How Princeton creates its own luck
KenPom.com says Princeton is one of the luckiest teams in college basketball. What the computer model doesn't answer is why.
PRINCETON – The head coach of the Princeton Tigers enters the postgame press conference with two of his players. They’re bewildered winners once again.
“We have no real business winning that game,” says Mitch Henderson, going on to compliment Columbia. “We were on our heels. I don’t know how we won that game.” It’s variations on a theme Princeton fans will remember not only from earlier this season, but from rallies against Dartmouth and Penn in 2022-23, for example. I was even writing about the phenomenon during the first season of this newsletter, when Matt Allocco stunned Cornell at the buzzer.
They’re never out of a game at home. But they’d like to stop coming from behind.
“No, it’s not sustainable. Not for my heart, not for anything,” Henderson said Monday. “… People have said to me, you guys need to lose, so you learn how to – I don’t believe in that.”
Henderson turned to make eye contact with Xaivian Lee, theatrically demonstrating how hard he was trying to drill it into his guys: “But we need to play really, really hard all the time.”
So I asked Henderson: Don’t take it the wrong way, but do you believe in the saying, ‘Sometimes it’s better to be lucky than good?’
“Yeah, I don’t know,” he said. “We’ve had some great wins, but that one is unbelievable. I mean, I don’t know how that happened, so I don’t know. Yeah, you gotta get lucky sometimes.”
Monday marked Princeton’s largest comeback win of the season, turning a 20-point deficit late in the first half and a 33-15 halftime hole into a 71-67 victory. It was also the Tigers’ fifth time digging out of a double-digit hole to win: They trailed Iona by 16, Duquesne by 11, Merrimack by 14 and Akron by 15. Two of those games didn’t happen in Jadwin, so let’s not chalk up the theory entirely to home-court advantage.
Here’s why I asked about luck: After that game, Princeton’s “luck” rating on KenPom.com stood at +.147, and as of Thursday morning that made the Tigers the 10th-luckiest team in Division I men’s basketball.
What does that mean? Are the 14-4 Tigers lucking into wins, and are they due for a downfall?
Advanced metrics cannot tell the whole story, but they’re a great place to start.
The definition of ‘luck’
I don’t have a statistics degree, but most of us don’t, so I’m aiming to break this down for the regular fan. (You aren’t going to see algebraic formulas below, but if you’re into that sort of thing, StatsFriar on Substack went into great detail back when Providence was considered an abnormally lucky team.)
The quick-and-dirty explanation begins, though, with something most Ivy Leaguers can recite: the Pythagorean theorem. Ken Pomeroy figures win probabilities by using the same formula that Bill James came up with for Pythagorean wins in baseball, just with a different exponent. By plugging in his offensive and defensive efficiencies for a given team, Pomeroy can produce an expected winning percentage against an average opponent.
That’s step 1 of 2. “Luck,” in plainest terms, is the deviation between a team’s actual winning percentage and Pythagorean winning percentage. Underpinning the concept of luck is the belief, as Pomeroy writes, that “a team involved in a lot of close games should not win (or lose) all of them. Those that do will be viewed as lucky (or unlucky).” Strength of schedule – since teams aren’t facing perfectly average teams – is taken into account here in something called the correlated Gaussian method.
A vast majority of luck ratings on KenPom’s site fall somewhere between +.06 and -.06, not enough for a tangible impact on game results. Princeton’s luck has been mostly neutral before this year, except in 2018-19, when the Tigers finished the year ranked 10th (+.101). That season, they went 3-0 in overtime games and 7-1 in games decided by five points or fewer, including their thriller against Arizona State.
Where can we observe Princeton’s luck this year? It’s already 7-2 in games decided by five points or fewer – including, remarkably, its last six in a row against D1 opponents. The Tigers beat Monmouth, Rutgers, Akron, Harvard, Dartmouth and Columbia by an average of 2.5 points.
They’re getting it done in games that look like this…
But also ones that look like this:
The Tigers’ offensive and defensive efficiency over the course of the season tell the KenPom model that they probably should have dropped two or three of those. Thus, Princeton has one of the luckiest teams going. Case closed.
Not so fast
If basketball were played on paper, to borrow from the title of Dean Oliver’s basketball analytics bible, there would be no luck. Another way to view it is all the intangible stuff a model can’t take into account. Did the star player get enough sleep last night or was he up partying (I mean, studying)? How are the officials going to call the game? Is the coach going to make the right (or wrong) substitution or adjustment?
Henderson made the right substitution with 5:40 left Monday by sending in freshman Jack Stanton for the first time. Not only was Stanton coming in cold in the context of that game, he had only 28 seconds of Ivy League experience, having subbed in late against Harvard.
He entered between Columbia free throws, the latter of which made it 61-46 Lions.
“He destroys our team every day in practice, and I’m the knucklehead that doesn’t play him,” Henderson said. “And I was looking for him to do what he does against us, and he did it.”
Specifically, he needed another 3-point marksman on the floor to help cut into that deficit.
“When I got checked in,” Stanton said, “Coach comes up to me, whispers in my ear and goes, ‘Shoot it.’”
The Tigers as a whole were getting warmed up by then, drawing within seven before Stanton got his hands on the ball on a steal. He brought it from right to left, knocked down a three and cut it to 62-58, wowing Lee in the process.
“He sat for 35 minutes and came in and drilled a right-left. Like, that’s a ridiculous shot to make,” Lee said. “Watching the game, it might seem easy, but to sit that long and hit that shot is unbelievable.”
By then, Columbia was understandably flustered. The Lions didn’t have experience winning this type of game to draw from. They panicked against Princeton’s full-court press. Stanton got a second steal and nearly hit an acrobatic three to tie the game.
Instead, Blake Peters drilled two threes to grab a 66-65 lead and Lee, for the second time in as many games, went iso and got the shot he wanted for the go-ahead three in the final 10 seconds. It was the sort of shot everyone in Jadwin knew was going in; the stunners are starting to be less stunning.
I asked Henderson what intangibles besides the home crowd go into winning a game like that.
“Honestly, we talk about it, we work on it,” he said. “There’s something in the air with the way a team treats one another. And I think we treat each other well. We like – there’s good vibes. (The players) can answer this, but they believe they’re going to win. We talk about it a lot.”
“I think it starts from the top,” Lee said. “We expect – Coach always says we’re always winning no matter the situation. He wasn’t saying that as much today, but we always think we’re going to win. I mean, it’s 40 minutes of basketball, you’re talking about like luck there and whatever. Maybe, but I thought it was unlucky we came out and missed 10 straight threes to start the game. So eventually we’re going to hit shots. I think I always believe we’re about to make a run, and then sometimes it happens.”
The Tigers create their own luck with that self-belief and connectedness, with a helping hand from the growing crowds at Jadwin and a coach who has seen these comebacks through probably more times than he can remember.
But it simultaneously illustrates an unsavory reality of this team: the constant need to come from behind in the first place. In 10 of Princeton’s 16 games against D1 opponents, it has trailed at halftime.
“We lack urgency early in the games. And I’ve never been through it before with a team,” Henderson said. “We’re working hard at it together but we’re going to figure it out. It’s nice to win these games. I don’t think it’s sustainable. I think that’s the word you used. But I’d rather be lucky than good, honestly. So I’ve lost this game a lot. I’ve won this game now.”
When it happens so often it's not luck. It's coaching, changing strategies, press and zone. And players believing in themselves and teammates.