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When should NBA teams roll the dice on a 6 point swing?

7/23/2016

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The 6 point swing.

One of the biggest perceived momentum changing plays in basketball, where a team misses a 3 point shot and the opposing team drills a 3 pointer on the very next play, therefore causing a 6 point swing...

It’s seen as a high risk/high reward play, frowned upon by some coaches but in the modern 3 point shooting NBA it can be used as a weapon. A team that is behind on the scoreboard can bring back a deficit quickly and gain a head of steam with this momentum building strategy, but also drive the nail in the coffin and sure up a win when their team is leading deep into the 4th quarter.

But it’s not without its risks and as I’ll show below, if not executed correctly and by the right players it can do as much harm as good.

In this post I will look at which teams and players are using the 6 point swing effectively and ineffectively, then diving into some nerdy logistic regression calculations which will tell us how much of an effect the 6 point swing has on the outcome of the game. Don’t worry I’ll keep the geeky stuff to a minimum and just explain how much the 6 point swing can help or hurt a team.

Firstly let’s take a look at when NBA teams are going for the 6 point swing and if there are any patterns……
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It’s an even spread across the board in each quarter, which was a little surprising. I had assumed the 4th quarter would have seen a lift in usage from teams that were behind and trying to claw back compared to earlier in the game.

The average 3pt% when going for the 6 point swing is 35%. This is exactly the same as the NBA’s average 3pt%, meaning it might seem like a low percentage play but teams in general aren’t just jacking up a wild shot to go for a 6 point swing they are being as efficient as any normal 3pt shot taken.

So who’s using it as a strategy....

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Dallas, Houston, Charlotte and Atlanta are clearly ahead of the pack in applying this strategy and all shooting at very close to the league average in 3pt%.

No real surprises here as these 4 teams mentioned were ranked in the top 7 for overall 3pt shots attempted for the season, Dallas though was ranked 7th in overall 3pt attempts but 1st in going for the 6 point swing which is a fairly significant jump and clearly a strategy or green light for its players.

Whereas Minnesota, San Antonio, Milwaukee and Brooklyn are far more risk adverse and go for the 6 point swing less than half the times of Dallas. This is consistent with their overall trend on overall 3pt shooting for the season, all ranked in the bottom 6 for 3pt attempts.

The LA Lakers, Utah & Minnesota are all shooting well below the league average on a 6 point swing attempt.

Which players have the green light to go for the 6 point swing and which players need to stop before they get a coach fired? Here is the top 25 in overall attempts…

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From an attempts perspective, 3 names jump out at me.

Marvin Williams is in the top 10 for 6 point swing attempts? Wouldn’t have picked this, he’s shooting a deadly 45% as well!

Kings big man DeMarcus Cousins is 17th in attempts! And shooting a coach killing 24%. Ouch. D’Angelo Russell is also not afraid to shoot them, but he should be.

Here is the top 20 in 6 point swing 3pt% when having at least 15 attempts for the season…
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Some seriously good shooting numbers here! John Wall at 68%! Yikes.
 
Now let’s look at the opposite end of the spectrum, the bottom 25…………

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Some serious coach killing numbers above.
 
Let's take a look at how to execute the 6 point swing well, here is an example of the Mavericks executing a simple “pick and pop” screen that sees Dirk Nowitzki wide open for a 3 pointer.


And here is what you don’t want to do.  Down 2 points with 3 minutes to go in the 4th quarter, you don’t want this shot from DeMarcus Cousins who is averaging 24% from 3pt land in these scenarios.


We have established that teams are clearly using the 6 point swing to complement their overall 3pt attempt strategy, but what effect is it having on winning and losing an actual game?

To find out, I have taken all of the data from this past season and focused on the 4th quarter of games where the margin a team is winning or losing by is no more than 10 points and where a team goes for a 6 point swing.

Running a logistical regression calculation over this data, we find out what the chances of a team winning or losing a game are depending on if they actually pull off the 6 point swing or not in the 4th quarter.
For the nerds out there the average predictive accuracy for this logistical regression is 87.4% (ROC Curve AUC = 0.96)

For non-nerds, this means that predictions below on winning or losing are pretty accurate.  
So to be clear…

It’s the 4th quarter and your team is either winning or losing by no more than 10 points and you try for a 6 point swing, what are the chances that you win the game if you pull off the 6 point swing vs missing the shot on the 6 point swing?
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So overall, the numbers are showing us that if it’s a 1 possession game (meaning you are either up or down by 3 points before going for a 6 point swing) then you roughly increase your chance of winning by 4% if you make the shot in the 4th quarter.

How significant is that? Well if I told you that executing 1 single play in the 4th quarter could increase your chances of winning by 4% would you take it? If I have on offensive set for John Wall in this situation, then I’m certainly going for it.



Thanks again to www.nbastuffer.com for providing play by play data for the past season


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