I decided over the weekend to go ahead and do a deep dive into the Pelicans' defensive woes to sort out fact from fiction. And those struggles are unfortunately fact. As of the morning of 12/20, the Pels are 27th in the NBA in DRTG at 110.6, 28th in Defensive Efficiency at 1.076, and just generally not getting it done.
A lot of reasons had been suggested, some seemingly quite plausible, others less so. I took a look at many of them, broke them into 3 categories as biggest problems, problems with less direct correlation to bad defense, and then things that did not appear to be major problems in and of themselves.
METHODOLOGY & RESULTS
Not knowing exactly what I was looking for, I cast a wide statistical net here, and actually was tipped off to what turned out to be one of the major stories by a random Q&A blurb from Kevin Pelton's "Mailbag" over at ESPN (here).
I researched Defensive FG%, Defensive Rebounding, Strength of Schedule, Opposing Points in the Paint, Turnovers, 3pt Defense, Pace, The Twin Towers lineups, The Three Guard lineups, and Fast Break Points given up. And as it turns out most of those items did not end up being leading indicators. The three largest concerns were 1) Strength of Opposition; 2) The Three Guard Lineup; and 3) Three Point Defense. I suppose one notable point for the rest might be that the Pels really have no particular defensive strengths, so that any weaknesses they have are exaggerated and not countered by strengths. So there could be a cumulative effect here rather than any one magic bullet.
Here's a breakdown summary of the results:
Defensive FG% -- a promising result, the Def FG% issues seem related to strength of opposition rather than bad Pels defense making weak teams look strong
Defensive Rebounding -- not significant, slightly below average and concentrated in 2 players, but overall within norms
Strength of Schedule -- merged into the Defensive FG% analysis, Pels have faced the 5th hardest schedule, and one of the toughest groups of offensive opponents
Opposing Points in the Paint -- not good, but roughly equal to many better defensive teams. Certainly not enough alone to explain the D.
Turnovers -- can't prove it does NOT, but numbers show that other teams with similar TOs are fine defensively + has been steady on the season for the Pels
3pt Defense -- the 3rd area of major concern, the Pels have been bad, and bad 3pt defense = bad NBA defense, gotten worse under the three guard lineup too
Pace -- steady all year, but significance would likely be tied into the Three Guard Lineup which has also sped the Pelicans up considerably
The Twin Towers lineups -- Pels have actually been better defensively this year with both bigs on the floor than not, so this isn't it
The Three Guard lineups -- the Rondo/Moore/Jrue lineups have been a huge huge problem defensively, in particular with Boogie back there alone behind them
Fast Break Points -- definitely a poor transition defense team, as tracked by multiple metrics, but not every bad transition D team is bad overall defensively
So, to the numbers. I'm breaking things into 3 different categories, + I'll start with the areas which showed the greatest correlation, and then move on to the ones that are not as clear or may not be really damaging. I'll make a new post for each different group because there are a LOT of numbers in here, and I'm well aware of the too many numbers at once = eyes roll into the back of your head phenomenon.
P.S. Note that I used a number of different sites for these numbers, some of which seems to use slightly different formulas than others. When that was true I used multipliers to adjust all numbers to basketball-reference's calculations. In each such case I list the original site's calculations as for instance 109.3(wowy) and then what that number equals in bballreference numbers.