Mook's Midrange: Why the Boston Celtics are losing ground in the three-point revolution

https://celticswire.usatoday.com/2018/03/19/mooks-midrange-why-the-boston-celtics-are-losing-ground-in-the-three-point-revolution/




Mook's Midrange: Why the Boston Celtics are losing ground in the three-point revolution








By: Greg Cassoli | 7 hours ago




The three-point revolution is underway throughout the NBA. The Boston Celtics have been active participants, but now it’s time to really lean in.
The three-point shot is critically important to the Boston Celtics’ offense. The Celtics fire up 34.0% of their shots from the field from beyond the arc, the sixth highest rate in the league, per Cleaning the Glass. They convert them at an impressive 37.4% clip, ranking fifth in the NBA, per Basketball Reference.

Boston’s robust collective three-point percentage is reflective of the fact that its roster is stocked with quality shooters and its offense is built to generate open looks from deep. Upon closer examination, however, the Celtics’ percentage from downtown may also be reflective of a fundamental offensive inefficiency.

Boston is shooting 49.4% on its two-point field goal attempts, per Basketball Reference. That means their average value of a two-point shot is 0.988 points, while the average value of a three-point look stands at 1.122. That may not seem like a massive difference on its face, but it is.

If the Celtics maintained their shooting percentages and replaced a two-point shot with a three-point shot on just six possessions per 100, their offense would jump from 16th in efficiency to 11th, per Cleaning the Glass.

That math isn’t likely to hold perfectly in reality. Increased volume is typically accompanied by decreased efficiency. Boston would almost certainly see a drop in its percentage from beyond the arc, but the extra point afforded from deep is enough to offset any real concern.

If the Celtics want to maximize their overall offensive efficiency, then they should look to shoot whatever volume of three-point attempts will begin to bring the average value of their two-point and three-point attempts into equilibrium.

Boston has a ton of wiggle room to experiment with here. They would only have to convert 32.9% of its total three-point attempts to generate the same average value of its two-point shots to date. For perspective, the Celtics would have to miss 296 consecutive three-point looks in order to reach that point.

So what’s holding them back? Why not start bombing away from deep? The answers to those questions lie in the complexities inherent to running an NBA offense. Let’s take a look at some of the biggest hurdles.


OPPORTUNITY COST

The Celtics can’t opt to hoist more three-point attempts without sacrificing shots from elsewhere on the court. Determining exactly what looks get redistributed beyond the arc is critically important to understanding whether or not Boston upping its three-point attempt rate is a viable strategy.

Layups and dunks, for example, cannot be replaced by contested 25-footers. Context, as always, matters. We’ll use Marcus Morris as an example

The potential benefits of turning contested midrange jump shots from Morris into contested three-point jump shots is significant. Morris frequently operates in the midrange because he is comfortable there, but that doesn’t mean allowing him to do it is sound strategy.

Morris has hit on 42% of his midrange looks for the year, a more than respectable rate that ranks in the 75th percentile league-wide, per Cleaning the Glass. He’s really good at scoring in that manner. But in order to produce the same average value of a midrange shot this year from three-point territory, Morris would have to hit on just 28% of his attempts.

With such a low bar, asking Morris to get a bit uncomfortable may be worth it. The same is true up and down Boston’s roster.

In fact, the only players that have produced more average value on two-point shots as compared to three-point shots are Aron Baynes, Daniel Theis and Greg Monroe, none of whom figure to play a prominent role in redistributing the Celtics’ shot profile to emphasize three-point shooting.


DISREGARD FOR INDIVIDUAL NUMBERS

Convincing players to pursue a strategy that is likely to result in lower individual three-point percentages will require a certain level of buy-in that may be difficult to generate. Brad Stevens’ staff was able to get it in the past, but it hasn’t been quite the same this year.

Players are typically benchmarked against the league average conversion rate, regardless of volume. Those comparisons have real consequences for a player’s perception in the league, ability to stay employed and earning potential.

Let’s stick with Marcus Morris as a hypothetical case study. It does not behoove him to up his volume from deep until the points he generates on three-point attempts reaches equilibrium with his two-point efforts, unless he knows the broader NBA ecosystem will understand and appreciate exactly what’s going on.

If, for example, he doubles his three-point attempt rate by replacing long twos with triples and his accuracy from beyond the arc drops to 33%, he runs the risk of being labeled a bad shooter. In actuality, Morris would have likely created significantly greater offensive value for his team, something he deserves commendation for, not criticism.

At the heart of this contradiction is a flaw in the conventional means of assessing three-point shooting ability. Competence from beyond the arc isn’t contextualized within a player’s full portfolio of shots.

That’s shifting some. The Houston Rockets are on the forefront of the mathematical revolution and it’s helped them produce the most efficient offense in NBA history.

