PDA

View Full Version : Offensive Efficiency



Saratoga2
12-13-2014, 08:10 AM
I was musing about basketball and realized I was unsure about the definition used for Offensive Efficiency. My thoughts, which are not a concise definition, are as follows.

Possessions:
Each team has about the same number of possessions per game. These vary depending on pace. Say for an example a team has 70 possessions in a particular game, which of course are opportunities for scoring plays. Turnovers of all types deduct from possessions while offensive rebounding provide additions possessions (shot opportunities). If the team has 15 turnovers and 10 offensive rebounds it would have 65 of 70 opportunites to score in the example above.

Scoring plays:
The players can take two point shots or three point shots. Since the probability of hitting shots is lower for three pointers I see no reason other than to lump them as points per shot taken. Scoring can result at a higher efficiency due to ball movement and assists or just because of the superior talent of players. It still boils down to points per shot taken and by association per shot opportunity.

The other scoring opportunities are from the free throw line. There there can be any of three possibilities:
One point opportunity when fouled on a made basket. The result is either 0 or 1 point.
One and one opportunity (2 potential points). The result is either 0, 1 or 2 points.
Two free throws (2 potential points). The result is either 0, 1 or 2 points.

The efficiency of free throw shooting is the points made out of the potential points. Sorry, if a player misses the front end of a one & one he is 0 for 2 in my book.

My view is that the team had 70 possessions for that particular game and it scored so many points, meaning it scored so many points per possession. Am I being unclear? Is that the way offensive efficiency is calculated?

CDu
12-13-2014, 08:46 AM
Roughly speaking, yes. Efficiency is the number of points expected per X number of possessions. Many places will use 100 possessions as the denominator. So if your efficiency is 122, it means you are expected to score 122 points per 100 possessions.

vick
12-13-2014, 09:53 AM
The other scoring opportunities are from the free throw line. There there can be any of three possibilities:
One point opportunity when fouled on a made basket. The result is either 0 or 1 point.
One and one opportunity (2 potential points). The result is either 0, 1 or 2 points.
Two free throws (2 potential points). The result is either 0, 1 or 2 points.

The efficiency of free throw shooting is the points made out of the potential points. Sorry, if a player misses the front end of a one & one he is 0 for 2 in my book.

In practice, the number of possessions consumed by free throws is generally just estimated by multiplying ~.44 (in the NBA) or ~.475 (in college) times free throw attempts. So the efficiency of players and teams who get a lot of "and ones" are slightly understated by the common possession-based metrics (e.g. ORtg).

Reilly
12-13-2014, 10:00 AM
I'm not clear on what the definition is.

Why are you deducting turnovers from possessions? If I have the ball for 10 possessions and have 10 turnovers, I'm 0 for 10 on my possessions and in my efficiency -- I'm not 0 for 0.

When I played in high school, we used to keep an efficiency stat that involved how many times we scored on trips down the court. So if we got 1 or 2 points on a FT/FTs, we were 1 for 1 on that trip, and if we got 2 points on a FG, we were 1 for 1 on that trip, and if we did not score we were 0 for 1 .... and if we brought the ball down the court and put up 5 shots on that possession thanks to 4 offensive rebounds and scored on the 5th shot, we were 1 for 1 on that possession. I'm guessing the modern efficiency stats are not calculated like that one was several decades ago, but it helped give us a rough idea of how efficient we were.

vick
12-13-2014, 10:17 AM
I'm not clear on what the definition is.

Why are you deducting turnovers from possessions? If I have the ball for 10 possessions and have 10 turnovers, I'm 0 for 10 on my possessions and in my efficiency -- I'm not 0 for 0.

When I played in high school, we used to keep an efficiency stat that involved how many times we scored on trips down the court. So if we got 1 or 2 points on a FT/FTs, we were 1 for 1 on that trip, and if we got 2 points on a FG, we were 1 for 1 on that trip, and if we did not score we were 0 for 1 .... and if we brought the ball down the court and put up 5 shots on that possession thanks to 4 offensive rebounds and scored on the 5th shot, we were 1 for 1 on that possession. I'm guessing the modern efficiency stats are not calculated like that one was several decades ago, but it helped give us a rough idea of how efficient we were.

Your possession calculation (i.e. your denominator) is actually very close to the way it's calculated in efficiency stats. For example, Kenpom uses:

Possessions = FGA -OR + TO + .475*FTA

which is pretty much exactly the way I think you are calculating your denominator, except for the slightly different FT calculation.

To get efficiency though, most people just divide points by possessions so that you account for free throw percentage and three pointers.

Saratoga2
12-13-2014, 03:20 PM
Your possession calculation (i.e. your denominator) is actually very close to the way it's calculated in efficiency stats. For example, Kenpom uses:

Possessions = FGA -OR + TO + .475*FTA

which is pretty much exactly the way I think you are calculating your denominator, except for the slightly different FT calculation.

To get efficiency though, most people just divide points by possessions so that you account for free throw percentage and three pointers.

I guess the free throw basis is statistical based on data taken over many games. That is probably done because FTs are not broken down in the game record where the one and ones are concerned. Otherwise, I think I pretty much line up with the method you list above.

Bill

WakeDevil
12-13-2014, 06:20 PM
The correct word is effectiveness. I never tire of telling people this.

Efficiency refers to subjects such as appliances.

Duvall
12-13-2014, 06:32 PM
The correct word is effectiveness. I never tire of telling people this.

Efficiency refers to subjects such as appliances.

Ship sailed on that one - it's efficiency. You can take it up with Dean Oliver and others, but that would probably be a waste of your time.

Reilly
12-13-2014, 07:19 PM
The correct word is effectiveness. I never tire of telling people this.

Efficiency refers to subjects such as appliances.

Efficiency works for me ...

"the ability to do something [SCORE POINTS] or produce something [POSSESSIONS WHERE POINTS ARE SCORED] without wasting materials, time, or energy[WITHOUT WASTING THE TIME/ENERGY INVOLVED WITH AN EMPTY POSSESSION]"

http://www.merriam-webster.com/dictionary/efficiency