The NBA in 2009-2010 in Pictures and Tables

Posted on 04/09/2011 by

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There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

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Recently, I’ve been coming up with all sorts of fun equations:

Possesions= Field Goal Attempts +.44* Free Throw Attempts + Turnovers -Offensive rebounds

Plays = Field Goal Attempts +.44* Free Throw Attempts + Turnovers = Possesions + Offensive rebounds

I’ve done this as a way to better analyze just what is going on in the league. The end goal is to break the game into three facets:

  • How good each team is at getting the ball in the hoop on the offensive end (My version of the O-rating let’s call it the Offensive success rate)
  • How good each team is at keeping the ball out the hoop on the defensive end (My version of the D-rating let’s call it the Defensive success rate
  • How good each team is at getting the ball back after a shot and not giving it back after the opponent shoots. In essence, I want to know how many extra plays each team generates or gives up. Well call this one the Rebounding Edge.

Now the logic behind these equations is sound and follows the earlier work of others but there were some questions raised.

Relax, I'm going to answer them

What is an offensive play? How many offensive play are there in a game? How many of these generate actual rebounding opportunities and not simple bookkeeping rebounds?

Don’t worry I’ll explain.

First off, we have plays. To me a play is the core unit in a basketball game. It is very simply put a sequence of actions that begins with a team gaining or keeping possession thru a jumpball,a personal foul or a rebound ends with a shot, a shooting foul or a turnover. The game thus boils down to scoring on offensive plays, keeping the opponent from scoring on defensive plays and generating more offensive plays for yourself thru rebounding. With that definition and the data it should be simple to use:

Plays = Field Goal Attempts +.44* Free Throw Attempts + Turnovers = Possesions + Offensive rebounds

To work out the number of plays. Except it ‘s a little more complicated. You see the NBA is weird in the way it does it’s bookeeping. To quote from wikipedia:

“Rebounds are divided into two main categories: “offensive rebounds”, in which the ball is recovered by the offensive side and does not change possession, and “defensive rebounds,” in which the defending team gains possession. A majority of rebounds are defensive because the team on defense tends to be in better position (in other words, closer to the basket) to recover missed shots. Offensive rebounds lead to another opportunity to score for the offensive team, either right away or by resetting the offense. A block is not considered a rebound. Team rebounds are credited to a team that gains possession of the ball after any missed shot that is not cleared by a single player (i.e. deflected out of bounds after the shot, blocked out of bounds, etc.). A team rebound is never credited to any player, and is generally considered to be a formality, as according to the rules of basketball, every missed shot must be rebounded whether a single player controls the ball or not. ………..Note that a ball does not need to actually “rebound” off the rim or backboard for a rebound to be credited. Rebounds are credited after missed shots, including air balls.”

Why is that weird? Well, the NBA counts a rebound for every shot missed and that includes the 1st of a 2 shot Free throw opportunity. You may guess this skews the numbers a bit.

Sigh.

The Work? Never done.

 

Time to datamine.

I went thru all the play by play numbers for the 2009-2010 season broke them down and made some nice graphs for your enjoyment.

Pure Epic Win for y'all

Let’s start with shooting:

That’s just ok. This however is cool:

Non 3 pt. Jumpers? Bad idea.  Either take it in or shoot it from three. It’s so bad in fact that the FG % for 3 pointers is better than for plain old jumpers. If I count every jumpshot it’s about 39% FG and .78 point per shot that’s an additional 3 point for every ten additional 3 pt shot taken.

Let’s look at Free throws:


Funny that the more free throws the better the shooting. Please note that 52.1% of all Free Throws become Rebounding Opportunities.

Let’s look at rebounding:


Eliminating the bookeeping rebounds makes a significant difference in the numbers. Interestingly, team rebounds go principally to the offense off misses and blocks.

Let’s put this all together now:

And that provides a good baseline for comparison. As for those constants and those equations to use (to avoid having to datamine in the future):

Total % of Total
Free Throws that represent Offensive Plays (2 or 3 Shot Fouls) 25865 43.4%
Free Throw Misses that represent Rebounding Opportunities 7491 52.1%

Not too far off. The equations become:

Possesions= Field Goal Attempts +.434* Free Throw Attempts + Turnovers -Offensive rebounds

Plays = Field Goal Attempts +.434* Free Throw Attempts + Turnovers = Possesions + Offensive rebounds

and a new one

Rebounding Opportunities=Field Goal Misses +.521* Free Throw Misses

And that is a hell of a lot of work for a few days.

Yeah. It's like that.

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