Avery Bradley shocking defensive +/-

[action781]

Was digging through some stats today and I found something interesting.  Defensive box plus/minus is defined as "A box score estimate of the defensive points per 100 possessions a player contributed above a league-average player, translated to an average team."  Avery Bradley has posted a negative defensive plus/minus compared to average players on average teams over the past three consecutive seasons (-1.4, -0.9, -0.3).  Further, let's look at Avery compared to the Celtics team defensive rating (points per 100 possessions) over the past three seasons:

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

http://www.basketball-reference.com/players/b/bradlav01.html

Our team's defense has been worse when he's on the floor for three consecutive seasons now.  This doesn't feel like it passes the eye test, but this is no small sample, we're talking about 6,819 total minutes of game time AB has played which I'd guess is somewhere around 10,000 or more possessions.

I always thought AB was a truly elite defender, a player that I put very high on my do not trade list for that very reason, but what gives here?  Is Avery Bradley an overrated defender?  Or does anyone have any alternative theories?

[DefenseWinsChamps]

Was digging through some stats today and I found something interesting.  Defensive box plus/minus is defined as "A box score estimate of the defensive points per 100 possessions a player contributed above a league-average player, translated to an average team.  Avery Bradley has posted a negative defensive plus/minus compared to average players on average teams over the past three consecutive seasons (-1.4, -0.9, -0.3).  Further, let's look at Avery compared to the Celtics team defensive rating (points per 100 possessions) over the past three seasons:

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

Our team's defense has been worse when he's on the floor for three consecutive seasons now.  This doesn't feel like it passes the eye test, but this is no small sample, we're talking about 6,819 total minutes of game time AB has played which I'd guess is somewhere around 10,000 or more possessions.

I always thought AB was a truly elite defender, a player that I put very high on my do not trade list for that very reason, but what gives here?  Is Avery Bradley an overrated defender?  Or does anyone have any alternative theories?

Best on ball defender in the NBA. He really takes opposing ball-handlers out of rhythm. The eye test tells us that.

But he is not good off-ball. Loses his man. Doesn't help like he should. Doesn't rotate quickly.

All in all, I still like having him on the court with other good team defenders.

[TheSlipperyWhistle]

Its really easy to fall in love with the on ball defense, because its raw, in your face, lateral quickness, steals, for a dunk on the other end. But team defense is not a strong suit for Bradley as mentioned above. This is why he looks so good on the court, but appears to be at best average in the metrics. I agree with the second posted, I still like him out there, though his play does not always translate to the statistics. Honestly, his offense is becoming arguably better than his defense. He is just about the only person I want coming off a screen straight into a jumper, maybe Thomas.

[BitterJim]

I have yet to find a defensive stat that doesn't have some really questionable rankings (ex: Sully is 10th in Defensive Rating last year), so I wouldn't worry

Also, keep in mind that Bradley mostly plays with IT (a below-average defender), and you can see how things like +/- can be skewed

Edit:  He also has Smart, another great defender, backing him up, which will impact +/-

Edit 2: He also is a starter, which means he generally plays against better players (ie other teams' starters)

[Ilikesports17]

Was digging through some stats today and I found something interesting.  Defensive box plus/minus is defined as "A box score estimate of the defensive points per 100 possessions a player contributed above a league-average player, translated to an average team.  Avery Bradley has posted a negative defensive plus/minus compared to average players on average teams over the past three consecutive seasons (-1.4, -0.9, -0.3).  Further, let's look at Avery compared to the Celtics team defensive rating (points per 100 possessions) over the past three seasons:

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

Our team's defense has been worse when he's on the floor for three consecutive seasons now.  This doesn't feel like it passes the eye test, but this is no small sample, we're talking about 6,819 total minutes of game time AB has played which I'd guess is somewhere around 10,000 or more possessions.

I always thought AB was a truly elite defender, a player that I put very high on my do not trade list for that very reason, but what gives here?  Is Avery Bradley an overrated defender?  Or does anyone have any alternative theories?

Avery is a terrific on ball defender, but his overall defensive impact I have always felt was far less than Marcus Smarts. However thats a high bar. RPM is a tricky stat. AB plays with IT and is backed up by Smart so it could be misleading.

That said with winning 1st team all defense I think his D is overrated I would love to sell high on him except Im not sure we can survive without his shooting.

[snively]

Was digging through some stats today and I found something interesting.  Defensive box plus/minus is defined as "A box score estimate of the defensive points per 100 possessions a player contributed above a league-average player, translated to an average team.  Avery Bradley has posted a negative defensive plus/minus compared to average players on average teams over the past three consecutive seasons (-1.4, -0.9, -0.3).  Further, let's look at Avery compared to the Celtics team defensive rating (points per 100 possessions) over the past three seasons:

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

Our team's defense has been worse when he's on the floor for three consecutive seasons now.  This doesn't feel like it passes the eye test, but this is no small sample, we're talking about 6,819 total minutes of game time AB has played which I'd guess is somewhere around 10,000 or more possessions.

I always thought AB was a truly elite defender, a player that I put very high on my do not trade list for that very reason, but what gives here?  Is Avery Bradley an overrated defender?  Or does anyone have any alternative theories?

Best on ball defender in the NBA. He really takes opposing ball-handlers out of rhythm. The eye test tells us that.

But he is not good off-ball. Loses his man. Doesn't help like he should. Doesn't rotate quickly.

All in all, I still like having him on the court with other good team defenders.

He defensive plus-minus was excellent in 11/12. Helped that he was stepping in for a geriatric Ray, but still, I think his defense has declined as he's taken on more offensive responsibility and gotten more cautious post shoulder injuries.

He has moments of elite on-ball defense, but he doesn't pressure the ball as consistently as he used to. Doesn't fight over screens as recklessly.

