Fielding statistics and defense
I’ve been thinking about defense with the team’s recent woes. Dave wrote a large article on evaluating defense a while back that stands up nicely, and I came across an interesting post randomly that I thought I’d pass along: “Comparison of Fielding Statistics” which compares 2006 data from six different stats and comes to some interesting conclusions about their utility.
I have some quibbles with the piece’s logic in places, specifically the comparison of stat “features” leading to
So, based on that table, I would have to say that UZR and PMR have the best methodologies, with a nod to the Fans data because they can provide such unique insights into player skill.
The problem is that this doesn’t at all evaluate methodologies. If I came up with a defensive metric called Random Runs that claimed to be built on hit-location data, zones, ball type, batter handedness, ballpark-adjusted, and player skill types, and I did all of those things horribly, that’s not a better system than something that does fewer things the right way, even though you’d check off those boxes.
The particularly interesting thing is the easy-to-scan graphs of system-to-system results. It’s interesting to see that in the 2006 data, the correlation is both highly significant and not anywhere near as good as you see from offensive contribution measures.
It all goes to reinforce something I’ve been saying for years — recognize that defensive tools are still pretty rough, but looking at a couple of them you’ll be able to get a pretty good idea of how good a particular player is with the glove.