 105 injury report listings; NYJ had 230, which was miles ahead of even 2nd-place NE (174).

by theslothook :: Mon, 03/11/2013 - 4:20am

Shennanigans indeed

by nat :: Mon, 03/11/2013 - 10:11am

Thanks. Sorry you aren't feeling well. Be better soon!

I wasn't being "persistent"; I was replying to another commenter. Even if I were being persistent, so what? Relax, man! It's a comment thread.

From your number, it looks like Belichick is shifting more "probables" into "questionable" than the league does as a whole, or possibly pushing less-than-healthy players onto the field more often, or maybe being better about reporting "doubtfuls" or "outs" than other teams. That leaves a lot of questions, but it's still way more informative (and in keeping with the FO style) than an amorphous "shenanigans" assertion.

More could be done on this topic, sure. But I understand it was only a side topic in the article. Maybe you can tackle the ins and outs of injury reporting in general in some future article.

by Danny Tuccitto :: Mon, 03/11/2013 - 11:56am

No worries. Yeah, we've got a couple of long-term projects in the works for AGL.

by mrh :: Mon, 03/11/2013 - 10:39am

Could there really be a Jeff Fisher effect? I highly doubt it, primarily because, in addition to hiring Fisher, St. Louis purged their roster last offseason. I'd guess that, as a general rule, if a team gets rid of a bunch of injury-prone guys, it's not going to be as injury-plagued.

I guess by "Jeff Fisher effect" you mean that he has the power to heal the sick and lame? And are arguing that he doesn't actually have healing powers. It could be that the "Jeff Fisher effect" is to purge injury-prone players and that those decisions were driven by him as much as or more than by the GM//front office.

This may have been done before and I may dig around and look, but has FO ppublished on research on the correlation between AGL and the age of the players that go into that calculation?

by Anonymousse (not verified) :: Mon, 03/11/2013 - 12:15pm

"which was nearly 20 percent more often than the 50 percent participation rate questionable is supposed to represent."

The injury rules also state that if a player misses any part of a practice due to injury/health, they need to be listed. So you'd expect them to be high.

Part of BB having Brady as Questionable/Probable for years is that Brady used to sit out a lot of the throwing drills. My guess was to go easy on the shoulder.

by Dean :: Thu, 03/21/2013 - 9:36am

It's impossible to know, but I wonder how much worse the injuries would be if we didn't have the various safety measures put in place by Goodell over the past few years?