The T-Ranketology algorithm had three teams in the tournament that the selection committee found underserving: St. Bonaventure, Saint Mary's, and South Carolina.
It's pretty obvious what they have in common: they all start with the letter "S". Frankly, anti-S discrimination is as good a theory of why the committee does what it does any other. But let's dig a little deeper into their resumes, and that of the other cause célèbre, Monmouth.
T-Ranketology was not surprised by Monmouth's exclusion, as they were the 12th team out according to the algorithm. This is because they got killed in the "resume" column because of their three bad losses to sub-200 teams.
Monmouth is a tough case because they had the four great wins in the non-conference, against UCLA, USC, Notre Dame, and Georgetown -- all away from home. Since high-major teams have no incentive to play true mids or low-majors on the road, the only path for a team like Monmouth to an at-large bid is go giant slaying on the road, and that's exactly what they did.
Unfortunately, the UCLA and Georgetown wins ended up not looking so great in the committee's eyes, because Georgetown was a sub-100 RPI team and UCLA was 99th. (Indeed, if they'd lost to Georgetown that would counted as a "bad loss"!) This is true even though those were both true road games, which makes them impressive wins by any measure, except any measure the committee pays attention to.
In the end, it was the three sub-200 losses that killed them. I'm pretty sure no team has ever gotten an at-large bid with three losses in that category. This is somewhat unfair to Monmouth, of course, because most at-large contenders do not play very many sub-200 teams on the road. As a result, we don't have an intuitive feel for how often at-large contenders should really lose these games. Monmouth played 11, and they went 8-3. That's not good, but how bad is it?
Easy answer: too bad. I think Monmouth is in the tournament if they go 9-2 in those games. But it was three strikes you're out.
South Carolina was the last team in according to T-Ranketology, and no one is weeping over their omission from the field. They played a crappy schedule, which got them out to a 14-0 start. They were even 20-3, but went just 3-6 in their last nine games. Although their schedule was weak, they actually performed admirably against it, compiling +2.0 WAB, which means they won two more games than you'd expect an average bubble team to win. But (as we'll see) the committee comes down hard on teams that didn't "challenge" themselves during the non-conference, and South Carolina's OOC SOS was 271st according to the RPI.
Since South Carolina is a major conference team that has no excuse for playing such a weak schedule, and they were right on the bubble by all metrics, no one cares about saying sayonara to South Carolina. Hmm, maybe I should write a song called "Sayonara, South Carolina."
In my opinion, Saint Mary's was the real snub this year. T-Ranketology had them into the field easily as an 8-seed, and they were in a majority of final brackets at bracketmatrix.com. They had a weak nonconference schedule, but Seth Burn has already detailed how well they performed against the schedule they played, in terms of Wins Against Bubble. They also did well in other metrics traditionally associated with good tourney resumes, such as elo.
Ultimately, they were done in by their lack of "good wins." Their record against the top 100 was great -- 6-3, but the committee cares most about number of wins, not winning percentage. And in the all important "wins against top 50" they had just two. And both those were against Gonzaga, which only squeaked into the top 50 after they beat Saint Mary's in the WCC championship game.
This is a case, I think, where the committee was forced to come face-to-face with the absurdity of its own metrics. Heading into the game against Gonzaga, Saint Mary's had a blank resume, highlighted by zero top-50 wins. They lost that game, convincingly. But now, because of that loss, they had an infinitely better resume, with two top-50 wins. How could a loss possibly improve their resume so much?!
That's a little thing called cognitive dissonance, Jack.
The committee did what anyone does when experiencing cognitive dissonance: it moved on as quickly as possible. Buh-bye, Saint Mary's.
The Bonnies were the last of the S-nubs, and the most surprising, as they were in most every final bracket. But upon examination, their big calling card was a high RPI. The rest of their resume metrics were bubblicious, or worse: 49th in elo, 50th in "resume" (good wins minus bad losses), and 69th in WAB. I shed no tears for St. Bonaventure. Indeed, their exclusion is another sign that raw RPI is (appropriately) not much of an independent factor in the deliberations.