Saturday, December 18, 2010

NBA Advanced Defensive Statistics

I've been working on some new defensive statistics which I need to introduce to the public.

Some of this builds on work developed by Dean Oliver. The rest I came up with on my own.

One of my biggest problems with statistics in general is that they are extremely biased in favor of offense. And advanced basketball statistics are no different.

I've been on a mission to create a statistic for everything a basketball player does to help his team win, or lose, and credit it accurately to improve player and team evaluation.

And these defensive statistics are another step in that direction.

I must again tell you that this article is about to get really nerdy right now, talking about the minute details of various basketball scenarios, so consider yourself warned.


The first defensive concept is the stall.

A stall is mainly when an offensive player tries to score on a defensive player, but the defensive player prevents the scoring attempt, usually forcing the offensive player to pass the basketball.

It is a stall and not a stop because there was no shot attempt; the defender didn't prevent a score; he only delayed a scoring opportunity due to the possession being still alive with the ball in the hands of the offense.

Like almost everything else, some of these will be judgment calls; but you can usually tell when an offensive player is trying to score.

I'll stick with Oliver's language on this next one and go with forced miss.

A forced miss is when a defensive player forces an offensive player to miss a shot. He can do this by either contesting the shot or by blocking the path of the offensive player and forcing him shoot farther away from the basket than he could have without the path block.

Forced misses which are not contested and don't involve a path block will be credited to the team.

A forced miss plus a rebound equals a stop.

When the same player who forced the miss gets the rebound, he will be credited with a full stop.

A stop can also be defined more broadly as anything a defensive player or team does to create a change of possession without any points being scored by the offense.

So drawing charges, getting steals, forcing shot-clock violations and a wide variety of other things will be counted as stops as well.

And as Dean Oliver pointed out, fouling a player who goes to the line and misses both free throws will be counted as a stop, assuming the defense secures the rebound after the second free-throw miss.

½ Stops. When one player forces a miss and a different player gets the rebound, the stop will be divided into two equal halves, the forced miss half and the rebound half.

And each player will be given ½ stop.

¼ Stops. When two players force a miss or two players combine for a rebound, the ½ stop for the forced miss or rebound will be split in half and each player given ¼ stop.

Let's say two defensive players double-team a player in the post and force him to miss a shot, and a third defensive player gets the rebound.

The forced-miss half of the stop will be divided in two, and the two players will be given ¼ stop each for forcing the miss.

Since only one player got the rebound, he will be credited with his regular ½ stop.

¼ stops for the rebound half are for plays when one defensive player deflects the rebound, and a second recovers it.

Let's get really complicated and look at one more scenario.

A player dribbles the ball across half court and is immediately double-teamed.

The ball pressure from the trap forces him into a bad pass which is deflected by a third defender and recovered by a fourth for a steal.

This stop would be split into two equal halves, the ball-pressure half and the steal half.

The two trapping players would be given ¼ stop each for the ball-pressure half, and the players who got the steal would be given ¼ stop each for their combined play on the steal half.

Because these fractions can get out of hand, whenever more than two players combine for ½ of a stop, it will be credited to the team.


Now let's move over and look at some team defensive statistics.

The best way to stop a team from scoring is to not let them shoot the basketball.

You can't score without shooting, right?

So one of the things which will be tracked is the percentage of no-shot stops a defensive team gets, meaning they did something to change possession and get the ball back from the offense before the offense had the opportunity to attempt a field goal.

For a team which can't get a no-shot stop, a one-shot stop is the next best thing. That obviously means that the offense came down and missed one shot, and the defense got the rebound and ended the possession.

And the percentage of times a defense does that will be logged as well.

No-shot stops may be called "none-and-dones" and one-shot stops "one-and-dones."

Another thing is that not all stops are created equally.

Live-ball stops are the best because they give the team the opportunity to get fast-break points. So teams will be measured on their field goal percentages after live-ball stops, dead-ball stops and after made baskets for comparison.

These statistics can also be used for offense.

One of the biggest problems for Golden State is that they have too many no-shot possessions on offense. It absolutely killed them in road games at the Lakers and at Oklahoma City this year.

Finally, I'll be looking at dunks and layups.

I'm sure we can all agree that the two easiest shots to make in basketball are an uncontested dunk and an uncontested layup.

Field goals allowed will be looked at to see what percentage were uncontested dunks and layups and what impact this had on the field goal percentage allowed by the defense.

As I wrote before, I don't have nearly the resources or the manpower to track this information on a large scale but will do some games from time to time.

