As far as I can tell Vernon has been himself in centerfield making all the routine plays and making his share of exciting and difficult plays. I wouldn't say he's suddenly turned into superman or anything but I haven't been to as many live games this year so I'm not sure if his jumps and routes when tracking flies has gotten any better. There was some room for improvement and he did drop some weight in the off-season but I'd be surprised if he improved that much.

If stats like zone rating are subject to a human scorer's decision on what balls are and aren't in a fielder's zone then that's all the more reason to take them with a grain of salt. Plus it's less than half a season so the stat is still quite prone to sample size I think. Wells is very good in center, one of the best in the league. But I'm not sure that he's better than guys like Hunter or Cameron.

http://www.tangotiger.net
The stringer will record where on the field the ball is hit. They have grid locations, and they select the appropriate grid he hit the ball it.

For example, this is Retrosheet's grids:
http://www.retrosheet.org/location.htm

Not that much place to make a mistake, but also, not enough grids for. STATS has much smaller grids (can't seem to find it right now), and I prefer those.

The decision for "zone of responsibility" is made independent on the scorer. The scorer simply marks the grid location of where the ball landed or was caught. Someone else will say "mark zones X, Y, Z as zone of responsibility for the CF". So, any ball hit to those locations will count as an opportunity.

There are of course plenty of things wrong with ZR. But, those problems are handled by UZR. For one, if you have a lefty or right batter, the zone of responsiblity would shift. ZR doesn't do that, but UZR does. ZR doesn't distinguish between a high flyball or a screaming liner, but UZR does. Park is another.

In any case, I don't meant to debate the merits of ZR or UZR.

The one thing that any opponent to ZR/UZR would have is the quality of scorekeeping. We do have high correlation year-to-year in UZR (an r of .50). 1000 fielding plays has as much significance as 500 hitting plays, if your metrics are UZR and Linear Weights, respectively.

So, we still have some ways to go. Scorer bias is either something random and a slight bother, or it could be something rather real.

Grid location should be the easiest thing to mark. Whether a ball is hit hard/medium/soft, or is a liner instead of a fly or pop, those things are a little harder. But, if we can't get the grids right, that certainly doesn't help those championing ZR and UZR.

So, I want to get to the bottom of this.

***

As for sample size: it's certainly possible. That's why I'm asking for visual confirmation. Can we reasonably say that, up to now, Wells has not caught 14 balls in his zone of responsibility, while getting to 8 others that were outside his zone (or some combination like that, say 20 balls in his zone, and 14 outside his zone)?

Like I said, it's something hard to believe could have happened.

***

Someone just emailed me that they will be in the pressbox today, so maybe we'll get somewhere here.

I really have no business talking about this at all, but could Wells covering for Rios on one side and then sometimes Berg on the other side account for this?

What I mean is with Rios' inexperience and Berg's, uh, skill level, Vernon seems to have had to cover more territory. It seems to me that I can recall him making a number of catches near foul ground in right field this year.

Good question Hank, it makes some sense IMHO, although I also probably have no business talking about this stuff. Suppose Dave Berg is in LF with Vernon in CF, both know that Berg is not a good fielder. Would it stand to reason then that they both realize that Berg's effective "zone" is going to be smaller for that day? And that Vernon would be responsible for some balls that normally would fall into the zone of an average LF? Or in other words as Hank says, wouldn't playing beside sub-par outfielders increase the ZR of a fielder who is actually pretty good?

NFH and Tango,

Actually the comparison between ZR last year and this year is odd. Both Wells and Reed Johnson's ZR are much higher. Cat's was very low last year.

There are some reasons why Vernon would in fact have a better ZR this year than last:

1. he lost a significant amount of weight over the winter; I do think he's covering more ground,
2. I believe that the team line drive percentage is down (mostly due to the departure of Hendrickson).

But, as Craig said, I seriously doubt that he's getting to 96% of balls in the zone, i.e. that he's that much better than Damon, Beltran, Kotsay and Cameron this year.

One other thing about Vernon. His RFs have consistently been in the 2.4-2.6 range. This year is no different, despite the addition of Lilly to the staff. Usually, top centerfielders are in the 2.8-3.2 range.

FWIW, the ZR for Hinske are the same this year as they always have been. I doubt that this is accurate as well. His range does appear to me to have improved. I guess we'll have to wait for UZR and Pinto at the end of the year.

