It's all about the rebounding

[Boris Badenov]

I got curious about what's driven our success this year. We've heard a lot about defense, holding opponents' 3pt% down, our own 3pt shooting, etc.

It's quite surprising actually. This team is actually shockingly similar to last year's...with one big difference.

First, shooting percentages on offense:
     17-18: 44/37/76
     16-17: 45/36/81

Second, "hustle plays" (blk/stl):
     17-18: 8.6/3.8
     16-17: 7.5/4.1

Moving/valuing the ball (ast/to):
     17-18: 23/15
     16-17: 25/13

Defensive shooting percentages:
     17-18: 45/33/76
     16-17: 43/33/76

Pace:
     17-18: 96.2
     16-17: 96.8

Offensive rating:
     17-18: 108
     16-17: 111

So you can see, a slight decline on offense. Not really defending much better on shooting percentages, nor stealing/blocking at much higher rates. Not playing at a slower pace.

And yet,

Defensive rating:
     17-18: 98
     16-17: 108

This is a huge difference. So, why?

Here's the answer:

Own rebounds (off/def/tot):
     17-18: 10/37/48
     16-17: 9/33/42

Opp rebounds (off/def/tot):
     17-18: 9/33/42
     16-17: 11/34/45

That's basically the whole thing. We are not a hugely more efficient team on either end - we are just creating a hell of a lot more possessions for us, and many fewer for the other team. And it's by rebounding better. We were -3 rpg last year, and we are +6 this year, so that's a net swing of nine possessions - which amounts to around 9 fewer points per game for the other team if they score half the time.

It also happens on our end of the court: +4 drb for us and -2 orb for opp (see the bolded numbers). On the other end, we are getting one more orb and they are getting one fewer drb. So, it makes sense to me that it shows up as giving up fewer points, mostly via fewer possessions for our opponents.

Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

[Androslav]

You are right, but I think the explanation is not in rebounding, but just size in general, which also translates to easier rebounding. Our 1-3 spots had cummulative growth of a foot an a half, while not losing speed.

When we play baskeball I'm sure we all prefer to be guarded by smaller, less strong defenders with shorter wingspans, as things get much easier.

I am glad that's not the case with our team for another year.

[Fafnir]

Its not just rebounding.

The difference between opponent eFG% .503 (2016-2017) and eFG% .478 (2017-2018) is pretty meaningful as is the increased amount of turnovers forced.

[footey]

TP to BB. Good analysis.

[ThePaintedArea]

...
And yet,

Defensive rating:
     17-18: 98
     16-17: 108

This is a huge difference. So, why?

Here's the answer:

Own rebounds (off/def/tot):
     17-18: 10/37/48
     16-17: 9/33/42

Opp rebounds (off/def/tot):
     17-18: 9/33/42
     16-17: 11/34/45

That's basically the whole thing. We are not a hugely more efficient team on either end - we are just creating a hell of a lot more possessions for us, and many fewer for the other team. And it's by rebounding better. We were -3 rpg last year, and we are +6 this year, so that's a net swing of nine possessions - which amounts to around 9 fewer points per game for the other team if they score half the time.

It also happens on our end of the court: +4 drb for us and -2 orb for opp (see the bolded numbers). On the other end, we are getting one more orb and they are getting one fewer drb. So, it makes sense to me that it shows up as giving up fewer points, mostly via fewer possessions for our opponents.

Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

Yes, great analysis.

But I think that there is one other crucial factor:

Opponent FT makes per FG attempt
17-18:  .174 for fifth in the league
16-17:  .223 for 23rd in the league

In short, Boston is one of the top handful of teams at (not) losing points from fouling. This number usually gets better when defensive rebounding improves, because offensive rebounders get fouled a lot. But, no secret, it also gets better when all five guys are staying in front of their man and don't need help.

We've started hearing about "switching lineups", where five versatile defenders counter screens by just switching; this is what the Celtics are evolving toward.  Switchability was a problem for Thomas and Bradley last season because of their size.

Looks like Tatum is already stepping into a versatile role; I for one didn't know what to expect about his defense, and thought that it might be a while before he could effectively switch up because of his weight. But instead he's been terrific on bigger players - ask Aaron Gordon.

[playdream]

I got curious about what's driven our success this year. We've heard a lot about defense, holding opponents' 3pt% down, our own 3pt shooting, etc.

It's quite surprising actually. This team is actually shockingly similar to last year's...with one big difference.


Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

Glad somebody notices this, if you watch the game it's apparent they are feeding their defense with their rebounding

[Chris22]

As Pat Riley once famously said, "No rebounds, no rings."

[The Oracle]

I got curious about what's driven our success this year. We've heard a lot about defense, holding opponents' 3pt% down, our own 3pt shooting, etc.

It's quite surprising actually. This team is actually shockingly similar to last year's...with one big difference.


Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

Glad somebody notices this, if you watch the game it's apparent they are feeding their defense with their rebounding

They are rebounding better because of the way they are defending.  Simply because of the fact that there are more capable, longer, bigger defenders on the perimeter allows the big men to hang back and not extend all the way out to the 3 point line.  The rebounding is better because the defense that they are able to deploy is much, much more conducive to defensive rebounding.  The big men no longer have to babysit I.T. and Avery every time a screen is being set on them.  The bigger wings are also naturally better rebounders as well as more capable of keeping their opponent off the glass.

[Chris22]

I got curious about what's driven our success this year. We've heard a lot about defense, holding opponents' 3pt% down, our own 3pt shooting, etc.

It's quite surprising actually. This team is actually shockingly similar to last year's...with one big difference.


Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

Glad somebody notices this, if you watch the game it's apparent they are feeding their defense with their rebounding

They are rebounding better because of the way they are defending.  Simply because of the fact that there are more capable, longer, bigger defenders on the perimeter allows the big men to hang back and not extend all the way out to the 3 point line.  The rebounding is better because the defense that they are able to deploy is much, much more conducive to defensive rebounding.  The big men no longer have to babysit I.T. and Avery every time a screen is being set on them.  The bigger wings are also naturally better rebounders as well as more capable of keeping their opponent off the glass.

We are rebounding better because we are a bigger and stronger team than last year.

[Big333223]

Not just size, but I also think toughness is an underrated defensive characteristic. Kelly Olynyk was a smart defender who was usually in the right spot and did the right thing. I think the same about Daniel Thies but he's much tougher and more willing to mix it up in the paint and make things happen. Same goes for Amir Johnson's minutes going to Baynes.

And as great of a defender as Avery was, he's not a tough guy. He's smart and quick and does a lot of great things on the defensive end but sometimes you just need the other team to worry about himself, physically.

[Boris Badenov]

But I think that there is one other crucial factor:

Opponent FT makes per FG attempt
17-18:  .174 for fifth in the league
16-17:  .223 for 23rd in the league

In short, Boston is one of the top handful of teams at (not) losing points from fouling. This number usually gets better when defensive rebounding improves, because offensive rebounders get fouled a lot. But, no secret, it also gets better when all five guys are staying in front of their man and don't need help.

This is probably what explain's Fafnir's observation, right?

Its not just rebounding.

The difference between opponent eFG% .503 (2016-2017) and eFG% .478 (2017-2018) is pretty meaningful as is the increased amount of turnovers forced.

And indeed, opponent's FTA has gone from 25 to 19 per game.

But I think PaintedArea may be right about this being tied to rebounding as well. I went and looked at data on opponents' FTA and defensive rebounding and they are correlated. See the chart here:



For perspective we are the second from the left in 2016-17. We are now 4th in defensive rebounding% and 3rd in opponent FTA per game.

[mmmmm]

I got curious about what's driven our success this year. We've heard a lot about defense, holding opponents' 3pt% down, our own 3pt shooting, etc.

It's quite surprising actually. This team is actually shockingly similar to last year's...with one big difference.

First, shooting percentages on offense:
     17-18: 44/37/76
     16-17: 45/36/81

Second, "hustle plays" (blk/stl):
     17-18: 8.6/3.8
     16-17: 7.5/4.1

Moving/valuing the ball (ast/to):
     17-18: 23/15
     16-17: 25/13

Defensive shooting percentages:
     17-18: 45/33/76
     16-17: 43/33/76

Pace:
     17-18: 96.2
     16-17: 96.8

Offensive rating:
     17-18: 108
     16-17: 111

So you can see, a slight decline on offense. Not really defending much better on shooting percentages, nor stealing/blocking at much higher rates. Not playing at a slower pace.

And yet,

Defensive rating:
     17-18: 98
     16-17: 108

This is a huge difference. So, why?

Here's the answer:

Own rebounds (off/def/tot):
     17-18: 10/37/48
     16-17: 9/33/42

Opp rebounds (off/def/tot):
     17-18: 9/33/42
     16-17: 11/34/45

That's basically the whole thing. We are not a hugely more efficient team on either end - we are just creating a hell of a lot more possessions for us, and many fewer for the other team. And it's by rebounding better. We were -3 rpg last year, and we are +6 this year, so that's a net swing of nine possessions - which amounts to around 9 fewer points per game for the other team if they score half the time.

It also happens on our end of the court: +4 drb for us and -2 orb for opp (see the bolded numbers). On the other end, we are getting one more orb and they are getting one fewer drb. So, it makes sense to me that it shows up as giving up fewer points, mostly via fewer possessions for our opponents.

Maybe this doesn't surprise anyone else, but I guess I thought it would be more of a mix of things.

If you think about it, it makes sense I guess. We have Tatum, Brown, Smart and Rozier all rebounding at excellent-to-elite levels for their positions. Al has picked up. Baynes and Theis are better than Amir. Etc.

