Beating their Opponents: Introducing Wins Prevented

Posted on August 11, 2011 by


Arturo Galletti is the Co-editor and Director of Analytics for the Wages of Wins Network. He is an Electrical Engineer with General Electric in the lovely isle of Puerto Rico, where he keeps his production lines running by day and night (and weekends) and works on sport analysis with his free time.

“The only real defense is active defense”

Mao Tse-tung

One of the commonly heard caveats to the Wins Produced numbers (and in fact for all box-score regressed metrics) is that they don’t fully capture individual defense. The typical argument goes that Player X cannot possibly be that good as he gets killed by his opponent.

Right Boys?

This has always bothered me. Is it really that hard to tell if a player does a better than average job at shutting down their opponent?

I say no.

Let’s take a look at how well each player’s opponent’s did over the course of the 2010-2011 NBA season.Introducing the Wins Prevented rankings for 2010-2011:

The results were downright peculiar.

A few explanations on method before we get to the discussion portion of the program:

  • I am looking at the production of the average opponent for each player in terms of Wins Produced per 48 minutes. I do this on a game to game basis by looking at average production by position (as opposed to play by play). What this means in practical terms is that it’s an approximation that’s improves the closer a player’s minutes per game edge towards 48 minutes. To that end I will focus on players with a large sample size (>1500 Minutes played).
  • Pay attention now, because this is where it gets funky. When I started looking at this back in the day, I focused on opponent performance versus league average’s. The more I thought about it though, the more unfair that seemed. Players do not get to pick their teammates for the most part. I decided to look at player opponent performance versus the performance of the average team opponent. I want to identify player’s who are better defenders than you would expect based on their  team and/or system.

Let’s take a look at the top 20 to illustrate what I mean by peculiar:

Kevin Durant, Dwight Howard, Iguodala, Kobe, Rajon Rondo, Kirilenko and Thabo are not that surprising to me in that Top 20.  But Stephen Curry at number 1 was a stunner. Kevin Love, Kevin Martin and Nick Young are also big surprises. To be fair it shouldn’t be, in all those cases the players in question managed to keep their opponents from producing at a significantly lesser rate than the rest of their team.

The Bottom 20 has some surprises as well:

John Wall was a total turnstile for the Wizards and this was not surprising (to be fair he is very,very young) . Chandler being number 2 is a stunner (this may be a function of the Dallas zone defense though). The jaw dropper for me is Tim Duncan, who may very well have reached the end of the road.

Fooled you didn't I?