by Steven Buzzard
A growing sentiment that has started to crop up with a lot of the talking heads in the league is that the Colts would be pretty terrible if Peyton Manning was playing because the defense has been so atrocious. These same people love to state the obvious and point out that Peyton Manning doesn’t make tackles. However, a lot of stats analysts have known over the years that the Colts offense has actually helped the Colts defense in 3 key ways.
1) They stay on the field a long time and limit the total number of drives per game
2) By staying on the field they give the defense great field position despite terrible special teams
3) By getting leads the defense can force more turnovers
So approximately how much of the collapse of the defense can be attributable to the defense collapsing and how much to the offense collapsing? Since 2003 the Colts have allowed approximately 20 points per game. This year they are allowing 31.5 for an increase of 11.5. Also note that this year league wide scoring is at a record pace and is trending at about 1.1 points over historical averages. These changes are due to a variety of things such as increased passing efficiency, increased passing attempts, changes on kickoff rules, etc. This is very important and is something we will keep in mind throughout the evaluation.
By failing to stay on the field the Colts offense has extended the game fairly substantially. Since 2003 the defense has faced approximately 10.3 drives per game. So far through 8 games the Colts defense has had to defend against 11.1 drives per game. Additionally due to league wide changes there has actually been a decrease in total drives this year of 0.65. So the Colts defense has seen an increase of 0.82 drives per game when they would have expected to see .65 less for a net effect of 1.47 more drives per game. At their current clip of 34.7 yards per drive these additional 1.47 drives per game has been worth 51 additional yards per game. If we use an approximate 12.5 yards per point that is an approximate impact of 4.1 points per game.
In addition to the additional drives per game the defense starting line of scrimmage has also declined as anticipated. From 2003 through 2010 the Colts defense had an average starting field position of 29.5. This year they have faced an average starting position of 31.65 for an increase of 2.15 yards. Additionally, due to changes to the kickoff rules the actual league wide starting position has decreased by 1.85 yards. So essentially the Colts defense is facing 2.15 yards of worse field position where as the league average is facing 1.85 yards better putting the Colts defense at 4.0 yards worse per drive than we would have expected for an average historical Colts defense. Over 89 drives that is equivalent to 357 yards or 28.5 points and a 3.6 per game clip.
The one thing that many people will recognize about the Colts defense is that they are “built to play with the lead”. This essentially gives them the chance to send their star DE’s after the QB creating strip sacks, force bad throws early, and creating turnovers. We can see this clearly in the numbers as well. With the Colts not building leads they aren’t creating turnovers. Historically the Colts defense has forced 1.7 TO’s game compared to 0.9 thus far this year. Many websites have approximated the value of a turnover at somewhere between 40-45 yards. For simplicity’s sake let’s calculate the value of a turnover as 45 yards. In this example, the lack of turnovers is costing the Colts 38 yards per game or 3.0 points. Clearly part of the value of the turnover is better field position for the offense and not just less points allowed by the defense but it is still an impact to the final point differential at the end of the day. Additionally, this entire decrease can’t be attributable to the offense the way the first two items can be but certainly some percentage of it can be. Even if an amount as small as 50% is due to playing with a lead the lack of turnovers may end up affecting the total points allowed by at least 1 point per game.
Now that we have seen that the defense is giving up approximately 7-10 points more per game due solely to the collapse of the offense we can see how much of the collapse can be directly attributable to the defense. Again we will start with yards per drive as our basis to keep things consistent. Historically the Colts have allowed about 30.8 yards per drive vs 34.7 that they are allowing this year for a change of about 3.9 yards. Offenses on average are getting 1.1 yards per drive more than historical averages meaning the Colts defense is playing 2.8 yards per drive worse per game than would be expected. This equates out to about 20 yards per game and 2.5 points per game directly attributable to the defense.
The current year Colts team is giving up about 11.5 points per game more than they have historically given up. Based on some basic analysis it appears that approximately 7-10 of those points are because the offense is not helping them out as much as they have in the past and about 2.5 of those points are due to the defense just underperforming. While 2.5 points per game is a fairly significant decline in defensive performance it isn’t unprecedented, in fact the standard deviation in points allowed by the Colts is 3 points per game and has underperformed historical averages by 2.5 twice in 9 years. The thing that is unprecedented is the number of drives, field position, and TO rates all of which are at all time extremes. Clearly these aren’t the only aspects that go into total points allowed but it is a significant portion. At the end of the day maybe Peyton Manning was the most valuable player on the Colts defense even if he wasn’t and never will be making tackles.
Tuesday, November 1, 2011
by Steven Buzzard