Thoughts?

Ultimately, it comes back to size and positions and the nature of the lineups that Brad is putting on the floor.

Last year, we deployed "3-small" lineups (lineups that included 3 out of the group: Thomas, Bradley, Smart, Rozier & Jackson) on 18.2% of our possessions.

This year, we have deployed "3-small" lineups (out of the group:  Irving, Smart, Rozier & Larkin) on just 10.02% of our lineups.

That right their is a massive difference because in 3-small lineups, that means you have someone like Smart or Rozier playing the "small forward" spot.

Our defensive ratings and rebounding rates were consistently _massively_ better in '2-small' lineups vs '3-small' lineups last year.

Consider, that lineups with Isaiah, Avery & Marcus had a DRb% of 68.9% and a DRtg of 115.1 points per 100.   If you look at lineups that include Isaiah & Avery while excluding Marcus (& Terry & Demetrius as well),  the DRb% jumped to 73.3% and the DRtg fell all the way to 108.9.  That's a huge difference.

And that same sort of difference held true in almost all the various 2-small vs 3-small comparisons.  It wasn't about any one player, it was about forcing a small guy to defend a much bigger guy at the SF spot.

It didn't help that often in these "3-small" configurations we were also sliding Jae up to play the 4.

Also, in games where we have faced an opposing 'big center' Brad has become confident in using Baynes and Theis heavily.   He's had them on the floor for a combined 40+ minutes in several of the games during this winning streak.   Last year, when facing a team with a big center, we'd often try to counter by 'going small' with Al at the 5 and Jay or Jonas at the 4.   This would tend to help our offense, but hurt our rebounding and defense.

Not only is playing Baynes or Theis putting their talents on the floor more, it is also setting Al up to have a better size match up at the 4.

All three of Horford, Baynes and Theis are current grabbing rebounds at a rate of over 10+ per 36 minutes.

Last year, none of Horford, Amir or Kelly grabbed boards at a rate higher than 8.4 per 36.

So, in  a nutshell:  Better beef at the 5 (Baynes & Theis) and far, far, far less usage of "3-small" lineups.

(Of course, there is a correlated increase in "3-wing" lineups that results from the latter.)

[The Oracle]

This year Horford, Baynes and Theis as a group are defending far less on the perimeter than Horford, Amir and K.O. were last year.  This allows them as a group to be in better position, more often to defensive rebound.  Baynes and theis are also used a lot less on the perimeter offensively and therefor in a position much more conducive to offensive rebounding. 

There are plenty of drawbacks to deploying less offensively skilled big men like Baynes.  For everything you gain with a player like he is you also lose spacing, ball handling, shooting etc.  The C's currently have a 93.3 offensive rating with Baynes on the floor, 113.3 without him.

[Rosco917]

It's more than just rebounding, although rebounding I'm sure has a part in it.

It's also about athletic long defenders closing out on 3 point shooters. It's about athletic size and length being able to switch and successfully defend multiple positions.

Players like Brown, Semi, Smart, and Tatum having the ability to defend multiple positions, and do it very well.

Mix in Kyrie buying into the defensive system, and Horford being free to chase down the ball, while Baynes does the dirty work, and it's easy to see why our defense is much improved. 

[mmmmm]

Additional lineup factors towards this that are different from last year:

So far this year, Kyrie has played 33% of his possessions as the only 'small'.  That is, in those lineups (which includes the starters) he has been on the floor with either 2 wings + 2 bigs or 3 wings + 1 big.  In these configurations, the team defensive rating has been a stifling 100.1 points per 100 possessions and the DRB% has been a fantastic 78%.   So far this year, a 100.1 defensive rating would be tied for 2nd in the NBA.

Last year, Thomas played only 10% of his possessions as the only small.   In those lineups the team DRtg was 104.9 and the DRB% was an almost identical 77.6%.   While the 104.9 DRtg doesn't sound as impressive as the 100.1 mentioned above, it's all relative.  Last season, a 104.9 DRtg would have ranked as 3rd best team defense in the NBA.

Wow.  This, along with the other info in my other comment, is pretty interesting.    It's basically pointing towards the nature of Brad's lineups and how much he is using certain types of lineups as the dominant factor difference.   Because the data shows that the 'one guard' lineups with Isaiah in them last year actually performed almost exactly the same (in league-relative ranking) on defense and rebounding as the 'one guard' lineups with Kyrie have this year (and on a MUCH bigger sample size).    The real difference with that between last year and this year is how often we are using such a configuration.   Last year, it was something that got used rarely, just a tenth of the time.   This year, it is our starting configuration.

This (a) gives me new respect for the impact of a coach's decisions but also (b) makes me lament why it took Brad so long to figure this out.   We should have been using more one-guard lineups (and fewer 3-guard lineups) _last_ year!