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David Locke - Yesterday 10:19 AM - Public
Once the NBA lockout started to eliminate games Tyrone Corbin realized his first season as an NBA coach wasn’t going to allow him the luxury of a full training camp and a full pre-season to implement his systems.
With this knowledge, Corbin astutely decided that he would make significant changes to the defense system the Jazz had been running while leaving the offense the same. Corbin changed where the Jazz send the wing ball handler, how they will defend the pick and roll and increased the emphasis on defensive rebounding.
Through an extensive numbers analysis early signs are the changes are pointing the Jazz in the correct direction.
You are going to have to stick with me and wade through a bunch of really geeky stuff.
The NBA game can be broken down to the individual possession. Last year, each possession averaged 1.045 pts (this year is 1.0 so far). Certain shot locations yield better results on average. For example, a trip to the free throw line averages 1.48 pts per possession, a shot at rim averaged 1.28 pts per possession, a three pointer yields 1.03 pts per, a 3-9 footer averages .73, a 10-15 footer averages .76 and a 16-23 footer yields .75.
SHOT LOCATION AVERAGE PTS PER POSSESSION
Free throws 1.48
Shots at Rim 1.28 (63.4% FG)
3 pointers 1.03 (50.9% efg
10-15 footer .76 (38%)
16-23 footer .75 (37.5%)
3-9 footer .73 (36%)
ALL POSSESSIONS 1.045
The first key to a good defense is to get teams to take the lowest percentage shots. If you are sending people to the foul line regularly and allowing three point attempts you can’t be a good defensive team. The best defensive teams are able to run people off the three point line and force them into shots that is .3 pts less potent. If a team does that 10 times a game they are 3 pts better for the night. That simple adjustment moves a team from the 22nd ranked defense in the NBA to the 11th. Amazingly, that could win you as many as 6 to 9 games a year.
Using this knowledge the website hoopdata.com has created something called the Opponents Expected Effective Field Goal%. (Effective Field Goal % gives extra weight to a three point shot since it is worth 50% more points.) This allows you to see if your defense is forcing teams to shot from where you want them to on the floor. The 5 best last year were Orlando, Houston, San Antonio, Phoenix and Chicago. Phoenix shows that if all you ever allow is open looks it doesn’t matter where a team shots from. The worst were some of the worst defensive teams.
In the past the Jazz defense was fighting against the numbers.
We have established the least efficient defensive possession is to send someone to the line. For years, the Jazz have led the league in sending opponent to the line. For the last three years, nearly 13% of the Jazz defensive possession ended with someone at the free throw line, tops in the NBA.
The Jazz were one of the top teams in the NBA at forcing turnovers at 14% of possessions the last few years.
That leaves 73% of the Jazz defensive possessions where a shot is taken. The key is to make sure the shot is taken from the least efficient spots. You would like to believe with all the fouling the Jazz did that they would have prevented teams from shooting at the rim and have a very good Opponent’s Expected Effective Field Goal %. The opposite was true.
In 2009-10 the Jazz were the 7th worst (OXeFG%) and in 10-11 they were the 12th worst. Digging in a little deeper in 09-10, the Jazz allowed teams to shot the highest efficiency shots at an alarming rate. In 2009-10, the Jazz allowed opponents to shot 24% of their shots from 3 point range (5th most in the NBA), they allowed shots at the rim 33% (14th most in the NBA), whereas on the mid range shots with low efficiency Jazz opponents didn’t shot them very often. They shot the 3 to 9 footer 10%of the time (10th fewest), the mid range 7.5% (the 2nd fewest) and the long range two 24% of the time (league average).
In 2010-11 the same was true. The Jazz sent people to the line, the most efficient shot, at the highest rate in the NBA, and on the 73% of possessions when a shot was taken allowed the 12th worst expected effective field goal %. The Jazz protected the rim better last year holding team to 29% of their shots from the rim (league average) but they allowed the 6th highest % of shots to come from three point range.
This year the defensive changes by the Jazz are getting opponents to shot from the least effective spots on the floor. The Jazz are still fouling way too much. They send people to the line 7th most in the NBA, but they are down to just 11.8% of possessions. You would like a larger change, but changing two to three possessions from a free throw line trip to a regular shot or even a jumper is worth as much as 2 points a game.
The Jazz have made considerable progress on possessions with FGA. The Jazz have the 5th best opponent expected field goal % in the NBA. The league’s shooting is down 1.8% EFG from last year, the Jazz OeEFG% is down from 49.9 to 46.8, 3.1% pts. That is significant.
The first change is at the three point line, where the Jazz allowed 24% of possessions to be three’s and now are only allowing 19.9%. In addition, the Jazz have increased the amount of possessions where a jumper from 10 to 23 feet is taken from 31% of possessions to 37%. In addition, rim shots are down from 29% of possessions to 26% of possession.
Add all this together (you can see here with his link) and the Jazz defense on average should be allowing 3.2 pts less per game than they did a year ago. 1 point is worth about 2.6 wins per season so this is a considerable change.
What this tell us is that the changes the Jazz have implemented are heading in the correct direction. Teams are no longer getting the highest percentage shots and the Jazz defense is able to dictate where shots are coming from.
However, 6 games into the season despite the changes the defense still well below average, ranking 18th in the NBA. In comparison that is much better than the 24th of last season. Considering where the Jazz are allowing the shots to come from it should get considerably better.
This year opponents have shot the 10 to 15 footer at 43%, league average is 38%, and the 16 to 23 footer at 40.2%, league average is 37.5%, at unnatural rates and those will regress to the mean.
