Message Board Basketball Forum - InsideHoops Defensive rating (DRtg) How you calculate it and use it
 Register FAQ Members List Calendar Mark Forums Read

 NBA Forum NBA Message Board - NBA Fan Forum

03-30-2011, 07:30 AM   #1
Micku
NBA rookie of the year

Join Date: Dec 2008
Posts: 6,779
Defensive rating (DRtg) How you calculate it and use it

How you calculate it:

The lower the defensive stat is, the better your defense is.

The Defensive rating stat is simply:

Quote:
 For players and teams it is points allowed per 100 possessions.

This means you divide points allowed and 100 by the number of possessions.

There are a lot of ways to calculate the number of possessions, but it is usually calculated by this formula for the defensive equation:

Quote:
 .96 * (FGA − ORb + TO + (.44 * FTA))

- http://sonicscentral.com/statsite.html (this site shows the many ways you could calculate for different situations)

- http://en.wikipedia.org/wiki/APBRmet...mon_statistics

Quote:
 The .96 multiplier adjusts for team rebounds. Because these are not considered offensive rebounds, the formula slightly overestimates the number of possessions per team without the multiplier.

- http://en.wikipedia.org/wiki/APBRmet...mon_statistics

To sum it up, you have to do this formula:

Points allowed * 100/.96 * (FGA − ORb + TO + (.44 * FTA))

How to use it:

The defensive rating is suppose to measure the quality of defense. But it is invalid to compare it other seasons because defensive rating is proportional to the possessions and pacing. When the number of possessions goes up, the defensive rating also goes up. This is also true for the offensive rating:

Quote:
 Milwaukee led the league in field goal percentage and assists and did well in offensive rebounds. The Bucks' 99.3 rating, though it led the league would now be among the worst in the NBA. New Jersey had an offensive rating of 99.9, which was second to last in '87-88. Because the pace of the game is so much slower now, the Nets adjusted points per game rating was 101.7, much lower than the Bucks' 109.2.
- http://www.rawbw.com/~deano/helpscrn/rtgs.html

This is list of the average number of possessions each year:

- http://arturogalletti.wordpress.com/...ting-for-pace/

As the number of possessions goes down, you would see defensive rating goes up. Notice how 2004 has the lowest possession rating out of 32 years span (exclude 1999). It also has the lowest pacing. It's no coincidence that year also had the lowest defensive rating.

This also could mean that 2003-04 wasn't the best defensive year. It just means that the league was incredibly slow. If you would have put those teams in another era, they would probably been force to run more. This is true with other great teams, vice versa.

The defensive rating is inflated with the number of possessions you have. It is only valid when comparing with a similar pacing/possession rating season. It may be only right to use defensive rating for one season at a time instead of comparing.

 03-30-2011, 08:22 AM #2 Christofire Banned     Join Date: Feb 2011 Posts: 1,631 Re: Defensive rating (DRtg) How you calculate it and use it defense still dictates PACE....it's not a coincidence that the PACE picked up once hand-checking was curtailed yet again. Hand-checking + zone defense made defense as tough as it has ever been. Spurs and piston made a religion out of holding teams to 80 pts and lower. I get what you're saying, but the defensive rules are what dictates the PACE of play.
 03-30-2011, 08:27 AM #3 Christofire Banned     Join Date: Feb 2011 Posts: 1,631 Re: Defensive rating (DRtg) How you calculate it and use it it's like this If you're playing a team that runs a press the entire time and uses no zone techniques and no hand checking. Naturally you run and gun them out of the Jim. On the other hand if you're team that hand checks and uses zone techniques in conjuction with that you're gonna slow the other teams game down. because of more defensive resistance. great defensive teams slow teams down and force them to use more of the clock. Not very many teams could've came to the Palace of auburn hills talking about "we're going to run and gun" Last edited by Christofire : 03-30-2011 at 08:31 AM.
 03-30-2011, 08:42 AM #4 cteach111 Local High School Star   Join Date: Oct 2009 Posts: 1,547 Re: Defensive rating (DRtg) How you calculate it and use it isn't DRtg just the opposing teams ORtg?
 03-30-2011, 10:23 AM #5 Yao Ming's Foot You're welcome     Join Date: Apr 2010 Posts: 4,556 Re: Defensive rating (DRtg) How you calculate it and use it Hint: The number of possessions used is different for every team and every year of the formula. Example 1. My team gives up 100 pts to the fast paced Warriors (100 possessions) 100/100 multiplied by 100 = 100.0 DEF RATING Example 2 My team gives up 100 pts to the slower paced Pistons (75 possessions) 100/75 multiplied by 100= 133.3 DEF RATING
03-30-2011, 10:41 AM   #6
Micku
NBA rookie of the year

