Context

Amongst all the complaints levied against the 2005 Dodgers, one that stood was that Paul DePodesta didn't value defense. After all, he broke up the "best double play combination in baseball" to sign Jeff Kent. He then followed this up by putting Jose Valentin at third and using the non baseball savvy Hee Seop Choi at first.

Meanwhile, Ned Colletti supposedly understood the value of defense and put his players into place. Admittedly, I felt that while the 2006 Dodgers weren't that much better than the non-injured 2005 team, the Dodgers defense was greatly improved.

I was looking up some defensive numbers for other purposes, and this caught my eye:

2006 Dodgers defensive efficency: .691
2005 Dodgers defensive effiency: .706

While individual defensive stats aren't perfect, defensive efficiency is simply the percentage of balls in play turned into outs. This is the definition of what a defense is supposed to do, so the logical conclusion is that that the 2005 Dodgers, who were so maligned for their defense, were a better fielding team than the 2006 Dodgers.

Looking at the numbers, you might make the argument that there's not much gained by converting balls into outs an extra 1.5 percent of the time, but if the 2006 Dodgers had a .706 defensive efficency, they would have finished third in the league in that stat, rather than 20th, so one and a half percent is a big difference.

What caused this sudden downturn in the defense? A couple things come to mind.

The first is outfield defense. The 2005 Dodgers had, at least theoretically, and outfield of Jayson Werth, Milton Bradley, and J.D. Drew, three guys who can play an above average centerfield. In 2006, it was Ethier, Lofton, and Drew. I think I've covered Lofton's defensive deficiencies enough, but Ethier was pretty bad this year as well (95 rate2), leaving Drew as the sole defensive contributor in the outfield (110 rate2).

The second, larger factor is Dodger Stadium's severe shift in Park Factor from 95 to 102. Why this happened, I can't say. The most obvious change is the decrease in foul territory, but I don't see how that would result in an increase in doubles (if ESPN's park factors are to be trusted.) All I can say is that for some reason, runs were much easier to come by at Dodger Stadium this year. I'm not sure how much this would sway defensive efficiency, but it is a factor.

The moral of this story is a couple of things. The first is that we tend to focus on what we have gained rather than what we lost. Sure, Furcal, Garciaparra and Mueller were all nice defensive upgrades, but we probably gave those advances back by losing Bradley and Werth. The second is how hard it is to put a full seasons worth of data into context. We remember the acrobatic catches and judge a player?s defensive worth based on the relatively few highlight reel catches they will make over a given year. However, the mundane plays that are made time and time again are far more important in the long run, and they form basis of a player's defensive value. This is why, even with the flaws inherent in defensive metrics, I trust them more than what people who "watch a lot of baseball" have to say about defense. It's just too hard to absorb a season's worth of plays, but it?s a job that the dreaded computer is perfect at.