Tuesday, July 10, 2007

Defensive Contributions In Basketball

I recently stumbled across the ACC Stats & More blog, and I've found some stuff there that I haven't seen anywhere in the college hoops blogosphere. Of particular interest is PAPER:

PAPER represents the number of points a player would contribute to a league-average team over the course of a 16-game conference season, relative to the expected contribution of a hypothetical league-average player. Only statistics from conference games are used. PAPER does not simply assign a set value to the various statistics that individuals accumulate. Instead, it uses a model of a typical league possession and introduces the player's net contribution to determine what the expected scoring output would be.

What PAPER's telling us--how many points a player adds to his team above/below what an average player would--is a concept borrowed from baseball analysis. It's a marginal lineup value for hoops. The most interesting thing to me about PAPER is that it approximates defensive value. That's a murky area in basketball for obvious reasons (it doesn't help that the box score stats we have to evaluate defense tell only a small part of the story), but separating the individual from the team isn't totally infeasible.

The ratings are here. You'll probably scoff at where Brandon Costner is located on the list, but keep in mind that this is for conference games only, and Costner wasn't very efficient in league play (it's his offense that's dragging him down). He turned the ball over too much and shot rather modestly (his ORTG in conference play was 100.9, if that helps).

Other notes:

-- The five members of the ACC All-Defensive team were Jamon Gordon, Zabian Dowdell, DJ Strawberry, Ekene Ibekwe, and Josh McRoberts. According to PAPER, the writers did a good job--four of the five are rated as above average defensively.

-- Ben McCauley's defense...uh, yikes. Ben had 9 blocks and 10 steals in 16 regular season conference games and was a terrible defensive rebounder, so you can see where the rating is coming from. McCauley is an example of why understanding a player's net contribution is important. I'm not saying PAPER's right about him, but you can see, in tangible terms, how defense may impact a player's value.

-- There's my man Anthony Harris right near the bottom, not surprisingly. By any measure, Anthony, you suck. But that's why I dig you. Not too far above Harris are Jack McClinton and Sean Marshall, two overrated players who provide little aside from high volume shooting. Marshall preposterously averaged almost three more field goal attempts per 40 minutes than Jared Dudley during the ACC regular season. Which, had I been running the country at the time, would've been a punishable offense.

So what do you guys think? Does this pass the sniff test for you?

Although I never use them here, I do have individual defensive ratings for everyone in the ACC. Later this week I'm going to see if there's a general agreement between PAPER and the DRTGs.