Buxton - 5/3 Statcast

[amjgt]

http://m.mlb.com/news/article/228161150/twins-byron-buxton-shows-off-blazing-speed/

 

Here's what I don't understand...

 

They said Davis' batted ball had a 73% hit probability, but Buxton's catch had a 49% catch probability. 

 

a) That adds up to well over 100%. How is anything other than exactly 100% possible

When I see a "49% catch probability" that would me to believe roughly half the CF in the league would make that play and there really wasn't anything special about it. Also it gets a 4-star rating, which looks like it happens roughly on the order of once per day across MLB. Calling it 49% seems like a severe undersell. 

 

Also analyzed was his triple, which was the fastest home-to-third this year..... and he let up.

[gunnarthor]

Yeah, I have no idea but I'm not remotely surprised on his triple being the fastest. When the ball sneaked past Davis I was honestly thinking inside the park HR.

[ashbury]

"He needed 4.2 seconds to cover 67 feet, giving it a catch percentage of 49 percent, which equates to a four-star play."

 

As an ex-QA guy, I just bounce that back to Development and say, "there's a bug, I don't know exactly which of those four numbers is wrong, you diagnose it, I have to move on."

[70charger]

 

"He needed 4.2 seconds to cover 67 feet, giving it a catch percentage of 49 percent, which equates to a four-star play."

 

As an ex-QA guy, I just bounce that back to Development and say, "there's a bug, I don't know exactly which of those four numbers is wrong, you diagnose it, I have to move on."

 

As a developer, I don't like you very much right now.

[Bill]

I will guess that the hit probability computations do not account for where fielders are actually standing when the ball is hit.  My understanding is that the catch probability computations do account for the starting position of the fielders.

[Doomtints]

He may end up only rising to average-ballplayer with his bat -- but he will still be a star due to his defense.

 

Looking forward to his bright future.

[amjgt]

 

I will guess that the hit probability computations do not account for where fielders are actually standing when the ball is hit.  My understanding is that the catch probability computations do account for the starting position of the fielders.

 

Seems like that unnecessarily eliminates the impact of a shift.

 

In fact, a really interesting metric would compare "defensive placement independent hit percentage" (DPIHP) with "batted ball inferred hit percentage" (BBIHP).

 

This would give you a "Defensive shift efficacy" (DSE). The larger the difference (assuming it's positive), the better you are using the shift.

 

--- OK. the acronyms could use some work ---

[amjgt]

So, given that the hit percentage was 73%, the BBIHP = 27%

 

Since the Buxton's catch percentage was 49%, can I assume positioning increased Buxton's opportunity to catch that ball by 22%?

[Bill]

It seems that hit probability is calculated based upon exit velocity and lauch angle.  As far as I can tell, it does not account at all for where fielders are positioned or whether a ball is hit, e.g. to straightway center or in a gap.

 

http://m.mlb.com/news/article/217705412/statcast-introduces-hit-probability-for-2017/

[amjgt]

 

It seems that hit probability is calculated based upon exit velocity and lauch angle.  As far as I can tell, it does not account at all for where fielders are positioned or whether a ball is hit, e.g. to straightway center or in a gap.

 

http://m.mlb.com/news/article/217705412/statcast-introduces-hit-probability-for-2017/

 

That's probably the case, but in my opinion that doesn't tell the whole story. Since there is almost always some sort of shift on for every batter, telling me the odds of something being a hit if everyone was where they were "supposed" to be, is relatively meaningless.

 

Going by this, the system probably thinks Joe Mauer is super unlucky, when in reality teams have just figured out how to effectively shift him.