Mind you, I'm not disputing the numbers at all. They are what they are. There are a lot of numbers out there, though, and some of them don't necessarily mean what people sometimes claim they mean. The paradigmatic case is running back attempts, how when Running Back X has 25 or 30 or somesuch carries in a game, his team's record is like 17-1; not surprising, because a running back tends to only get 25 or 30 attempts in a game his team is already winning. Line yards are one attempt to characterize something that's hard to characterize in a statistical fashion, but I'm not sure how effectively it manages that.
To the extent line yards fairly and accurately reflect the level of performance of the back and the offensive line in the context of the broader offense, we should expect Adjusted Line Yards to remain relatively constant if we hold those constant. Now, this is difficult to do so, because nothing ever stays exactly the same.
Take, for instance, the Titans from 2010 to 2011. All five starting linemen were the same, and Chris Johnson once again had the majority of the carries, but Jake Scott got worse, Chris Johnson appeared to be giving significantly less than full effort, and, oh yeah, Chris Palmer was at offensive coordinator instead of Mike Heimerdinger, there was a different quarterback, some changeover at receiver, and a change at tight end.
All is not lost, though. At FO, beyond the main Adjusted Line Yards statistic for both offense and defense, we break that down into directional numbers based on where a run is listed at going in the NFL's official play-by-play. There's ALY, but also Left End ALY, Left Tackle ALY, Middle/Guard ALY (which includes runs listed as being at left guard, up middle, and right guard), Right Tackle ALY, and Right End ALY. The Titans have actually been a fairly consistent organization over the fifteen years for which we have Adjusted Line Yards available, so I want to use some of those breakouts to see if there's consistency in the numbers when there's almost perfect consistency in the rest of the environment.
The answer, unsurprisingly, is you see a relatively large amount of variation even when you would expect things to stay the same. Take, for instance, 2009 to 2010. Chris Johnson had most of his success running right, and the Titans ranked 6th in Right End ALY at 4.81. With the same players-CJ, Scott, Stewart, and tight end corps, including Alge Crumpler and Bo Scaife, plus Mike Heimerdinger calling the plays-the Titans fell from 6th to 30th, from 4.81 ALY to 3.07 ALY. Either the same group of players went from one of the league's best to one of the league's worst, or there's more going on.
Another good example is runs Left Tackle from 2001 to 2003, when the vast majority of the carries went to Eddie George, running behind LT Brad Hopkins, LG Zach Piller, and TEs Frank Wycheck and Erron Kinney, with Mike Heimerdinger calling the plays. They were the league's worst unit in 2001 with 2.34 ALY, then the same group a year later put up an ALY of 4.32, a respectable 14th, before declining some the next season to 3.86 ALY, 22nd. That's ... not very consistent.
A third example: 1997 to 1998, Left End and Left Tackle. Brad Hopkins was the left tackle, Bruce Matthews the left guard, Eddie George the running back, and Les Steckel the offensive coordinator. In 1997, this combination produced mediocre results running Left End, 3.63 ALY, 24th, but very good results running Left Tackle, 4.85 ALY, 6th. In 1998, though, things changed. The results running Left End improved to 4.26 ALY, 12th, while runs Left Tackle declined to 4.06 ALY, 15th. There was a change at tight end-Frank Wycheck was still the lead player, but the Oilers acquired Jackie Harris, which led to the diminution of Mike Roan's role, but that shouldn't have been enough to produce that kind of change in results.
There are a couple more examples I could use, but I think you get the general point: Adjusted Line Yards do a highly imperfect job of accurately reflecting the skill level people involved in creating them. Instead, like all of the individual statistics put out by Football Outsiders, they're an indication of the level of accomplishment of the player(s) involved admixed with a strong leavening of influence from everything else happening on the team.
A final note for this post: here's a clue where the Titans located the hypothesis when it came to some of the offensive line struggles:
- 2005: Traded third-round pick to Buffalo Bills for Travis Henry;
- 2006: Used second-round pick to select LenDale White;
- 2007: Used second-round pick to select Chris Henry; and
- 2008: Used first-round pick to select Chris Johnson.