UZR
Description:
Ultimate Zone Rating (UZR) is one of the two best publicly available defensive statistics, if not the best. UZR is tougher to understand intuitively than the Dewan +/- system, but the basic gist is that UZR puts a run value to defense, attempting to quantify how many runs a player saved or gave up through their fielding prowess (or lack thereof). There are a couple different components to UZR, including:
- Outfield Arm Runs (ARM) – the amount of runs above average an outfielder saves with their arm by preventing runners to advance.
- Double-Play Runs (DPR) – the amount of runs above average an infielder is in turning double-plays.
- Range Runs (RngR) – is the player an Ozzie Smith or an Adam Dunn? Do they get to more balls than average or not?
- Error Runs (ErrR) – does the player commit more or fewer errors compared with a league-average player at the position?
These categories are then all compiled into one mega-stat, UZR. Since UZR is measured as runs, it can be compared easily with a player’s offensive contributions (wRAA) tit for tat.
Context:
2010 UZR Values
Things to Remember:
- Since UZR is a counting statistic like RBIs or HRs, the more playing time a player accrues, the higher (or lower) their UZR will be. In order to compare players with different amounts of playing time, UZR can be scaled on a 150 game basis (UZR/150). If you want to compare a player with 90 games played to someone with 140, UZR/150 would be the way to do so.
- Beware of sample sizes! Like with any defensive statistic, you should always use three years of UZR data before trying to draw any conclusions on the true talent level of a fielder.
- UZR is park-adjusted, meaning it adjusts for the fact that some left fielders play primarily in Fenway while some play in PETCO. That sort of thing.
Links for Further Reading:
Intro to UZR – Big League Stew
Another Intro to UZR – River Ave Blues
The Mike Silva Chronicles: UZR – The Book Blog
Background to UZR, Pt. 1 – Baseball Think Factory
1
Wait why would dividing UZR by 150 even things out? shouldn’t you divide it by the number of games they played and then multiply by 150? Or is UZR/150 just the name of the statistic
Good question. Instead of thinking of it as UZR divided by 150 (because it’s not that simple), consider it as UZR per 150 games.
I know this is a year old post, but just in case someone reads this, how come Jose Lopez has a UZR of 8.1 and a UZR/150 of 7.5 at 3B in 2010? He played in 150 games that year, albeit Yahoo says he DH’d in eight games, and played 3B in 142. Still, if this is a counting stat, shouldn’t his UZR/150 be higher…? I have to assume its not as simple as UZR divided by games played at the position, multiplied by 150…?
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Still has a long way to go. For example, anyone who has seen A. Cabrera play knows he is one of the best defensive shortstops in the AL. Yet he is ranked dead last. Suzuki is also very underrated.
I’ve had the same question as CamraMaan; is UZR/150 actually scaled to 150 games played or some amount of innings, like 1350? I’ve tried to figure it out both ways and it never seemed like UZR/150 was based on 150 games or 1350 innings of a player’s production.
I’m assuming Kincaid’s explain is correct here: http://www.fangraphs.com/forums/topic.php?id=3256 ?