NFH and Tango,

Actually the comparison between ZR last year and this year is odd. Both Wells and Reed Johnson's ZR are much higher. Cat's was very low last year.

There are some reasons why Vernon would in fact have a better ZR this year than last:

1. he lost a significant amount of weight over the winter; I do think he's covering more ground,
2. I believe that the team line drive percentage is down (mostly due to the departure of Hendrickson).

But, as Craig said, I seriously doubt that he's getting to 96% of balls in the zone, i.e. that he's that much better than Damon, Beltran, Kotsay and Cameron this year.

One other thing about Vernon. His RFs have consistently been in the 2.4-2.6 range. This year is no different, despite the addition of Lilly to the staff. Usually, top centerfielders are in the 2.8-3.2 range.

FWIW, the ZR for Hinske are the same this year as they always have been. I doubt that this is accurate as well. His range does appear to me to have improved. I guess we'll have to wait for UZR and Pinto at the end of the year.

You guys bring up great points. Like I said, ZR has a static area that counts as the "zone of responsibility". If Wells is playing a big shift to the left or right to cover for his poor fielders, and if hitters are still hitting the balls there, then this might very well answer the question. That is, his putouts count towards his numerator, but since they were caught outside his zone, they do not count towards his denominator.

What I mean is with Rios' inexperience and Berg's, uh, skill level, Vernon seems to have had to cover more territory. It seems to me that I can recall him making a number of catches near foul ground in right field this year.

To extend this logic a little futher, is ZR like slugging percentage?

If a centrefielder makes enough "out of zone" plays, can they have a ZR or greater than 1.000?

This is all pretty interesting stuff. A few questions though. Wouldn't the skill of the LF/RF's not count in this? As Hank says, poor corner guys could help Vernon's numbers, and this does seem to make sense-BUT...
1. Vernon's still gotta get to the ball. If he were the ONLY outfielder, he can't be expected to make plays down each line, just cause he's the only guy there. So he's gotta have terrific range to make up-probably even slightly make up-some of this gap.
2. What's the exact significance of the "bonus balls" as Tangotiger suggests? It seems that if he catches a ball outside his ZR, then it simply doesn't count, so that seems to make this argument of poor corner guys moot. Perhaps I'm reading into it wrong.

Vernon certainly does look a little swifter out there. But as Mike points out, Hinske looks a whole lot swifter too and his ZR is unaffected, so who knows.

FWIW, the ZR for Hinske are the same this year as they always have been. I doubt that this is accurate as well. His range does appear to me to have improved. I guess we'll have to wait for UZR and Pinto at the end of the year.

IIRC, ZR tells you how many outs he's making.

Hinske is fielding the ball cleanly more frequently, but because of his weak/inaccurate arm some of those balls are not being turned into outs. It looks like his arm is much improved from previous years (and his low error total backs this up). But (IMO) he's still below average at flinging the ball across the diamond to 1B.

This is all pretty interesting stuff. A few questions though. Wouldn't the skill of the LF/RF's not count in this? As Hank says, poor corner guys could help Vernon's numbers, and this does seem to make sense-BUT...
1. Vernon's still gotta get to the ball. If he were the ONLY outfielder, he can't be expected to make plays down each line, just cause he's the only guy there. So he's gotta have terrific range to make up-probably even slightly make up-some of this gap.
2. What's the exact significance of the "bonus balls" as Tangotiger suggests? It seems that if he catches a ball outside his ZR, then it simply doesn't count, so that seems to make this argument of poor corner guys moot. Perhaps I'm reading into it wrong.

Vernon certainly does look a little swifter out there. But as Mike points out, Hinske looks a whole lot swifter too and his ZR is unaffected, so who knows.

Darn double post. Further about Hinske-Jacko, if ZR is how many outs one's making, shouldn't his ZR still be increased. Agreed he doesn't have the best arm-especially on balls down the line, he's seemingly gotten to more balls. So even if he only actually makes an out on a very few of those extra balls he's getting to, his ZR should still be higher. And I think his arm is improved-I would say mainly in getting rid of some pump fakes/stutters/getting the ball out of his glove. He started a pretty slick 5-4-3 the other day.

What's the exact significance of the "bonus balls" as Tangotiger suggests? It seems that if he catches a ball outside his ZR, then it simply doesn't count, so that seems to make this argument of poor corner guys moot. Perhaps I'm reading into it wrong.


