Bronco Mike did a very well reasoned and researched post about what it takes to be a top ten D or a top 10 O in the NFL:
Many of the those who commented were hopeful that our D could improve to be in the top 10 in 2012. That would entail quite a bit of improvement over the 2011 defense. How much is that though? - here are the absolute numbers that would be needed to get the D to a top ten in each category (relative to 2011 numbers)
3.9 fewer points per game (24.4 to 20.5)
25.4 fewer yards per game (357.8 to 332.4)
0.2 fewer yards per play (5.4 down to 5.2)
2.2 more yards per point (14.7 up to 16.9)
9 more forced turnovers (21 up to 30)
improve QB rating against by 12.5 (93.2 down to 80.6)
The Broncos D was in the top ten in sacks and 3rd down % allowed in 2011.
So how realistic are these improvements? I looked at the past decade in the NFL to find what is a realistic improvement year over year in any one of these categories for a D. In doing so I found what the biggest changes from year to year look like (both good and bad) for any of these categories. I also tried to comment on the history of the teams that made the most dramatic year over year improvements (how did they do it?). Make the jump with me and see what I found...
Points Per Game
Arguably the most critical statistic for any defense, the 24.4 points that Broncos gave up in 2011 was a farely large improvement over 2010 (5.0 points better). However, that 5.0 point improvement is not in the top five from the past decade. in order to make a big jump, your D has to be crap the year before...
#5 - (Tie) 2010 Lions and 2009 Broncos - 7.8 ppg improvement. The 09 Broncos had an almost completely new TEAM with a new defense and a fairly creative defensive coordinator. The defense was historically good for the first 6 games and then became a mediocre to poor D once McD started overriding Nolan. The 2010 Lions had a defensive line that was anchored by rookie All-Pro Suh, but they also had a lot of high draft picks on the D that started to finally "get it." The 2009 Lions allowed a horrific 30.9 ppg, so while their improvement was dramatic, the 23.1 ppg that they allowed in 2010 was only good for 19th in the league. So if anything, the 2012 Broncos might be where the 2011 Lions were. The 2011 Lions actually regressed to 24.2 ppg allowed (23rd).
#3 - (Tie) 2004 AZ Cardinals and 2005 Bears -8.1 ppg improvement. The 2003 Cards had the worst scoring D in the league at 28.2 ppg. Their improvement was large and it moved them from 32nd to 12th in scoring D in one year. The 03 Cards were 4-12 and were outscored by 227 points over the course of the season. The 04 Cards improved to 6-10 and were only outscored by 38 points total. Two rookies played a big role in this turnaround - Darnell Dockett and Karlos Dansby - their 2nd and 3rd round picks (Larry Fitzgerald was their 1st rounder). The 2004 Bears were pretty good defensively (13th in pts), but the 05 Bears were the best D in the league allowing only 12.6 ppg. The 05 Bears only had one rookie starter (FS 6th rnd pick - Chris Harris), but they had a bunch of players really coming into their own - Briggs, Vasher and Tommie Harris. They also got career years out of a couple of defenders (Ogunleye and Mike Brown).
#2 - 2008 Ravens -8.8 ppg. The 2007 Ravens D was a shadow of it's former self - allowing 24 ppg (2nd in the league) - and could no longer make up for the shortcomings of the anemic offense. The 08 Ravens had no rookie starters on D, but the offense improved enough to help the D make a dramatic improvement. The really interesting thing is that the 08 Ravens actually forced fewer turnovers than the 07 Ravens who only allowed 15.2 ppg.
#1 - 2011 Texans -9.3 ppg. The 2010 Texans D was bad, really bad, allowing 26.7 ppg (29th). The 2011 Texans brought in a new defensive coordinator and a new defensive scheme. Only 5 of the 2010 defensive starters started in 2011 for the Texans ( Smith, Cody, Cushing, Quin and Jackson). The 3-4 replaced the 4-3 and the Texans found that they had much better personal for the 3-4. Gone was #1 overall pick Mario Williams, 1st rnd pick (#10 overall) Amobi Okoye, LB Kevin Bentley, LB Zach Diles and safeties Bernard Pollard and Eugene Wilson. With the changes the Texans improved from 29th to 4th in ppg (16.7). The Texans D only allowed 30 or more points once - 40 to the Saints - and routinely held teams below 20 (7 straight games).
