The full title of this exercise is New Year's Resolution: Learn More About UZR, My Definition of a Boombastic Fielding Statistic.-Compact disc to the prime is optimist, fans and friends I'm universally cosmicThe lead up to and the actual acquisition of LF Jason Bay by the Mets involved a lot of discussion about UZR and it's merits or lack thereof. My goal in writing this post is to learn more about defensive metrics in general and UZR specifically. I claim no expertise of the subject. This post (and hopefully resulting comments) could be considered both an educational tool for myself and anyone reading it, and also a cry for help.In order to better understand where I'm coming from I think I must reveal a few things about myself. That's convenient because another one of my New Year's Resolutions is be more open and honest about myself with others. So here goes.I am not a math expert. In fact, math was one of my worst subjects in school after roughly 6th grade. Once math class began to concentrate on Algebra, Geometry or Trigonometry, I was hopelessly lost at sea. Unfortunately the Math Patrol Boat never came along and plucked me from the cold math water, wrapped me in a warm math blanket and fed me some warm math soup. Worse still, the Lets Go Smoke A Joint In The Woods Behind The Maintenance Building Patrol Boat came by more than a few times. So any brain cells that may have absorbed some of the tenets of these subjects were probably lost somewhere in the woods behind the maintenance building. Worst of all, Danica McKellar's books were written too late to save me.So I don't come at this subject from any particularly geeky or nerdy perspective. I have noticed that some people who don't embrace UZR react to it by saying anyone who espouses it "has never played the game" and "needs to get out of the lab." That's just ignorant and avoids dealing with the existence of 21st century statistics.-When I kick rhymes there's something said to do damage, hits so strong even superman needs a handIn my attempts to learn more about it the one thing I've learned for sure is that it's not simple or easy, at least not for me. The fine folks at Baseball Think Factory couldn't even explain it in one part. For those of you interested enough to read the explanation for yourselves, be sure you're in a comfortable chair and have plenty of free time before clicking through to read Part 1 and Part 2. I have read both parts twice and the only thing I'm confident I got out of it was a headache. But there are a few important points that I believe I got from it and it is these points that I wish to share, and it is these points with which I need your help to make sure I haven't taken them incorrectly.I don't want to discuss Jason Bay specifically because I fear any discussion will get bogged down either because of some emotional involvement in Bay as a player, or because I simply make a mistake in trying to convey something I believe I have learned about his defense. UZR statistics first came into play in 2002. So in order to discuss them without getting bogged down I am going to discuss them in a more general way.To begin my explanation of what I believe I know about defensive metrics I am going to start by talking about Lee Mazzilli and home runs. Strange, yes, but bear with me. If you've come this far Mazzilli and his home runs will make sense later.During Mazzilli's first go-round with the Mets from 1976-1981, I grew from an 11 year old boy to a 16 year old young man with a driver's license. They were years of tremendous growth (and some fun trips to the woods behind the maintenance building) and Mazzilli was an important part of them. One of the most interesting, odd things I noticed about Mazzilli was that he hit exactly 16 home runs in 3 consecutive years. I haven't studied how often major leaguers hit exactly the same number of home runs in 3 consecutive years so maybe it's not so odd but to me at the time it was.Now the astute among you have already searched your memory banks or favorite website and are thinking "Grave, Mazzilli never hit 16 home runs in 3 consecutive years, what are you smoking?" For those of you who don't already know, Mazzilli hit 16 home runs in 1978 and 1980, and 15 home runs in 1979. But in 1979 Mazzilli hit a home run (which tied the game) in the All-Star game, thus 16 home runs in 3 consecutive years.The number of home runs Mazzilli hit isn't so much the point, he's just a familiar figure I'm using in an attempt to draw you in. Hopefully it worked. Because you see my point about Mazzilli's home runs is not how many he hit, but how does the number of home runs he hit compare to his fellow players. I know Mazzilli was primarily a center fielder then with the Mets and I know that he hit 16 home runs, but how do I know how that compares with other center fielders of his era? Well, I don't know. I do know I'd have to do a lot of research to find out the answer.-Why must I try to lie and build an alibi, when all you ask is just for me to be meWhat I believe UZR does is compare any fielder at his specific position to every other fielder at his specific position in any given year. Lets pretend that for 3 consecutive years Mazzilli had an UZR of 3.7 as a center fielder. I believe this does not mean his performance was exactly the same in center field each of those 3 years. I believe this does mean that compared to the average performance (actually the mean performance) of all center fielders in each of those 3 years, Mazzilli saved 3.7 UZR runs more than the average.I believe this average or mean performance fluctuates annually depending upon the performance of all center fielders. So any one of Mazzilli's hypothetical 3.7 UZR years may have been more or less impressive than another, depending on the performance of all other center fielders playing that year.Unlike 16 home runs, which tells us very little about the player's power in comparison to any other player by virtue of the number 16 alone, a 3.7 UZR tells us almost everything about a player's defense compared to his peers. I believe it is formulated specifically so that in looking at any player's UZR for any one position in any one year we can tell precisely how that player compares to his peers at his position.So back to Jason Bay if I dare. For left field in 2009 Jason Bay had an UZR of -13.0, which I believe tells me that compared to all other left fielders for the 2009 season, Bay allowed 13 more UZR runs than the mean performance of all left fielders. What I believe this does not mean is that Jason Bay sucks as an outfielder. It does not mean that we should turn away whenever he is in pursuit of a fly ball, nor does it mean that we should cry ourselves to sleep about the possibility of him playing the outfield regularly at Citi Field.What I believe it does mean is that in 2009 Jason Bay was 13 UZR runs worse than the average left fielder was in 2009. What I believe it does mean is that, compared to his peers, he can more appropriately be described as among the worst as opposed to among the best. But we all need to bear in mind, he is still a competent major league outfielder deemed by multiple managers of multiple franchises to field his position adequately enough to be put out there day after day, especially when balanced with his offensive production.-I sought beauty through the dust of strife, I sought meaning to my music addictionIf you've actually read this far, first of all kudos and thank you. Secondly you may have noticed that I used the italicized phrase I believe a number of times. This is where my learning process comes in. I used that phrase because in being honest with you I had to convey that I don't know what I expressed to be true, I merely believe that I understood enough about the metrics involved to make these statements. If I'm wrong that's fine, now is the time for you to jump in and comment to tell me where I'm wrong so I and anyone reading this can be less wrong in the future.Also, I have referred a few times to UZR runs above. To continue all this soul baring honesty, I must admit I don't quite know the definition of UZR runs or how they compare to literal runs scored by any team during any baseball game, so some help with that would be greatly appreciated.Thank you all and I raise a glass of champagne to anyone who has made any New Year's Resolution. Good luck to us all in keeping them.-Yo, where'd everybody go?