Sunday, August 29, 2010

From Negative Grohmentum with Love

For the uninitiated, Negative Grohmentum is the effect that teams whose coaches win conference coach of the year will usually see their teams get worse (and often significantly worse) the following season. It's named after three-time ACC Coach of the Year and newly-minted defensive coordinator on the Flats Al Groh, who managed to win the award and regress on a regular basis. Here's what the numbers looked like last summer:

There's no doubt that we have a strong correlation between a coach winning coach of the year and then his team getting worse. 78% of the teams in this situation this decade have seen their record regress the following year. 34% of the teams in the sample saw their record get worse by at least three games. By way of comparison, Phil Steele likes to look at net close wins and yards per point in finding teams that were especially lucky or unlucky in the previous season and are therefore due for a correction. (Page 299 if you're following along at home.) Teams with three net close wins have been weaker or the same the next year 76.7% of the time. Teams with 11.56 offensive yards per point or less have been weaker or the same 72.3% of the time. Teams with 19.85 defensive yards per point or more have been weaker or the same 77.6% of the time. Again, 78% of the teams whose coach won coach of the year have been weaker (not just weaker or the same, but weaker full-stop) the next year.

So how negative was the Grohmentum last year?

SEC - Nick Saban improved by two games, Bobby Johnson regressed by 4.5 games, and Houston Nutt was unchanged.

Big Ten - Joe Paterno was unchanged.

Big XII - Bob Stoops regressed by 3.5 games and Mike Leach regressed by two games.

ACC - Paul Johnson improved by 1.5 games.

Pac Ten - Mike Riley regressed by one game.

Big East - Brian Kelly improved by 1.5 games.

So four coaches saw their teams get worse, three got better, and two were unchanged. Three of the six BCS conferences were won by coaches whose teams should have gotten work. 2009 was a bad year for Negative Grohmentum. Anyway, if we are still buying that it has an effect, here are the coaches whose teams would be taking a step back this year:

SEC - Nick Saban
Big Ten - Kirk Ferentz
Big XII - Mack Brown
ACC - Paul Johnson
Pac Ten - Chip Kelly
Big East - Brian Kelly

We seem to have some mortal locks for regression this year, but how much guidance do we need to know that Alabama is unlikely to match a 14-0 season or that Iowa, Texas, and Georgia Tech will have a hard time doing better than they did last year? Negative Grohmentum is having a low self esteem moment.

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