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Puzzling NBA – long two point shots edition part 2

11 May

After part 1 of this series we know that long two point shots are ineffective and the most effective shots in NBA are at the rim and outside 3pt line, so let’s follow it up with another question:
what’s the potential gain from that not-so-hard-to-discover knowledge?

Thanks to http://hoopdata.com/shotstats.aspx I compiled a list for all teams in the last 5 seasons with their shots selection and thanks to http://www.basketball-reference.com I added some columns with respective team’s offensive statistics. You can find it at the end of this post but let’s jump right into conclusions:

Correlation Coefficient between “how often teams take good shots” [measured by adding all shots at the rim and outside 3pt line and dividing it by all shots taken by respective team] and
it’s Effective Field Goal Percentage is 0,51 while it’s Offensive Rating is 0,361. It means that 25% of team’s eFG% and 13% of team’s Offensive efficiency can be explained by shots selection alone!

If you are not impressed let me rephrase that, when you compare teams that are above and below average in terms of percentage of shots taken at the rim and outside 3pt line, you will get results like this:

Win% ORtg eFG%
above average 0,535 108,32 0,506
below average 0,464 106,48 0,491

That’s a difference like between teams around Top10 and Top20 in the league!

In those 5 seasons there were only 4 teams which were above average each year: Phoenix Suns, NY Knicks, Houston Rockets and Denver Nuggets and only once among them offense was worse than Top17 [those Knicks who attempted a lot of threes but couldn’t make them] while they were fixtures near the top.

So I’ll ask again: WHY DO TEAMS ATTEMPT MORE LONG TWOS THAN THREES!?!

Is it simply a case of smart defense? Because we know that long two is the worst possible shot in basketball, we know that teams who avoid them are better offensively and those who take them in bunches are worse offensively…. and yet there are plenty of those shots…

Team’s Shots Selection

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3 Comments

Posted by on May 11, 2011 in Unanswered Questions

 

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3 responses to “Puzzling NBA – long two point shots edition part 2

  1. Leszczur

    May 16, 2011 at 13:42

    The choice between “long 2’s” and 3 pointers could possibly be explained by two reasons:
    1. Relative scarcity of good 3 point shooters.
    I guess what drives coaches crazy is taking those contested threes, by inefficient shooters. If you want yourself pulled to the bench – just start jacking those bombs up.
    2. Simply by availability of the shot. In modern NBA offensive schemes are drawn in a way that most of the time you have 2 guards beyond 3pt line, center down low and wing players somewhere in between (sometimes one of the wings goes to the corner – like Spurs with Jefferson/Bowen).
    The thing is – we need to know how shot selection translates to offensive rebound chances. Is corelation between shot and OffReb bigger for 3PA than for long 2’s? My gut feeling is that it’s not, which means – you may take worse shot, but hedge it with higher chance for an offensive rebound.
    And then your overall points per posession may be better off even if you take those long, low percentage 2’s.
    This regular season – out of the top 7 teams in 3PA none was in Top10 in OReb% (two were in Top15), while most were somewhere between 21 and 28 in the league. To me this is a clear signal to take a cautious approach with 3PA volume as long shots give long rebounds and if you’re unlikely to get one yourself – it creates opportunities for a fast break for your opponent, which in return hurts your defense and DRtg.

     
    • wiLQ

      May 16, 2011 at 22:04

      > I guess what drives coaches crazy is taking those contested threes, by
      > inefficient shooters. If you want yourself pulled to the bench – just start
      > jacking those bombs up.

      But are they safe by jacking those long contested twos?
      Which one is worse in your opinion: contested long two or a contested three?

      > The thing is – we need to know how shot selection translates to offensive
      > rebound chances. Is correlation between shot and OffReb bigger for 3PA than for
      > long 2’s? My gut feeling is that it’s not, which means – you may take worse
      > shot, but hedge it with higher chance for an offensive rebound.

      Why do you assume that shooter have to rebound his own miss?
      It shouldn’t be done by one of his teammates who is already closer to basket…?

      > This regular season – out of the top 7 teams in 3PA none was in Top10 in
      > OReb% (two were in Top15), while most were somewhere between 21 and 28 in the
      > league. To me this is a clear signal to take a cautious approach with 3PA
      > volume as long shots give long rebounds

      Or it could be a matter of personnel: if you have a lot of good 3pt
      shooters you don’t have many good rebounders on the floor ;-)
      What’s more, IMHO attacking offensive glass is simply a tactical decision.

      Anyway, Thanks for the comment!

       

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