Comments on: What Mean Do You Regress Defensive Metrics To?

By: Aqua Narc

Aqua Narc — Fri, 20 Nov 2009 12:52:58 +0000

5 bucks says Dayton Moore was the “AL GM” who said that Holliday sucks in the field.

Also, did Yoda write the title to this post?

By: The Real Neal

The Real Neal — Fri, 20 Nov 2009 03:27:19 +0000

Or it could be that Mike Cameron steps in front of Braun and Hart to catch a lot of balls that both of the outfielders could catch. Which would:

1. Explain the disparity in Braun’s score
2. Explain why Hart who used to play center is a ‘bad’ right fielder
3. Explain why Cameron who is clearly in the decline phase of his fielding career, like just about every other center fielder for the last 120 years, seems to be rejuvinated by joining the Brewers.
4. Illustrate the other flaw with UZR that I forgot above.

By: The Real Neal

The Real Neal — Fri, 20 Nov 2009 03:11:05 +0000

Well it was five years ago.

Off the top of my head – line drives, throwing, the way that hits through the hole get apportioned responsibility to the fielders, advanced scouting and defensive alignment, the ability of pitchers to pitch to a gameplan… and then there’s the standard misuse of statistics. You can’t say “my sample size is 500 plays” and then start applying things like park factors and pitchers factors to your sample of 500 – because what you in reality are doing is cutting up your samples so that you no longer have samples large enough to apply any confidence interval.

Even MGL guesstimated his SD to be 5 runs. The reason he can’t give an actual confidence interval is because the statistical analysis is so fudged.

By: Paul Thomas

Paul Thomas — Fri, 20 Nov 2009 01:27:41 +0000

I’m not really sure how true this is. I know fans are instructed not to think about defensive metrics and not to think about what other people have said, but… why would you expect that to be any more effective with a jury voting on baseball skill than with a jury voting on convictions?

There’s no way to get a pool of people who are untainted. Given that, I’d rather rely on experts (ideally several of them).

By: CH

CH — Thu, 19 Nov 2009 19:36:26 +0000

I love any article that implores people to think for themselves and not treat ANY single piece of information as gospel, whether we’re talking about baseball or anything else. So, thanks.

By: Fresh Hops

Fresh Hops — Thu, 19 Nov 2009 19:30:54 +0000

Exactly. This isn’t actually a difficult thing to reason about. It’s not “can I trust this?”, it’s “How much can I trust this?” If you have a decent sample of UZR, the answer is +/- 5 runs; taking their three year average (if you have that much data) with a slight weight toward recent performance is a good idea. Finally, you should always expect players to be a little more average than they have been in the past–that’s just regression to the mean (or, if you have a very small sample, a lot more average.)

Once you’ve done all that, you should use additional information you have about the player–recent injuries, recoveries, learning, aging, can all be factored in to suggest that a player will be a little different from the number we arrived at after reflecting on brute UZR data. Oh, and of course to the point of this article: there’s scouting information as well.

By: walkoffblast

walkoffblast — Thu, 19 Nov 2009 18:25:03 +0000

I have yet to see a credible source suggest Ellsbury did not let an above average amount of balls fall in front of him for whatever reason this year.

By: Logan

Logan — Thu, 19 Nov 2009 16:34:33 +0000

I’ve heard that joke before.

By: ineedanap

ineedanap — Thu, 19 Nov 2009 15:07:35 +0000

Simple solution:

“What Mean Do You Regress Defensive Metrics To, @ssh0le”

By: Joe R

Joe R — Thu, 19 Nov 2009 14:45:52 +0000

I still think Ellsbury is a much bigger point of contention than, say, Teixeira. Most of Ellsbury’s perceived value is his glove, but his UZR was terrible.

And then you have some people who think he’s the best defensive CF in Red Sox history already, and others who think he plays like a blind man.

I like Crasnick, though, his stuff is well worth reading.