A Bubble Analysis: Stephen F. Austin vs. Purdue

Today Ken Pomeroy had an article in The Athletic about Stephen F. Austin and their bubble case. In it, he referenced my work on WAB. For those unfamiliar with the process, WAB stands for Wins-Above-Bubble. From the article:

“It’s fairly easy to understand as it attempts to answer this question: How well did a team do against its schedule relative to what would be expected from an average bubble team? WAB is a great concept and puts us close to a completely objective system for making tournament selections.”

Ken goes on to review Stephen F. Austin’s schedule and their results. I felt it would be good to supplement that with a visual breakdown of the math here. I’ll break there schedule down into two parts here:

Opponent-Location for Opponent Bubble EW% Result WAB Result
Duke-Home 0.1125 1 0.8875
Rutgers-Home 0.2686 0 -0.2686
Alabama-Home 0.3801 0 -0.3801
Net Result 0.2388

Those are they tough road games for any bubble team to face. 1-2 is a good result for an average bubble team. That’s something bracketologists seem to be reasonably willing to concede. What they have a problem with is SFA’s loss at home to Texas A&M Corpus Christi. They argue that the loss cancels out the win over Duke, leaving their resume unworthy of inclusion. Let’s look at the “other” 22 games SFA has played so far this season:

Opponent-Location for Opponent Bubble EW% Result WAB Result
Sam Houston St.-Home 0.7544 1 0.2456
Arkansas St.-Home 0.7811 1 0.2189
McNeese St.-Home 0.8668 1 0.1332
Lamar-Home 0.8866 1 0.1134
Central Arkansas-Home 0.8894 1 0.1106
Northwestern St.-Home 0.9111 1 0.0889
Texas A&M Corpus Chris-Home 0.9136 1 0.0864
Abilene Christian-Away 0.9213 1 0.0787
Nicholls St.-Away 0.9276 1 0.0724
New Orleans-Home 0.9355 1 0.0645
Drexel-Away 0.9513 1 0.0487
Southeastern Louisiana-Home 0.9565 1 0.0435
Louisiana Monroe-Away 0.9689 1 0.0311
North Carolina Central-Away 0.9699 1 0.0301
Niagara-Away 0.9729 1 0.0271
Texas A&M Corpus Chris-Away 0.9746 0 -0.9746
New Orleans-Away 0.9813 1 0.0187
Houston Baptist-Away 0.988 1 0.012
Incarnate Word-Away 0.993 1 0.007
LeTourneau-Away 1 1 0
Arlington Baptist-Away 1 1 0
Paul Quinn-Away 1 1 0
    Net Result 0.4562

Yes, the loss to Texas A&M Corpus Christi really was that bad. It more than cancels out the Duke win. But… Stephen F. Austin went 21-0 in the rest of their schedule, and that counts too. In fact, altogether, even with the loss to TAM-CC, they have done well outside of their three major road games. Wins at Sam Houston State and Arkansas State aren’t a given for a bubble team.

The fact is, it’s hard to go 22-3 vs. SFA’s schedule. Bart Torvik agrees. ESPN agrees. Both have SFA in the top 50 in their resume metrics, at 44th, and 46th respective. That has nothing to do with how good they are. Bart has them 123rd, while ESPN has them 126th. Their resume is solid even if they’d be a clear underdog on a neutral court to the next team we’ll be looking at, Purdue.

First off, you can find a full review of Purdue’s schedule here. Before I break their schedule down, let me note that SFA got a net total of 2.32 WAB in their 22 wins and -1.62 WAB in their three losses. Purdue has faced a much tougher schedule. Let’s start by looking at their wins:

Date Team Opponent-Location for Opponent Bubble EW% Result WAB Result
02/08/20 Purdue Indiana-Home 0.3776 1 0.6224
01/12/20 Purdue Michigan St.-Away 0.4676 1 0.5324
11/29/19 Purdue VCU-Neutral 0.5528 1 0.4472
02/05/20 Purdue Iowa-Away 0.5664 1 0.4336
01/24/20 Purdue Wisconsin-Away 0.5728 1 0.4272
01/02/20 Purdue Minnesota-Away 0.6049 1 0.3951
02/01/20 Purdue Northwestern-Home 0.6512 1 0.3488
12/04/19 Purdue Virginia-Away 0.6738 1 0.3262
12/17/19 Purdue Ohio-Home 0.7896 1 0.2104
12/08/19 Purdue Northwestern-Away 0.8713 1 0.1287
12/28/19 Purdue Central Michigan-Away 0.9298 1 0.0702
11/06/19 Purdue Green Bay-Away 0.9523 1 0.0477
11/23/19 Purdue Jacksonville St.-Away 0.9659 1 0.0341
11/16/19 Purdue Chicago St.-Away 0.9976 1 0.0024
Net WAB: 4.0264

Purdue has generated 4.03 WAB in their 14 wins. That’s better than what SFA has generated in their 22 wins. Alas, the problem is we live in a world with credits and debits. Purdue’s 12 losses:

01/18/20 Purdue Maryland-Home 0.1682 0 -0.1682
02/15/20 Purdue Ohio St.-Home 0.1895 0 -0.1895
01/09/20 Purdue Michigan-Home 0.2212 0 -0.2212
11/13/19 Purdue Marquette-Home 0.2593 0 -0.2593
01/28/20 Purdue Rutgers-Home 0.2686 0 -0.2686
01/05/20 Purdue Illinois-Home 0.2988 0 -0.2988
11/30/19 Purdue Florida St.-Neutral 0.3778 0 -0.3778
12/21/19 Purdue Butler-Neutral 0.4289 0 -0.4289
02/11/20 Purdue Penn St.-Away 0.4715 0 -0.4715
01/21/20 Purdue Illinois-Away 0.6071 0 -0.6071
12/15/19 Purdue Nebraska-Home 0.6736 0 -0.6736
11/09/19 Purdue Texas-Away 0.777 0 -0.777
Net WAB: -4.7415

Losing at Maryland and Ohio State is understandable. The WAB penalty there isn’t too brutal. Alas, Purdue has also lost at home to Texas, Illinois, and Penn State. They also lost at Nebraska, which isn’t something a bubble team would do more than one-time-in-three. Purdue has some nice accomplishments, but on balance a bubble team would expect 14.72 wins against their schedule. Winning 14 isn’t great in that context.

Mind you, Purdue is a much better team than SFA. It’s not remotely close. But their resume is more than a full win worse.

In closing, what SFA has accomplished might not look impressive, but when you dig into the details, it’s a solid resume. Purdue might pass the eye-test with flying colors, but if you care about wins and losses, they don’t currently belong in the NCAA field. To use a golf analogy:

SFA’s schedule is a par 3.72. They’ve shot a 3 on it.

Purdue’s schedule is a par 11.28. They’ve shot a 12 on it.

That’s why SFA currently belongs and Purdue does not.


  1. Rdawg said:

    Would you be able to publish a list of the Bubble EW%s for each team/ location? Would be interesting to see how that compares to the NET quadrants actually used.

      • Rdawg said:

        Curious as to why the Pythag data, particularly for Sagarin, does not match up with the actual Sagarin rankings? For instance, the Pythag data would suggest Duke is the best team, but Duke is 5th in the Sagarin rankings. Michigan State, West Virginia, Louisville, Arizona, and Oregon are other examples of teams seemingly overrated by the Pythag data. Conversely, Maryland, Kentucky, Dayton, and Creighton are underrated. Can you explain the discrepancies?

      • sethburn said:

        Check out the Predictor column on Sagarin’s page. That’s what I am using.

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