Let me tell you something: I'm a fan of UZR. I love it, I love it, I love it. So when Mitchel Lichtman (also known as MGL—he's the man who publishes UZR) decided to stop making it public last season, I was crushed. UZR was really by far the least flawed, best thought-out fielding system out there. It was better than Zone Rating because it incorporated all balls in play. It was better than David Pinto's PMR because it had better park factor applications and did not include putouts for infielders. It was better than Clay Davenport's DFTs because it used much more detailed data.
Anyways, let me try to explain this system in as few paragraphs as possible. First, I split up a team's Balls In Play (BIP) based on the number of ground balls, fly balls and line drives they allowed. This allows me to estimate how many outs should have been made by infielders and how many outs should have been made by outfielders. For infielders, only grounders count, while for outfielders, I use outfield line drives and fly balls less home runs.
Next, I find a team's BIP against left-handed batters and right-handed batters. Using "Position Rates" published by Charlie Saeger, I estimate how many balls in play were hit to each fielder.
These are the two biggest advantages of my system over any other non-PBP system. Because I use batted ball data and because I know how balls were put into play by left-handed batters and how many were put into play by right-handed batters, I can come up with a razor sharp estimate of each fielder's "chances." Therefore, the greatest disadvantage a non-PBP system has in comparison to a PBP system is minimized.
He uses it to rate all players except for 1B, pitchers and catchers. The ratings are for 2004. He'll publish 2005 after the season.
He uses RAA as a measuring tool. The Sox rated by position are, minimum 450 ABs in 2004:
Edited by absintheofmalaise, 29 September 2005 - 12:25 PM.