Pre-Season Rankings

Hey football fans! Who’s ready for kickoff? I know you’re all on the edge of your seat for tonight’s Utah vs. Montana State tussle so I’d better get the pre-season rankings out quick!

It’s been an interesting offseason. Here’s a quick reminder of what we learned:

• We learned that guys that wear sweater vests can still commit major NCAA violations
• We learned that The U is still The U and that Nevin Shapiro is the new Uncle Luke
• We learned that Jordan Jefferson has 49 pairs of athletic shoes
• And just yesterday, we learned that Texas A&M would rather get beat up on by the SEC than by their older brother

 Interesting indeed! Of course, the big news that actually involves football was the offseason conference re-shuffling. The big moves were made by Nebraska, who left the Big 12 to join the Big 10, Colorado who left the Big 12 to join the Pac 12 and Utah, who took a step up from the Mountain West to the Pac 12 but BYU, who left the Mountain West and are now independent, and Boise State, who left the WAC for the Mountain West, made moves of their own that will also impact the college football landscape. These moves could have a major impact on the national championship picture but we’ll leave that discussion for later.

 I take a fully Bayesian approach to ranking college football teams, which means that I must specify a prior distribution in order to fit my model. The prior distribution represents our prior belief about the relative strength of the teams before the season starts. Many ranking systems (Jeff Sagarin’s, for example) use last season’s final rankings as a prior distribution but I don’t think this makes sense given the large amount of turnover in college football. Instead, I use a combination of published pre-season rankings that I translate into the number of points above and below average for all 120 teams. A blog post providing a full description of the prior is forthcoming. My pre-season rankings are my rankings based only on the prior. My pre-season top 10 can be found below (full rankings can be found on my personal website: www.biostat.umn.edu/~josephk/ps_rankings_2011.pdf).

Rank	Team	Rating	Record	SOS1	SOS2	E(FR)	P(WARG)
1	Alabama	24.72	0-0	3.09	0.093	9.95-2.05	0.06
2	Oklahoma	24.58	0-0	4.83	0.082	9.97-2.03	0.075
3	Oregon	23.88	0-0	3.46	0.124	10.14-1.86	0.074
4	Florida State	23.32	0-0	2.29	0.167	10.21-1.79	0.076
5	LSU	23.04	0-0	7.67	0.037	8.98-3.02	0.013
6	Stanford	22.06	0-0	2.33	0.200	10.22-1.78	0.087
7	Boise State	21.5	0-0	-4.2	0.390	10.88-1.12	0.25
8	Oklahoma State	20.8	0-0	3.78	0.105	9.5-2.5	0.035
9	Texas A&M	20.66	0-0	4.88	0.097	9.43-2.57	0.031
10	Arkansas	20.24	0-0	4.74	0.053	8.95-3.05	0.008

 As most of you know, Alabama, Oklahoma and Oregon are the pre-season favorites and all start the season about 25 points above average (note: a team’s rating can be interpreted as the number of points a team is above or below average), which is about average for the best team in the country at the end of the season. Also included in the table are two measures of strength of schedule (SOS¹ and SOS²), the expected final record (E(FR)) and the probability that they win all remaining games (P(WARG)). SOS¹ is the average rating of a team’s opponents. Most teams in the top 10 have an SOS¹ between 2 and 7.5 with the exception of Boise State, who’s SOS¹ is -4.2. To put that in perspective, the average team on Boise State’s schedule is about as good as 72 ranked Nevada. SOS² is the probability that a team that is 25 points above average would go undefeated with the given team’s schedule. This is perhaps the more relevant measure of strength of schedule for college football as going undefeated is the only sure way to assure that you will play for a national title (assuming that you’re from a BCS conference, of course). The differences SOS² among teams in the top 10 are not trivial. For example, an elite team would have only a 5% chance of going undefeated with LSU or Arkansas’s schedules, a 20% chance of going undefeated with Stanford’s schedule and a whopping 40% chance of going undefeated with Boise State’s schedule! This goes to show that even though Boise State is a very good football team they have a much easier road to going undefeated that the rest of the top 10.

