We’re about two weeks away from Nebraska formally joining the Big Ten and Colorado and Utah formally joining the Pac-10 to be renamed the Pac-12. With these changes, the Big 12 will adopt a true round robin in basketball. The Big 12 will become the fourth BCS conference with an 18 game conference schedule. Only the SEC and ACC will maintain a 16 game conference schedule in basketball.

Should the SEC and ACC add more games? The benefit of more conference games is the added revenue and interest that conference games provide. The cost seems to be the lost opportunity to schedule other quality opponents in the non-conference schedule. But what about the competitive aspect? Do the odds of making the NCAA tournament increase or fall with an 18 game schedule?

One way to answer this question might be to look at what has happened when various conferences have lengthened or shortened their schedule in the past. Today, I look at these changes, examining how successful conferences have been at putting teams in the NCAA tournament from the time the field was expanded to 64 teams in 1985.

From 1985-1997, the Big 8 had a 14 game schedule. With a 14 game schedule, conference teams made the tournament 55% of the time. But since the schedule has been lengthened to 16 games, Big 12 teams have only made the tournament 44% of the time. The SEC provides the opposite example. From 1985-1992, the SEC had an 18 game schedule. With an 18 game schedule, SEC teams made the tournament 47% of the time. But with a 16 game schedule, SEC teams have only made the tournament 42% of the time.

The results point in opposite directions, but there is one common denominator here. Both the SEC and Big 8 changed their schedule length because of expansion. And those additional teams watered down the quality of the basketball product in both leagues. The addition of weaker basketball teams was probably the reason the leagues placed relatively fewer team in the tournament. Indeed expansion mostly makes the comparison of schedule length a useless exercise.

Here are the numbers for the ACC:

1985-1991, 14 conference games – 70% in NCAA tournament

1992-2011, 16 conference games – 50% in NCAA tournament

That 70% number looks great, but that was when the ACC was focused on just being a dominant basketball conference. Adding football schools has simply diluted the product over time.

The numbers in the Big East are equally misleading.

1985-1991, 16 conference games, 62% in NCAA tournament

1992-1999, 18 conference games, 40% in NCAA tournament

2000-2007, 16 conference games, 41% in NCAA tournament

2008-2011, 18 conference games, 53% in NCAA tournament

At least the Big East proves that expansion doesn’t always have to make basketball worse. The addition of football schools in the 90’s diluted the product substantially. But when the ACC raided the conference in 2005, the Big East made a concerted effort to attract schools with rich basketball histories. Those basketball-focused schools have helped the league place a higher percentage of teams in the NCAA tournament in recent years. But these changes do nothing to help us figure out whether schedule length matters. 

Perhaps the most informative situation is what has happened in the Big Ten. Because the Big Ten has had the most stable league membership, it provides the best evidence of the meaning of schedule length. Since, Penn St. joined the league in 92-93, the conference schedule length has changed twice, without any expansion or contraction.

1993-1997, 18 games, 53% in NCAA tournament

1998-2007, 16 games, 50% in NCAA tournament

2008-2011, 18 games, 52% in NCAA tournament

(Quick note: The change in 1998 happened when the Big Ten added a conference tournament. The Pac-10 has also added a conference tournament twice within this time period with no noticeable change in tournament odds. The Pac-10 has placed 41% of its teams in the field with a conference tournament, and 40% without a conference tournament.)

The Big Ten numbers suggest that maybe an 18 game schedule is better. But this effect is so small, the sample size is so small, and the alternative explanations are so prevalent, that this is a ridiculous basis to argue in favor of an 18 game schedule. Maybe someday we’ll get enough data to say something meaningful about schedule length. In the meantime, the only lesson to draw is that historic prestige matters. If you improve the average basketball prestige of member schools, you’ll place more teams in the field. If you add football schools without basketball prestige, you’ll place less teams in the field.

And that’s great news for the Big 12 which loses two schools (Colorado and Nebraska) with limited basketball success. If the Big 12 starts getting a higher fraction of teams in the tournament, don’t praise the tougher 18 game schedule. Praise the loss of Colorado and Nebraska.