The Decline of Big Ben Wallace or Making Too Much of a Tiny Sample

The Chicago Bulls entered the season expecting to contend for the Eastern Conference title, and perhaps an NBA championship.  At least, that was my expectation.

After three games, though, Chicago has yet to win once.  And when we look at the box scores from these games it’s easy to find one huge problem – the play of Big Ben Wallace.

Putting the 2007-08 Big Ben in Perspective

Let me start by noting that Ben Wallace has had an extremely productive NBA career.  Across eleven seasons his Wins Produced stands at 176.6 and his WP48 [Wins Produced pr 48 minutes] is at 0.348.  When we think of elite NBA players, Wallace is one of the few non-scorers who make the cut.

But this year it’s a very different story.  In three games Big Ben has been out-rebounded by Ben Gordon, Luol Deng, Andres Nocioni, Tyrus Thomas, and Joe Smith.  If we look at per-minute rebounding, we can add Thabo Sefolosha to the list.  In fact, Wallace has only grabbed more rebounds – on a per-minute basis – than Kirk Hinrich, Chris Duhon, and Aaron Gray.  And Gray has only played three minutes this year. 

When we look at Wallace’s overall production – via Win Score – we see how immensely unproductive he has been.  The average center will post a per-minute Win Score of 0.225.  In three games, Wallace has posted a per-minute Win Score of 0.074, 0.040, and 0.066.  His average is 0.061.  In sum, he has had three incredibly bad games.

To put this in perspective, let’s look at what Wallace has done across the past two seasons.  In 2005-06 – his last year in Detroit – Wallace posted a Win Score per-minute of 0.365.  If we look at his game-by-game performance, we see that he was only below average (below 0.225) in 13 games. Or in 84% of games played he was above average.  Only twice did he have back-to-back below average games and he never was below average in three consecutive contests.

Last year he joined the Bulls.  His Win Score per-minute for the season fell to 0.320, but he was still above average. If we look at his game-by-game performance we see that in 77 games he was below average 19 times.  Or in 75% of games played he was above average.  Four times he posted back-to-back below average games, but again he was never below average in three consecutive contests.

This year he is not just below average, he is awful.  How often has Big Ben posted a Win Score per-minute below 0.075 in a game?  In 2005-06 this happened twice. And one of these was the last game of the season when the Pistons had already clinched the best record in the league.

Last year Wallace had five truly bad games.  Still, he never had two in a row, let alone the three dreadful efforts we have seen to start this season.

So what’s happened?

Whenever I see performance change dramatically I suspect injury.  And when we look at pre-season performance, there is some reason to think this is the story.  In the pre-season Big Ben posted a 0.263 Win Score per-minute.  In other words, he was above average.  But he left the last game of the pre-season with a sprained ankle.  The story is that this injury was not serious. Certainly he has logged thirty minutes a game in the first three contests of the regular season.  His inability to perform, though, suggests this injury might be having a lingering effect.

Of course it could be that Wallace is just suddenly old.  Of course, that explanation doesn’t tell us how he was above average in October.  Did he suddenly get older in the past two weeks?

Scaring Chicago Fans

I think – although I don’t know – that the issue is injury, not age.  But let’s imagine the issue is age.  Let’s imagine that what we have seen for three games is what we are going to see the entire season.  If that is the case, Chicago has real problems (or in other words, if you are Bulls fan this scenario is quite scary).

Last year Big Ben posted a 0.281 WP48.  If he was this productive in 2007-08, and he played 30 minutes in each contest, he would produce 14.4 wins this season.  Wallace’s current Win Score per-minute translates – via PAWSmin – into a -0.165 WP48.  If this is what Wallace produces in 2007-08, he will produce a -8.4 wins.  That is a 22.8 swing in the standings.  In other words, the Bulls go from being a top team in the Eastern Conference to probably not making the playoffs.

If what we saw in three games is the Wallace we are going to see all year, I suspect he would stop getting 30 minutes per game.  So I doubt the Bulls would be quite this bad.  Still, if these three games are indicative of the future, Chicago’s plan to contend for a title in 2008 has just gone away.

Let me close by noting that we have only seen three games this year. If I were being a good researcher, I would wait a few weeks before commenting on this story.  I mean, this is a really, really small sample. 

But it’s Sunday, I am listening to the Lions on my computer, and I needed something to do.  So I decided to write a story about Big Ben where I make too much of a really small sample.  And ignore the fact that virtually every other Chicago Bull – except Ben Gordon — has also been below average this season.  Tomorrow I hope to comment on Anderson Varejao, where I think I have a bit larger sample to review.

- DJ

Our research on the NBA was summarized HERE.

The Technical Notes at wagesofwins.com provides more information on the published research behind Wins Produced and Win Score

Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:

Simple Models of Player Performance

Wins Produced vs. Win Score

What Wins Produced Says and What It Does Not Say

Introducing PAWSmin — and a Defense of Box Score Statistics