So what does this mean for the Broncos? - There is recent precedent for teams making huge jumps, jumps significantly greater than that which the Broncos need to make to move into the top 10. The most historically fitting examples would be the 2010 Lions and the 2004 Cards. Unfortunately for the Broncos, neither team continued their improvement, both regressed with the Cards allowing 4.1 more points in 05 than in 04 and the Lions regressing slightly as mentioned above. So who should the Broncos focus on as a precedent for continued year over year improvement in ppg? The three best examples are
The Bears from 03-05 who went from 22nd in ppg (21.6) to 1st in two years time (12.6)
The Titans from 05-08 who went from 31st (26.3) to 2nd (14.6) in three years time
The 49ers from 08-11 who went from 22nd (23.8) to 2nd (14.3) in four years
All three of those teams were focused on and known for their defenses during that time frame of continued improvement. Have the Broncos focused on D since Fox and Elway have been in control? I could argue either way. Another way to ask the question is - "how often does a team make an improvement of >3.9 ppg?" It has happened 55 times in the past decade, so roughly 5 teams - or 1/5th of the league - do it every year. Giving up 3.9 or more ppg than the year before happened 54 times over the past decade. So the odds of getting that much better are the same as the odds of getting that much worse.
For grins here are the worst backsliders in ppg from one year to the next over the past decade
All of these teams had really decent to good defenses that collapsed pretty spectacularly in one year.
Yards Allowed Per Game
I started with the most important stat, so if you have lost interest at this point just skip to the survey and leave a comment.
A team can give up a bunch of yards without giving up huge numbers of points (bend-don't-break). Two really good examples of this are the Packers and the Pats from last season. That being said, giving up fewer yards is a good thing and it is interesting to see what the historic precedence is for changes in this year over year. The best:
#5 2005 New Orleans. -71.7 ypg. The pre-bounty hunting Saints were able to shave over 1000 yards allowed off their 2004 total of 6141 yards. Despite this they lost four more game in 05 than in 04 - go figure.
#4 2003 Dallas. -75.6 ypg. The 2002 Cowboys had a horrible offense that kept their D on the field way too long. Their offense improved enough to allow the D to play more rested in 2003 and the D responded by giving up almost 1300 fewer yards.
#3 2009 NYJ. -77.1 ypg. The Jets went from 18th in points allowed in 08 to 1st in 09. This was a direct result of allowing 1300 fewer yards. Revis was in his second year in 09, but the biggest difference was the improvement in their three down lineman in 2009 (two of whom did not start in 08).
#2 2007 TEN. -78.1 The Titans jumped from 31st in ppg to 8th and the 1300 fewer yards allowed were a huge reason for this. The starting front 4 for the Titans in 07 was dramatically improved against both the run and the pass - accounting for 30 of the teams 40 sacks and lowering the ypc from 4.6 down to 4.0 relative to 06.
#1 2011 HOU. -93.1. The Texans allowed 6031 yards in 2010 and only 4571 in 2011. Cutting nearly 1600 yards allowed is such a huge change that I doubt it has ever been down before in the NFL.
The Broncos were able to cut 33 yards allowed in 2011 relative to 2010. in some years that would be a really good improvement (top 5) but last year it wasn't even in the top 10. Cutting another 25 yards allowed seems to be a fairly realistic and obtainable mark. Six teams improved their yards allowed by 25 or more last season. That level of improvement has happened 67 times over the past decade (23%). Since the Broncos were 20th in yards allowed last year there is still plenty of room for improvement.
Here are the teams that have regressed the most in yards allowed during the past decade - the Broncos show up on this list
Yards Per Play
So you might have a D that gives up a whole bunch of yards because the offense forces them to be on the field for so much of the game. So measuring a D by yards per play is a way to get around this. Here are the first biggest improvements in YPP over the past decade
#3 2009 Broncos -1.1 The 08 Broncos gave up 6.1 ypp (31st in the league).
