An Undefeated Conference Season?

Well, since I made the last post, Pittsburgh beat Duke, Memphis beat Georgetown, Mississippi beat Clemson, and Michigan St. beat Texas, so that now only 9 undefeated teams remain. Of course, 3 of those games were between unbeaten teams, so it was bound to happen.

An event that is not quite as rare is an undefeated conference regular season. With the exception of 2001 and 2002, at least two teams have gone undefeated in conference play in each of the last 10 years:

2007 - Memphis (CUSA) and Winthrop (Big South)
2006 - Bucknell (Patriot), George Washington (A10) and Gonzaga (WCC)
2005 - Davidson (Southern) and Pacific (WAC)
2004 - Austin Peay (OVC), Gonzaga (WCC) and St. Joseph's (A10)
2003 - Kentucky (SEC), Penn (Ivy), and Weber St. (Big Sky)
2002 - Kansas (Big 12)
2001 - none
2000 - Cincinnati (CUSA), Penn (Ivy), and Utah St. (Big West)
1999 - College of Charleston (Southern), Duke (ACC), and Utah (WAC)
1998 - Princeton (Ivy) and TCU (WAC)

Which teams are most likely to do so this coming year? Using Jeff Sagarin's PREDICTOR as of today, the 20 most likely candidates are listed below:

Rank Team Conf Prob. conf games
1 Winthrop, BSth 13.2% 14
2 Morgan St., MEAC 11.5% 17
3 Gonzaga, WCC 8.9% 14
4 Holy Cross, Pat 6.7% 14
5 Memphis, CUSA 6.3% 16
6 Butler, Horz 5.7% 18
7 Kansas, B12 5.5% 16
8 West Virginia, BE 5.5% 18
9 Duke, ACC 4.7% 16
10 Hampton, MEAC 3.6% 18
11 St. Mary's, WCC 3.4% 14
12 Davidson, SC 3.0% 20
13 Texas Arlington, Slnd 2.9% 16
14 Xavier, A10 2.7% 16
15 Brown, Ivy 2.0% 14
16 MD Baltimore County, AE 1.9% 16
17 Rhode Island, A10 1.5% 16
18 Alabama St., SWAC 1.4% 18
19 North Carolina, ACC 1.4% 16
20 South Alabama, SB 1.2% 18

Here are the conference-by-conference leaders:

A10 - Xavier 2.73%
ACC - Duke 4.73%
AE - MD Baltimore County 1.92%
ASun - East Tennessee St. 0.47%
B10 - Wisconsin 0.51%
B12 - Kansas 5.47%
BE - West Virginia 5.45%
BSky - Portland St. 0.12%
BSth - Winthrop 13.20%
BW - UC Santa Barbara 0.66%
CAA - Virginia Commonwealth 0.26%
CUSA - Memphis 6.34%
Horz - Butler 5.69%
Ivy - Brown 2.03%
MAAC - Siena 0.44%
MAC - Miami OH 0.70%
MEAC - Morgan St. 11.50%
MVC - Drake 0.82%
MWC - New Mexico 0.43%
NEC - Robert Morris 0.08%
OVC - Austin Peay 0.14%
P10 - UCLA 0.06%
Pat - Holy Cross 6.71%
SB - South Alabama 1.24%
SC - Davidson 2.99%
SEC - Tennessee 0.80%
SWAC - Alabama St. 1.44%
Slnd - Texas Arlington 2.85%
Sum - IUPUI 0.76%
WAC - Nevada 0.53%
WCC - Gonzaga 8.89%


Notice that in some of the conferences (like the WCC, and MEAC) two teams have a nontrivial chance at going undefeated. With this in mind, here are the conferences ranked by the probability that any of the teams goes undefeated:

rank conf teams prob
1 MEAC 12 15.1%
2 BSth 8 13.2%
3 WCC 8 12.3%
4 Pat 8 6.7%
5 CUSA 12 6.4%
6 ACC 12 6.1%
7 BE 16 6.0%
8 Horz 10 5.9%
9 B12 12 5.6%
10 A10 14 5.1%
11 Slnd 12 3.3%
12 SC 11 3.1%
13 SB 13 2.3%
14 Ivy 8 2.1%
15 AE 9 2.0%
16 SWAC 10 1.4%
17 Sum 10 1.4%
18 SEC 12 1.1%
19 WAC 9 0.9%
20 MVC 10 0.9%
21 BW 9 0.8%
22 B10 11 0.8%
23 MAC 12 0.8%
24 MWC 9 0.7%
25 ASun 12 0.6%
26 MAAC 10 0.6%
27 CAA 12 0.5%
28 BSky 9 0.3%
29 OVC 11 0.3%
30 NEC 11 0.1%
31 P10 10 0.1%

From these probabilities, you can easily calculate the chance that at least one D1 team will go undefeated in conference play this season. In this case, the probability is 67.2%. This seems slightly low since 90% of the last 10 years it happened, but maybe we would have seen a similar number in 2001 or 2002.