About WAB Watch

What is WAB?

WAB, created by Seth Burn, stands for Wins Above Bubble. It's the number of wins you have minus the number of wins a bubble team would average against your schedule. WAB is not a power rating - it is a résumé, rating. It measures what teams have accomplished.

Example: If a bubble team would be expected to go 10-10 against a team's schedule, but the team is actually 15-5, the team's WAB is +5.0. If the team were 5-15, the team's WAB would be -5.0. If the team is 10-10, the WAB is even or 0 WAB.

WAB is a team's résumé, summarized into a single number. It tells you a lot about how a team performed against its schedule.

WAB, Power Ratings, and this site

Multiple systems can calculate WAB using different power ratings. The NCAA publishes WAB rankings based on NET ratings, though NET ratings themselves are not published - only the rankings. NET also does not have any preseason ratings or priors.

This site aims to surface the game-by-game WAB for a given team.. Instead of binning results in four arbitrary quadrants, you can assign a weight or value to every game using WAB.

WAB does not reward teams for _good_ losses or punish teams for _easy_ wins.

How to Calculate WAB

Step 1: Start with Power Ratings

You need a power rating system that can predict the probability of each team winning each game. Examples include KenPom, Bart Torvik, Massey, Sagarin, and EvanMiya. This site uses Bart Torvik's public power ratings.

In order to calculate WAB, you would use the adjusted offense and defense ratings:

Pythag = Offense^11.5 / (Offense^11.5 + Defense^11.5)

Step 2: Calculate Win Probability for Each Game

For each game, calculate the probability that a bubble-quality team would win against that opponent, plus account for home court advantage.

The formula for game predictions:

(A - A*B) / (A + B - 2*A*B)

where A is the bubble team's rating and B is the opponent's rating.

Step 3: Sum Expected Wins

Add up the win probabilities across all games to get the expected number of wins for a bubble team against that schedule.

Example: If a bubble team has a 40% chance in game 1, 60% in game 2, and 50% in game 3, expected wins = 0.4 + 0.6 + 0.5 = 1.5 wins

Step 4: Calculate WAB

WAB = Actual Wins - Expected Wins

If a team has 15 actual wins and a bubble team would be expected to get 10 wins against that schedule, the WAB is +5.0.

Built By

WAB Watch is built by Chris Gallo, publisher of Bless your Chart, a data viz newsletter about college sports. This site is built with R by generating static HTML files with light CSS and javascript.

Data sources and thank yous

WAB is a metric made popular by Seth Burn and visible on useful college basketball analytics sites like barttorvik.com. The data to generate the WAB on this site is from Torvik's public power rankings and the bigballR package. Without Torvik's generous data, nothing on this site would be possible.

Any quadrant and NET data is from the NCAA.

This site was built with help and guidance from Ryan Campbell (Fifth Factor) and Connor Bradley (@cobrastats).

More College Hoops Resources

If you are seeking more college basketball data, check out these resources:

Basket Under Review | KenPom | Hoop Explorer | Evan Miya