What Is 'Wins Above Bubble?' Explaining the NCAA's New Favorite Metric

If you’re a college basketball fan, here’s how to keep tabs on WAB.

UCLA and its bubble peers would do well to consider WAB ahead of Selection Sunday. | Rick Osentoski-Imagn Images

When it comes time to put together the NCAA tournament brackets, college basketball’s powers-that-be love a good acronym.

First there was RPI (Ratings Percentage Index), a metric that dates to the earliest years of seeded brackets. RPI eventually gave way to NET (NCAA Evaluation Tool), the sport’s signature catch-all measurement for the last decade. KPI, too, has been a frequent flyer.

Now, a new metric appears poised to break contain. That’s WAB—Wins Above Bubble. On Wednesday, David Cobb of CBS Sports urged fans to master it, and it’s received more and more play in tournament discussions this season.

Here is a pocket guide to the measurement sweeping the nation.

What is WAB?

WAB stands for Wins Above Bubble, and it measures—broadly speaking—the number of wins a team has against its schedule relative to how an average bubble team would fare against that same schedule.

Here’s how it works in practice. Let’s say Team A plays a difficult regular-season schedule, against which we would expect the average bubble team to go 14-17. Team A, however, rips off a rock-solid 20-11 record. Team A, then, would have a 6.0 WAB.

Think of it like Wins Above Replacement in baseball, which measures the number of wins a player generates relative to the number of wins a hypothetical replacement player would generate.

Who invented WAB?

Seth Burn, a gambler who runs this blog, is widely credited with introducing WAB in Feb. 2015. It is, however, worth noting that the NCAA calculates WAB differently from Burn.

Which teams lead in WAB right now?

Per Burn’s measurement, the 10 men’s college basketball teams with the highest WAB as of Thursday are Michigan (10.19), Duke (8.84), Arizona (8.18), UConn (7.54), Houston (6.99), Purdue (6.73), Illinois (6.70), Nebraska (6.46), Iowa State (6.39), and Gonzaga (6.21).

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