To understand outcomes, it's important to ask "why?"
The Jazz last year were a crummy team. Why? I've already answered a part of the question: defense. But I want to delve a little deeper: why was their defense crummy?
Well, Dean Oliver highlights what he calls the Defensive Four Factors: eFG% allowed, Turnovers forced, Defensive Rebounds, and FT's per FGA given up. When you look at these, you see that the Jazz were decent in regards to rebounds (14th in the league). And while the FTA's per FGA's wasn't great (20th), that is probably the best Jazz ranking in my lifetime. No, the real bugaboos were the eFG% allowed (26th) and turnovers forced (29th).
So today, I'm looking at the eFG%.
First of all, for those who don't understand what eFG% is, I'll explain. It stands for "Effective Field Goal Percentage." You can think of it as how well teams shoot, with an adjustment for the fact that a 3P is worth an extra point. It basically gives you how many points a team scores per shot (while cutting out points from FTA) and then making it look like FG%.
The average eFG% last year was 50.1%.
The Jazz allowed opponents to shoot 51.8%.
To translate this into points, that means that the Jazz would have allowed nearly 2 1/2 fewer points per game had the allowed only a league average eFG%. This accounts for 80% of the team's defensive problems, in terms of DRtg.
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There are basically two ways a team can allow a high eFG%:
- Allow opponents to shoot well.
- Allow opponents to take more shots from the best areas (at the rim or 3PA)
I was curious to see which it was: did the Jazz simply allow too many open shots (and thus let teams shoot well), or did the Jazz allow opponents to get more efficient shots. Or some of both?
What I found actually surprised me a bit.
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This began with me NOT actually investigating this issue. I was looking at a great site called nbawowy -- it allows you to see very specific stats when different players are on the court together (thanks to Andy Larson for helping me remember it). I was curious about how the team's offense worked when Gordon Hayward and Alec Burks were playing together (a post for another time—but as a teaser, let's just say there are some exciting things).
Anyway, when I was messing with it, I clicked on the button "Opponents" and saw some interesting things*:
(A note about the findings: because Enes Kanter and Derrick Favors rarely played together after November, it's pretty useless to try to find the stats for all five of the F5 together. So what I did is look at the combinations where 3, 4, or all 5 played. So you'll see ranges in the stats since I'm looking at different combinations.)
- The young guys, our guys going forward this year, gave up a shot 0-3 feet away from the rim on about 32-36% of the possessions.
- They allowed teams to shoot about 65-67% on these close to the rim shots.
- They allowed teams to shoot 47% from corner 3's, but only 15% of all 3PA's were from corners
- They allowed teams to shoot 33-35% form 3 overall, and about 20-22% of all shots were 3PA
Comparing these to the NBA average, the 3P shot was not really a problem for them last year. Teams shot slightly below average and shot fewer than average. Teams did shoot very well from the corner 3, but actually shot fewer than average.
No, it's not the 3P shot that killed the team last year.
It's that stuff at the rim. They allowed teams to shoot WAY too many shots at the rim AND shoot at a very high percentage. To give some context, only 3 teams shot more than 33% of their shots at the rim, and only 4 teams shot better than 67% at the rim. We're basically seeing the average team scoring like the Rockets at the rim. THAT is what killed the team last year.
And it's important to note, that the problems with shots at the rim were significantly worse for the young F5 than it was for the rest of the team.
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I wrote previously that defense is the biggest way Quin Snyder can improve the team. This investigation today shows that with our guys going forward, the coaching staff needs to specifically focus on preventing and challenging shots at the rim much better.
Well, I hope so.
I think do think Trey Burke will often struggle to keep his guy in check ... and a penetrating PG definitely helps open up shots at the rim and from three. Plus Kanter's ability to play defense remains a mystery at this point. But Exum, Burks, Hayward, Favors, and Rudy Gobert sure seem to have the raw tools to stop penetration and protect the rim. And I have never seen anything that makes me believe these guys aren't willing to work.
I'm hoping that all they need is (a) to be taught, (b) an intelligent scheme that will work, and (c) dedication to implement it.
We'll see how it goes.