Positional Adjustments

[tangotiger]

I saw discussion regarding positional adjustments in a thread.

 

I'll just start this one so we can focus the discussion. Feel free to ask your questions, and I'll see how I can help...

[John_Havok]

The real TomTango….or what might be the best trolling attempt in recent memory.

 

Either way I’m down for the show.

[BTS]

Welcome to BJMB, Mr. Tango

[tangotiger]

The real TomTango….or what might be the best trolling attempt in recent memory.

 

Either way I’m down for the show.

 

It is indeed me. Here's proof:

 

http://tangotiger.net/files/bluejaysmessageboard.txt

[Laika]

Hi Tom

 

Is there any merit to the idea that the assumptions in positional adjustments only apply to players who are bad/fringe at the position? I've read this as some sort of critique of positional adjustments. Something like "the sample is mostly based on players who are bad at a given position because the good ones don't get moved off the position".

 

I can think of anecdotes of good defensive players who moved down the spectrum and did not see measured performance boosts. e.g. Marcus Semien was a consistent +5 SS before moving to 2B and he is a +4 or so 2B by UZR rather than the +10 you'd expect. Daulton Varsho is a +12 CF moved to LF and is a +10 instead of the expected +22 LF. Obviously these are just anecdotes and there could be particular explanations.

[Omar]

Once you're done with positional adjustments I wouldn't mind getting more detail on validity (or lack thereof) of randomness. I know you have some strong opinions about that.

[Spanky99]

What's your go to in defensive metrics, DRS/UZR or OAA?

[tangotiger]

What's your go to in defensive metrics, DRS/UZR or OAA?

 

OAA is mine.

 

OAA uses actual ball location and actual player location.

[tangotiger]

Hi Tom

 

Is there any merit to the idea that the assumptions in positional adjustments only apply to players who are bad/fringe at the position? I've read this as some sort of critique of positional adjustments. Something like "the sample is mostly based on players who are bad at a given position because the good ones don't get moved off the position".

 

I can think of anecdotes of good defensive players who moved down the spectrum and did not see measured performance boosts. e.g. Marcus Semien was a consistent +5 SS before moving to 2B and he is a +4 or so 2B by UZR rather than the +10 you'd expect. Daulton Varsho is a +12 CF moved to LF and is a +10 instead of the expected +22 LF. Obviously these are just anecdotes and there could be particular explanations.

 

It's easier to separate infield from outfield. And it's also better if we differentiate between UZR/DRS and OAA.

 

So, speaking specifically about outfield:

UZR/DRS compare the performance of players to the average for that position

 

OAA compares the performance to the average outfielder, regardless of position

 

As a result, OAA will DIRECTLY allow you to compare a LF to a CF to a RF without ANY adjustments. The average CF for example is close to +5 runs above the average outfielder. The average LF is -5 runs, and the average RF is 0 runs.

 

Naturally, in UZR/DRS, the average of each is 0. And so, you CANNOT DIRECTLY compare players at each position. You need a "positional adjustment" to fix this issue. The positional adjustments that I offered 15 years ago was that the average CF is about +6 runs above the average outfielder, while the LF and RF were -3 runs each.

 

As you can see, we have more refined data in the Statcast age, more accurate data. At the same time, those adjustments were based on data from 15 to 25 years ago. It's just as possible the talent level of players has indeed changed.

 

That's the main problem with the positional adjustments: they require constant monitoring. We don't have that problem with OAA, because everyone is always compared to the same single standard for that season.

[tangotiger]

Once you're done with positional adjustments I wouldn't mind getting more detail on validity (or lack thereof) of randomness. I know you have some strong opinions about that.

 

When it comes to Statcast data, this is not an issue. We are measuring the players using actual data, not inferred data.

 

Do you have an example that you are thinking about?

[bluejaysinternNo5]

Unrelated to the current discussion, but are there any unexplored areas of baseball statistics, analytics, or simulation that have your interest?

[John_Havok]

My question about OAA, i know it takes player positioning into account, batted ball data, runner speed, and a few other things for infielders.

 

My question is, for a 1b who is positioned at a certain spot, RH glove, and a ball goes down the line just far enough to get past him... does OAA compare him strictly to other batted ball events where the 1b that started in relatively the same spot and relatively the same batted ball velocity and batted ball location to determine whether or not another 1b would have made the play?

 

 

Or is it just a simpler... the guy has X amount of time to get to the ball and then X amount of time to convert it to the out and just determines whether or not that is possible with varying degrees of difficulty?

