Blog Entry

2010 CFB Final Top 25, NCAA RPI Style

Posted on: March 14, 2011 8:47 pm
 
During the college basketball season, we hear and read alot about the RPI (Ratings Performance Index), and fans eagerly wait for the updates to come out during the week to see where their favorite team stacks up.  I've expressed my opinion of the college football rankings many times, human and computer created.  There's not a more subjective system out there, but is the NCAA RPI for basketball any better?  Unlike the BCS computer rankings, the RPI has no human interface, other than those who plug in the numbers.  It's based strictly on a team's winning percentage, their opponents winning percentage, and the opponents' opponents winning percentage.  The NCAA RPI also determines a strength of schedule based on the latter two elements, and SOS is included in the formula for rating all of the teams.  

Last night, while watching the bracket special on CBS, the thought crossed my mind what a final college football ranking would look like using the NCAA formula for rating basketball teams.  So I gathered all of the numbers for the top 45 teams with the best win/loss records, and put together a final top 25 based on the NCAA RPI.  I was very surprised to see the results, as I'm sure you will be too as you peruse through the ratings below.   

1.  Auburn 14-0

SOS: 4
RPI: .6586

2.  LSU 11-2

SOS: 2
RPI:  .6419

3.  Texas A&M  9-4

SOS: 1
RPI:  .6353

4.  Oklahoma 12-2

SOS:  6
RPI:  .6328

5.  Alabama 10-3

SOS:  3
RPI:  .6274

6.  Arkansas 10-3

SOS:  5
RPI:  .6255

7.  Missouri 10-3

SOS:  9
RPI:  .6153

8.  South Carolina 9-5

SOS:  7
RPI:  .6069

9.  Stanford 12-1

SOS:  14
RPI:  .6060

10.  Notre Dame 8-5

SOS:  8
RPI:  .6028

11.  Florida State 10-4

SOS:  11
RPI:  .5999

12.  Oklahoma State 11-2

SOS:  16
RPI:  .5985

13.  Ohio State 12-1

SOS:  24
RPI:  .5982

14.  Florida 8-5

SOS:  10
RPI:  .5936

15.  TCU 13-0

SOS:  35
RPI:  .5912

16.  Boise State 12-1

SOS:  28
RPI:  .5908

17.  Virginia Tech 11-3

SOS:  15
RPI:  .5901

18.  Michigan State 11-2

SOS:  22
RPI:  .5897

19.  Oregon 12-1

SOS:  26
RPI:  .5884

20.  Mississippi State 9-4

SOS:  12
RPI:  .5859

21.  Nebraska 10-4

SOS:  19
RPI:  .5774

22.  Wisconsin 11-2

SOS:  29
RPI:  .5768

23.  Nevada 13-1

SOS:  36
RPI:  .5755

24.  NC State 9-4

SOS:  20
RPI:  .5743

25.  West Virginia 9-4

SOS:  23
RPI:  .5708

Now, lets say the NCAA sponsored a 16-team playoff after the bowl games, based on the final RPI results.  The top 16 teams in the RPI get a bid, and are seeded as rated.  The brackets would've featured the following matchups for the 2010 season playoffs:

EAST BRACKET
1. Auburn versus 16. Boise State
8. South Carolina versus 9. Stanford

4. Oklahoma versus 13. Ohio State
5. Alabama versus 12. Oklahoma State

WEST BRACKET
2. LSU versus 15. TCU
7. Missouri versus 10. Notre Dame

3. Texas A&M versus 14. Florida
6. Arkansas versus 11. Florida State

Let me know how this affects your opinion now on the BCS formula for ranking teams.  The above top 25 is objective as it can get, without human interaction and opinion the BCS rankings are inundated with.

I'm curious how the RPI would work throughout the college football season, so I may try this for the 2011 season.  I suppose the best time to start it would be after the fourth week of play.  If I'm able to take the time to accomplish this, I'll post weekly updates.