Yes, you are reading this wrong. ZR = "total plays made" divided by "total plays in zone of responsibility"

So, if you make a play outside your zone, it counts in the numerator, but not denominator. If Wells is playing half the PAs like it's a Bonds shift, you'll certainly start getting weird numbers. You can have a game where he makes 4 plays as outs, but only 3 of them were in his zone, so his ZR, for that game, would be over 1. Yes, stupid (unless the ZR definition has changed; they do change it every other year).

Ah, thanks Tango, that does make a whole lot more sense. And in the school/grading sense, it truly is a "bonus" ball.

Looking at the ESPN link of the other CF's, a few things stood out to me.
1. How in the world does Alex Sanchez have 8 errors? He's not played any position but CF-that's a good 3 or 4 years worth of errors for many outfielders and it's only June.
2. Poor Corey Patterson. The Cubs RF's are the only ones below 2. Not surprising as it's widely known Sosa's fairly worthless in the field, but him being out so long I would have thought Hollandsworth would have brought that higher.
3. Vernon's only got 1 assist-tied for last. Hmmm.

Question from a ZR neophyte: how does ZR account for balls that should be turned into DPs but result only in a FC? Is it like an error, in that as long as you get a single out the player isn't penalized?

So even if he only actually makes an out on a very few of those extra balls he's getting to, his ZR should still be higher. And I think his arm is improved-I would say mainly in getting rid of some pump fakes/stutters/getting the ball out of his glove. He started a pretty slick 5-4-3 the other day.

Is it possible that Hinske cheats towards SS more when Gomez is playing? This could explain his ZR being the same when your eyes are telling you he's improved...

I'm almost positive that the denominator counts "1" for any play hit to a fielder's zone, regardless of the potential for the number of outs (0,1,2,3).

The numerator counts the number of outs made. Now that I think about it, I'm pretty sure that infielders would get 2 in the numerator if they started a DP. Maybe OF also get a 2 if they throw a runner out after a putout. Of course, Wells only has 1 assist, so that doesn't explain it.

Questions about the Ball Location Codes:

1) Does any zone with only one number (8, 4M) automatically count as a zone of opportunity? Does a zone with two numbers (78, 34S) count as a full zone for both, or a half zone for both?

2) If Wells catches a fly ball in "78D", with Berg playing LF, Wells gets 1/1 and Berg gets 0/0, right?

3) If Wells catches a fly ball in "7D", is Berg penalized for not making the play? In other words, is it Wells 1/0, Berg 0/1?

(Note: "X/Y" means "X plays made divided by Y plays in zone of responsibility")

First off, note that those zones are Retrosheet, and not STATS. ZR is a STATS thing, and so, they would use the STATS grids. Anyway...

Not all grids are given to a player. Some grids are considered "no-mans-land". That's why the average ZR of each fielder is in the .8x level, while overall, the MLB average outs per BIP is .70. That is, there are some BIP where it doesn't count against anybody.

Also, I don't think liners or infield pops are counted. Again, not really sure, as the ZR definition changed all the time.

So:
1) You'd have to use the STATS zones.
2) Right, if 78D belongs to the CF. There's no zone sharing of responsibility.
3) I think it's 1/0, 0/0. Again, depends on the definition of the day.

***

(All numbers for illustration.) This is why UZR is so wonderful. Take the case of the ball hit to 78D. Say that when a LH comes to bat at the Skydome against a flyball pitcher, and he hits a hard flyball, a ball hit to that zone with those conditions is converted into an out 68% of the time. If you have 78% of those plays converted into an out with Wells and Berg there, then you've got +.10 outs per play.

How you split that up is a source of debate. Maybe Wells gets +.12 and Berg gets -.02, etc. There's a long debate over this, and you can read MGL's UZR articles about that.

The important thing is that UZR quantifies all those ones and zeroes that zones of responsibility forces you to make. It's obvious that there is a distribution of responsibility, and that's what UZR tries to do. And not in the 2-dimensional space of grids, but in n-dimensions that includes the batter, pitcher, park, turf, runners, out.

All the more reason we need the FoxPuck to come back as the FoxBall, so that we can pinpoint where that damn ball is at all times. And, GPS on players would be cool too. Kill 2 birds with one stone, and put it in their wedding band.

And, GPS on players would be cool too. Kill 2 birds with one stone, and put it in their wedding band.

