Defensive Catching question...

[SABR Matt]

Hey Tango...I'm curious about something...

When you did your defensive catching study wherein you looked to see how frequently catchers allowed WP/PB/SB/CS etc with each pitcher they caught (which was a brilliant study BTW)...why not try the same approach to see how those catchers impacted their pitchers' performance? Why not try to see if there are catchers who actually do lower their pitchers' ERAs?

[Tango Tiger]

Runs allowed is a function of many variables, not the least of which is timing and the park. If I had decided to do the study for all the variables, the random variations of the runs component would overwhelm the deltas of the catcher/pitcher dynamic. As well, since I didn't control for aging, it would be more likely that aging impacts K/BB numbers than it impacts SB/CS numbers (just a guess).

Therefore, if you want to learn something real, you have to break it down into something granular, so that you can strip away as much of the noise / timing that the catcher simply does not influence.

[SABR Matt]

Hmm...fair points.

I still think there is potential for a study similar in mode to the catcher study to be run to check the hypothesis that catchers impact pitching skill. There are definitely confounding factors that would make it non-trivial, but I think that's the way to go eventually to see if all of this chatter about game-calling has merit.

[misterdirt]

Tom Hanrahan has already done a very interesting study on catcher's effect on ERA that was printed in the November 1999 issue of "By the Numbers". It found there was a relationship between catcher's experience and ERA of certain pitchers. The results are in contrast with an earlier study by Keith Woolner printed in the 1999 Baseball Prospectus that found no significant effect.

[Tango Tiger]

Hmm...fair points.

I still think there is potential for a study similar in mode to the catcher study to be run to check the hypothesis that catchers impact pitching skill. There are definitely confounding factors that would make it non-trivial, but I think that's the way to go eventually to see if all of this chatter about game-calling has merit.

I agree that you can do a study on game-calling. Going from game-calling to runs allowed means going through a fog of noise to get there. If the intent is to look at game-calling, then, look at game-calling. Look at K/BB, look at what happens by count. If you have pitch location, speed, velocity, look at that too.

[SABR Matt]

Hmm...I wasn't quite as "plugged in" in 1999....I don't think the 1999 BTN issue is still readily available...how do I go about finding it?

[misterdirt]

My error. Hanrahan's latest (and best) article was in Nov. 2004. It was an update of an earlier article of Aug 1999. I combined the dates when I wrote my post. Both articles are on Phil Birnbaum's (BTN editor) web site.

[misterdirt]

Birnbaum also authored an article for BTN which attempted to evaluate the ability of a catcher to frame a pitch. He calculated what changing a single pitch call from a ball to a strike each game would be in terms of runs per game and runs per season.

[Tango Tiger]

Hmm...I wasn't quite as "plugged in" in 1999....I don't think the 1999 BTN issue is still readily available...how do I go about finding it?

Go to google and type this in
"by the numbers" Hanrahan

And then you will find this website:
http://www.philbirnbaum.com

[SABR Matt]

Gracias guys.

I'll be very interested in reading this one...

[Northernclan]

A Chuck Rosciam has done a recent study (2004) on the factor you want and several others which he combines to arrive at a catcher's overall "true" effectiveness. Go to Retrosheet, click on archives, and look for his article which is an attempt to measure a catcher's defensive effectiveness. Your data he calls something like CERA, or a catcher's era when catching, but this is only part of the picture.

[misterdirt]

Rosciam's study is so bad on so many levels that it should serve as an example of how not to do a research study. Stick with Hanrahan and Birnbaum.

[SABR Matt]

LOL...save me some time MrD...tell me what Rosciam did wrong in your opinion (I haven't yet read the study, just curious)

[misterdirt]

What I would say wouldn't make much sense unless you had read the study and when you read the study I don't think you'll need my help to know what he did wrong.

[SABR Matt]

LOL...noted for future reference. :)

[misterdirt]

I probably shouldn't have sugar coated my original assessment of the Rosciam study but you know how I hate to cause offense. I probably should have just come out and said what I really thought.