#1 2011 Jags and Texans. -1.2 The Texans gave up 6.0 in 2010. The Jags gave up 6.3. The Texans improvement has been discussed previously. The Jags made an amazing jump from dead last to 6th in ypp. They did this while firing their head coach, installing their DC as the interim HC and only having 6 defenders start 13 or more games. I wasn't able to find a simple explanation for the dramatic improvement in ypp.
There have been 43 instances over the past ten seasons (43/288 = 15%) where a team has reduced there ypp allowed by 0.5 or more. There were 57 instances where the value went up by more than 0.5 relative to the previous season (57/288 = 20%). So it was more common for defenses to get significantly worse than it was for them to get significantly better in this stat. The numbers get better if you move to a larger change - 0.7 ypp up or down. In that case it's 7% bad to 8% good. A change of 0.2 fewer ypp for the Broncos is readily obtainable as it has happened 94 times over the past decade (33%).
Here are the worst teams in terms of regressing
Yards Per Point
This is a defensive stat where the higher the value the better, generally. Epic defenses don't give up much of either (yards or points) so their values can actually be lower than teams that give up yards but avoid giving up points due to getting redzone turnovers. The #3 scoring D from 2011, Baltimore, had a 17.4 value. New Orleans had the same value, 17.4, despite being 13th in scoring D. Teams that are good at stiffening in the red zone so they give up FGs instead of TDs tend to have really good values here. Here are the best teams in terms of improvement year over year:
#5 2010 Packers. +5.3 (from 15.3 to 20.6). The 2010 packers gave up 25 more yards per game, but 57 fewer total points (3.6 points per game). I don't really have a good explanation since they only forced 3 more turnovers and the roster was pretty stable
#4 2006 Ravens +5.8 The Ravens D was good both years, but the improvement in points (-6.1) dramatically outpaced the improvement in yards allowed (-20.2). The reason - Ed Reed and Ray Lewis missed a combined 16 games in 2005. Both were back with a vengeance in 2006.
#3 2005 Bears. +6.0 see the discussion above for the reason why the 2005 Bears were so good relative to the 04 Bears.
#2 2011 49ers +6.4 see the previous discussion of the 2011 49ers.
#1 2009 Cowboys +7.3 This is another instance where the previous year's D was so bad that improvement to mediocrity made a huge difference. The 12.9 yards per point allowed by the 08 Cowboys was 30th in the league. They were 8th in yard allowed, but 20th in points allowed. In 2009 they were about the same in yards allowed (9th), but they moved all the way up to 2nd in points allowed. Hence the dramatic improvement in yards per point. The interesting thing is that they forced 17 FEWER turnovers in 2009 than 2008. Again I am not sure why the dramatic improvement in points allowed year over year other than Theo Ratliff having a career year at NT.
For the Broncos to make into the top ten in this stat next year they would need to increase their yards per point by 2.2 or more. This had happened 48 times over the past decade (17%).
Here are the five worst teams in terms of getting worse in this stat year over year
I am going to just show the five worst and the five best here because this post is getting really long. The Good
and now the bad
the Broncos need to force 9 more turnovers to get into the top ten in this defensive stat. There have been 49 instances of a team improving by 9 or more forced TOs year over year (17%). There will be no complaints from me if that number is more like 15 or 16 more forced in 2012 relative to last year.
Change in Opposing QB rating
This stat of course could be misleading, but it would be hard to argue that Broncos do not need to improve in the this category. Here are the best five in terms of single year improvement
In all of these instances, the team was horrible against the pass the year before (OQbR = 94 or more) and improved to average or above average in the season listed.
The -12.5 improvement needed by the Broncos has happened 44 times or 15% of the time. The average QB rating allowed in the NFL last season was 84.5, but there were many teams clustered in the low to mid 80s with only a few outliers.
Here are the teams that went the wrong direction year over year
The 2004 Patriots look so bad because the 2003 Patriots were THAT good. Opposing QBs had a rating of 56.2 against the 03 Pats.
OK. Give yourself a pat on the back. You survived another one of my math heavy posts. Hopefully you have a much better idea now of how much or little the Broncos can hope to improve statistically on defense next season.