[max215]

Was digging through some stats today and I found something interesting.  Defensive box plus/minus is defined as "A box score estimate of the defensive points per 100 possessions a player contributed above a league-average player, translated to an average team.  Avery Bradley has posted a negative defensive plus/minus compared to average players on average teams over the past three consecutive seasons (-1.4, -0.9, -0.3).  Further, let's look at Avery compared to the Celtics team defensive rating (points per 100 possessions) over the past three seasons:

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

Our team's defense has been worse when he's on the floor for three consecutive seasons now.  This doesn't feel like it passes the eye test, but this is no small sample, we're talking about 6,819 total minutes of game time AB has played which I'd guess is somewhere around 10,000 or more possessions.

I always thought AB was a truly elite defender, a player that I put very high on my do not trade list for that very reason, but what gives here?  Is Avery Bradley an overrated defender?  Or does anyone have any alternative theories?

Best on ball defender in the NBA. He really takes opposing ball-handlers out of rhythm. The eye test tells us that.

But he is not good off-ball. Loses his man. Doesn't help like he should. Doesn't rotate quickly.

All in all, I still like having him on the court with other good team defenders.

Spot on. He's amazing on-ball, but off-ball he's lackadaisical and gets lost. He also lacks the versatility to guard anything but point guards and small 2s. For these reasons, I consider Smart to be the vastly superior defender, despite Bradley's reputation.

[PickNRoll]

I've been saying this for years.  He is an elite 1 on 1 defender, but is prone to mental lapses.  Smart is, overall, a superior defender.  So is Crowder, at a different spot obv.

[sdceltsfan]

Wouldn't you also need to compare this parallel to each respective minutes True Shooting % to give a blanket statement like that some actual credibility?

Maybe guys are just hitting a higher percentage of their shots, by coincidence, during the times Bradley is on the court. Not necessarily who he's guarding, but other players on the opposing team.

Wouldn't you have to run each opposing teams/players stats to see if there was a dip or spike in FG% when Bradley is on the court. Plus you also have to factor Free Throws, which is why true shooting percentage came to mind. Maybe teams are getting to the free throw line more often when he is in the game.....and by more often, I mean by circumstance, not a dip in Celtics team-defensive performance.

When it comes to measuring D, we have raw, factual stats like BPG, SPG, DEF REB, but the rest is kind of based on "eye test", as mentioned before. I refuse to think that Avery Bradley is solely responsible for dips in overall team defense, when he happens to be on the court.

[Fafnir]

Down with unadjusted +/-

[guava_wrench]

I don't know why you mention "factual". All stats are factual. They are just equations relating raw numbers.

Are you implying that at-bats is raw and factual, hits are raw and factual, but batting average isn't "factual"?

[Fafnir]

Also please don't cite a stat without providing a link, it makes it very hard to figure out what site/stat/definition you are referring too. It is adjusted +/- but that was unclear to me.

[myselfonline]

I don't think these numbers include the teams defensive ratings when a particular player is on the floor.

I feel like AB's value also comes from how he motivates the team to play lock down defense. He leads by example with his on ball defense. This leads other players to do the same.

[action781]

I don't think these numbers include the teams defensive ratings when a particular player is on the floor.

I feel like AB's value also comes from how he motivates the team to play lock down defense. He leads by example with his on ball defense. This leads other players to do the same.

I think you're misinterpreting the stats.

2015-16:  Celtics - 103.6 pp100;  AB - 106 pp100
2014-15:  Celtics - 104.5 pp100;  AB - 107 pp100
2013-14:  Celtics - 107.7 pp100;  AB - 109 pp100

The "Celtics" numbers refer to how many points the celtics as a team gives up every 100 possessions regardless of who specifically is on the floor. 
The "AB" numbers refer to how many points the celtics as a team gives up every 100 possessions when Avery Bradley is on the floor.
So the Celtics give up more points than normal when Avery is on the floor.

Also, keep in mind that Bradley mostly plays with IT (a below-average defender), and yocan see how things like +/- can be skewed

Edit 2: He also is a starter, which means he generally plays against better players (ie other teams' starters)

I looked this bold-faced claim up on 82games.com and it does check out.  Avery played most of his minutes alongside IT.  That could be an explanation.

I don't think the "starter" argument makes any difference since that would make all starters look like poorer defenders, which isn't the case if you dive into the numbers.

[action781]

Wouldn't you also need to compare this parallel to each respective minutes True Shooting % to give a blanket statement like that some actual credibility?

Maybe guys are just hitting a higher percentage of their shots, by coincidence, during the times Bradley is on the court. Not necessarily who he's guarding, but other players on the opposing team.

Wouldn't you have to run each opposing teams/players stats to see if there was a dip or spike in FG% when Bradley is on the court. Plus you also have to factor Free Throws, which is why true shooting percentage came to mind. Maybe teams are getting to the free throw line more often when he is in the game.....and by more often, I mean by circumstance, not a dip in Celtics team-defensive performance.

When it comes to measuring D, we have raw, factual stats like BPG, SPG, DEF REB, but the rest is kind of based on "eye test", as mentioned before. I refuse to think that Avery Bradley is solely responsible for dips in overall team defense, when he happens to be on the court.

If players are hitting a higher % of shots when Avery is on the floor compared to off the floor over a period of 10,000 possessions, the probability of that being "by coincidence" like you suggest is incredibly incredibly small.

As for teams shooting more free throws when he's in the game (like in end-of-game scenarios), that's an interesting idea, but it would affect the ratings of all 5 celtics players on the floor, and Bradley (our lone all-defensive teamer) has the lowest rating out of every single one of our rotation players except IT, so I don't think that can be it.  Also, we're more likely to send them to the foul line in end of game scenario if we're a losing team, not a 48 win team.