A Brief History on Sabermetrics Part IV (Fielding)

According to advanced metrics, Carl Crawford is one of the best fielders in the game

By Simon Stracher

Sorry again for the long layoff, just has been a busy week. Enjoy Part IV of A Brief History on Sabermetrics: Fielding Edition.

1. UZR (Ultimate Zone Rating) - UZR is, in my opinion, the best defensive statistic available to the public. UZR is tough to understand, but the basic gist is that UZR puts a run value to defense (like wRAA but for defense), attempting to quantify how many runs a player saved or gave up through their fielding ability (or lack thereof). There are a couple different elements to UZR, including (from www.fangraphs.com):

• 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?

Also, 10 runs saved by UZR's standards equals one win for WAR. Likewise, -10 runs is -1 win for WAR.

Context (from www.fangraphs.com):

2010 UZR Values

2. DRS (Defensive Runs Saved) - John Dewan’s method of evaluating fielding is called the Dewan +/- system (in this case it is called DRS), and like UZR, it uses runs to rate players as above or below average on defense. Joe Posnanski of Sports Illustrated explains it best in this quote:

“…as I understand it, the numbers determines (using film study and computer comparisons) how many more or fewer successful plays a defensive player will make than league average. For instance, if a shortstop makes a play that only 24% of shortstops make, he will get .76 of a point (1 full point minus .24). If a shortstop BLOWS a play that 82% of shortstops make, then you subtract .82 of a point. And at the end, you add it all up and get a plus/minus.”

This is a complicated defensive stat that I personally dislike, and I would recommend using UZR. UZR and DRS will not agree on every single player (because defensive stats are not 100% accurate) but they are comparable and will agree more than they disagree.

Context (from www.fangraphs.com):

2010 Defensive Runs Saved

When looking at these statistics, you have to remember that these are not 100% accurate. While they are much better than fielding percentages or reputation, you should not make any final judgements on a player's fielding ability just by looking at UZR or DRS. Also, there are no viable defensive statistics for catchers, so you just have to take scout's opinions and CS%. My final thought is that when looking at players UZR's or DRS's, you need to look at their average over three seasons. These statistics are like BABIP; they can fluctuate a lot, and you need time to determine what the player's true fielding value is.

I hope you enjoyed this post, and hopefully my next post on miscellaneous Sabermetric stats will be up in 2 days or less.

(Statistics in courtesy of: www.fangraphs.com).