(The title of this post has been changed so as to avoid giving the impression that the intention is to criticize Jahlil Okafor. This post is intended to examine the usage of Jahlil Okafor, which should become clear upon reading. Further data and clarifications are available here.)

Background of The Ewing Theory

In 2009, Bill Simmons of ESPN popularized “The Ewing Theory,” which describes the phenomenon of a sports team performing better when its star player is not playing. The “theory” gets its name from Patrick Ewing and his 1999 Knicks. After the 8-seed Knicks lost Ewing to injury in the Eastern Conference Finals, they won 3 out of 4 games against the heavily favored 2-seed Pacers and went to the NBA Finals.

The Knicks may have gotten very lucky during those 3 wins over the Pacers without Ewing, and Ewing may have actually been the Knicks’ best and most valuable player. A 4-game sample may be too small to draw conclusions like “Patrick Ewing hurt his own team when he was on the court.” However, there is an abundance of evidence that establishes the fact that Jahlil Okafor hurts Duke basketball when he’s on the court, so much so that The Ewing Theory could be appropriately renamed The Okafor Theory.

The Okafor Theory

Okafor has been heavily hyped for years as the next great American center. The eye test checks out – Okafor has a more polished and impressive offensive post game than any college freshman, perhaps in history. His basic stats are impressive: during his freshman season at Duke, he’s scoring over 18 points and grabbing over 9 rebounds per game, while shooting over 66% from the field. These are the kinds of raw stats that impress voters for national awards and accolades, and Okafor is regularly lavished with praise for his ridiculous offensive repertoire. Many people who have watched Duke play all season, however, have noticed that Duke seems to play better without Okafor sometimes.

Well, there is evidence to suggest that it’s not just sometimes. It’s almost all of the time.

Okafor’s Glaring Negative Impact on Defense

When Okafor is on the court, Duke’s defense has allowed 1.094 points per possession (ppp) in conference games (15 ACC games through the Virginia Tech game of February 25). In those same games, when Okafor is off the court, Duke’s defense has allowed 0.943 ppp. Duke’s defense has allowed 0.151 ppp fewer during the ACC schedule with Okafor off the court than with Okafor on the court.

To give a sense of the magnitude of 0.151 ppp, during the average Duke game with 67.2 possessions for each team (according to Kenpom.com), a 0.151 ppp difference would result in Duke’s defense allowing about 10 fewer points. Obviously, this does not mean Okafor playing zero minutes instead of 40 minutes would yield 10 fewer points allowed for Duke, since that’s not how real life basketball works, but it should be clear that 0.151 ppp is substantial. The sample size is not small – 745 defensive possessions for Duke with Okafor on the court and 261 defensive possessions for Duke with Okafor off the court.

This should not be much of a surprise to even the biggest Okafor/Duke basketball supporters, since Okafor has typically looked apathetic and flat-out terrible on defense this season. This is understandable, since big men are known to take a while to learn how to play good defense, and Okafor is only 19 years old. He could very well become a great defender in a few years, but that’s irrelevant to Duke and college basketball, since Okafor is almost definitely going pro after this season. As a giant with a 7’6″ wingspan, Okafor was always going to provide some defensive value for Duke if he did nothing but stand near the rim with his arms straight up, though he often fails even at that.

When Okafor goes off the court, he is most often replaced by Marshall Plumlee, a role player who has a few strengths and several extreme weaknesses, but one of Plumlee’s strengths is having what seems like infinitely more defensive awareness than Okafor. This shouldn’t be surprising when Plumlee has 3 more years of college experience than Okafor. The idea that Plumlee could provide more defensive value than Okafor is at least somewhat reasonable to most basketball fans. The idea that a mere energy guy off the bench like Plumlee could provide more overall value than Okafor is likely to be considered preposterous, laughable, idiotic, etc., by most. That idea will be discussed below.

Okafor’s Stunning Negative Impact on Offense

When Okafor is on the court, Duke’s offense has scored 1.125 ppp in conference games. Make no mistake, this is a great mark for offensive efficiency unadjusted for strength of schedule, given that the average strength of Duke’s ACC opponents is well above that of a nationally average team. According to Kenpom.com, the top adjusted offensive efficiency in the nation for the entire season thus far is Duke’s 1.221 ppp. But what if someone told you…

When Okafor is off the court, Duke’s offense has scored an incredible 1.300 ppp in conference games. Duke’s offense has scored 0.175 ppp more during the ACC schedule with Okafor off the court than with Okafor on the court. The sample size is 768 offensive possessions for Duke with Okafor on the court and 233 offensive possessions for Duke with Okafor off the court.

