Nick's defense..UZR

[AgentOrange]

I don't really have much more to add. Thank you for explaining your points 1970 and Mackus. I would like to hear what you have to say to baltfan's post. That makes interesting points as well.

[Mackus]

I suppose I am not comfortable assigning numbers to defense. I feel the margin of error is very high when you do that because in order to assign the number, it takes a huge human element.

And scouting reports are what, mechanical?

There is definitely a human element to all of this. The defensive stats try to eliminate as much as possible by creating standards. Its obviously not completely gone and there is still subjectivity, but much less so than traditional scouting. And stats aren't supposed to replace traditional scouting, they are supposed to augment it. Use both.

[El Gordo]

It is amazing to me that the defenders of UZR get involved in discussions such as this since it it universally said that year to year UZR is basically useless. Of course, the issue that I have is how is it that we know that UZR over three years is accurate but over 1 year tends to not be? And don't just tell me it is because the sample size gets bigger. If there are errors in the method in which UZR is calculated they could very well be getting multiplied as the number of years increase.

It is very hard to take this stat very seriously given the obvious errors that it makes. It would be one thing if the stat sometimes didn't properly credit a player but last year Franklin Guiterrez was supposedly the greatest defensive outfielder by a long shot. His UZR was 31. This year it is 7.5.

This year Carl Crawford is the OF UZR leader at 22.1. Yet in 2007, when I am sure he was faster, his UZR was -2.5.

Marco Scutaro, who the Red Sox signed because they said he is a great defender (Yes those Red Sox that are universally lauded as the franchise that is among the most stat conscious and best evaluators of talent), has a UZR of -2.4. Oh, that is only one year you say. Well the year before it was -.9. the year before that it was 6.6, but that and 2007 (1.1) were the only years the guy was ever positive. Are the Red Sox just stupid when they said he was a great fielder?

For those of you that still defend this stat, please explain to me how you know that it is accurate? When you look at the list of players when ranked by UZR, how do you know that the stat is properly evaluating defense? Are you just depending on someone telling you that it works? If not, are you depending on your own eyes and looking at a list to see if it seems accurate? And if you are doing the latter, how is that any different than using your own eyes in the first place?

I don't know why you are addressing this to me I don't rely on UZR nor do I understand how it is determined. I prefer the Fielding Bible and here is a description of their methodology:

John Dewan

"My book, The Fielding Bible, goes into great length (ad nauseum to some) describing the new fielding system we developed at Baseball Info Solutions, the Plus/Minus System. Video Scouts at BIS review video of every play of every major league game and record detailed information on each play, such as the location of each batted ball, the speed, the type of hit, etc. Using this in-depth data, we’re able to figure out how each player compares to his peers at his position. How often does Derek Jeter field that softly batted ball located 20 feet to the right of the normal shortstop position, for example, compared to all other major league shortstops?

A player gets credit (a "plus" number) if he makes a play that at least one other player at his position missed during the season, and he loses credit (a "minus" number) if he misses a play that at least one player made. The size of the credit is directly related to how often players make the play. Each play is looked at individually, and a score is given for each play. Sum up all the plays for each player at his position and you get his total plus/minus for the season. A total plus/minus score near zero means the player is average. A score above zero is above average and a negative score is below average. Adam Everett turned in the highest score we’ve had in four years of using the system with a +43 at shortstop in 2006. That means he made 43 more plays than the average MLB shortstop would make."

[freethebirds]

It is amazing to me that the defenders of UZR get involved in discussions such as this since it it universally said that year to year UZR is basically useless. Of course, the issue that I have is how is it that we know that UZR over three years is accurate but over 1 year tends to not be? And don't just tell me it is because the sample size gets bigger. If there are errors in the method in which UZR is calculated they could very well be getting multiplied as the number of years increase.

It is very hard to take this stat very seriously given the obvious errors that it makes. It would be one thing if the stat sometimes didn't properly credit a player but last year Franklin Guiterrez was supposedly the greatest defensive outfielder by a long shot. His UZR was 31. This year it is 7.5.

This year Carl Crawford is the OF UZR leader at 22.1. Yet in 2007, when I am sure he was faster, his UZR was -2.5.

Marco Scutaro, who the Red Sox signed because they said he is a great defender (Yes those Red Sox that are universally lauded as the franchise that is among the most stat conscious and best evaluators of talent), has a UZR of -2.4. Oh, that is only one year you say. Well the year before it was -.9. the year before that it was 6.6, but that and 2007 (1.1) were the only years the guy was ever positive. Are the Red Sox just stupid when they said he was a great fielder?

For those of you that still defend this stat, please explain to me how you know that it is accurate? When you look at the list of players when ranked by UZR, how do you know that the stat is properly evaluating defense? Are you just depending on someone telling you that it works? If not, are you depending on your own eyes and looking at a list to see if it seems accurate? And if you are doing the latter, how is that any different than using your own eyes in the first place?