[max silver]

I have a question pertaining OAA as well. This season Daulton Varsho has excellent defensive metrics across the board save for an anomalous -2 OAA in left field. There is a massive discrepancy between his DRS and OAA in left field this season where he has accumulated 7 DRS in 509 innings vs the -2 OAA. Do you have any inkling why there is such a large discrepancy? How are events such as balls lost in the sun treated by OAA? I recall Varsho has lost a few balls in the sun this season and wonder if this could be factoring into his results up to this point.

[John_Havok]

How much, if at all, is OAA influenced by the number of opportunities a player gets ?

[tangotiger]

My question about OAA, i know it takes player positioning into account, batted ball data, runner speed, and a few other things for infielders.

 

My question is, for a 1b who is positioned at a certain spot, RH glove, and a ball goes down the line just far enough to get past him... does OAA compare him strictly to other batted ball events where the 1b that started in relatively the same spot and relatively the same batted ball velocity and batted ball location to determine whether or not another 1b would have made the play?

 

 

Or is it just a simpler... the guy has X amount of time to get to the ball and then X amount of time to convert it to the out and just determines whether or not that is possible with varying degrees of difficulty?

 

It is mostly the latter part the "simpler" explanation. The model is very intuitive, and simply asks the question you are asking: how much time does the fielder need to get to the ball, and how much time does the fielder need to throw (or run) to the target base. And at the moment that the fielder/ball intersect, where is the batter/runner, and how much time will that player need to get to the target base.

 

And so, we simply ask: who will win the race? It's EXACTLY the way you evaluate fielders while watching the play develop. And so, the model is matching reality.

 

There are some nuances to 1B and 2B and SS and 3B that requires a bit extra work to make sure that we're all aligned to what "average" is. The twist and turns of the body, the running in and throwing across the body etc. But that's a secondary effect to the simpler intuitive time-distance model.

[tangotiger]

I have a question pertaining OAA as well. This season Daulton Varsho has excellent defensive metrics across the board save for an anomalous -2 OAA in left field. There is a massive discrepancy between his DRS and OAA in left field this season where he has accumulated 7 DRS in 509 innings vs the -2 OAA. Do you have any inkling why there is such a large discrepancy? How are events such as balls lost in the sun treated by OAA? I recall Varsho has lost a few balls in the sun this season and wonder if this could be factoring into his results up to this point.

 

We make available EVERY SINGLE PLAY, with video, right here:

https://baseballsavant.mlb.com/savant-player/daulton-varsho-662139?stats=statcast-r-fielding-mlb

 

Go about half-way down, hover over any of the dots to see the Catch Prob. Then click the dot to see the video. We are extremely transparent here. So, feel free to click those, and then link back here any play you think is questionable.

 

Yes, "lost in sun" is a real thing, and I know Varsho had at least one. Unfortunately, we are not tagging "lost in sun" or "hit the catwalk" in our play events. If he has two of them, then he gets minus 2 OAA, if they were otherwise routine plays.

[tangotiger]

How much, if at all, is OAA influenced by the number of opportunities a player gets ?

 

Go to my last post about Varsho. We are simply evaluating each play, one at a time. Each play gets a plus/minus. And we add those up. It's really as simple as it sounds.

[tangotiger]

Unrelated to the current discussion, but are there any unexplored areas of baseball statistics, analytics, or simulation that have your interest?

 

If you follow me on my blog, you will see I am currently delving into the bat swing.

[Laika]

We make available EVERY SINGLE PLAY, with video, right here:

https://baseballsavant.mlb.com/savant-player/daulton-varsho-662139?stats=statcast-r-fielding-mlb

 

Go about half-way down, hover over any of the dots to see the Catch Prob. Then click the dot to see the video. We are extremely transparent here. So, feel free to click those, and then link back here any play you think is questionable.

 

Yes, "lost in sun" is a real thing, and I know Varsho had at least one. Unfortunately, we are not tagging "lost in sun" or "hit the catwalk" in our play events. If he has two of them, then he gets minus 2 OAA, if they were otherwise routine plays.

 

This chart with the video links is great. Is it only available for OF at the moment? I tried to click through and find it for a couple of infielders but it looks like the same chart defaults to their batted balls, as opposed to fielded balls.

[tangotiger]

This chart with the video links is great. Is it only available for OF at the moment? I tried to click through and find it for a couple of infielders but it looks like the same chart defaults to their batted balls, as opposed to fielded balls.