Another way to look at the pre-season rankings is to consider the top 15 teams with the best chance of going undefeated:

P(WARG) Rank	Rank	Team	P(WARG)
1	7	Boise State	0.25
2	17	TCU	0.117
3	11	Virginia Tech	0.112
4	52	Houston	0.088
5	6	Stanford	0.087
6	4	Florida State	0.076
7	2	Oklahoma	0.075
8	3	Oregon	0.074
9	1	Alabama	0.06
10	24	West Virginia	0.036
11	8	Oklahoma State	0.035
12	12	Wisconsin	0.032
13	9	Texas A&M	0.031
14	13	Notre Dame	0.029
15	29	BYU	0.018

 This list looks quite a bit different than the top 10. Yes, most of the top 10 are present but teams like TCU, Virginia Tech and Houston also have a great chance of running the table even though they are not at the top of the rankings. It’s also worth noting that these calculations do include conference championship games. Conference championship games pose an extra challenge when trying to run the table because it tacks an extra game on the schedule against a quality opponent. This means that teams in the Big 10 and Pac 12 are now less likely to go undefeated than they were in the past because their conferences will play a conference championship games at the end of the season. In contrast, Oklahoma might be the biggest beneficiary of the conference reshuffling as the Big 12 will not play a conference championship game for the first time since 1995.   

 I don’t know about you but this has me excited. I hope you are too! I can’t wait until kickoff.

Welcome to the 2011 season!

Hello football fans and welcome to what will hopefully be another exciting season. Welcome back to those that have followed the rankings in the past and a warm welcome to those of you that are following the rankings for the first time. The rankings started out of a conversation with a grad school classmate about how to predict who would play in the BCS national title game in 2007 and I’ve been providing updated rankings weekly ever since. Every week during the season, I update my statistical model for ranking college football teams and simulate the remainder of the season 10,000 times to get a better idea of how the season will play out. Admittedly, my model is similar to other rankings systems that can be found on the internet but I think the results of simulating the season (and my always witty commentary, of course) contribute to our understanding of college football in a way that can’t be found elsewhere. If nothing else, I have a blast writing this blog and the rankings certainly enhance my enjoyment of the college football season. I hope this blog will do the same for you!

Bowl Preview

Hey football fans! The bowl season starts tomorrow. I better get my bowl preview out before it’s too late!

Below you will find basic information for each bowl including: name (I didn’t have room for all of the wacky sponsors, sorry), favorite, underdog, line based on the current version of my rankings, probability of an upset and date for the game.   

That’s an awful lot of information and, to help you out, I thought I would summarize a few interesting points:

• I’m sure you’re all interested in what I have to say about the National Championship Game. The rankings have not been a fan of Auburn all season and, not surprisingly, I have Oregon as a ten point favorite over Auburn. The national perception is that the Pac 10 did not have a good year but my rankings have the strength of the Pac 10 as nearly equal to the strength of the SEC. Combine that with the fact that Oregon didn’t play many close games, compared to Auburn, who had several close calls, and you can see why my rankings have Oregon as the solid favorite.
• There seems to be a lot of enthusiasm for this year’s BCS match-ups but the rankings do not see these games being as competitive as last year. Oregon and Oklahoma are favored by ten and fourteen points, respectively, and only the Rose Bowl has a line of less than five (TCU by 4.76). In contrast, none of last year’s games had a ten point spread (the Sugar Bowl was close at 9.74), three of the games had smaller spread than this year’s Rose Bowl and two were expected to be closer than a field goal.
• A lower-tier bowl that’s drawing a lot of attention is the Las Vegas Bowl, which features Boise State and Utah. Boise and Utah have been the strongest non-BCS conference teams of the BCS era. Both team’s regular seasons ended in disappointment. It will be interesting to see who rebounds for a good bowl showing. The rankings think it will be the Broncos by fourteen.
• Presented without comment: this year, there are 35 bowls, meaning that 70 of the 120 Bowl subdivision teams are above average.
• The title sponsors get wackier every year. Last year, my favorite was easily the Beef ‘O’ Brady’s St. Petersburg Bowl. Beef ‘O’ Brady’s is back but there are several other great options this season. The AdvoCare V100 Independence Bowl is a classic (AdvoCare V100 is a diet supplement) and the BBVA Compass Bowl is pretty good too (until year realize that BBVA Compass is a holding company and not a compass manufacturer), but the title of best sponsor is clearly a dogfight between the Bell Helicopter Armed Forces Bowl and the Military Bowl Presented by Northrop Grumman. (Do I lose points for the bad pun?)