Join Date: Dec 2008
Posts: 6,779
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Christofire defense still dictates PACE....it's not a coincidence that the PACE picked up once hand-checking was curtailed yet again. Hand-checking + zone defense made defense as tough as it has ever been. Spurs and piston made a religion out of holding teams to 80 pts and lower. I get what you're saying, but the defensive rules are what dictates the PACE of play.

It does. But not in a way that you think.

One theory is that defense actually increase the pacing:

Quote:
 Contrary to what we might initially assume, as defense gets better the league’s overall pace will increase. Normally, we’d assume that a higher pace would lead to more points on the scoreboard. Not in this case. I know, it goes against your natural instincts, but the teams mentioned that are controlling the defensive pace of the game are forcing early, poor offensive possessions such as difficult shots and turnovers. These result in more possessions in a given game, thereby raising the overall pace by it’s current measurement. Of course, not everyone will subscribe to the theory, thank goodness. We still need your Mike D’Antoni-types; it adds flavor, a literal change of pace. And many that do try to do so will have varying degrees of success in doing so. But the overall trend is already well underway, only the numbers didn’t jive until now.

- http://www.shoot-hoops.com/defensive...k-defense-era/

But pacing is not that. Usually it just means more possessions and the game is faster. What defense is suppose to do is stop you from scoring. Any team could adjust the pace of the game. The slowest team in the game isn't exactly the best team defensive.

And:

Quote:
 You hear it said all the time by announcers…the coach would love to have his team control the tempo in a game. Run & Gun teams want to force their opponent to get up and down the court at their pace. Slowdown teams want to work the shot clock each possession and shorten the contest. Every coach and team has a pace it likes to play, but from a betting perspective, does it help us to compare teams’ paces in order to get an edge over the oddsmakers on side and total plays? I’m here to look at that subject in the NBA, while revealing some trends you will be able to use the rest of the way for each team regarding pace. This piece turned out to be rather lengthy, but hopefully as you browse through some of the distinctive team trends below, you’ll feel it was worth the effort.

- http://forums.statfox.com/statfoxnew...cleid~5959.htm

So, it could be the exact opposite sometimes.

Pacing just means that you have more possessions, which could mean that you play a lot faster. Teams can slow the game down, and participate in a longer half court offense. But it doesn't mean that the defense is better because the game is faster or slower.

This just shows that the pacing is different. People in the 80s used to run down the court, set a screen and shoot the ball, mid-range. People in the 00s walk down, set multiple screens, and shoot the 3. Different styles.

03-30-2011, 10:44 AM   #7
Calabis
Good college starter

Join Date: Jun 2010
Posts: 3,131
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Micku How you calculate it: The lower the defensive stat is, the better your defense is. The Defensive rating stat is simply: - http://www.basketball-reference.com/...y.html#def_rtg This means you divide points allowed and 100 by the number of possessions. There are a lot of ways to calculate the number of possessions, but it is usually calculated by this formula for the defensive equation: - http://sonicscentral.com/statsite.html (this site shows the many ways you could calculate for different situations) - http://en.wikipedia.org/wiki/APBRmet...mon_statistics Also when you do your own calculation, don't be mad if your calculation is slightly off. - http://en.wikipedia.org/wiki/APBRmet...mon_statistics To sum it up, you have to do this formula: Points allowed * 100/.96 * (FGA − ORb + TO + (.44 * FTA)) How to use it: The defensive rating is suppose to measure the quality of defense. But it is invalid to compare it other seasons because defensive rating is proportional to the possessions and pacing. When the number of possessions goes up, the defensive rating also goes up. This is also true for the offensive rating: - http://www.rawbw.com/~deano/helpscrn/rtgs.html This is list of the average number of possessions each year: - http://arturogalletti.wordpress.com/...ting-for-pace/ As the number of possessions goes down, you would see defensive rating goes up. Notice how 2004 has the lowest possession rating out of 32 years span (exclude 1999). It also has the lowest pacing. It's no coincidence that year also had the lowest defensive rating. This also could mean that 2003-04 wasn't the best defensive year. It just means that the league was incredibly slow. If you would have put those teams in another era, they would probably been force to run more. This is true with other great teams, vice versa. The defensive rating is inflated with the number of possessions you have. It is only valid when comparing with a similar pacing/possession rating season. It may be only right to use defensive rating for one season at a time instead of comparing.