 

Correct, outfield only.

 

Infield has more variables to consider, so it's not as easy to show in this manner.

[max silver]

We make available EVERY SINGLE PLAY, with video, right here:

https://baseballsavant.mlb.com/savant-player/daulton-varsho-662139?stats=statcast-r-fielding-mlb

 

Go about half-way down, hover over any of the dots to see the Catch Prob. Then click the dot to see the video. We are extremely transparent here. So, feel free to click those, and then link back here any play you think is questionable.

 

Yes, "lost in sun" is a real thing, and I know Varsho had at least one. Unfortunately, we are not tagging "lost in sun" or "hit the catwalk" in our play events. If he has two of them, then he gets minus 2 OAA, if they were otherwise routine plays.

 

I wasn't aware it was possible to review plays in this fashion, this is incredibly cool stuff.

 

Does the OAA system directly account for fielder positioning? This particular play is rated as a 99% probability catch, but based on how far Varsho had to run this seems like a far more difficult play in reality. It appears that this particular play would have required a diving catch to be made.

 

https://baseballsavant.mlb.com/sporty-videos?playId=9a0e28b5-d93c-4286-879a-86585c7af65e

 

This particular play is assigned a 70% difficulty rating, which also makes me question whether fielder positioning is a factor in breaking down these plays. A line drive which hits this high up the wall appears to be a very difficult play to my eyes.

 

https://baseballsavant.mlb.com/sporty-videos?playId=9f6510c8-aea4-40a2-8e3f-6c48e507124d

[John_Havok]

If you had to self-critique OAA in any way, what improvements would you shoot for?

[Omar]

When it comes to Statcast data, this is not an issue. We are measuring the players using actual data, not inferred data.

Do you have an example that you are thinking about?

 

I was thinking along the lines of what is considered Clutch hitting. Can we chalk it up to just randomness? Is there actually such a thing as a clutch hitter? I know this topic comes up every now and then on this board.

[connorp]

If this is truly a sabr wizard, I’d like to know:

1) Is he in any fantasy leagues

2) if so, is he any good in them?

 

Ie: does this advanced knowledge help other than selling some articles:)

 

I’ll present the “old school 1b” quandary later

[tangotiger]

I wasn't aware it was possible to review plays in this fashion, this is incredibly cool stuff.

 

Does the OAA system directly account for fielder positioning? This particular play is rated as a 99% probability catch, but based on how far Varsho had to run this seems like a far more difficult play in reality. It appears that this particular play would have required a diving catch to be made.

 

https://baseballsavant.mlb.com/sporty-videos?playId=9a0e28b5-d93c-4286-879a-86585c7af65e

 

This particular play is assigned a 70% difficulty rating, which also makes me question whether fielder positioning is a factor in breaking down these plays. A line drive which hits this high up the wall appears to be a very difficult play to my eyes.

 

https://baseballsavant.mlb.com/sporty-videos?playId=9f6510c8-aea4-40a2-8e3f-6c48e507124d

 

It definitely includes positioning. In the first play, Varsho went the wrong way initially. So, this is a GOOD example of the system working.

 

The second play is a wall-play and is more problematic. Right now, we aren't looking for how high a ball is off the wall, just if it's "playable". That has more to do with tracking limitations.

[tangotiger]

If you had to self-critique OAA in any way, what improvements would you shoot for?

 

See my above note on wall-balls.

[tangotiger]

I was thinking along the lines of what is considered Clutch hitting. Can we chalk it up to just randomness? Is there actually such a thing as a clutch hitter? I know this topic comes up every now and then on this board.

 

You mean "clutch fielding" or something? If you mean clutch hitting, then let's table that for a different thread.

[tangotiger]

If this is truly a sabr wizard, I’d like to know:

1) Is he in any fantasy leagues

2) if so, is he any good in them?

 

Ie: does this advanced knowledge help other than selling some articles:)

 

I’ll present the “old school 1b” quandary later

 

I last played in the early 90s. Yes, I did fine.

 

I don't sell articles, I work at MLB.

[connorp]

Then, maybe he can clear up my gripe on wRC+ that was made recently.

 

Say Player A plays for the Rockies. Say he has reverse extreme splits and hits ways better on the road and bad at home. Don’t you think it would be disingenuous to negatively yield down the runs he creates based on park factor?

[John_Havok]

defense thread connor, if he has time im sure we could get into an offense thread also