A few months ago I wrote a web program that lets you look up all the injuries to baseball players over the past ~10 years and also shows you their PITCHf/x data.
http://injurydb.drivelinebaseball.com/
It’s pretty eye-opening when you see how many pitchers have landed on the DL and how much it costs teams!
Really nice stuff Kyle, I looked up Carlos Zambrano, it is a very interesting. As I’ve closely watched him I’d never had realized his fb avg was dropping but clearly over time it is. It’s also interesting that throughout his time he’s had days where he was 3-4 mph avg faster than his “norm”, makes you wonder what the deal was.
It’s not worth getting into here, but the data that I use is raw PITCHf/x data and needs to be corrected. The release points are not consistent because camera systems installed in each park are not perfectly calibrated with each other. A 1-inch parallax error can cause serious problems as the ball crosses the plate, for example.
So this stuff is interesting to look at, but can’t be used for serious analysis. Fastball velocity should be more stable across parks, however, so that’s not a bad metric to use.
That was my first train of thought, the equipment is different from park to park and therefore the speeds might vary from one to another.
It’s not so much the velocities (they are fairly stable) but rather the pitch classifications and the x/z-axes of release point.
All part of equipment I feel, that would include placement, setup, clarity and some of the zeroing of the gun itself.
Wouldn’t all parks be the same? I don’t understand the differences from different parks in the mlb.
The angle that they place the gun to the plate could be one difference, so that is a mechanical difference but it still would vary park to park.
They do not use a radar gun for velocity.
what do they use then?
what do they use then?[/quote]
im pretty sure they use a camera and a computer system and it times from the release point as it croses the plate. It could be more complicated but im guessing all thats done is a distance formula like d=(x2-x1)2 + (y2-y1)2, they also have the time it was realesed from his hand and crossed the plate and then put it into a simple S=D/T formula to get the velocity