LMAO!!!!!!!! Try explaining that to YAOLEFTFOOT

03-30-2011, 10:48 AM   #8
Calabis
Good college starter

Join Date: Jun 2010
Posts: 3,131
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Micku It does. But not in a way that you think. One theory is that defense actually increase the pacing: - http://www.shoot-hoops.com/defensive...k-defense-era/ But pacing is not that. Usually it just means more possessions and the game is faster. What defense is suppose to do is stop you from scoring. Any team could adjust the pace of the game. The slowest team in the game isn't exactly the best team defensive. And: - http://forums.statfox.com/statfoxnew...cleid~5959.htm So, it could be the exact opposite sometimes. Pacing just means that you have more possessions, which could mean that you play a lot faster. Teams can slow the game down, and participate in a longer half court offense. But it doesn't mean that the defense is better because the game is faster or slower. This just shows that the pacing is different. People in the 80s used to run down the court, set a screen and shoot the ball, mid-range. People in the 00s walk down, set multiple screens, and shoot the 3. Different styles.

Goshdamn someone with some damn sense ......can you by chance do a rating of the 87-88, 88-89 Pistons D with the adjusted pace factor, they had a 102.9 with a 98 Pace Factor(I believe in 87-88), I'm sure if it was lower they would have a lower rating

03-30-2011, 10:49 AM   #9
Micku
NBA rookie of the year

Join Date: Dec 2008
Posts: 6,779
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Yao Ming's Foot Hint: The number of possessions used is different for every team and every year of the formula. Example 1. My team gives up 100 pts to the fast paced Warriors (100 possessions) 100/100 multiplied by 100 = 100.0 DEF RATING Example 2 My team gives up 100 pts to the slower paced Pistons (75 possessions) 100/75 multiplied by 100= 133.3 DEF RATING

Indeed. You just showed why possessions do matter in evaluating defensive rating.

If the possessions are high, you have more offensive possessions. Which means you would have more chances to score and defensive stops.

If you have lower possessions, then you would have less chances to stop a person. Your second example showed a demonstration of bad defense while the 1st showed an example of better defense.

The 1st example had the opposing team with more possessions of the ball, and they did a better job limiting the opposing team to 100. While the 2nd example had the less amount of possessions, but scored the same amount of points.

This shows that defensive rating is proportional to possessions.

Last edited by Micku : 03-30-2011 at 10:59 AM.

03-30-2011, 10:53 AM   #10
Yao Ming's Foot
You're welcome

Join Date: Apr 2010
Posts: 4,556
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Micku Indeed. You just showed why possessions do matter in evaluating defensive rating. If the possessions are high, you have more offensive possessions. Which means you would have more chances to score and defensive stops. If you have lower possessions, then you would have less chances to stop a person. Your second example showed a demonstration of bad defense while the 1st showed an example of better defense. The 1st example had the opposing team with more possessions of the ball, and they did a better job limiting the opposing team to 100. While the 2nd example had the same amount of possessions, but scored the same amount of points. This shows that defensive rating is proportional to possessions.

Of course it is. Its points allowed per 100 possessions. It normalizes points allowed so that you can compare it in a slow paced league and a fast paced one. That doesn't make it unfair.

03-30-2011, 10:55 AM   #11
Yao Ming's Foot
You're welcome

Join Date: Apr 2010
Posts: 4,556
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Micku Indeed. You just showed why possessions do matter in evaluating defensive rating. If the possessions are high, you have more offensive possessions. Which means you would have more chances to score and defensive stops. If you have lower possessions, then you would have less chances to stop a person. Your second example showed a demonstration of bad defense while the 1st showed an example of better defense. The 1st example had the opposing team with more possessions of the ball, and they did a better job limiting the opposing team to 100. While the 2nd example had the same amount of possessions, but scored the same amount of points. This shows that defensive rating is proportional to possessions.