UPDATE: 1/31/2011

Here are some other situations where a player will be credited with a stall: (1) when he deflects a ball out of bounds, (2) when he deflects a ball which gets recovered by the offense, (3) when the offense is trying to pass to his man but his ball denial doesn't allow the pass attempt, (4) when his ball pressure on the passer forces the offense away from who it was trying to pass the ball to, (5) when he forces a jump ball and the offense maintains possession, (6*) when he bumps or blocks off an offensive player moving without the ball and disrupts the play, (7*) when he blocks the path of a dribbler not attempting to score and disrupts the play.

*UPDATE: 5/26/2011, 5:00 AM

It should also be noted that stalls can and will be divided into ½ stalls and ¼ stalls just like stops, and when more than two players combine for ½ of a stall it will be credited to the team.

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Saturday, December 11, 2010

The Cavalry

Imagine starting out on a long and challenging journey and realizing shortly after you left that you weren't going to make it.

You've gone too far to turn back but not nearly far enough to reach your destination. You're running out of food and supplies and know that the end is near.

It is just a matter of time.

As you lie there waiting for the end to arrive and wondering how you got yourself into this awful situation, you hear something in the distance.

Weak and barely alive, you look up just long enough to see men on horseback coming to your rescue. They arrive and give you the food, supplies and the manpower you need to survive trip.

It would be quite a relief.

Although all of the teams which have suffered through injuries this season aren't in a situation as desperate as this, some are.

And fortunately, the cavalry has either arrived or is on the way.


Carlos Boozer missed the first month of the season with a broken hand.

Chicago suffered two blowout losses to Orlando and Boston as he worked himself into the lineup but has won four in a row since, with impressive wins over Oklahoma City and the Lakers.

Chicago should only get better as Boozer, Joakim Noah and Derrick Rose play more games together.

They currently sit at fourth place in the East.


Los Angeles started the season strongly, but slowly, the absence of Andrew Bynum is starting to catch up to them.

Bynum practiced fully this week for the first time and appears to be on track to return next week.

It doesn't take many words to describe the impact his return will have on the team. We've all been watching Los Angeles during championship runs over the past three seasons and know how important he is to the team.


Miami has been on a roll since Mario Chalmers (ankle) made his way back into the rotation.

He still looks to be limping at times, but his impact cannot be denied.

Miami's offense has a much better flow to it thanks to his contagious passing, which makes the team highly-entertaining now and fun to watch. has one of the greatest advanced statistics of all time. It breaks down turnovers by type and focuses in on what it calls the "Assist/Bad Pass" ratio.

This helps identify the most accurate passers by eliminating all other turnovers from consideration and only looking at the turnovers a player makes while passing the basketball.

As of the time of this post, Chalmers averages 10 assists for every passing turnover he makes.

Compare that to Chris Paul (7.7), Deron Williams (6) and Steve Nash (5.1).


This is a team which simply can't catch a break.

After waiting nearly a month for Baron Davis and Chris Kaman to return and racking up the worst record in the association in the process, both players returned in early December.

And what happened?

It turns out Kaman's ankle wasn't quite ready yet, and Davis started struggling with a hamstring problem, a different injury than the knee which kept him out for so long.

Davis has continued to play, but Kaman will be out for at least three more weeks.

The cavalry may not arrive in time to save the Clippers this season.


The only team which has suffered more with injuries than the Clippers is the Minnesota Timberwolves.

It got so bad for them that at one point they were down five players (Jonny Flynn, Luke Ridnour, Martell Webster, Nikola Pekovic, Wayne Ellington) in a game at Charlotte, a game which they almost won.

Flynn (hip) and Webster have both been cleared to play their first games this season, and Pekovic returned last week to solidify the big man rotation.

Flynn has been rehabbing by playing a few games in the development league while Kurt Rambis is waiting to get Webster some good practice time before putting him back in the lineup.

Flynn and Webster are both major, impact players for Minnesota.

Webster had an outstanding preseason and had Minnesota looking like one of the most improved teams in the league before he had to have back surgery and miss the start of the season.

And Jonny Flynn is one of the most gifted, young point guards in the NBA.

David Kahn may not have made the right decision in drafting him ahead of Stephen Curry and Brandon Jennings, but he certainly didn't make the wrong one either.

Minnesota looks to be on their way back.


Golden State has lost six games in a row, but all were against playoff teams from last year and some of the best teams in the NBA so far this season.