There are those that dislike the aesthetics of Houston’s play and not every team has the pieces to run the same system that the Rockets employ. But the volume of three-point attempts they hoist is not entirely contingent upon a specific scheme.

What makes Houston unique is that it’s convinced its players that firing away from beyond the arc, while potentially harmful to their individual reputations, is a worthwhile strategy to be a part of. Boston would have to replicate a similar mindset across its roster if it wanted to have equivalent success.


SYSTEMIC IMPACT ON OFFENSE

This final point relates fairly closely to concerns related to opportunity cost. If the Celtics were to make a conscious effort to shoot more threes, they would need to consider the ways in which it may influence their offense more broadly.

It’s not particularly hard to envision Boston prioritizing three-point shooting without major changes to its offensive philosophy. The Celtics would really just have to ask everyone not named Marcus Smart to be a little less discerning when deciding whether or not to pull the trigger.

There are plenty of decent three-point looks that Boston passes on in an effort to find even juicier opportunities. That’s generally a good thing. All else equal, wide open shots are better than lightly-contested shots. The three-point line doesn’t always allow for everything to be equal, however.

In fact, its very existence is meant to establish a variation in value. In some instances a contested look from deep is a better shot than an open two.

Hunting threes can’t come at the expense of the ball and player movement that makes the Celtics’ offense hum. If Boston’s offense is a sentence, then shooting more threes is the act of changing its punctuation, not re-writing the whole thing.

_______________________

The thoughts outlined above are not new. They are the principals that are driving the NBA’s current three-point revolution, of which the Celtics have been willing participants.

There is room to embrace three-point shooting even more fully. Boston could benefit mightily by doing so. It’s been curious to see the offensive distribution regress this year compared to previous seasons, where Boston was close behind Houston as a leader of the pack in Moreyball.

Stevens tends to be full of surprises in the postseason, so it will be interesting to see whether the team’s shot selection changes. Midrange mavens like Marcus Morris will be getting plenty of minutes and shots in the condensed playoff rotation, so they will need to push for efficiency more than ever.



bob



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Interesting post. It hammers home something that comes up alot on this board - the game is changing. Actually, it has changed. Not sure how I feel about it. I still think that there is something to be said for a league that values athletes like Jordan and visionaries like Bird and Magic over sharp shooters like Steph. I kind of miss the old game; not necessarily the slow 90s game, but the fast pre-90s game where 3s were less used. I wonder if the league would have introduced the 3 pt shot all those years ago if they had known how it would change the game.

Shamrock1000 wrote:Interesting post. It hammers home something that comes up alot on this board - the game is changing. Actually, it has changed. Not sure how I feel about it. I still think that there is something to be said for a league that values athletes like Jordan and visionaries like Bird and Magic over sharp shooters like Steph. I kind of miss the old game; not necessarily the slow 90s game, but the fast pre-90s game where 3s were less used. I wonder if the league would have introduced the 3 pt shot all those years ago if they had known how it would change the game.

I don't have the figures for the 1980's (they are not available) - but they are available from 2000-01 on to the present - and the fact is that the 3 point shot has had only a small affect on the number of shots taken close to the basket (10' in)

The year 2000-01
Percentage of shots taken from 10 feet in = .441
The year 2017-18
Percentage of shots taken from 10 feet in = .436

In 2000-01 the 3 point shooting rate was .170 - in 2017-18 it is .336.
And yet teams are still getting their share of higher percentage up close shots - now at the expense of the medium range jumper.

swish

swish wrote:

Shamrock1000 wrote:Interesting post. It hammers home something that comes up alot on this board - the game is changing. Actually, it has changed. Not sure how I feel about it. I still think that there is something to be said for a league that values athletes like Jordan and visionaries like Bird and Magic over sharp shooters like Steph. I kind of miss the old game; not necessarily the slow 90s game, but the fast pre-90s game where 3s were less used. I wonder if the league would have introduced the 3 pt shot all those years ago if they had known how it would change the game.

I don't have the figures for the 1980's (they are not available) - but they are available from 2000-01 on to the present - and the fact is that the 3 point shot has had only a small  affect on the number of shots taken close to the basket (10' in)

 The year 2000-01
    Percentage of shots taken from 10 feet in = .441
 The year 2017-18
    Percentage of shots taken from 10 feet in = .436

  In 2000-01 the 3 point shooting rate was .170 - in 2017-18 it is .336.
  And yet teams are still getting their share of higher percentage up close shots - now at the expense of the medium range jumper.

  swish

Thanks Swish. That was a very smart post. I was under tbe impression that athletic drives and visionary passes that get players shots close to the hoop were in decline, but your numbers suggest otherwise. Just goes to show how our impressions are often greatly removed from the truth - thank god for numbers.