If your superstar theory is to come to fruition, you have to identify a potential breakout star who can instantly impact... I would propose Mike Martin is the only player with that potential on our team today. *IF* a competent 3-tech DT emerges, that might be the easing Martin needs to have a blowup year and become a Suh-like dominent force. A dominating interior lineman is the quickest way in my opinion to improve a defense as a dominating interior lineman can singly disrupt both an interior run game and timing passing game, leaving a DC to scheme around a quick passing game or outside running game. But Martin has to stay healthy and Big Will or Ash HAS to show up as a sufficient DT. If they don't, it's last year all over again where Martin gets double-teamed until his ankles break.
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The realm of the possible (updated)
In my last diary I suggested that there might be some room for extra defensive improvement due to the upgrade at DC from Greg Robinson to Greg Mattison. Although I am in general agreement with Brian that massive improvements in the defense should not be expected, I began to wonder what was possible--that is, in the past 5-6 years, has a team improved its defense by leaps and bounds? To that end, I looked at scoring defense ranks of all 120 FBS teams from 2003-2010 to see how teams improved from year to year. Based on the numbers at Rivals, here is how the data shake out:
Note: the x-axis represents changes in rank (negative is good), the y-axis number of examples (out of 840 [120 teams * 7 years]). So the distribution is more or less normal, with a change of 80 rank positions (in either direction) being the maximum, more or less. The largest improvement in our dataset is 94 positions, so if that is the maximum possible then Michigan in 2011 could move up from the 102nd scoring defense (in 2010) to 8th (in 2011). HOORAY!
I had originally suggested that this level of improvement was unlikely, but turd ferguson pointed out that my percentages were misleading, because middling- to highly-ranked defenses simply cannot improve by a large margin. Looking at teams ranked 91st or worse in scoring defense, then, we get the following chart: 
You can see that teams with bad defenses improve 20 ranks on average, in part because they have more room to improve than they do to regress. 31% of the time teams ranked 91st or worse improve 30 ranks or more; and 17% of the time they improve 50 ranks or more. To get into the top quartile of defenses, a team ranked 102nd (like Michigan) needs a 70 rank (or more) improvement, which has happened 5% of the time. Looking at the teams with huge improvements, it is difficult to generalize about how they did it. Here are the most improved teams in each year for which we have data (bolded numbers represent the year in which the big improvement was made):
| 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | |
| Iowa St | 112 | 39 | 16 | 107 | 96 | 112 | 43 | 76 |
| TCU | 27 | 106 | 12 | 5 | 16 | 2 | 6 | 1 |
| UCLA | 56 | 67 | 110 | 27 | 34 | 82 | 33 | 87 |
| Uconn | 60 | 41 | 21 | 94 | 11 | 24 | 60 | 22 |
| N Illinois | 39 | 66 | 37 | 42 | 89 | 16 | 31 | 16 |
| Nebraska | 6 | 74 | 25 | 30 | 115 | 84 | 2 | 8 |
| A&M | 118 | 45 | 98 | 32 | 56 | 115 | 104 | 27 |
In some cases they seem based on the emergence of a superstar player on defense. For instance, Suh for Nebraska in 2009, which jumped from the 84th scoring defense to 2nd, or Von Miller for Texas A&M, which jumped from the 104th scoring defense in 2009 to the 27th in 2010.
In other cases you have teams that are consistently fairly good who for some reason have a collapse but then recover to their old form. UConn, for instance, usually has a pretty good scoring defense. In 2005, they were 21st, and in 2007 they were 11th in the country, but in 2006 they were 94th. Likewise, TCU has a pretty amazing scoring defense but in 2004 they were 106th in the country. The year before they were 27th, the year after they were 12th. They had some NFL talent, but all 2nd day draft picks or free agents.
Michigan is obviously not in the second type of team. Our defense hasn't been top 20 since 2006. It seems likely that for Michigan to have a good-to-great defense next year, something unexpected will have to happen. The most probable in my opinion is that one or two of our defensive players becomes dominant. Note: my excel spreadsheet is available for download here.
My guess is Washington shows up as the savior at NT to free the other three up to really dominate the game.
for this year. While I don't expect miracles we have all of the things that quantify a BIG statistical jump working for us. We return the most starters, our main rivals take a big hit in returning starters. We have the coaching change from several underperforming coaches to 3 stellar D line coaches, 2 with a long proven track record. We not only have emerging talent (Gordon-Ryan-Demens,) but we also have players who we all thought were ready to turn the corner, we have star talent returning from injury (Woolfork-Floyd-Martin) and we have overburdened talent (Martin-RVB-Roh) suddenly being taken off the leash and properly utilized. We're switching from a 3 man front to an (at times) 5 man front. We had a tougher road schedule last year and the easier home schedule this year. We have our main competitors offenses taking large steps backwards, while ours adds better clock management and it seems like the planets have aligned themselves just to give us a big statistcal jump. We'll likely not be where we ultimately want to be this year, but we couldn't arrange it much better to make a bigger 1 year improvement unless we switched to a weaker conference.