The Wade Boggs rule?

http://me.woot.net
My visual, i.e., not statistically valid, impression of Vernon is that he makes difficult outs into very easy outs.

I have seen several times this year a fly ball hit in the gap to which my natural reaction is "It's going to drop in." Vernon isn't running very hard, he doesn't put his glove up to catch it, just holds it at his shoulder level -- and yet the ball appears in his glove, like magic. I haven't been observing closely enough to tell you just where these balls are being caught, though.

Thanks for the info, tangotiger. I just wanted to have an idea of how the zones work -- I'm going to score tonight's Jays-Expos game for fun and I've never appended location codes onto the end of my scoring (I score it "S8" instead of "S8/F8S").

Another question: One of the Jays' radio guys, Mike Wilner had a lively debate a few days ago with a post-game caller who argued Wilner's statement that "Hinske is the best defensive 3B in the AL." Caller said Hinske was the second worst because, at the time, he was second-worst in the AL in ZR. Is ZR anything more than an interesting seconday statistic, or does it actually reflect a player's true defensive abilities?

Seconday = secondary. Darn those tpyos.

http://www.battersbox.ca/archives/00001454.shtml
Rob, I don't know if Tango agrees, but here's my opinion. ZR attempts to measure something much more important (range) that fielding percentage, but there are deficiencies in the statistic (see above) which are more significant than the deficiencies in other measures of range. COMN for the link to the "Consensus is King" thread, in which various defensive measures are discussed extensively.

Thanks for trying to enlighten someone who knows nothing about advanced statistics. Hell, I thought Raul Mondesi was an excellent defensive outfielder the entire time he was a Blue Jay (don't yell, I was 15 then and have learned a lot in two years) and didn't even know what OBP was until I read Moneyball last August.

Needless to say, now I laugh at my friend who ranks baseball players by RBI.

My visual, i.e., not statistically valid, impression of Vernon is that he makes difficult outs into very easy outs.

On balls hit behind him, yeah. Best in baseball. Better than Beltran, better than Hunter, better than anyone. He's all-world going back to the track... I really believe this.

On balls hit in front of him? I don't even think he's average. He gets bad (slow) jumps and plays balls on a hop that better centerfielders turn into outs. Put Lofton (say) and Wells in the same outfield over a year and Wells will save 15 doubles but give up 20 extra singles.

I speculated to Tangotiger in our discussion about this that the ZR thing may be related to that... that the balls in front of Wells are getting mislabelled.

In order of significance:

UZR, ZR, Range Factor.

RF is like times on base per game. It's easier for the leadoff hitter to lead here. But, without chances or PAs, it makes it tough for it to be real valuable.

ZR is like OBA. OBA doesn't distinguish between a HR or a walk. ZR treats all balls in zone to be the same quality.

UZR is like OPS. OPS tries to properly weight the HR and walk. UZR tries to properly weight the types of plays a fielder has to make.

Things like what Saeger, Davenport, Bill James, and Michael Humphries do: it would be somwhere between a shade worse than ZR to a shade better than ZR. Why is that?

They all start off with the same thing: known plays made (akin to Range Factor). Then, they try to estimate the plays not made (to try to get the opps, akin to getting ZR). In addition, they try to take into account the GB/FB tendency of the pitcher, LH/RH batter breakdowns, and park. These are the things that UZR already knows for sure, but what these 4 guys try to estimate. UZR also has the all-important grids, which makes it leaps and bounds above these 4 (if the grids can be trusted.... and, except for Wells, the grids seem fine).

So, that's why what these 4 guys do is somewhere on par with ZR. If you want to argue it's a bit better or a bit worse, I won't disagree.

My wife is putting my kid to bed, so I might as well continue. I'll refer to the system by the 4 guys as... hmmmmm... what would be four... suits in a deck?.... how about the 4Kings?

The 4Kings will start off with Wells and say that he makes 2.6 plays per game. It sounds low, but then they'll try to come up with what an average player would have done. They'll figure that Tor doesn't give up lots of FB, maybe the park depresses flyballs, etc, and work that to 2.4 plays per game. So, Wells would be +.2 plays per game above average, or +32 plays per 162 games.

Now, if the league avg CF has a ZR of .87, and if the league avg CF playing in the same conditions that Wells plays would make 2.4 plays per game, then 2.4/.87 = 2.76 plays in zone.

