The 2011 Defense: The Pace of Evolutionary Change

Submitted by OysterMonkey on July 20th, 2011 at 1:47 PM

[Ed-M: Bumped because this totally punctuated my equilibrium. The best indicator yet of year-to-year defensive evolution. And great news: the mean has magnetism!]

Richard Goldschmidt hypothesized that the incremental changes to organismal phenotypes over the course of even thousands of generations was insufficient to explain the change from one species to another. He posited that evolutionary change is powered by great leaps forward, instances of saltatory mutation that generate a new species from the old. Goldschmidt’s ideas were ridiculed, mostly, and with good reason. The overwhelming evidence of population genetics and the theoretical triumph of the Neo-Darwinian synthesis seem to indicate that evolutionary change is effected gradually over time by the additive effects of allele substitutions in the genetic makeup of a given population; population change happens slowly, if at all.

But there are situations in which sudden changes to an organism’s ecological niche—a new predator or prey introduced, migration or population bottlenecks, climate change, a massive meteor falling from the sky and killing all the dinosaurs—opens up the opportunity for rapid (on the geological time scale) evolutionary change.

The defense was bad last year. And bad the year before. And the year before that. A number of reasons have been put forward for the awfulness. The defense was decimated. Really decimated. Seriously, it was decimated. GERG is a force of nature complete with his own effect. The coaches thought making in-game adjustments was tantamount to cheating. And so on. At the risk of overstraining the metaphor, it certainly felt as if we were watching the extinction of that species of animal previously known as the Wolverine defense. It’s at the very least an endangered species. But if the combination of the addition of Hoke and Mattison, Nebraska joining the BIG, and the tattoo-laden implosion of the 614 area code don’t count as a change in the environment that opens the possibility of rapid change, then my metaphor has no validity at all.*

Folks have tried to take a stab at what might happen this year, based on small sample sized studies of returning starters, even smaller sample sized bits of anecdotal evidence, and a healthy dose of Hoke-A-Mania! I collected data from on total defense numbers from 2006 through 2010 and analyzed year to year changes for every team, based on total defense rankings. Even though I’ve got five years of data, I’m going to talk in terms of “Base year” and “Year 2;” since I wasn’t looking to find multi-year trends in defensive performance all I care about is the movement from one year to the next. So with five years of data I have four years (2006-2009) worth of data in my “Base year” set and four years (2007-2010) in my “Year 2” set

This diary doesn’t propose to do anything other than aggregate a little bit of data about what we can expect based on very recent history and to show how many teams over the last few years have been outliers. From there we can start to see what Michigan’s chances are of bucking the odds of Darwinian uniformitarianism.

Natura non facit saltum: The Case For Phyletic Gradualism

My first task was to look at the aggregated data on a very coarse grain. I wondered how much movement there was in rank from year to year, so I grouped teams into sets of ten based on their base year finish (top ten teams, teams 11-20, etc.) and then tracked where those clusters of teams finished on average in year 2.

The result:

So the 40 teams in the data set that finished in the top ten in the base year averaged a finish at around 20 year 2. If a team finished in the 111-120 rank range, they could expect to be at around 95 in year 2. The obvious thing that jumps out is regression at the two ends of the line. This suggests what should be obvious: it is difficult to sustain excellence or ineptitude. So, by staying terrible last year, Michigan is already an outlier. Yay? But as you move away from the ends of the line, the movement away from the base year gets less and less, so that teams that are average appear to stay average.

Then, since I care mostly about one of the teams at the gruesome end of the line, I looked more closely at teams that finished the base year in the 90-120 range, and got this for my troubles:

This looks at every spot in the ranking from 90 to 120 and plots the year 2 average for the teams that finished at each of those spots. There is a lot of noise here, because for each ranking spot there are only four data points, but the trend line is pretty much what we’d expect. The worse you are in the base year, the worse you can expect to be in year 2.

So the numbers look gloomy, suggesting that expecting much movement in one year is a recipe for disappointment. These numbers provide the baseline for the geological timescale. The pace of change appears to be slow.

Hopeful Monsters: The Case for Saltationism

Despite this evidence of evolutionary stasis there have been a number of teams who’ve managed macromutation from one year to the next, both up and down. Since 2006, 37 teams out of a possible 278 (obviously only teams ranked 51 or worse could possibly make a 50 spot leap) have managed a leap of 50 or more spots in the ranking from one year to the next, and 107 out of 378 possible have made jumps of 25 or more spots.




 Population size


50 spot leap





25 spot leap





For what it's worth, these percentages are higher than I expected prior to compiling the numbers. It's not worth anything, by the way.

My original goal was to analyze the factors that these saltatory leaps might have in common, but finding reliable data on returning starters, experience, changes to coaches or defensive co-ordinators, etc. has proven difficult. I might try to look in detail at a few case studies to see if there are any similarities between Michigan 2011 and the hopeful monsters who point to the possibility of rapid change, but provide a link to my table so that anyone else who may want to can do the same.

Viva la evolucion.

*Yes, I’m aware my metaphor already has no validity at all.

Edit: I think this is what the first commenter is asking for.



July 19th, 2011 at 10:20 AM ^

The graphs make it easy to compare 90th place to 91st place, but that's not what I want to look at.  I want to quickly compare year 1 results to year 2 results for all of those spots.  A y=x line would make that a little easier.

restive neb

July 19th, 2011 at 5:15 PM ^

Although you don't have the trendline for year 2 in that last graph, it looks like it would be nearly parallel (slightly steeper in slope?) to the base year line.  The difference in slope is probably not statistically significant, which leads me to conclude that a typical team anywhere in the bottom quarter defensively could expect an improvement of ~ 20 places in overall position.


July 19th, 2011 at 10:36 AM ^

...were entering Year 2 with a new HC and DC? What effect does that sort of major environmental shift have on the evolutionary process and the likelihood of a macromutation in the postive direction?

Surveillance Doe

July 19th, 2011 at 10:47 AM ^

It seems to me we've had a number of diaries containing the pieces of a truly informative diary on what we might see on the defensive side of the ball this season. I enjoy reading them and appreciate the work of their authors, but I would love to see someone take the next step and put it all together.

Perhaps it hasn't happened because, once you account for past performance, youth, staff changes, scheme changes, etc., you end up with a tiny simple size or no sample at all. But has anyone given it a shot? I would be very interested to see how the data above changes when narrowed to more closely resemble our current situation.

By the way, I enjoyed the evolution analogy. Nicely done.


July 19th, 2011 at 11:07 AM ^

It's harder to go from 51 to 1 than 110 to 60, maybe there is a better way to compare than on an absolute change in ranking, i.e. 25 or 50 positions in your analysis. This is maybe overly simply but you could use a ratio: change in ranking/original ranking.


July 19th, 2011 at 11:26 AM ^

I knew that not all 50 spot leaps are made equal, and I considered the ratio idea, but if you go in terms of change in ranking/original ranking then you get some very skewed equivalences.

For example, between 2006 and 2007 Ohio State went from 12 to 1 and Pitt went from 87 to 5. Those two are basically equivalent ratios though. I would definitely think Pitt's movement is much more impressive.

So I figured I'd have to calibrate the ratios somehow, and got tired of thinking about it.

Gulo Blue

July 19th, 2011 at 6:51 PM ^

Averaging rankings has an inherent normalizing effect.  Unless somebody is number 1 every year, nobody comes out number one after you average.  You re-rank after averaging the base year data (by grouping in tens), it seems like you should re-rank after averaging the year 2 data also.  Worst year 2 performance is #120, best is #1.  Good idea to take a look at this...thanks for doing it.


July 19th, 2011 at 10:32 PM ^

Macro change is coming for a cute, cuddly, fuzzy beaver in one's face employed in 2010 as an edible tool publicly used by a Michigan coach (used to inspire a defense?). The beaver will become extinct before the start of this season (Thank God),and will be absented from the food chain. This macro change which will take place this season, should result in a higher than expected degree of tangible defensive success for 2011 as compared to 2010 resulting in a top 50 finish.

Even the memories of a bad taste in the mouth will be long forgotten. Yes!!

An appetite for victory also will be restored by a new (some say old species of) highly efficient coaching staff; potentially resulting in unexpectedly unprecedented change for the better.


July 20th, 2011 at 3:15 AM ^

I am surprised by the fact that 13.3% made a 50 spot leap.  I would have expected much less.  I find that encouraging for the upcoming season.

