There is an absurdly excellent piece (first in a two-parter) up on Barking Carnival (the SBN University of Texas blog) about quantifying the impact that coaches have. You should go read it. Here's a taste:
Conceptually, success in any team sport (hence "quality") can be explained as the intersection of two factors: the ability of the players ("talent") and the value added by (or subtracted from) their environment, including stuff like strategy, game technique, strength and agility training, cooperative team relationships, etc. We'll call that "coaching", since the coach is accountable for most of those factors.
The fundamental relationship between talent and coaching appears to be best described as multiplicative, not additive. Meaning, the best teams almost invariably have both. You can't win FBS championships with South Dakota State talent nor can you win championships with a drunk idiot mule at the helm, Barry Switzer notwithstanding.
So far we have this basic equation: C(oaching) x T(alent) = Q(uality).
RichmondLonghorn has given us good proxy data for T (Rivals, Scout data) and Q (F/+, S&P+, Sagarin). What I'd like to do is plug that data into the equation and solve for C.
The bottom line for Wake: two of the worst teams in the years looked at (2010, 2012), which places Grobe in the elite company of Paul Wulff, Ted Roof, Jon Embree and Turner Gill with multiple appearances on the "worst teams" list. The 2010 season does not make the list for "worst coaching" seasons, but 2012 does. Also on that list: RichRod and Rick Neuheisel (three times apiece, at that), Mack Brown, Lane Kiffin, Randy Shannon, and Mr. Decided Schematic Advantage Charlie Weis.
Best coaching seasons? Bill Snyder takes the top season, but the names cropping up multiple times: Nick Saban, Chip Kelly, RichRod again, Bobby Petrino (!), and... Greg Schiano (!!!).
One name to keep a note of: Toledo coach Matt Campbell has only coached 3 seasons, but has done an excellent job in each of them. He has also upgraded recruiting during each of his seasons. If we do decide to replace Grobe, he might be an excellent replacement.
P.S. The comments section is also worth a read. An example:
I did some quick averaging of Coaching scores for selected coaches:
1 Chris Petersen 88.10521356by codaxx on Nov 26, 2013 | 10:36 AM
2 Ken Niumatalolo 83.35031652
3 Kevin Sumlin 78.59250384
4 Chip Kelly 78.59031538
5 Gary Andersen 78.27
6 Matt Campbell 78.01045839
7 Bronco Mendenhall 77.6863601
8 Jim Leavitt 76.65193511
9 Bobby Petrino 76.52479317
10 Nick Saban 75.91163343