So, since we know that Wells made 2.6 plays per game, and since the 4Kings estimate 2.76 plays in zone, then they figure his ZR would be 2.6/2.76=.942.

See? Whether they try to figure out how many plays an avg CF would make (2.4) or whether they try to figure out how many hits landed around Wells (2.76-2.6=.16), it doesn't matter. The 4Kings are trying to get to the same thing.

To be sure, they do a darn good job at it. But, my issue with them is that as of 1972, they shouldn't be trying to estimate these things. They are known. Pre 1972, they can do it their way. But, it's just wrong to use an inferior system (trying to estimate known things like GB/FB tendencies, and LH/RH splits), when you have the data. And, it also doesn't fly that you want to be consistent and use only one system historically. It doesn't make it any better. You may think you are comparing apples to apples, but you are not. Not unless you think the errors are systematic enough year-to-year. And, if the errors *are* systematic, then you definitely don't want to use such a system.

I'm generally with Tango on the conceptual merits of both the direct zone rating and the indirect estimation methods. There is one defect in most (all?) zone rating systems, particularly with respect to outfielders. There are great differences between different balls hit into a zone depending on whether they are fly balls or line drives, and no one, as far as I know, measures the important objective difference between the two (time between contact and ball hitting glove or turf). Some measure it subjectively depending on arc of the batted ball, but much is lost in this subjectivity.

The fly ball into right center which hangs for such time that both the right fielder and the center fielder camp underneath tells us next to nothing about the defensive contributions of either, regardless who catches it. The line drive (or the blooper) into right center tells us much.

Mike, I agree. I have long suggested that the scorers keep the most basic and easiest thing to measure: hang time. Sometimes we try to make things so darn complicated. Hang time would be a snap to do, especially with replays.

Interesting discussion. Re: hang time, I think measuring this would be a great idea, and could also be useful for evaluating hitters. For example a batter who happens to have hit a higher than average number of line drives straight at outfielders for outs can have his hitting ability properly recognized. In cases like this I suppose things will eventually average out (the line drives will start to find gaps) but it's not clear (to me, anyway) how many at-bats that would take, and in the mean time, there will be a discrepancy between perceived performance (measured in all the usual stats) and actual performance (i.e. what the batter did to the ball).

Someone from Batter's Box gave me a contact name. I contacted him twice. On the second contact, he said he changed his mind about discussing this with me. It was rather strange, since my question was one of procedure and not opinion. It sure sounds like something strange is going on with the scoring.

Since I published the above link, Wells's ZR is now down to .931 overall. In that time period, he made 59 plays on 69 balls in zone, for a ZR of .854. He was 161 for 167 before that (.964).

If he's a true .920 player, that means his performance when I first made the note went from 2 SD from the mean one way to 2 SD away from the mean the other way.

I sure wish I had the data.

Thanks very much, Tango, for sharing this. I am definitely withholding all judgments on changes in defensive ability until the end-of-season data (UZR, Pinto and others) is in. Here in Toronto, there is a consensus that Eric Hinske's defensive ability has improved this year, but it is not clear how much. The ZR shows no improvement, but in light of your experience and the Wells' data, I am taking that with a grain of salt.

I don't think there's a bigger fan of UZR than me. First time I saw ZR in the STATS Scoreboard, my first thought was: "How did Alomar and Griffey do on balls at the edge of the zone?" I was not alone in that thought, as the next year, STATS answered that very question. And hence, the start of UZR. MGL's taken it to the next level, since there are many variables at play here, though the zone information is the most important.

The problem is with the definition of what constitutes a zone in ZR. Jeter's numbers are also very good in ZR, but MGL's published his mid-year UZR, and they are still below average (though not as bad as usual). I almost get the feeling that:
1 - The scorers are doing their job
2 - The guys who are putting out the ZR are not selecting the zones properly. That is, they are not using the data properly. It's not the data, but the guys using the data.

It's of course unfair for me to try to criticize some unnamed person like that. But no one is talking. To the extent that I can have an opinion based on the best available evidence, it's the one that makes the most sense.

My current position is to trust the quality of the scorers more than to trust the efforts of the stat producers.

Tango, can you point me to MGL's mid-season UZR? I was not aware that he had published it. Thanks.

He's only published bits and pieces, at Fanhome and Primer.

Here's one link I've found through google:
http://www.baseballthinkfactory.org/files/newsstand/newsblog_discussion/21064/