When those numbers drop we will really see the benefits of the Jazz defensive changes. With these changes the Jazz could move from a bottom 6 defense in the NBA last year to a top 12 this year
With this knowledge, Corbin astutely decided that he would make significant changes to the defense system the Jazz had been running while leaving the offense the same. Corbin changed where the Jazz send the wing ball handler, how they will defend the pick and roll and increased the emphasis on defensive rebounding.
Through an extensive numbers analysis early signs are the changes are pointing the Jazz in the correct direction.
You are going to have to stick with me and wade through a bunch of really geeky stuff.
The NBA game can be broken down to the individual possession. Last year, each possession averaged 1.045 pts (this year is 1.0 so far). Certain shot locations yield better results on average. For example, a trip to the free throw line averages 1.48 pts per possession, a shot at rim averaged 1.28 pts per possession, a three pointer yields 1.03 pts per, a 3-9 footer averages .73, a 10-15 footer averages .76 and a 16-23 footer yields .75.
SHOT LOCATION AVERAGE PTS PER POSSESSION
Free throws 1.48
Shots at Rim 1.28 (63.4% FG)
3 pointers 1.03 (50.9% efg
10-15 footer .76 (38%)
16-23 footer .75 (37.5%)
3-9 footer .73 (36%)
ALL POSSESSIONS 1.045
The first key to a good defense is to get teams to take the lowest percentage shots. If you are sending people to the foul line regularly and allowing three point attempts you can’t be a good defensive team. The best defensive teams are able to run people off the three point line and force them into shots that is .3 pts less potent. If a team does that 10 times a game they are 3 pts better for the night. That simple adjustment moves a team from the 22nd ranked defense in the NBA to the 11th. Amazingly, that could win you as many as 6 to 9 games a year.
Using this knowledge the website hoopdata.com has created something called the Opponents Expected Effective Field Goal%. (Effective Field Goal % gives extra weight to a three point shot since it is worth 50% more points.) This allows you to see if your defense is forcing teams to shot from where you want them to on the floor. The 5 best last year were Orlando, Houston, San Antonio, Phoenix and Chicago. Phoenix shows that if all you ever allow is open looks it doesn’t matter where a team shots from. The worst were some of the worst defensive teams.
In the past the Jazz defense was fighting against the numbers.
We have established the least efficient defensive possession is to send someone to the line. For years, the Jazz have led the league in sending opponent to the line. For the last three years, nearly 13% of the Jazz defensive possession ended with someone at the free throw line, tops in the NBA.
The Jazz were one of the top teams in the NBA at forcing turnovers at 14% of possessions the last few years.
That leaves 73% of the Jazz defensive possessions where a shot is taken. The key is to make sure the shot is taken from the least efficient spots. You would like to believe with all the fouling the Jazz did that they would have prevented teams from shooting at the rim and have a very good Opponent’s Expected Effective Field Goal %. The opposite was true.
In 2009-10 the Jazz were the 7th worst (OXeFG%) and in 10-11 they were the 12th worst. Digging in a little deeper in 09-10, the Jazz allowed teams to shot the highest efficiency shots at an alarming rate. In 2009-10, the Jazz allowed opponents to shot 24% of their shots from 3 point range (5th most in the NBA), they allowed shots at the rim 33% (14th most in the NBA), whereas on the mid range shots with low efficiency Jazz opponents didn’t shot them very often. They shot the 3 to 9 footer 10%of the time (10th fewest), the mid range 7.5% (the 2nd fewest) and the long range two 24% of the time (league average).
In 2010-11 the same was true. The Jazz sent people to the line, the most efficient shot, at the highest rate in the NBA, and on the 73% of possessions when a shot was taken allowed the 12th worst expected effective field goal %. The Jazz protected the rim better last year holding team to 29% of their shots from the rim (league average) but they allowed the 6th highest % of shots to come from three point range.
This year the defensive changes by the Jazz are getting opponents to shot from the least effective spots on the floor. The Jazz are still fouling way too much. They send people to the line 7th most in the NBA, but they are down to just 11.8% of possessions. You would like a larger change, but changing two to three possessions from a free throw line trip to a regular shot or even a jumper is worth as much as 2 points a game.
The Jazz have made considerable progress on possessions with FGA. The Jazz have the 5th best opponent expected field goal % in the NBA. The league’s shooting is down 1.8% EFG from last year, the Jazz OeEFG% is down from 49.9 to 46.8, 3.1% pts. That is significant.
The first change is at the three point line, where the Jazz allowed 24% of possessions to be three’s and now are only allowing 19.9%. In addition, the Jazz have increased the amount of possessions where a jumper from 10 to 23 feet is taken from 31% of possessions to 37%. In addition, rim shots are down from 29% of possessions to 26% of possession.
Add all this together (you can see here with his link) and the Jazz defense on average should be allowing 3.2 pts less per game than they did a year ago. 1 point is worth about 2.6 wins per season so this is a considerable change.
What this tell us is that the changes the Jazz have implemented are heading in the correct direction. Teams are no longer getting the highest percentage shots and the Jazz defense is able to dictate where shots are coming from.
However, 6 games into the season despite the changes the defense still well below average, ranking 18th in the NBA. In comparison that is much better than the 24th of last season. Considering where the Jazz are allowing the shots to come from it should get considerably better.
This year opponents have shot the 10 to 15 footer at 43%, league average is 38%, and the 16 to 23 footer at 40.2%, league average is 37.5%, at unnatural rates and those will regress to the mean.
When those numbers drop we will really see the benefits of the Jazz defensive changes. With these changes the Jazz could move from a bottom 6 defense in the NBA last year to a top 12 this year
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