Look again

03-30-2011, 10:59 AM   #12
Micku
NBA rookie of the year

Join Date: Dec 2008
Posts: 6,779
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Yao Ming's Foot Of course it is. Its points allowed per 100 possessions. It normalizes points allowed so that you can compare it in a slow paced league and a fast paced one. That doesn't make it unfair.

It does make it unfair. Because it is proportional the number of possessions. If the possessions are higher, then the defensive rating goes higher.

Since possessions also adds the amount of FGA, it is unfair to compare a league who averages less possessions than a team that averages more possessions. It doesn't work that way.

And with the 2nd one

"While the 2nd example had the less amount of possessions, but scored the same amount of points."

Sorry for the typo.

---

And I see what you did. Usually there are more possessions, the team scores more. This also adds into pacing.

When you put in a team who average 75 possessions and allowed 100 points, it showed bad defense than a team who allowed 100 points with 100 possessions. That 75 possessions team would have a very high FG% rating probably, or just kept scoring like mad.

It doesn't work that way though. Usually more FGA means more chances for FG make. And since the FG of the 80s were in the 50% or above, it also shows that it's inflated.

Last edited by Micku : 03-30-2011 at 11:06 AM.

03-30-2011, 11:05 AM   #13
Yao Ming's Foot
You're welcome

Join Date: Apr 2010
Posts: 4,556
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Micku It does make it unfair. Because it is proportional the number of possessions. If the possessions are higher, [b]then the defensive rating goes higher. Since possessions also adds the amount of FGA, it is unfair to compare a league who averages less possessions than a team that averages more possessions. It doesn't work that way. And with the 2nd one "While the 2nd example had the less amount of possessions, but scored the same amount of points." Sorry for the typo.

Def rating is impacted by how many pts you give up per possession. Thats it. If you only give 1 pt per possession in a 300 possession per game league your D Rating is 100. If you give up only 1 pt per possession in a 10 possession per game league its still 100.

 03-30-2011, 11:06 AM #14 LilBTheBasedGod   Posts: n/a Re: Defensive rating (DRtg) How you calculate it and use it gay
03-30-2011, 11:07 AM   #15
Micku
NBA rookie of the year

Join Date: Dec 2008
Posts: 6,779
Re: Defensive rating (DRtg) How you calculate it and use it

Quote:
 Originally Posted by Yao Ming's Foot Def rating is impacted by how many pts you give up per possession. Thats it. If you only give 1 pt per possession in a 300 possession per game league your D Rating is 100. If you give up only 1 pt per possession in a 10 possession per game league its still 100.

Exactly. And if a team has more possessions, it usually leads to more scoring across the board. At least more chances of scoring.

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts vB code is On Smilies are On [IMG] code is On HTML code is Off
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home InsideHoops Main Basketball Forums     NBA Forum     College and High School Basketball Forum     Off the Court Lounge     Fantasy Basketball Forum         Fantasy Premier League     Football Forum     Sneaker Forum     Video Games Forum     Streetball Forum     G League Forum, Minor League and International Basketball Forum     NBA Draft Forum     WNBA Forum NBA Team Forums     Atlanta Hawks Forum     Boston Celtics Forum     Brooklyn Nets Forum     Charlotte Hornets Forum     Chicago Bulls Forum     Cleveland Cavaliers Forum     Dallas Mavericks Forum     Denver Nuggets Forum     Detroit Pistons Forum     Golden State Warriors Forum     Houston Rockets Forum     Indiana Pacers Forum     Los Angeles Clippers Forum     Los Angeles Lakers Forum     Memphis Grizzlies Forum     Miami Heat Forum     Milwaukee Bucks Forum     Minnesota Timberwolves Forum     New Orleans Pelicans Forum     New York Knicks Forum     Oklahoma City Thunder Forum     Orlando Magic Forum     Philadelphia 76ers Forum     Phoenix Suns Forum     Portland Trail Blazers Forum     Sacramento Kings Forum     San Antonio Spurs Forum     Seattle SuperSonics Forum     Toronto Raptors Forum     Utah Jazz Forum     Washington Wizards Forum

All times are GMT -4. The time now is 10:47 AM.

InsideHoops Home
NBA Rumors
NBA Daily Recaps
NBA Videos
Search Site