Beginner’s guide to KenPom rankings

Statistics from KenPom have grown in popularity, so here’s your quick guide to what they mean

If you’re a college basketball fan and you haven’t heard the name Ken Pomeroy, perhaps you’ve heard the shortened version, KenPom. Pomeroy, who was recently brought on as a contributor to Seth Davis’ new venture The Fieldhouse, has independently run his own website, aptly named KenPom, for several seasons now.

And if you haven’t heard of Pomeroy or his website, you’ve probably at least heard or seen reference to the statistical archive he keeps. In recent seasons, allusions to the idea of efficiency or adjusted efficiency have become more popular as those who talk about college basketball seek to understand the game in a way beyond the basic box score statistics that show up in the morning newspaper. These terms frequently show up in our articles as well and as such, we thought it might be helpful to put together a primer in case you stumble your way onto the KenPom front page and aren’t sure what you’re looking at.

Pomeroy’s website ranks every Division I team by adjusted efficiency margin (AdjEM), which is simply the team’s adjusted offensive efficiency minus its adjusted defensive efficiency.

There are two concepts to unpack here. The first, the idea of offensive and defensive efficiency, is simply a team’s points scored or conceded per 100 possessions in order to adjust for the fact that team’s play at different paces. The second, the adjustment, is largely based on scheduling, opponent quality and game location. It’s a way to account for not all college basketball teams playing one another. The goal is for AdjEM to represent how many points a specific team would outscore an average Division I team by per 100 possessions.

So, why are these efficiency metrics so important? Because traditional statistics like points per game can be misleading. Consider the following comparison of two defenses. Last season, Michigan’s opponents scored 66.4 points per game, but West Virginia’s averaged 66.7. Which team had the better defense?

Based simply on the above you might think the two teams have rather comparable defenses, but in reality, one is significantly better than the other and it all comes back to how fast they play. The Wolverines play at a slow pace while the Mountaineers’ hectic high pressure style generally means games have way more possessions and more opportunities to score. Once you extrapolate these defenses out to per 100 possessions and account for opponents, Michigan’s defense looks much worse. Last season, the Wolverines ranked 69th in adjusted defensive efficiency at 99.2 while West Virginia ranked fourth at 89.4 points per 100 possessions.

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Pomeroy’s site, which features a subscription option with plenty of other statistics, also offers free access to adjusted tempo statistics so you can do some comparisons like the above for yourself. On the front page, you can also check out a team’s strength of schedule and its luck factor, which is just a measure of a team’s actual record and its expected record.

In short, KenPom provides additional tempo-free metrics that allow college basketball analysts, fans and teams new ways to evaluate just how good teams are in a way that accounts for all of the different factors that complicate some of the more traditional numbers we’re used to.