Open Command

Quantifying pitch execution!

[Open Command @open_command]

I'll be using this account to publicly share the results of OpenCommand, a computer-vision based command tracker.

Ideas in mind:
- MLB command leaderboards
- Target maps
- Pitcher command trends
- Pitcher tactics changes
- Reply to this tweet if you have ideas!

[Doyoung-Tom Kim @tomdoyo]

Some news:

I decided to open source my command project. It's called OpenCommand.

This means anyone can see the code (and even the data)!

I hope this gives more people a chance to pursue and share cutting edge baseball research.

Anyways, here's how to measure command: 🧵

1/N

[Open Command @open_command]

PSA: Open Command is at the GM meetings!

We're offering a wide range of services to teams, agencies, & players.

DMs & email open for inquiries

[Open Command @open_command]

This was also kind of wrong because there IS a steep hockey stick when you look at RA9 instead of xERA.

The minimum command you need to reliably be in the big leagues is around a 12-inch mean miss!

[Open Command @open_command]

As @pitchprofiler & others mentioned, maybe there's some "minimum command" to be a viable pitcher (throw enough strikes).

I managed to find *some* hockey stick going on but it looks like it's driven by K% dropping (not BB% going up disproportionately).

It's hard to show in MLB because these pitchers already proved they could throw strikes in the minors!

[Open Command @open_command]

Yeah so command is correlated to RA9 - xERA but stuff isn't

This is the most absurd result I've ever seen

[Open Command @open_command]

So turns out command is worth TWICE as much. Using xERA was a mistake and underestimated its importance.

On RA9, command is 2/3 as important as stuff.

Anyone have an idea on why such a big gap? I've always considered xERA to be RA9 but faster. But it's missing something?

[Open Command @open_command]

@georgerlewis Yoo

[Open Command @open_command]

So turns out command is worth TWICE as much. Using xERA was a mistake and underestimated its importance.

On RA9, command is 2/3 as important as stuff.

Anyone have an idea on why such a big gap? I've always considered xERA to be RA9 but faster. But it's missing something?

[Open Command @open_command]

For reference, going from worst stuff in the league to best is worth 3 ERA.

So, stuff is arguably 3x as important as command (at the MLB level)!

[Open Command @open_command]

@georgerlewis The correlation gotta be tiny though

[Open Command @open_command]

@georgerlewis Sounds plausible but 2x is a pretty big difference

[Open Command @open_command]

@tangotiger Why the difference tho

xERA is xwOBA

[Open Command @open_command]

@georgerlewis So something like no allowing walks when you can't afford to, and allowing walks when it's not so bad?

[Open Command @open_command]

Parker Messick had his 2nd worst command day of the year yesterday.

He dropped from 80th to 12th percentile command, walking 4 batters in 2.1 innings.

[Open Command @open_command]

So, if command's internal reliability is 0.5 and stuff's is 0.5, we can only observe ~30% of command's effects.

Even if command 100% stabilizes at pitch 1, it still needs to wait for stuff to stabilize to be effective.

3/3

[Open Command @open_command]

3 things are true at the same time:
- Command is worth 1/3 Stuff
- Command stabilizes almost as fast as Stuff
- Adding Command on top of Stuff doesn't dramatically improve ERA prediction

Why? 🧵

1/3

[Open Command @open_command]

The problem is that command's influence is observable *conditional* on stuff. (Raw command is uncorrelated to ERA)

It's a huge survivorship bias (good stuff guys get away with bad command) - there's a negative correlation between stuff and command.

2/3

[Open Command @open_command]

@GoCubs49 @RTS_Owen @pitchprofiler Doesn't explain the K% hockey stick though

[Open Command @open_command]

As @pitchprofiler & others mentioned, maybe there's some "minimum command" to be a viable pitcher (throw enough strikes).

I managed to find *some* hockey stick going on but it looks like it's driven by K% dropping (not BB% going up disproportionately).

It's hard to show in MLB because these pitchers already proved they could throw strikes in the minors!

[Open Command @open_command]

@GoCubs49 @pitchprofiler Yeah idk what's going on

[Open Command @open_command]

@GoCubs49 @pitchprofiler Oh yeah there is, worse command pitchers have better stuff, but the hockey stick with K% (might) mean worst command pitchers have worse stuff which is weird

[Open Command @open_command]

@GoCubs49 @pitchprofiler On the surface it means the opposite: the worst command pitchers also have worst stuff. This is despite removing position players.

But maybe there's something in what you said, maybe there's only so much a good stuff helps you with chase

[Open Command @open_command]

@Ja_jacks_ 👇

[Doyoung-Tom Kim @tomdoyo]

We can adjust for tendencies by offsetting the target by the avg pitcher × pitch type miss pattern.

E.g. Logan Webb's changeup averages 13in below the glove

This is the current math behind "inferred" targets.

But there are 2 huge flaws with it. Can anyone guess what they are?

10/N

[Open Command @open_command]

I'll be using this account to publicly share the results of OpenCommand, a computer-vision based command tracker.

Ideas in mind:
- MLB command leaderboards
- Target maps
- Pitcher command trends
- Pitcher tactics changes
- Reply to this tweet if you have ideas!

[Doyoung-Tom Kim @tomdoyo]

Some news:

I decided to open source my command project. It's called OpenCommand.

This means anyone can see the code (and even the data)!

I hope this gives more people a chance to pursue and share cutting edge baseball research.

Anyways, here's how to measure command: 🧵

1/N

[Open Command @open_command]

@JenMineau13 There should be but I'm not sure what the y axis should be in that case

[Open Command @open_command]

For reference, going from worst stuff in the league to best is worth 3 ERA.

So, stuff is arguably 3x as important as command (at the MLB level)!

[Open Command @open_command]

Going from worst command in the league to best is worth 1 ERA!

There's a strong correlation between xERA (unexplained by Stuff+) and command.

And it gets really interesting because some pitch types are way more dependent on command than others (see below)