It has been a long time since I have been in any evolution classes, but I seem to recall that fossil evidence for gradual evolutionary change -ie a bird's small beak becoming larger, then medium size, then medium large, then large size- is lacking.  Some postulate that this is because fossils are infrequently formed and then more infrequently found.  Others believe that evolution is more fits and starts- either the mutation works and a new species propagates(the Large beak) or does not work and it quickly dies off.  I thought that this latter theory was now more accepted, but perhaps I am out of the loop. 

As an aside, I heard Stephen Jay Gould give a talk at Michigan, and he was great.  I miss opportunities such as that.  We don't get that much here in Hawaii.  Of course, there are other aspects of paradise that make up for it.



July 20th, 2011 at 6:44 AM ^

is consistent with the fossil record, but I don't think it has broad support in the evolutionary biology community. Gould was its big advocate and he had a few acolytes, but I don't think it was ever widely accepted.

But I mainly left it out because I didn't need another iteration of evolutionary theory for my analogy.


July 20th, 2011 at 12:55 PM ^

19 of the 100 or so instances of 25+ spot leaps were in a new coach's first year. 37 had new D-Coordinators.

Maybe most relevant to Michigan, Brady Hoke's last three teams (2008 Ball State, 2009 and 2010 SDSU) have all improved by at least 25 spots from their prior year's rankings.



July 20th, 2011 at 2:57 PM ^

I like that so many of the educated readers of the blog have set out to find data-driven reasons for optimism with this defense, even when just about all of them result in disappointment.  I think the bottom line in my mind are these facts:

  • Realistically we shouldn't expect more than a 20-30 spot improvement in the rankings this year.
  • If there were ever a team to fall into line as an outlier for a larger jump it would be this Michigan team for all the factors mentioned
  • It really will come down to health.  Last year would have been different with a healthy Wolfolk and Martin the entire year.  Same thing goes for this year - aside from DE, SLB, and maybe CB there is little depth and experience beyond the starters.


D.C. Dave

July 20th, 2011 at 3:14 PM ^

To me, this is the best line in the entire piece, which is an interesting examination overall. It's also my main reason for hopein 2011: What are the statistical odds that one head coach, in three seasons out of 131, would oversee the three worst defenses in school history? He not only sustained ineptitude, he was able to achieve greater ineptitude with each new season. One would think that, perhaps due to nothing more than statistical norms, that at least one of those three defenses would be superior to some other horrible defense in the other 128 seasons. But that was not the case.

The message is that the evaluation, schemes, positioning of players and game-planning were so bad that RichRod and his staff were able to fail well below what could be expected statistically. And it is why I continue to believe the defense, now that it has proven defensive coaching, will revert to the norm and make a substantial improvement. And this gives us a reason to hope that the current players may have more talent than we've seen translate to the field, and the improvement this season may be greater than what could typically be expected, simply because the sustained ineptitude defied all norms.


July 20th, 2011 at 3:17 PM ^

of D's that jumped 50+ spots because Michigan has everything needed, i.e.,

1. elite D coaching

2. lots of returning starters

3. lots of *experienced* returning starters

4. above average 4-year recruiting

IMO teams with 1-4 are set up for maximal progress.  In '11 I expect Michigan's D to be somewhere around 30; and then 15-ish in '12.

btw, great read.  enjoyed it.

The Barwis Effect

July 20th, 2011 at 4:37 PM ^

Somebody needs to look at what factors (philosophy change, coaching change, team health, upper-class laden team, etc.) allowed Pitt, Kansas, and NIU to jump 80+ spots and then determine whether any of those same factors are present here.


July 20th, 2011 at 4:50 PM ^

NIU changed head coach; 08 was Kill's first year.

Kansas and Pitt changed neither head coach nor defensive coordinator.

One of the problems, I think with looking just at the teams that got better and trying to figure out what they have in common is that your sample make you think you're onto something, when in reality what you have is what you'd expect from a random sample.

For instance, 19 out of 100ish teams changed head coaches and 37 changed co-ordinators. But if that's more or less the percentages of coaches that are changed each year, then coaching changes aren't necessarily predictive.



July 20th, 2011 at 4:21 PM ^

First, nice job.  I think that problem that you are encountering is that there are just way too many variables to take into account to accurately predict anything (as you noted).