All of these things, plus we no longer have the youngest and shallowest defense in the B1G (and I believe it was one of the youngest in all of college football). Moreover, some of the upperclassmen were only playing because of injury and lack of young studs.
The OP's analysis is very much appreciated and does provide some hope, but as for the "conclusions and implications" section I think there's a third theory to help explain the potential for a significant improvement: last year we had a perfect storm of factors come together to result in a terrible defense. This year there could be a perfect storm of factors to create a significant jump in the defensive rankings. I'm trying not to get my hopes up too high, but I truly do expect us to be ranked in the 50s or 60s, with the potential for 40s or even 30s if we start clicking, winning, get on a roll, and get some attitude.
In 2007 they gave up an avg. of 37 ppg, including the embarassing 76 to Kansas. Tom Osborne fires Callahan. Brings in Bo Pelini, defensive background, to be head coach. Nebraska's defense improves 31 positions.
Projecting defensive performance for 2011 in terms of how big a jump in the rankings is required is, I think, somewhat misleading. It makes it seem like a statistical miracle is required to return to any kind of respectability. The remarkable statistical anomaly is already in the books: it is the epically, historically atrocious performance of last year's defense. That, let us hope, was an unfortunate outlier that Michigan fans will never again bear witness to.
If, instead, we simply forget all historical statistics and try to objectively compare the 2011 Michigan defense with the other 119 FBS teams in terms of talent, experience, and coaching, I think we would conclude that it is not a top 20 unit, but something like 40th would be a reasonable estimate. I don't think it is unreasonable or unrealistic for Michigan fans to expect a return to semi-normalcy following the recent excursion into the twilight zone of bad defenses.
I like stats -- a lot -- but I think there needs to be more discussion about WHY Mattison would be another 30 spots (I abhore straight rankings, but that's a different matter). In other words, you need a mechanism. In Brian's post the other day the mechanism was returning starters. In this diary, the mechanism is...nothing.
The only thing this data says is that we should expect the average improvement in ranking; we should expect nothing. Why isn't he worth 80 spots? How do we know he's worth anything at all?
entitled the GERG effect. These data don't speak to that issue at all, I agree. I wasn't claiming that, though.
Including a bowl game, this team could win 6 games or it could win 11. There is a lot of "possible" this season. And because of the wholesale coaching changes, we won't really have any idea until the games happen. The games that really count will be ND (loss), MSU (win), Nebraska (loss), and Ohio (win).
If Hoke continues the upward trend and they go 9-3, the bandwagoneers will all be satisfied that the program is "going in the right direction." That would be a great start.
Thanks for putting in the work on this and posting. I have a note about a statistical issue that makes these numbers pretty misleading, though. Part of the reason that you so rarely see jumps of, say, 70 spots is that only a fraction of teams could possibly make that jump no matter how much their D improves. If a team's D shot from #65 one year to #1 the following year, that wouldn't qualify as extreme improvement with the way you've set this up. In fact, that would count as a team that failed to make a 70-spot jump (since it'd be in your denominator but not your numerator).
One simple analysis that might be interesting would be to take the handful of defenses that finished right around where Michigan finished last year (say 5 in each direction over 10 years for about 100 teams) and plot where they finished the following year. This might give a better feel for the distribution of past outcomes.
Thanks for picking that up. I'll update the discussion to reflect this.
an improvement from 102nd to 70th seems realistic to me. The 70th ranked team in PPG allowed last year was Idaho at 28.3. With an easier schedule, improved scheme, coaching, and personell, that sounds about right.
I know that the board has had numerous discussions related to the defense and how much we as fans can/should expect it to improve. I find these posts to be very interesting. I hope the defense shows up this year.
One thing that a defense must do, and has been missing, is intimidate the players accross from them. I don't care if guys are out of position, or if they miss tackles, or the other side happens to be more athletic right now; but I do care about how much effort and physicality is being put into it. a lesser athlete can always make up ground by being more physical and simply intimidating the other side. When was the last time we had a Michigan defense where to a man you could say you would not want to be hit by any of those guys? I can't remember the last time I saw a solid de-cleater where a Michigan man was on the giving side and not the receiving side. I just want them to HIT SOMEONE.
As my college defensive coordinator used to say "find someone and make them your B$TCH!"
I
...shoulda known better with a girl like you.
