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Tennessee and Luck: A KenPom Evaluation

What is KenPom’s “luck” and where does Tennessee stand?

For those analytically savvy types, Ken Pomeroy’s website dedicated to analyzing basketball teams based on deeper statistical method is something they’re probably familiar with. It’s a website I often use when trying to determine how good a team has actually been throughout the season.

One stat that’s stood out to me as interesting is the “luck” rating, which effectively compares a team’s actual output to their expected output, where positive numbers indicate greater “luck.” In that way, it’s similar to the Pythagorean win-loss record that is fairly prevalent in certain baseball circles.

Although the stat doesn’t necessarily indicate that a luck-driven team is guaranteed a letdown, it implies that fans and analysts should proceed cautiously about highly praising these programs prematurely. In other words, it’s a metric where you don’t want to see your team in, or near, the top spot; conversely, you don’t want to see it at the bottom, either. A high luck rating suggests an overachiever, i.e., a team that’s going to return to earth at some point, in my opinion. Conversely, a low luck rating suggests the team is underachieving, which is certainly a bad place to be.

This season, the Navy Midshipmen (9-1) are currently ranked first in the luck rating, but come in 167th overall by KenPom’s overall rankings. Cleveland State (172nd), Santa Clara (131st), Southern Illinois (192nd), and, surprisingly, Clemson (36th), round out the top five. That’s all well and good but you’re likely wondering, if for no other reason than curiosity, where does Tennessee stand? Excellent question!

Tennessee, the sixth ranked overall KenPom team, comes in at 113th in luck rating with a relatively low +0.035 output; in other words, they’re three-and-a-half-hundredths of a win better than they are otherwise expected to be. In my opinion, it’s beneficial for a team to fall somewhere in the middle of this list, which is approximately where the Volunteers are. This is particularly good for a team that’s already considered good. That means they’re playing on par with expectations and those expectations are strong.

With that thinking in mind, it should theoretically be positive for a good team, e.g. a top 25 team, to have a rating of +/-0.000, suggesting they’re playing exactly in line with what’s expected of them. If the number five team in the nation is playing exactly how they’re supposed to be, then it would make sense that there’s a pretty good chance they’re actually a number five-caliber team in the country.

This stat is by no means the end-all, be-all of metrics, but it’s fun to measure and monitor, nonetheless. For comparison’s sake, Missouri is currently the “luckiest” team (11th, +0.161) in the SEC, while Mississippi is the “unluckiest” team (344th, -0.153). While metrics like AdjEM (adjusted efficiency margin) are better indicators of team performance, and are what KenPom’s metrics are based on, luck is a fun stat that can perhaps help paint a fuller picture.