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If you've read many of my posts, you'll see that I have strong negative feelings about the RPI. Many assume this is because of my particular rooting interest, but it is really because it is a truly terrible way to rank teams. I hope this helps explain some of that.
I don't begrudge the committee's rankings, they did their job according to specified criteria. My problem is that the criteria themselves are wrong. The RPI favors teams with certain types of schedules, in particular the conferences with 16 games instead of 18. It is possible to "game" the system, and I believe the ACC and SEC have.
Let's imagine 2 conferences, identical in every way, except one has 10 teams, with an 18 game double round robin schedule, and the other 15 teams, playing 16 games and only repeating 2 opponents. Assume each team plays exactly 30 games. The non-conference record for each of the 5 major conferences was between 71% and 78%, so we will assume each conference wins 75% of their non-conference games so the math is easier.
Here is how the 10 team conference will fare:
10 teams*12 non-conference games each equals 120. They win 90 of them. The conference schedule is 90 games. The record for the entire conference is therefore 180-120, a .600 winning percentage.
Here is the 15 team conference:
15 teams*14 non-conference games equals 210 total non-conference games. They will win about 158. The conference schedule is 120 games. The record for the whole conference is 278-172, a .6177 winning percentage.
Therefore, the 16 game conferences have a nearly 2% advantage in RPI before the season starts. .0177 may seem like a small amount, but remember that 75% of the RPI formula is based on your opponent's record and their opponent's record. The overall record of the conference is therefore tremendously important, as they make up the majority of your schedule. Games played within the conference are zero-sum propositions, since every team plays both the winner and the loser. They cancel each other out from the perspective of the rest of the conference. This makes non-conference games the key to raising conference RPI. Major conference teams tend to win most of their non-conference games, so playing more of them is essential to raising the overall record, and therefore the RPI.
This effect is magnified in the Big 12, where each opponent is played twice, doubling the importance of each non-conference game for the other teams in the conference. The margins are extremely thin in the RPI, especially in the middle. The difference between #50 and #70, according to realtimerpi, is .0189. An extra non-conference win for all of their conference mates may have made a big difference for Oklahoma State, West Virginia and TCU, who were all in that range. Perhaps it would've bumped them into the top 50, off the bubble and perhaps into the field. Sagarin actually has West Virginia in the top 25, but their RPI was hurt because they took so many losses to the teams above them in the Big 12. Take those games out, and replace them with a decent, but winnable non-conference game, and they likely make the tournament. In addition, if those 3 teams were in the top 50, it would've given Baylor 7 more top 50 wins, making their apparently weak schedule look a whole lot tougher.
Eight teams in the Big 12 took 4 losses to Texas and Baylor. In the ACC and SEC, most teams only play the other top teams once, so they avoid taking the extra loss. Since RPI only looks at record, and not the true quality of opponents, taking these extra losses is very harmful. I believe this is the reason that Sagarin and Massey each say that the Big 12 is underrated, because they dig deeper than just a superficial look at records. The SEC took a real beating this weekend, and every team that lost is rated higher in the RPI than Sagarin/Massey. I believe they are systematically overrated by the RPI. I don't know if that is the reason for the scheduling, but it seems to have worked out that way. This may not have been the Big 12's strongest year, but I don't think they got a fair shake. For reference, here is each major conference's non-conference winning percentage:
Big 12: .762
Pac 12: .719
ACC: .775
SEC: .754
Big 10: .713
Sorry for the long winded post, I spend way too much time thinking about these things.
I don't begrudge the committee's rankings, they did their job according to specified criteria. My problem is that the criteria themselves are wrong. The RPI favors teams with certain types of schedules, in particular the conferences with 16 games instead of 18. It is possible to "game" the system, and I believe the ACC and SEC have.
Let's imagine 2 conferences, identical in every way, except one has 10 teams, with an 18 game double round robin schedule, and the other 15 teams, playing 16 games and only repeating 2 opponents. Assume each team plays exactly 30 games. The non-conference record for each of the 5 major conferences was between 71% and 78%, so we will assume each conference wins 75% of their non-conference games so the math is easier.
Here is how the 10 team conference will fare:
10 teams*12 non-conference games each equals 120. They win 90 of them. The conference schedule is 90 games. The record for the entire conference is therefore 180-120, a .600 winning percentage.
Here is the 15 team conference:
15 teams*14 non-conference games equals 210 total non-conference games. They will win about 158. The conference schedule is 120 games. The record for the whole conference is 278-172, a .6177 winning percentage.
Therefore, the 16 game conferences have a nearly 2% advantage in RPI before the season starts. .0177 may seem like a small amount, but remember that 75% of the RPI formula is based on your opponent's record and their opponent's record. The overall record of the conference is therefore tremendously important, as they make up the majority of your schedule. Games played within the conference are zero-sum propositions, since every team plays both the winner and the loser. They cancel each other out from the perspective of the rest of the conference. This makes non-conference games the key to raising conference RPI. Major conference teams tend to win most of their non-conference games, so playing more of them is essential to raising the overall record, and therefore the RPI.
This effect is magnified in the Big 12, where each opponent is played twice, doubling the importance of each non-conference game for the other teams in the conference. The margins are extremely thin in the RPI, especially in the middle. The difference between #50 and #70, according to realtimerpi, is .0189. An extra non-conference win for all of their conference mates may have made a big difference for Oklahoma State, West Virginia and TCU, who were all in that range. Perhaps it would've bumped them into the top 50, off the bubble and perhaps into the field. Sagarin actually has West Virginia in the top 25, but their RPI was hurt because they took so many losses to the teams above them in the Big 12. Take those games out, and replace them with a decent, but winnable non-conference game, and they likely make the tournament. In addition, if those 3 teams were in the top 50, it would've given Baylor 7 more top 50 wins, making their apparently weak schedule look a whole lot tougher.
Eight teams in the Big 12 took 4 losses to Texas and Baylor. In the ACC and SEC, most teams only play the other top teams once, so they avoid taking the extra loss. Since RPI only looks at record, and not the true quality of opponents, taking these extra losses is very harmful. I believe this is the reason that Sagarin and Massey each say that the Big 12 is underrated, because they dig deeper than just a superficial look at records. The SEC took a real beating this weekend, and every team that lost is rated higher in the RPI than Sagarin/Massey. I believe they are systematically overrated by the RPI. I don't know if that is the reason for the scheduling, but it seems to have worked out that way. This may not have been the Big 12's strongest year, but I don't think they got a fair shake. For reference, here is each major conference's non-conference winning percentage:
Big 12: .762
Pac 12: .719
ACC: .775
SEC: .754
Big 10: .713
Sorry for the long winded post, I spend way too much time thinking about these things.