Wednesday, April 24, 2013

Marc Gasol & Advanced Defensive Stats

With Marc Gasol receiving Defensive Player of the Year he becomes the third straight center to win the award, which since Jordan won it in 1987-88 has only been won by centers and power forwards except for Gary Payton in 1995-96 and Ron/ Meta Artest/World Peace in 2003-04 (thus, giving some idea of the value of frontcourt, help defenders). What's interesting about Gasol's winning is that he's a relatively unimpressive nominee based on conventional defensive measures.

Looking at the performance of all players in the 2012-13 season that played at least 100 minutes and standardized over 36 per minutes of play (which simply helps take account for the fact that some players play more than others so we're interested in performance per minute of play rather than total performance, which would benefit players that play more minutes), Gasol is 127th in defensive rebounds (tied with Kawhi Leonard and Antawn Jamison), 75th in steals among just PFs and Cs, and 46th in blocks (to give some context, in both steals and blocks he is tied with Ronny Turiaf). Even among the more basic advanced statistics,  like DRB%, STL% and BLK% (basically, all just estimate the percentage of DRBs/ STLs/ BLKs that player achieved while on the floor), he's unimpressive. For DRB% Gasol is 105th, for STL% he's 60th among PFs and Cs, and for BLK% he's 45th among all players.

It is perhaps the two most advanced defensive stats (among popular advanced defensive stats) that signal Gasol's value as a defender. Gasol's defensive rating (DRTG), which is an estimate of the number of points a player gives up per 100 possessions, is 98, which is 4th in the league--one point behind Hibbert and Paul George and 3 points behind Tim Duncan, the leader. Based on defensive win shares (DWS), which is an estimate of the number of wins the player's defense contributes to his team, Gasol was second with 5.4 behind only Paul George's 6.3.

But, why if George leads Gasol in these two advanced measures did he not receive the award? (More so, how did he finish 7th in voting?) Perhaps that's the case because 5th in DWS was Roy Hibbert and much like George's high DRTG (which Hibbert shared) it may be the case that voters feel George's defense is bolstered by Hibbert's (and other phenomenal Pacer defenders, like David West's) defensive contribution. (Interestingly, LeBron, the runner-up for Defensive Player of the Year, didn't finish in the top ten of DRTG or DWS.)

Thursday, April 11, 2013

Syracuse 3FG Defense

During the NCAA Men's tournament Syracuse received much publicity and warranted praise for its 2-3 defense. (In fact, it received such recognition that even NPR ran a segment on it.)  The movement and the length of the defenders seemed to receive most of the credit for the zone's success. But there's something equally important that Jim Boeheim understands as well as anyone--college kids are not good jump shooters and the further from the basket you make them shoot the worse they get. Blame it on the 'AAU-I gotta do me' culture or Youtube dunk contests or whatever but what Boeheim gets so well is that if opponents do something poorly then make them do a lot of it.

Among division 1 college basketball teams over the last season, Syracuse had the third best opponent three point field goal defense percentage at 28.4%. (The two teams ahead of them--New Hampshire and Weber St--were sub 80 RPI teams and didn't play close to the competition that Syracuse did.) Among the top 100 division 1 basketball teams in terms of opponent three point field goal defense percentage Syracuse averaged the 7th highest opponent 3FGA per game at 21.7 (all 6 teams ahead of them allowed a higher opponent 3FG% and were from much lower-tier conferences than the Big East).

One way to look at this is--what was the value an opponent should expect for each shot attempt against Syracuse. For threes it was 0.852 points (28.4% opponent 3FG% x 3 points) and for twos it was only slightly higher at 0.854 points (42.7% opponent 2FG% x 2 points). But considering that two point attempts are far more likely than three point attempts to incur fouls and, thus, free throws (Syracuse's opponents averaged 19.1 FTA against them per game), opponents would have benefited even more by relying less on threes.

What became clear during the tournament was that not only did Syracuse's guards play excellent perimeter defense but the zone forced opponents to take a seemingly irrational number of contested threes--if history shows opponents that they have a low probability of making the shot then don't take it, or at least minimize the number of attempts. It wasn't just that their 5 tournament opponents shot 19% from the three, but the fact that their opponents averaged 23 3FGA while they should have known the three point attempt was an exceptionally low probability method for scoring points. (To give some reference, Montana took 31 3FGA, and Marquette and Michigan each took 24.) So what happened in the loss to Michigan? After shooting around 36% from threes in the first four tournament games, Syracuse shot 21%.