Okafor has made over 64% of his field goal attempts in ACC games. That’s great. People see the ball go through the hoop a lot when Okafor shoots it, often following a mesmerizing post move, and this makes people believe he’s a great offensive player. In many respects, he is indeed a great offensive player, but the issue is that Duke has a few players who are even more efficient but don’t shoot as frequently when Okafor is on the court with them.

Marshall Plumlee is basically useless in creating offense for himself or for others. His post moves are not in the same universe as Okafor’s and his hands seem to be made of stone, in contrast with Okafor’s suction cup hands. Basically, Plumlee’s great value on offense is simply not being Okafor.

In the NBA, the number of teams that run a large percentage of their offensive possessions through post ups has dwindled practically to zero. This is not just due to a lack of post scoring talent; a post up shot is one of the least efficient shots a team can take. According to play type stats by Synergy Sports, Al Jefferson is the most prolific post up scorer in the NBA this season, with 471 points off of post ups. Jefferson averages 0.95 ppp on those post ups, which lags behind the efficiency of the NBA leaders in isolation, as spot up shooters and as perimeter shooters off screens. Big men who are used as roll men off pick and rolls and as offensive rebounders/putback guys score much more efficiently than big men who are used as post up scorers. This is very much relevant to Duke basketball and Okafor, and it helps to explain the surprising result of Duke performing much better on offense without Okafor.

According to SI.com’s Luke Winn, Okafor was averaging 1.000 ppp on post ups for the season as of February 12, adjusted for strength of competition. Given how frequently Okafor post ups occur and the defensive attention he faces, that’s not a bad number at all. However, it’s not nearly as good as the overall number Duke’s offense can put up without Okafor using up so many possessions on post ups.

Some will argue that Duke needs to feed Okafor in the post to draw attention away from his teammates, who get wide open looks from 3 and in the paint due to Okafor double teams. This is irrelevant to the fact that Duke has scored an amazing 1.300 ppp against ACC competition when Okafor is off the court entirely, compared with a still-great-but-significantly-worse 1.125 ppp when Okafor is on the court. Okafor is not attracting defensive attention when he’s off the court.

Without Okafor, Duke’s excellent offensive guards take over the offense, with Plumlee playing the role of a highly efficient garbage man who puts back rebounds and only takes wide open layups/dunks otherwise. Okafor’s high turnover rate (18.5% on the season is the worst on the team) and bad free throw shooting (54.2% on the season is the worst on the team) no longer hurt Duke.

The Bottom Line Margins

Duke’s efficiency margin (how much Duke outscores its opponents by, per possession) in ACC play with Okafor on the court has been a meager 0.031 ppp. Duke’s efficiency margin in ACC play with Okafor off the court has been a phenomenal 0.358 ppp.

To give a sense of what a good efficiency margin is, the national championship favorites, Kentucky, would be expected to outscore a nationally average opponent by 0.338 ppp, according to Kenpom.com. Duke with Okafor off the court has been outscoring ACC opponents by more than Kentucky would be expected to outscore a team much worse than the average ACC opponent. The Duke team and the style of play we see when Okafor is off the court is absolutely national championship caliber. The Duke team and the style of play we see when Okafor is on the court is not close.

Is Marshall Plumlee Better at Basketball than Jahlil Okafor?

No. Nobody is saying that. Nobody who has ever seen these two players play basketball would ever say that.

What these numbers imply is that Okafor’s team would likely be better off this season if Okafor plays more of a Plumlee role in the offense and saves some energy to put in Plumlee-level effort on defense. Plumlee getting more playing time isn’t a necessary part of this equation, but Plumlee playing a little bit more would likely help Okafor on defense by giving Okafor more rest and allowing Okafor to defend more aggressively without such fear of fouling (Okafor’s fouls committed per 40 minutes of 2.9 is currently the 3rd lowest on Duke, only higher than Duke’s starting guards).

Okafor could be the best garbage man in college basketball, cleaning the glass, working to get open layups/dunks off the ball while the guards run the offense, and focusing more on defense. These numbers indicate that Okafor’s team would reach a significantly higher level on both offense and defense if Okafor took on this role. If he doesn’t accept this role or if the Duke coaching staff doesn’t want to believe what these numbers are saying, then it will be a shame (and a pleasure to Duke haters) to see Duke fail to come anywhere close to reaching its ceiling.

The Numbers in Full

The support for the ppp numbers with Okafor on the court and with Okafor off the court is provided below (click to enlarge).



