I've already linked to the numbers for 5/12 games from 1996 through 2005. For the 6/11 games I'm going to dip back 15 years, from 1992 through 2006. For my analysis, I have defined a "Major" conference as the 6 BCS conferences, the Big 8, the SWC (when it existed) and Conference USA from 1996 through 2005. "Mid-Major" is defined as the A-10, Colonial, Conference USA (since 2006), Great Midwest (when it existed), Metro (when it existed), MAC, MVC, MWC, WAC and WCC. "Small" conferences are all the rest.
The 6/11 game is often seen as an unimportant game. Upsets aren't seen as monumental, and winners are never considered to be major threats. We assume they'll get eaten up by the #3 and #2 seeds. The stats don't entirely bear that out:
Upsets are common, but not too common: Fifteen upsets over the last fifteen years. So, only one per year. This is actually less often than the 5/12 game. On four occasions every single #6 seed went through. Seven times saw one upset, and only four years saw #11 seeds getting a split.
Don't count on #11 seeds to carry on to the next round: Only four times have they moved onto the Sweet 16. Twice have they moved on the Elite 8 (Temple in '01 and George Mason in '06), and once to the Final Four (George Mason in '06).
Bet on #6 seeds for the Sweet 16: A remarkable 26 of the 45 winners of their first game went on to the Sweet 16. Seven of those have moved onto the Elite 8, but only one to the Final Four and Championship Game (Michigan in '92).
Mid-Major #6 seeds are losing their mojo: After going 4-0 in first round games from 1992 through 1995, they are only 2-3 since.
Can't go wrong with Major Conference #6 seeds: They are 39-12 in first round games and 20-19 in second round games.
If you need a #11 upset, no need to go with the Major Conference team: They are 4-10 as #11 seeds in the first round, 1-3 in the 2nd round. Mid-Majors are 7-23 in the first round, and a very solid 3-4 in the second round. Small Conference teams are 4-12 in the first round, and 0-4 in the second round.
So what conclusions can we reach? Well it's interesting that we don't see very many upsets. So don't go crazy picking #11 seeds all over the place. You're more likely to see success picking on #12 seeds, which is interesting from a psychological viewpoint. If you want to pick an upset or two, I can't tell you which teams to pick. Although if you want a Sweet 16 run for a #11 seed, go with a Mid-Major. This is bad news for Winthrop, a sexy Sweet 16 pick, as they would have to tread new ground. No Small Conference team I studied made it that far.
What about the #6 seeds? Looking at the overall resumes, there is no difference between Majors and Mid-Majors. But it seems clear that in recent years momentum has switched away from Mid-Majors. Schools from conferences like the WCC (Gonzaga in '02) and the Missouri Valley (Creighton in '03) are no longer a mystery. And they also have lost a little of the chip on their shoulder. Getting too much respect and love from tv analysts will soften a team. It's much harder to win when you're expected to win, and when you're looking ahead to the next game instead of putting everything on the floor from the opening minute. So, bet against Mid-Majors as #6 seeds.
As for the Major schools that are #6 seeds, go wild. The fact that 20 of the 51 have made the Sweet 16 is remarkable. In fact, the last time a Major Conference team didn't make the Sweet 16 as a #6 seed was 1994, and even in that year a future-Major made the run (Marquette, then in the Great Midwest Conference). So, definitely do not pick #3 seeds all the way through. Atleast one of them will go down before the Sweet 16. You can bank on it.
So, what am I recommending? This year we find that all four #6 seeds are from Major Conferences. The #11 seeds are a mix: 1 Major, 2 Mids, and 1 Small. In other words, all of what I just said isn't pointing to a likely upset. Personally, I can see upsets in any of the games. Winthrop is an outstanding team, and they are built for the Tournament, but they've gotten so much hype that it could backfire. They could fall on their face like Gonzaga did so many times at the beginning of the current decade. VCU and George Washington have both played great as of late, so either of them could pull off an upset. And as my stats have shown, both will be very viable Sweet 16 teams. Stanford is clearly the worst of the four #11 seeds. But it's possible that they could use all the "Stanford doesn't deserve to get in" stories as bulletin board fodder. But I wouldn't bet on it. They haven't impressed me all year, so I'm not picking an upset there.
What about the next round? Absolutely you need to pick atleast one team into the Sweet 16. I wouldn't go with Louisville, a team that lives and dies by the three. Texas A&M can play at a frenetic pace, which Louisville can only keep up with if their guards shoot the lights out. More likely I see them wearing out, missing back rim, and ending up with a double-digit loss. I wouldn't pick Notre Dame either. With such a great probability of them going down in the first round, I wouldn't risk them as a Sweet 16 team. And I don't like them in a matchup against the athletic guards of Oregon.
That leads us with Vanderbilt and Duke. To me, you've got to go with Duke. First of all, they're just a better team than Vanderbilt. Second of all, it's been a full decade since they missed the Sweet 16. Pitt is a good team, but Duke matches up well. They will be able to handle Aaron Gray down low, and they have the athleticism and perimeter defense to prevent Pitt from getting too many open threes off picks and kick-outs. Duke won't score 80+ points, but they won't need that many to take out Pitt. So, you need to pick an upset in the second round, and I'm going with Duke.
As always, if I really could predict the future I'd win a higher percentage of my bracket contests. But I hope these stats can help you fill out your brackets at least a little bit.