Padres bloggin' since 2007

UZR in the UT

March 31st, 2010 by Melvin

Photo by Dirk Hansen

I didn’t see this one coming.

It’s true, the Padre blogosphere likes to rag on the San Diego Union Tribune’s baseball coverage from time to time. I’ll admit, it can be fun to snicker from the back of the room while the mainstream media, who once derided new technologies like blogs and analytical approaches to evaluating baseball.

That said, critics from traditional news outlets do make some good points. One of them is that sitting in the back of the room shooting spit wads doesn’t contribute much to a conversation.

The Union Tribune appears to be coming around in its coverage using these new tools, though this process took a step backward when the most forward thinking of the bunch, Tom Krasovic, was let go.

This story begins in mid January, after the Padres traded Kevin Kouzmanoff to the A’s for Aaron Cunningham and Scott Hairston. Due to Kouz’s excellent fielding percentage last year, members of the traditional San Diego media (and others) called for him to be awarded a gold glove. The UT’s Tim Sullivan described his defense as “near flawless”. Here was my response, via Twitter (You do follow The Sac Bunt, right?):

@sdutSullivan Thinking Kouzmanoff is a defensive whiz because of fielding percentage suggests range isn’t important.

Fielding percentage by itself is a bad way to measure fielding. It doesn’t consider range, an important aspect of a player’s ability to turn his share of batted balls into outs.

Much to his credit, Mr. Sullivan made a note of this information in a subsequent article:

Though fielding percentage is often a misleading metric, in that it makes no allowances for the relative range of different players, Headley’s .907 rate was the lowest among big league third baseman who started at least 25 games last season. The frequency of Headley’s errors — he made five of them among 54 total chances — occurred at nearly six times Kouzmanoff’s clip.

Although he isn’t completely off the hot seat considering his “results” from Headley’s 54 total chances aren’t worth the pixels they’re read on. But I digress.

Ultimate Zone Rating, or UZR, is the most reliable freely available defensive metric. Unlike fielding percentage, it does consider range. UZR rates Kevin Kouzmanoff average to above average defensively, over the necessary sample size of a multiple seasons.

My attempt to contribute something positive to the discussion, no matter how helpful rolled up pieces of paper shot through a straw may be:

Shout out to @sdutsullivan for reminding readers that fielding % is misleading. Good work. Next up, UZR!

And wouldn’t you know it? Here comes a primer from Bill Center of the Union Tribune on UZR, published at 12am last night by that party animal.

It’s a good article which covers the positives and negatives of UZR, including its inability to measure the context of player positioning at the start of a play, and that catcher defense is still a challenge.

There is this note from 3rd base and infield coach Glenn Hoffman that gives me a giggle:

“So much of defense is based on what you see and what you feel over pure statistics.”

Well, ok. Statistics are an attempt to quantify what we see. They allow us to compare players using the same criteria over tens of thousands of performances. I don’t want to discount the important of scouting, especially if information is only available in small samples or unique immeasurable circumstances. But lets just say if they were my millions of dollars at stake, I’d have a second thought about basing decisions on things people “feel”.

But I don’t want to distract from Bill Center’s effort with this article. I’m glad for the opportunity to hear from players, coaches, and front office personnel about UZR. Cheers to Bill Center and the Union Tribune. This is a strong step in the right direction.

Also, someone at the UT owes me a beer. Or a job. I’m good for either.

Posted in media, statistics | 9 Comments »

9 Responses to “UZR in the UT”

  1. I found it interesting that a stats guys like Josh Stein also said they didn’t use UZR because it couldn’t measure range effectively.

    • Ray says:

      Stein said “UZR is probably a better measure over a long period of time rather than a month or even a season,” which is the same conclusion you’ll get from any sabermetrician worth his weight.

  2. Melvin says:

    Where does Stein say UZR doesn’t measure range effectively?

    Nobody ever said UZR is perfect. It has faults, which is why a few seasons of data are needed to get an accurate reading. But it’s still the best free tool we have. I’d rather use a good but not great measurement than a poor but not great measurement.

    If I developed my own defensive system, I would use that too.

    • I disagree that its a good tool.

      When you grade range based on a zone and not positioning it cannot be accurate. You are not actually measuring how far a player goes to get a ball and THAT is what range IS.

      And its speed of batted ball rating is laughable. Talk about subjective.

      During the 2010 season we will start to see the first of a true measure of range from Field FX. Until there is not an effective defensive metric.

    • Melvin says:

      How often does positioning change? Are there any fielders who are routinely in better positions than others? If so, then it sounds like it would need to be a consideration.

  3. Larry Faria says:

    Bad news, Melvin: no beer – the UT reporters are not allowed to pay for information. No job, either, if they let Krasovic go. Why go to work in a dying industry anyway?

    I think you’re misreading arguments against UZR. You’re saying it’s good but not great. They’re not saying it’s not great, they’re saying it’s not even good.

    I’m not going to rehash all the arguments, but the one anti-UZR argument I find most interesting is that, unlike the hitting and pitching sabermetrics, fielding involves too many factors that are outside the fielder’s control.

    One argument I’d heard involved Luis Aparicio, who had great range to his right in deep short with the White Sox, then had lesser range when traded to Baltimore, then got that range to his right back when he went back to the White Sox in his mid-30’s. The reason cited is that with Brooks Robinson to his right, his chances disappeared. The range factor per 9 innings data bear that out.

    I’m not ready to say defensive stats are useless, but UZR aggregates several defensive measures, while the batting and pitching stats don’t. There’s room to consider different types of hitters and pitchers, but the aggregate UZR seems to assume one ideal fielder. It can’t tell a player with slightly below average range and a strong arm from a player with above average range and a slightly below average arm. Both players have their uses on a ballclub.

    I’d like to see the individual defensive stats further refined and the aggregate UZR de-emphasized.

    • Melvin says:

      Interesting. I haven’t read too deep into the the nuances of UZR, but I know Websoulsurfer has mentioned the complications the number of chances can have on UZR’s calculation. I thought I remembered someone digging up info that explains why chances aren’t an issue with the stat, but I’m not finding it. It does seem like a somewhat obvious question that a smart guy like MGL could figure out, but you never know.

      About differentiating defenders range from their arms, I don’t see it as that big of a deal. If a player gets the put out because of his range or because of his arm, does that change anything? The ultimate measure of a defender is his ability to make outs, right? I can see a need for some to separate the two, but I don’t see that as a reason to throw the baby out with the bathwater.

      No question that defensive stats need further refinement, this will be an entertaining season as we break new ground with field fx.

      And yeah, newspapers are dying, but if they react quick enough at least part of them will survive. I think it would be a fun challenge.

      Cheers Larry, thanks for the thoughtful comments.

    • Ray says:

      Which sabermetric offensive stats don’t aggregate several measures?

  4. […] into his article, complete with a rough explanation of how it is derived. Truly amazing. Melvin at Sacrifice Bunt is also impressed. [h/t Gaslamp […]

Search Posts

The Sacrifice Bunt on Facebook The Sacrifice Bunt on Twitter


Sacrifice Bunt Shop

Sacrifice Bunt Shop