So, my way less scientific approach:\

Baseline - we were around 110 last year, depending on which metric you used, but bottom line is that were were as bad as a defense can be:

1)  Returning 8 defensive starters on a VERY young team - no more true freshman filling the ENTIRE secondary.  Experience is worth a ton.  Worth 15 spots

2)  Return of T-Wolf, a 5th year senior who may be our best secondary player on a team that was not so good in the secondary - worth 5 spots, minimum (because he will be able to at least cover a team's #1 receiver)

3)  Mattison / Hoke replacing GERG - Generally, a coaching change is a cause to expect some difficult periods of learning the new system.  Here, we are replacing a man who rubbed stuffed animals on the faces of 18-22 year old men during football games with one of the top DCs in the country.  From comments by Mattison, the team did not know how to do such basic things as tackle, cover, choose proper pursuit angles, etc.  GERG also played players in positions that they should never have played (Roh, for example).  Simply learning how to cover, tackle and be in the right place is worth 10 spots, and playing guys like Roh and BWC in their natural spots (while also getting a full season of Demens) is worth another 5 spots.

4)  No 3-3-5 - the 3-3-5 was an epic failure - it is simply not suited for B10 play.  Returning to a 4-3 instantly improve our pressure on opposing QBs, result in these things called "sacks" and take away some of the pass game from opposing QBs.  Worth 10 spots.

5)  MANBALL Offense - Disclaimer - this is NOT a criticism of the spread and shred that RR run, or a commentary on the effectiveness of last year's offense.  RR ran a VERY fast paced offense.  When it worked, we scored quickly.  Whe it didn't we gave up the ball quickly.  Either way, the defense was back on the field quickly.  Under the new system ,there will probably be less possessions for both teams, and time of possession should be closer to even.  Simply being on the field for less time will reduce the # of yards, points, etc. that our D gives up.  Worth 10 spots.

6)  Turnovers - we turned the ball over a lot last year.  This put the D back on the field and in a position to give up yards/points (usually both).  Denard was, for all practical purposes, a freshman last year.  In his second full year as a starter, I expect massive improvement in his turnover #s, as is common for second year starters.  Result - less situations where our D comes on the field with the ball well into Michigan's redzone.  Worth 5 spots.

7)  Schedule.  I do not expect another 67 point, triple overtime game this year (Illinois).  We will not be facing an OSU team led by TP.  These two factors alone are going to improve our final D #s by a few spots - 2 spots, maybe?

Total:  Improvement of 52 spots, putting us at somewhere around 58.  Right around average, which would be a massive improvement from where we were before.   


July 20th, 2011 at 4:47 PM ^

This whole diary jibes with overall common sense - mostly, good D's stay good, bad D's stay bad. Outliers correct harder to the middle than those in the middle of the pack. Fine.

I do think that all the studies that use Rankings and not yardage or points tend to be misleading. For instance - there's about 10 yards a game difference between the #75 defense in the nation and the #93 defense in the nation. An 18 spot disparity in rankings suggests there's a meaningful difference where there really isn't much of one.


July 20th, 2011 at 4:48 PM ^

Good read, thanks.  There are so many variables involved that trying to extrapolate one team's performance year-to-year based on what other teams have done is almost meaningless.  Assuming the schedule is more or less the same, for me there are three main factors that can influence a movement up or down.

- Quality of player

- Quality of coaching

- Experience

We stand to have significant improvements on all three this year.  That's what I'm banking on.


July 20th, 2011 at 5:22 PM ^

My research is in an evolutionary field so I appreciated this. I'm certainly hoping that our relative equilibrium on D is punctuated fiercely this season.

One correction, in case anyone else was confused: "salutatory" should be "saltatory". The latter refers to a sudden change between generations, whereas the former refers to a welcoming gesture or statement.



August 2nd, 2011 at 10:32 PM ^

I was watching Hoke's first press conference, yes, the whole thing, again... and anyway he mentioned that SDSU went from #113 ranked defense to #43 while he was there.   So, to the rescue with stats...


School/Year  TotDefRank/Yds/ConfRank   ScorDefRank/Pts/ConfRank 
SDSU 2006    113 / 460.75 / 9          113 / 37.17 / 9
SDSU 2007     74 / 382.00 / 5           98 / 30.50 / 7
SDSU 2008     43 / 353.77 / 5           36 / 22.08 / 5
So there you have it.  From basement to respectable in 2 years.  I think we can hope for similar results, but don't expect miracles this year.  I realize this is a bit redundant and late in the discussion, but like I said I just watched Hoke's talk and didn't want to make another Hoke & defense thread...   :)