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Two Quick UZR Points

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By the way, there's a scheduled network outage around 11pm tonight. Should last ~1hr or so.

I can't tell you how happy I am that this is a community that both uses UZR like it's nothing and understands the significance of playing defense. The conversation around here is miles ahead of what you'll find most anywhere else, and that fills me with no small amount of pride. It's with that in mind that I'd like to issue the following two brief reminders:

(1) Everybody talks about how UZR is unstable and unreliable, but you might want to check out this post over at Fangraphs. Read the comments, too, keeping an eye out for the tangotiger cameo. UZR isn't the most stable stat at our disposal, but in that regard it's not really that much worse than wOBA - a number nobody doubts - and I think that should put many fears to ease. So Raul Ibanez's UZR jumped from -10.4 to +7.3. Adam Lind's wOBA jumped from .325 to .394. Misinterpretation isn't the fault of the statistic.

(2) Never ever ever use one season (or less) of UZR to back up an argument if you can help it. MGL has made a ton of comments about this over at The Book Blog and I'd link to them if I could find them, but right now I'm scrambling to get this out before the scheduled outage for some reason. One season or half a season of UZR can tell you something, but just as is the case with pretty much any other statistic, sample size is king, and you have to look at a broader window of information. You wouldn't just use Adrian Beltre's performance at the plate in 2009 to project him going forward, right? No, you look at his track record and put everything together. It's the same with defense. Raul Ibanez isn't a good defender now. We just have more information that allows us to call him less bad.

If you're dealing with a rookie and you don't have much of a sample size, it's probably best to just ignore UZR altogether, or at the very least to try and combine it with scouting evaluations. If Carlos Triunfel comes up and UZR's -10 at some position through his first three months, he might be bad, but claiming he's a bad defender because he posted a bad figure through his first three months would be like saying Jack Zduriencik's an alcoholic because you saw him in a strip mall with a liquor store. Don't rush to judgment. The payoff of maybe being on to something isn't worth the risk of getting burned.