Saturday, November 14, 2009

The NBA in Polychromatic Form

If you're a regular reader of this site, you know I am a big fan of Hoopdata.com.  You'll probably find more numbers than you know what to do with there but don't worry, that's why you have me around.

One of the most useful pages on the site is the Four Factors team stats page.  Identified by Dean Oliver, the Four Factors outline the four biggest responsibilities a team has in order to win games: shooting well from the field, taking care of the ball, getting to the line often and grabbing offensive boards.  And consequently, a team needs to make sure their opponent does poorly in these areas.  All the other stuff is just details.

As far as I know, HoopData is the only site that charts the Four Factors complete with differentials.  And as far as I know, my site is the only one that lays on the lipstick.  The teams below are arranged by their efficiency differential rank.  Green is good, red is bad, and yellow is average in the category.

Quick primer. Offensive efficiency (OFF) is a measure of how many points a team scores per 100 possessions. Defensive efficiency (DEF) measures how many points a team allows per 100 possessions.  Effective field goal percentage (eFG%) weights three pointers more than two pointers because they're worth more.  Free throw rate is a team's proportion of free throw attempts to field goal attempts.  Turnover rate is the percentage of possessions that end in a turnover.  Offensive Rebound Rate (ORR) estimates the percentage of available offensive rebounds collected off of missed shots. Very quick primer.

So, what do we learn?

  • The Celtics have positioned themselves head and shoulders above the rest by controlling effective field goal percentage and turnovers better than anyone else.  Aside from J.R. Giddens who plays almost never, every single Celtic who's gotten floortime this year has an above-average effective field goal percentage.  Let that marinate. Well, the Celtics do have one weakness and that's grabbing their own misses. Rasheed Wallace grabs fewer offensive rebounds (3.1 ORR) than Nate Robinson (3.2) which may not be a complete surprise considering his perimeter habitat on offense.  This sore spot isn't as painful with their shooting percentage so high.   
  •  The Lakers miss Pau Gasol on the boards. The Lakers let their opponents extend their possessions by giving up way too many second chance opportunities.  Their 31.4 percent opponent offensive rebound percentage tops every team in the league if we ignore the Warriors, which we should.  Ron Artest hasn't filled the rebounding void left by the Lakers leading defensive rebounder last year.
  • The Grizzlies find themselves near the bottom in efficiency differential but they can be proud of a couple things.  To mitigate their shooting woes, the Grizzlies collect their missed shots better than any team in the league.  Also, they get to the charity stripe often and don't foul shooters.  However, their defensive ineptitude makes me wonder if they play the four-cherry-picker scheme.
  • The Toronto Raptors and the Milwaukee Bucks: a study in contrast.
  • If you want to find a team good at just about everything but not great in any one factor, look no further than the Dallas Mavericks. Their line looks like a sliced avocado.
  • Do the Cavs know they can rebound their own shots?  Doesn't seem like it.

3 comments:

Peter said...

My head hurts. Great work.

Crow said...

nbastuffer.com is doing some stuff with differentials but not displaying the discrete 4 factor differentials separately. The "Adjusted 4 Factors" applies weights from Wayne Winston to the 3 Factors found to be significant (all except getting to the line) and gives an overall impression of strength.

eFG% and turnovers were considered the most important factors with the former being by far the most important. So the Celtics are really in line with that thinking.

Crow said...

http://www.nbastuffer.com/2009-2010_NBA_Regular_Season_Advanced_Stats.html

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