Thanks to the folks at www.cfbtrivia.com for helping me to put this together.
Category: NCAAF
Comments

Since: Apr 14, 2008
Posted on: April 3, 2011 7:32 pm
 

2010 CFB Final Top 25, NCAA RPI Style

You are correct, these ratings represent post-bowl "RPI".  I fiddled with the numbers a little, added some factors and created a pre-bowl "RPI" based on end of regular season percentages.  I added a ratings percentage factor for schedule, based on the top 45 team's home, away and neutral results.  I removed all FCS opponent results, and deducted .10 for home and .02 for away percentages for those teams who played an FCS opponent.  Although the SOS was not affected, the overall RPI was.  Neutral results were unchanged.  I used a .48 factor for home results, and .52 for away results to arrive with an "RPI" for schedule and an even factor for neutral games.    This result was averaged in with other factors to determine the overall RPI.  I also removed FCS opponents from winning percentage and opponent winning percentage.  I left FCS results alone for opponent opponent percentage, since the calculation wouldn't make much of a difference in the overall RPI.  I tweaked the percentage factor for winning percentage, opponent winning percentage and opponent opponent winning percentage in order to arrive at a more realistic SOS.  Here's the result of a 2010 FBS football RPI using additional and tweaked factors using the top 45 teams in terms of win/loss record:

1.  Auburn  13-0  

SOS: 16
RPI: .3014

2.  TCU  12-0

SOS:  39
RPI: .2937

3.  Oregon  12-0

SOS:  40
RPI: . 2934

4.  Boise State  11-1

SOS:  32
RPI: .2828

5.  Ohio State  11-1

SOS:  31
RPI: .2789

6.  Stanford  11-1

SOS:  27
RPI: .2770

7.  Virginia Tech  11-2

SOS:  25
RPI: .2762

8.  Oklahoma State  10-2

SOS:  17
RPI: .2756

9.  Nevada  12-1

SOS:  34
RPI: .2745

10.  Wisconsin  11-1

SOS:  36
RPI: .2705

11.  Michigan State  11-1

SOS:  28
RPI: .2693

12.  Utah  10-2

SOS:  35
RPI: .2645

13.  Oklahoma 11-2

SOS:  6
RPI: .2607

14.  Arkansas 10-2

SOS:  9
RPI: .2552

15.  Texas A&M  9-3

SOS:  1
RPI: .2544

16.  Nebraska  10-3

SOS:  18
RPI: .2528

17.  LSU  10-2

SOS:  4
RPI: .2496

18.  Missouri  10-2

SOS:  10
RPI: .2485

19.  Northern Illinois  10-3

SOS:  45
RPI: .2440

20.  Alabama  9-3

SOS:  7
RPI: .2384

21.  Navy  9-3

SOS:  33
RPI: .2351

22.  South Carolina  9-4

SOS:  5
RPI: .2347

23.  Hawaii  10-3

SOS:  37
RPI: .2344

24.  West Virginia  9-3

SOS:  23
RPI: .2325

25.  Florida State  9-4

SOS:  11
RPI: .2321

The matchups for a 16-team playoff would look like this, if seeded per RPI:

BRACKET 1
#1 Auburn vs. #16 Nebraska
#8 Oklahoma State vs. #9 Nevada

#4 Boise State vs. #13 Oklahoma
#5 Ohio State vs. #12 Utah

BRACKET 2
#2 TCU vs. #15 Texas A&M
#7 Virginia Tech vs. #10 Wisconsin

#3 Oregon vs. #14 Arkansas
#6 Stanford vs. #11 Michigan State

This playoff features seven conference champions, from the MWC, WAC, Big 12, Big 10, SEC, PAC 10 and ACC.  If the NCAA ever sponsors a playoff in FBS, I would want all conference champions to be included.  This RPI model would've given us seven of them from arguably the seven best FBS conferences in 2010.  Of course, the current alignment in FBS football would need to be changed, but that is a different topic entirely.  I personally think there are too many teams in FBS, and that FBS could be split into two separate categories with conference realignment.  I'll write my thoughts down on this subject later. 




Since: Oct 23, 2006
Posted on: March 16, 2011 4:48 pm
 

2010 CFB Final Top 25, NCAA RPI Style

These are the stats for AFTER the bowl games right? What about before the bowl games where would the rankings be and the matchups in that case?



The views expressed in this blog are solely those of the author and do not reflect the views of CBS Sports or CBSSports.com