The team had gotten so razor thin up front that Vladimir Radmanovic started a few games at power forward.

David Lee returned from his elbow injury seven games ago, and Ekpe Udoh made his season debut last night against Miami. Louis Amundson returned recently as well to help shore up the depth at power forward.

Acie Law was a nice addition and will help fill the void while Stephen Curry recovers from his ankle injury and help when Curry comes back.

The schedule starts to lighten up a bit, and Golden State could finish the season in a good way assuming they can remain healthy and assuming Keith Smart utilizes all of the talent he has on this roster.

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Saturday, December 4, 2010

Around The Association

This was LeBron Week, so I guess it's time to chime in and say something about the Miami Heat.

The media have swooped down on Miami like vultures on a fresh carcass and done everything from fire the coach to trade one of the team's key players.

It has become really cool all of a sudden, like wearing a leather jacket and smoking cigarettes in the '70s, to say something bad about LeBron James or the Miami Heat.


Part of this hysteria is really nothing but overreaction.

Dan Patrick had the greatest observation of this phenomenon. He often talks about how football fans and reporters overreact and think they are going to the Super Bowl or think the season is over after their team wins or loses the first game or two of the season.

It is unfair to judge Miami at this point due to the number of players who have not been available.

Mario Chalmers battled an ankle injury and didn't play 20 minutes in any game until November 27 and has done so only four times so far this season.

Miami is 3-1 in those games.

I saw Chalmers play for about five minutes in the second half against Washington, his second game playing at least 20 minutes. There was more ball movement for Miami in those five minutes than there had been all season combined without Chalmers on the floor.

The Heat also obviously misses Mike Miller.

My only criticism of Erik Spoelstra is the limited playing time he has given Joel Anthony. For what it's worth, Miami is 7-1 when Anthony plays at least 20 minutes.

It probably has something to do with the fact that he leads the team with 1.2 blocks per game despite averaging only 18 minutes.

To those shoveling dirt on Miami's grave, you may want to tone down the rhetoric, unless you want to look really stupid in a few weeks.


The impact that injuries are having on this season can't be emphasized enough.

Golden State is the latest team to be bitten by the injury bug.

Golden State started the season as one of the best teams in the league at 6-2. Then David Lee injured his elbow and missed eight games.

The Warriors lost one of Lee's backups (Brandan Wright) to a back injury two games after Lee went out. They were already playing without top pick Ekpe Udoh, who hasn't played all season due to a wrist injury.

The result has been an incredibly thin front line which has seen the team limp to a 2-9 record in its last 11 games (1-7 without Lee).

It got so bad that Keith Smart had to resort to starting Vladimir Radmanovic at power forward for a few games before he ditched the idea and went back to Dan Gadzuric.

Neither idea worked, and the team is now struggling to find itself.


There has been a change in how clutch will be defined when games are analyzed.

Clutch will now be defined as the last two minutes of the game or overtime when no team is ahead by more than three points.

It was changed from the last five minutes because the five-minute mark just doesn't feel big enough or important enough when watching close games and because it is much easier to track the last two minutes of a game as compared to the last five minutes.

Players who make shots during this time will be judged based on whether their team is behind, tied or leading with the following priority:

(1.) Trailing
(2.) Tied
(3.) Leading

Priority will also be given based on the time the shot takes place, with the following order of importance:

(1.) 0-10 seconds
(2.) 10.1-24 seconds
(3.) 24.1-30 seconds
(4.) 30.1-1:00 minute
(5.) 1:01-1:30 seconds
(6.) 1:31-2:00 minutes

So a player who hits a go-ahead shot with two minutes left won't be considered as clutch as a player who hits one with 10 seconds remaining.

Game-winners will be defined as shots with 10 seconds or less in the fourth quarter or overtime which give a team the lead for good. This matches how Elias Sports Bureau defines and tracks game-winners.

Game-winning shots will be prioritized in the following order:

(1.) Lead-changing game-winners
(2.) Game-winners
(3.) Game-clinchers

Game-clinchers or icers or daggers aren't really game-winners because they come when the team is already ahead. But something had to be created for players who put games away like this.

Lead-changing game-winners are defined as the most clutch due to the player having so much on the line.

For a player who misses a shot with the score tied, the worst which can happen is that the game goes into overtime.

But a player who misses a shot when his team is behind loses the game. He then has to answer all of the questions about what happened and live for a minimum of 24 hours with the fact that he let his team down.

It is such a pressurized situation that players who step up to the challenge deserve more credit when they pull it off.

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