Happy Holidays! Enjoy the bowl season!

Bowl	Favorite	Underdog	Line	P(Upset)	Date
BCS National Championship Game	Oregon	Auburn	10.02	0.244	1/10/11
Sugar Bowl	Ohio State	Arkansas	6.53	0.326	1/4/11
Orange Bowl	Stanford	Virginia Tech	8.22	0.285	1/3/11
Fiesta Bowl	Oklahoma	Connecticut	14.08	0.165	1/1/11
Rose Bowl	TCU	Wisconsin	4.76	0.371	1/1/11
Cotton Bowl	LSU	Texas A&M	2.02	0.444	1/7/11
Capital One Bowl	Alabama	Michigan State	14.23	0.162	1/1/11
Gator Bowl	Mississippi State	Michigan	4.28	0.384	1/1/11
Outback Bowl	Florida	Penn State	8.65	0.275	1/1/11
Kraft Fight Hunger Bowl	Nevada	Boston College	8.47	0.279	1/9/11
BBVA Compass Bowl	Pittsburgh	Kentucky	7.39	0.305	1/8/11
GoDaddy.com Bowl	Middle Tennessee State	Miami (Ohio)	0.22	0.494	1/6/11
TicketCity Bowl	Texas Tech	Northwestern	6.92	0.316	1/1/11
Chick-fil-A Bowl	Florida State	South Carolina	2.68	0.426	12/31/10
Liberty Bowl	Georgia	Central Florida	9.81	0.249	12/31/10
Sun Bowl	Miami (Fla.)	Notre Dame	4.33	0.382	12/31/10
Meineke Car Care Bowl	Clemson	South Florida	6.65	0.323	12/31/10
Holiday Bowl	Nebraska	Washington	14.04	0.166	12/30/10
Music City Bowl	North Carolina	Tennessee	2.64	0.428	12/30/10
Pinstripe Bowl	Kansas State	Syracuse	4.76	0.371	12/30/10
Armed Forces Bowl	SMU	Army	3.27	0.41	12/30/10
Alamo Bowl	Oklahoma State	Arizona	2.53	0.431	12/29/10
Texas Bowl	Illinois	Baylor	3.44	0.406	12/29/10
Military Bowl	Maryland	East Carolina	14.12	0.164	12/29/10
Insight Bowl	Missouri	Iowa	0.44	0.488	12/28/10
Champs Sports Bowl	West Virginia	North Carolina State	2.29	0.437	12/28/10
Independence Bowl	Air Force	Georgia Tech	1.73	0.452	12/27/10
Little Ceasers Bowl	Toledo	Florida International	1.02	0.472	12/26/10
Hawaii Bowl	Hawaii	Tulsa	6.96	0.315	12/24/10
Poinsettia Bowl	Navy	San Diego State	2.17	0.44	12/23/10
Las Vegas Bowl	Boise State	Utah	14.67	0.155	12/22/10
St. Petersburg Bowl	Louisville	Southern Mississippi	2.79	0.423	12/21/10
New Orleans Bowl	Troy	Ohio	0.04	0.499	12/18/10
Humanitarian Bowl	Northern Illinois	Fresno State	6.35	0.33	12/18/10
New Mexico Bowl	BYU	UTEP	14.71	0.154	12/18/10

Full week 14 rankings can be found at my personal website:

www.biostat.umn.edu/~josephk/wk14_ranking_report.pdf