When “everyone’s back,” improvement skews heavily toward offense

Everyone’s back for Texas this season. (texassports.com)

We trust there will be some semblance of a season in 2020-21, and if that does occur while keeping everyone healthy, including coaches of varying ages, it will dwarf every other consideration. Then and only then will we be able to progress to minute considerations of basketball minutiae, like we used to do in the good old days.

What follows qualifies as a minute consideration of basketball minutiae. Teams like Texas, Richmond, Missouri, UCLA, Utah, Rutgers, Villanova, and, to a slightly lesser extent, Miami, Wisconsin, and Iowa will all have pretty much everyone back this season. All of the above will be expected to perform accordingly, and teams like the Longhorns, Bruins, Wildcats, Badgers, and Hawkeyes in particular can already be found on various preseason top 25 rankings.

In the recent past, major-conference teams that have returned at least 80 percent of their possession-minutes for a new season have tended to live up to high expectations by improving significantly on offense. It has been far more rare, though not unheard of, for a major-conference team that returns just about everyone to remake itself dramatically on the defensive side of the ball.

To be sure, improvement itself likely skews toward offense in basketball writ large, regardless of a team’s level of experience. What appears to be different about major-conference rosters with a very high degree of continuity is that this preexisting tendency is pushed to an extreme.

Over the last five years, major-conference teams that returned at least 80 percent of their possession-minutes have, on average, improved their adjusted efficiency margin at KenPom by 4.62 points over the previous season. The intriguing aspect of this boost in overall performance is that fully 83 percent of the increase has been driven specifically by improvement on offense.

Again, this is a collective figure produced by a population of 36 teams across 72 seasons, and the exceptions have indeed been notable. Wisconsin remade itself completely on defense in 2019, as did Illinois last year. By and large, however, an experienced major-conference team that shows improvement is getting that job done first and foremost on offense.

Do high-continuity rosters always improve? Almost. Teams with this level of returning experience outperform their previous season 86 percent of the time. Wichita State, on the other hand regressed in 2018. So have a few other teams.

Taking an experienced step backward
Regression in AdjEM with 80+ percent returning possession-minutes, 2016-20

                       year before    "everyone's back"   change
Minnesota 2018           16.00              5.08          -10.92
Northwestern 2018 15.81 8.57 -7.24
Wichita State 2018 26.14 19.03 -7.11
Saint Mary's 2020 17.31 15.19 -2.12
Providence 2018 12.43 12.17 -0.26

Who knew 2018 would be such a performance bloodbath for experienced teams? The Gophers, Wildcats, and Shockers were all ranked in the AP preseason top 25 that year. Minnesota at least has an explanation. That particular roster of experienced Gophers turned out to be riddled with suspensions and injuries.

Northwestern and Wichita State that same season, however, had fewer excuses. The only player the Wildcats had lost from the previous year’s historic run to the NCAA tournament was Sanjay Lumpkin (though Vic Law did miss five games in 2017-18). Similarly, WSU had said goodbye to Daishon Smith and no one else (though Markis McDuffie did miss the first 11 games in 2017-18). Nevertheless, each team struggled after a fashion. Northwestern flat-out struggled, posting a 15-17 record.

Conversely, Wichita State underperformed relative to expectations and, especially, relative to its peer group of equally experienced teams. The Shockers were ranked in the top 10 in the preseason both by humans and by laptops. Gregg Marshall’s team went a respectable 25-8 in 2018, earned a No. 4 seed in the tournament, and lost in the round of 64 to Marshall. It certainly wasn’t the kind of season to earn attention as uniquely disappointing, but in retrospect it appears to have been an oddly subdued performance.

No one had been prepared to pay attention to WSU the previous year, in 2017, because Fred VanVleet and Ron Baker had just departed. Yet that team of relative unknowns was outstanding on both sides of the ball thanks in large part to redshirt freshman Landry Shamet and an excellent defense. The “plus 4.62” predictive rule for the ensuing season would have to be adjusted, slightly, to allow for a team that was already approaching the performance horizon. Nevertheless, even a modest and customary improvement could have translated into a true national title contender.

Instead, Wichita State’s defense was newly and strangely lax. In real time, your faithful and intrepid but preoccupied correspondent (it was my first year doing Bubble Watch) noted only that it was “exceedingly surprising that a WSU defense that brought very nearly everyone back from last season should have charted such a drop in defensive effectiveness.”

Wichita State hasn’t been the same since that overlooked 2017 season, and no one could have foreseen that the decline would begin with, of all things, a rotation that returned nine of its top 10 players.

Not that there’s a straight line to be drawn between allegations of coaching misconduct and one underperforming season. Actually, the allegations go back years prior to 2018, a time during which, as seen here, the Shockers charted a remarkable and borderline historic ascent.

Better to say that, with the benefit of hindsight, something appears to have been statistically amiss with that 2018 team. The very same guys that had played defense in 2017 stopped, for whatever reason, doing so at the same level in 2018. That’s unusual. A “mass exodus” of players transferring out of the program ensued two years later.

Wichita State and a few other examples from 2018 notwithstanding, most teams that bring “everyone” back do improve just as we would expect. For the most part those teams so do thanks to achieving higher efficiencies on offense while, in effect, treading water on D. It’s not an iron law of basketball, but it’s a pretty strong tendency.