Tag Archives: statistics

More NBA spatial data

Adrian the Canadian — my designated Deadspin trawler — sent me an interesting graphic by Kirk Goldsberry and Matt Adams showing the highest percentage shooters from various regions of the court. You might recall that Goldsberry presented similar work at the Sloan Sports Analytics Conference in March (runner up for the research award). My take on this work is that, while interesting and impressive in terms of data, much of the spatial variation in shooting could be explained by factors other than location-specific shooting ability (this will sound familiar if you read my post yesterday on player tracking data).

First, random chance is an issue, especially when trying to identify the best shooters at each location. I think Goldsberry requires a certain number of shots for inclusion at each spot, but he doesn’t do the statistical analysis to determine whether the differences he presents are statistically significant (i.e., large enough such that they are probably not due to chance variation). His big surprise — Rondo leading the league in one mid-range zone — is likely based on a fairly small sample of shots.

Second, defensive position is missing from the analysis. A big red flag for this one is that Durant, at only 40% shooting, leads in the three point zone just to the shooter’s right at the top of the key. Every other three point zone has a guy over 50%. Unless there’s something challenging for right handers Continue reading

Optimal drafting

There’s a new paper out this month by Casey Ichniowski and Anne Preston concerning the NCAA tournament and the NBA draft (thanks to my PhD buddies Chris and Felipe for passing it along). Their argument is that unexpectedly strong tournament performance (especially team performance) causes players to be selected earlier in the NBA draft. This isn’t a bad thing though — in fact, they suggest that these strong tournament players tend to outperform their draft position in the NBA.

I believe their results saying that tournament performance affects draft position (this has also been shown by Chaz Thomas in an undergraduate thesis, and by David Berri, Stacey Brook, and Aju Fenn), and I mostly believe their results that strong tourney performers should be drafted even earlier, though their set up is a little odd for this second issue.

The clearest way to show that teams make mistakes in the draft Continue reading

Are the Patriots truly being punished for their insolence?

The last five years for the Patriots would make many people believe in karma. Since Tom Brady left his baby mama Bridget Moynahan for Gisele and Bill Belichick got caught videotaping other teams’ run throughs, here are the Patriots season results:

  • 2007: Crazy late game Super Bowl loss to the underdog Giants
  • 2008: Brady tore his ACL early in the season and they missed the playoffs despite going 11-5
  • 2009: Brady had a stinker in a first round loss to the Ravens
  • 2010: Finished 14-2, but Brady had another stinker in a second round loss to the rival Jets
  • 2011: Brady nearly blew it against the Ravens again in the AFC championship game and they sneaked into the Super Bowl, only to suffer another late game loss to the underdog Giants

Gisele continued her negative influence by blaming the loss on drops by the Patriots receivers (only Aaron Hernandez had a truly bad drop, and it was probably too late to matter). The Patriots have 60 wins over the last five years (12 per year), but no rings. If the Patriots go 15-1 next year and get a rematch with a 9-7 Giants team, the Giants will probably be favored. They can’t get past those guys.

Close games are generally decided by luck — Bill Barnwell gets into this at Grantland, but finds himself backtracking almost immediately to avoid angering Giants fans (“The Giants were not lucky to win Super Bowl XLVI because they fumbled twice and fell on both of them.”). There will be no backtracking from me! The Giants were lucky to win (as the Patriots would have been if they had won). Here’s the way the ball bounced Continue reading