I don't think your understanding a pretty basic idea. Defensive stats are more volatile and therefore require a larger sample size to provide usable data. That doesn't make them useless, it just means you need to take it with a grain of salt when comparing a player against himself season by season

[TGO]

You are completely misusing the stat if you think it says those things. If a LF and a Rf have the same rating that doesn't mean they are equivalent defensively.

You are also completely misusing it if you pay any attention to UZR for first basemen. They may as well not calculate it like they do for catchers. It's pretty useless for that position.

[byrdz]

So what do you do when scout says he's good, another says he's okay and another says he's not good?

Get Old#5fan's and his "own two eyes" opinion for the tie breaker?

[Sports Guy]

Do they do the defensive efficiency stat by player or just by team?

[blid]

I don't think your understanding a pretty basic idea. Defensive stats are more volatile and therefore require a larger sample size to provide usable data. That doesn't make them useless, it just means you need to take it with a grain of salt when comparing a player against himself season by season

Why are defensive stats more volatile? It seems to be a hitter (Brady, Bautista) is more likely to have volatile stats than volatile fielding ability.

(I know why defensive stats are more volatile: because there's not a good, easy way to measure them!)

[MatthewW]

Well how do we know that his highlight plays are on plays that he made a bad read on? How do we know that they aren't on plays that most OFers wouldn't get to anyhow?

I don't have a 'definite' or 'absolute' answer to this. What I do know is that virtually every 'great' catch he makes, I end up thinking... 'he should have been there to make that catch, easily.' There isn't THAT much room in RF at Camden Yards. And I don't need to look at the Fielding Bible to tell me he is below average moving to his left, and back as well.

I am by no means a fielding expert. Maybe I am not accurate in my 'he should have been there, easily' assessment. But way too many times, this is how I end up feeling with Nick.

[Sports Guy]

I don't have a 'definite' or 'absolute' answer to this. What I do know is that virtually every 'great' catch he makes, I end up thinking... 'he should have been there to make that catch, easily.' There isn't THAT much room in RF at Camden Yards. And I don't need to look at the Fielding Bible to tell me he is below average moving to his left, and back as well.

I am by no means a fielding expert. Maybe I am not accurate in my 'he should have been there, easily' assessment. But way too many times, this is how I end up feeling with Nick.

You can say this about many great plays.

[baltfan]

I don't think your understanding a pretty basic idea. Defensive stats are more volatile and therefore require a larger sample size to provide usable data. That doesn't make them useless, it just means you need to take it with a grain of salt when comparing a player against himself season by season

I think you are buying into the excuses. You also are ignoring the example that I gave in Scutaro. I was a Mathematics major in college and did coursework in mathematical modeling. Its not as if I just fell off the turnip truck. I truly grow tired of people assuming one doesn't understand statistics just because one doesn't believe in a particular one. I read Baseball Prospectus and go to Fangraphs on a daily basis.

The issue that I have with UZR is the same that many who buy into other sabermetric means of evaluating a player have with it. There are too many inconsistencies and too many excuses made for it for it to be a reliable way of evaluating defense.

[baltfan]

So am I to mistrust a stat that tells me that for just one season a Brady Anderson or a Jose Bautista is one of the game's best power hitters? If we use supposed "inconsistencies" as a reason to not use particular stats then we're not going to have many to choose from.

Homeruns are a stat that there can be no argument over. One cannot argue that for a given season Brady Anderson wasn't among the top home run hitters. So, this is a bad example.

If you are saying that there is variance in stats, I definitely agree with you. The problem with UZR is that it seems to be at odds with the perceptions of those with great experience at watching the game.

Markakis' UZR ratings over the past 3 years are 12, -6, and -5.5. Do you really believe he is a dead average fielder or has been so over the last three years? Who determined that 3 years was a large enough sample size so that UZR now is reliable?

[baltfan]

Actually there's more volatility because there are more variables.

Yes, more variables so more of a chance for error. More of a chance that there are errors that have not been accounted for.

The poster makes a very good point. You would expect more volatility in a players offense than one's defense. I assume you would agree with this. Given that, there should be less volatility in defensive stats. Instead there is more with UZR which is further evidence it is an unreliable stat.

[baltfan]

No, actually I don't agree with it.

Why would you say this? With hitting there are variations on the pitchers you will face in a given year, luck that is involved in BABIP, and swing mechanics can become an issue. Not to mention hitting a ball is extremely difficult.

Catching a ball it seems shouldn't be that much different year to year.

[Sports Guy]

OMG!!!! Dempsey, Oldfan's hero, just said Nick should win the GG! :clap3: