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Re: Defensive Metrics thread continued

Postby Big Pimpin » Tue Jan 06, 2009 7:35 pm

noseeum wrote:
Big Pimpin wrote:As far as your below vs. above average, I think that does happen on offense because there isn't one universally accepted measure (hopefully wOBA will be it). One person might value BA, another OBP, another values SLG, another OPS and another OPS+. Just as bigwords said, everyone has an opinion on what's the right measure is so how can there possibly be agreement. As an example, Mike Cameron was widely regarded as a disappointing offensive player during his time in Seattle. I could dig up the Bavasi quote from when he kicked him to the curb, but it doesn't matter. He had a low average and he struck out a lot. The fact is that he played in a park that greatly reduced his offensive effectiveness, and yet his bat was still worth at least a win on it's own merit, notwithstanding the fact that he was the best defensive CF alive during the time.


This is just not true. If someone still holds the opinion that BA is a more important stat than OBP, than that person is misinformed. Yes, there are various "opinions" about offense, but most of those opinions are wrong. Sure, baseball writers can think Jim Rice was great, but the numbers say he wasn't.

OBP is the most important offensive stat. It correllates most highly with runs. That is not an opinion. That's why OPS is a simple yet inaccurate stat. It overweights slugging. These are not opinions. They are facts.

Yes, there is research at the margins arguing what's the best sum total for offensive evaluation, OPS+, Win Shares, WOBA, etc. But those are summaries of statistics that are beyond dispute. This player walked up to bat 650 times last year, he walked 120 times, he stole 10 bases, he hit 40 homers, 36 doubles, 2 triples, struck out 92 times, had a .360 BABIP, 89% contact rate, etc. We don't have root statistics on defense like we do for offense, and that's the problem.

You can argue which sum total statistic is most accurate for offense, but the quality of the root statistics is so vastly superior to defense that all of the respected summary stats have a huge amount of evidence to support them.

For instance, why aren't we recording throwing errors and catching errors as different stats? Why when a ball that hit a player's glove but is ruled a hit are we not recording that he got to it but he couldn't make the play? It's not an error, but he got to it. We should record that somehow. Perhaps he kept it in the infield, but he didn't get the guy out at first. There's still immense value in that if there's a player on base already. Why is a shortstop getting credit for fielding a ball out of the zone when he's standing at second base in a shift when Giambi's up to bat? There's no skill in that. He stood where his manager told him to and the ball got hit right to him.

etc. etc. etc.


Actually wOBA correlates most closely with runs. ;-)

I just think it's silly to say that if people disagree on offense, then the ones on one side are misinformed, while simultaneously saying that all defensive metrics are basically wrong. That's simply your opinion. There are a lot of very smart, published people who happen to disagree with you very much.

And even if you agree that OBP is the stat, what does it mean? If you have a higher than average OBP by 15 points, how many runs better than average are you? What if you get on base well but only get singles? How does SLG play into run creation?

I agree that there are improvements to be made, but to just simply blow off all the metrics as you seem so wont to do just seems silly to me. That's all.
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Re: Defensive Metrics thread continued

Postby GotowarMissAgnes » Tue Jan 06, 2009 7:42 pm

Big Pimpin wrote:

I actually do think that hitting and defense are basically 1:1 and should be given equal weight. That being said, I don't think we can completely derive a player's skill level, only a range around how many runs that player will save (or cost) a team in a given year.



If I am understanding you correctly here, BP, it's an area where I would disagree. If by saying this you mean that a player's offensive value and defensive value should be given equal weight in assessing their contribution, I'm not with you.

Basically, baseball breaks down into scoring runs and preventing them. And roughly half of the game is scoring them (batting, running) and half of the game is preventing them (pitching and fielding). So, 50% of the game is offense and 50% is defense. And defense is both pitching and fielding. I don't think we have a perfect handle on the importance of pitching versus fielding, but at the very least things like homers, strikeouts, walks, etc have little to do with fielding. I think most people would probably divide it around two-thirds pitching and one-third fielding, but in any case, hitting basically must outweigh a player's defense.

And you can see that in the current run metrics. Something like batting and fielding runs or win shares always shows larger average contributions for hitting than for fielding. The top win shares for fielders, for example, in 2008 was 11 by Ichiro. The top batting win shares was 27. The average hitting win shares is usually between 2 to 3 times larger than the average fielding win shares (which is a close match to hitting being 50% of a position player's contribution and fielding being between 25% and 16.67%).

There are definitely some players, and even some positions, where that emphasis is much closer--we all know that defense is more important at SS, CF, C. Look at THT's win shares for SS. The top hitting is 14 and the top fielding is 8, a ratio of 1.75, compared a ratio of almost 2.5 for all players. For SS hitting is not even twice as important as fielding, and it's more like 50% hitting and 30% fielding. And for 1B, the top hitting win share is 27 and the top fielding is not even 4. For 1B it's more like 50% hitting and 8% fielding.

So, maybe I don't disagree if you mean that we have to put all these things in a runs format and add them up. That's exactly right, but I would say that all systems will then give more weight to hitting because it's the greater share of a position player's contribution. And, I would add, as I think you are also saying, that whatever runs measure we use, we'd have more confidence in our estimate of the hitting uns than the fielding runs.

If I was working on this I'd probably put it into a simulation/scenario analysis where I could set each player as a probability distribution of outcomes based on expected offense and defense and variation in that expected outcome (eg., a normal distribution with mean and st.d dev. of hitting and fielding runs). That would give me both the expected payoff from a change, as well as its estimated risk.
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Re: Defensive Metrics thread continued

Postby Big Pimpin » Tue Jan 06, 2009 7:53 pm

GotowarMissAgnes wrote:
Big Pimpin wrote:
Got it, and you're exactly right. ;-D

I guess there's still a disconnect because I don't see RZR as it stands as a metric that says anything about how good of a defensive player a guy is or even how many runs or plays he was above or below average. I'd be more interested in taking say, offensive runs created and defensive runs saved and seeing what kinds of variations there are. Just scanning through the batting runs and fielding runs (UZR) compared to average on FanGraphs, it appears there's a lot more variation in the offensive numbers.


As I said in my pm, apologies (in advance) if I seem like I'm lecturing..it's just my job.

I agree that it would probably be better to switch to something luke batting and fielding runs and maybe I'll see if I can look at it that way this weekend (although prepping for two classes might take precedence).

But, get back to basics. Those runs data are simply built on a structure that looks at the opportunities a player had for success (plate appearances for batters, balls hit into their zone for fielding) and the success they achieved with those opportunities (whether or not they get on base or hit the ball and what happened when they hit it; whether or not the fielded the ball and turned it into an out). There is a whole range of metrics that can be used to quantify those opportunities and successes in both fielding and hitting.

RZR is probably closest in comparsion to OBP. You can create a batting runs measure based only on OBP. It ain't perfect, but because we know OBP is a damn important part of a player's offensive value, it gets us a decent way towards the truth. Similarly, RZR, like OBP, tells us how many balls that were hit into the zone are caught by that player. Like a straight use of OBP, it ignores context like park factors and run environment. Like a simple OBP based batting runs measure, it misses the outliers, so-called "out of zone" events--just as OBP ignores the importance of outliers, like the difference between a homer and a single.

So, you are right--by themselves OBP and RZR don't tell us about runs or comparisons above or below average. We can certainly do the latter by looking at how a player compares to peers. We can also translate OBP and RZR into a runs based measure, although it will not be as accurate as other translations that account for what is not there. But, they both are credible enough measures of offense/defense and an important part of any system measuring player performance.


Yeah I see the value in it, I just think it misses the boat a bit because it doesn't adjust for the batted ball profile like the others. Without the adjustment for the difficulty of the "in zone" balls, I think it's missing something important. It would kind of be like looking at the offense numbers without taking into account the luck indicators, such as BABIP. You're always trying to answer the question "Is the number a true indicator (or at least a reasonable estimate) of how that player performed?"
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Re: Defensive Metrics thread continued

Postby Big Pimpin » Tue Jan 06, 2009 8:04 pm

GotowarMissAgnes wrote:
Big Pimpin wrote:

I actually do think that hitting and defense are basically 1:1 and should be given equal weight. That being said, I don't think we can completely derive a player's skill level, only a range around how many runs that player will save (or cost) a team in a given year.



If I am understanding you correctly here, BP, it's an area where I would disagree. If by saying this you mean that a player's offensive value and defensive value should be given equal weight in assessing their contribution, I'm not with you.

Basically, baseball breaks down into scoring runs and preventing them. And roughly half of the game is scoring them (batting, running) and half of the game is preventing them (pitching and fielding). So, 50% of the game is offense and 50% is defense. And defense is both pitching and fielding. I don't think we have a perfect handle on the importance of pitching versus fielding, but at the very least things like homers, strikeouts, walks, etc have little to do with fielding. I think most people would probably divide it around two-thirds pitching and one-third fielding, but in any case, hitting basically must outweigh a player's defense.

And you can see that in the current run metrics. Something like batting and fielding runs or win shares always shows larger average contributions for hitting than for fielding. The top win shares for fielders, for example, in 2008 was 11 by Ichiro. The top batting win shares was 27. The average hitting win shares is usually between 2 to 3 times larger than the average fielding win shares (which is a close match to hitting being 50% of a position player's contribution and fielding being between 25% and 16.67%).

There are definitely some players, and even some positions, where that emphasis is much closer--we all know that defense is more important at SS, CF, C. Look at THT's win shares for SS. The top hitting is 14 and the top fielding is 8, a ratio of 1.75, compared a ratio of almost 2.5 for all players. For SS hitting is not even twice as important as fielding, and it's more like 50% hitting and 30% fielding. And for 1B, the top hitting win share is 27 and the top fielding is not even 4. For 1B it's more like 50% hitting and 8% fielding.

So, maybe I don't disagree if you mean that we have to put all these things in a runs format and add them up. That's exactly right, but I would say that all systems will then give more weight to hitting because it's the greater share of a position player's contribution. And, I would add, as I think you are also saying, that whatever runs measure we use, we'd have more confidence in our estimate of the hitting uns than the fielding runs.

If I was working on this I'd probably put it into a simulation/scenario analysis where I could set each player as a probability distribution of outcomes based on expected offense and defense and variation in that expected outcome (eg., a normal distribution with mean and st.d dev. of hitting and fielding runs). That would give me both the expected payoff from a change, as well as its estimated risk.


Yeah I don't mean that we'd average the two together, simply that a player's offensive value (in runs) should be added to his defensive value (in runs) and that derives his value. Agreed on the position adjustments, Tango has done the work so that we can compare players across positions. Also agreed that we have more confidence in our hitting runs vs. fielding runs.

That being said, while your hitting runs might be greater than your fielding runs, your value will not necessarily be tied to that same ratio. For instance, while most of the very best players are more above average on the hitting side than the fielding side, there are still players who rate well above average due to defense. For instance, a guy like Beltre. He's slightly above average offensively, but he's one of the best defensive 3B alive, which is where he derives most of his value.
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Re: Defensive Metrics thread continued

Postby noseeum » Tue Jan 06, 2009 8:35 pm

Big Pimpin wrote:
noseeum wrote:
Big Pimpin wrote:As far as your below vs. above average, I think that does happen on offense because there isn't one universally accepted measure (hopefully wOBA will be it). One person might value BA, another OBP, another values SLG, another OPS and another OPS+. Just as bigwords said, everyone has an opinion on what's the right measure is so how can there possibly be agreement. As an example, Mike Cameron was widely regarded as a disappointing offensive player during his time in Seattle. I could dig up the Bavasi quote from when he kicked him to the curb, but it doesn't matter. He had a low average and he struck out a lot. The fact is that he played in a park that greatly reduced his offensive effectiveness, and yet his bat was still worth at least a win on it's own merit, notwithstanding the fact that he was the best defensive CF alive during the time.


This is just not true. If someone still holds the opinion that BA is a more important stat than OBP, than that person is misinformed. Yes, there are various "opinions" about offense, but most of those opinions are wrong. Sure, baseball writers can think Jim Rice was great, but the numbers say he wasn't.

OBP is the most important offensive stat. It correllates most highly with runs. That is not an opinion. That's why OPS is a simple yet inaccurate stat. It overweights slugging. These are not opinions. They are facts.

Yes, there is research at the margins arguing what's the best sum total for offensive evaluation, OPS+, Win Shares, WOBA, etc. But those are summaries of statistics that are beyond dispute. This player walked up to bat 650 times last year, he walked 120 times, he stole 10 bases, he hit 40 homers, 36 doubles, 2 triples, struck out 92 times, had a .360 BABIP, 89% contact rate, etc. We don't have root statistics on defense like we do for offense, and that's the problem.

You can argue which sum total statistic is most accurate for offense, but the quality of the root statistics is so vastly superior to defense that all of the respected summary stats have a huge amount of evidence to support them.

For instance, why aren't we recording throwing errors and catching errors as different stats? Why when a ball that hit a player's glove but is ruled a hit are we not recording that he got to it but he couldn't make the play? It's not an error, but he got to it. We should record that somehow. Perhaps he kept it in the infield, but he didn't get the guy out at first. There's still immense value in that if there's a player on base already. Why is a shortstop getting credit for fielding a ball out of the zone when he's standing at second base in a shift when Giambi's up to bat? There's no skill in that. He stood where his manager told him to and the ball got hit right to him.

etc. etc. etc.


Actually wOBA correlates most closely with runs. ;-)

I just think it's silly to say that if people disagree on offense, then the ones on one side are misinformed, while simultaneously saying that all defensive metrics are basically wrong. That's simply your opinion. There are a lot of very smart, published people who happen to disagree with you very much.

And even if you agree that OBP is the stat, what does it mean? If you have a higher than average OBP by 15 points, how many runs better than average are you? What if you get on base well but only get singles? How does SLG play into run creation?

I agree that there are improvements to be made, but to just simply blow off all the metrics as you seem so wont to do just seems silly to me. That's all.


You're misinterpreting me. Again. OBP correllates mostly with runs out of the "root" stats or root skills that an offensive player can have. Slugging has a lower correllation. wOBA is a combination of root stats, and therefore it of course correllates more highly than OBP. If it didn't, it would be useless.

In the list of important things for a hitter to be able to do, you might rank them as follows:
Get on base
Hit for power
speed/stealing bases
Take a lot of pitches
Smart base running

I'm not positive that's the order, but I know the first two are right.

As for your Jack Cust question, just because OBP is the most important offensive stat doesn't mean it's the only thing that matters in baseball. Sure, if Cust could play above average SS, or even a slightly below average one, and have the same offensive stats, he'd be an all star every year. Unfortunately, he spends half his time as a DH.

You're taking "it's difficult to measure" to mean, "DH's are just as important as short stops." I've never come close to saying anything like that.
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Re: Defensive Metrics thread continued

Postby Big Pimpin » Tue Jan 06, 2009 10:16 pm

The more I think about it, wOBA doesn't correlate with runs at all, except in the sense that you can use it to calculate runs created above or below average. There's probably no (or little) correlation to runs scored if that's what we were talking about.

And I don't think wOBA is a combination of root stats at all. My understanding is that it is regression/linear weights based. I don't think could create it from root stats if you tried.

And I didn't mention Cust at all, so don't get me started on that.

Over the past several years, we've made a ton of progress just on the offensive side. Ten years ago it was mostly BA, HRs, etc, which moved to OBP and OPS, with new breakthroughs and improvements every year. I know that defense isn't as easy to measure, but it's the same story. Smart people have been working on answering the question for years and it's getting better and better. I just think that if you blow it off you're missing an important part of a player's story. I also think that traditional scouting needs to come into play, if the scouts and metrics all agree, then you may have just found yourself a bargain or averted a disaster.
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Re: Defensive Metrics thread continued

Postby noseeum » Tue Jan 06, 2009 10:31 pm

Big Pimpin wrote:The more I think about it, wOBA doesn't correlate with runs at all, except in the sense that you can use it to calculate runs created above or below average. There's probably no (or little) correlation to runs scored if that's what we were talking about.

And I don't think wOBA is a combination of root stats at all. My understanding is that it is regression/linear weights based. I don't think could create it from root stats if you tried.

And I didn't mention Cust at all, so don't get me started on that.

Over the past several years, we've made a ton of progress just on the offensive side. Ten years ago it was mostly BA, HRs, etc, which moved to OBP and OPS, with new breakthroughs and improvements every year. I know that defense isn't as easy to measure, but it's the same story. Smart people have been working on answering the question for years and it's getting better and better. I just think that if you blow it off you're missing an important part of a player's story. I also think that traditional scouting needs to come into play, if the scouts and metrics all agree, then you may have just found yourself a bargain or averted a disaster.


Sorry, that was big words. Too many bigs in this thread!

I completely agree with everything you say here. I don't think anyone should give up pursuing the holy grail of offensive stats. The research out there right now is important. But it's steps in the chain. We're not there yet.

The things I asked for above? Sites like fangraphs, etc. would eat that up and have better defensive metrics for us in minutes if we had more discrete stats for defense. I think STATs inc and others that are currently compiling live game stats are really missing an opportunity to record much more information than they do right now.

With PitchFX, we now have access to pitch type, location, and velocity for every at bat in many stadiums. This information will further revolutionize the level of accuracy we can get in evaluating a hitter's component skills. This might not change much in terms of looking back at a player's offensive contributions in the past, but my guess is it will lead to a significant leap forward in predicting future performance for hitters.

For defense, I feel like we are still trying to prove the world is not flat, whereas we've already landed on the moon for offense. That's my view anyway. I applaud the efforts so far, but I can't wait for what we'll have in the future.
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Re: Defensive Metrics thread continued

Postby Big Pimpin » Wed Jan 14, 2009 6:09 pm

This basically sums up what I've tried to express in this thread pretty well, and probably more succinctly than I have. :-B
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Re: Defensive Metrics thread continued

Postby GotowarMissAgnes » Wed Jan 14, 2009 6:33 pm

Big Pimpin wrote:This basically sums up what I've tried to express in this thread pretty well, and probably more succinctly than I have. :-B


Again, the problem with this is that it starts with the assumption hitting and fielding come from the same distribution of outcomes. They don't. Hitting is a draw from a low mean, high variance distribution. Fielding is a draw from a high mean, low variance distribution. A random draw from the first is likely to be characterized by lots of variability. A random draw from the second is not.
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Re: Defensive Metrics thread continued

Postby Big Pimpin » Wed Jan 14, 2009 9:04 pm

GotowarMissAgnes wrote:
Big Pimpin wrote:This basically sums up what I've tried to express in this thread pretty well, and probably more succinctly than I have. :-B


Again, the problem with this is that it starts with the assumption hitting and fielding come from the same distribution of outcomes. They don't. Hitting is a draw from a low mean, high variance distribution. Fielding is a draw from a high mean, low variance distribution. A random draw from the first is likely to be characterized by lots of variability. A random draw from the second is not.


Again, they're quite comparable when measured in runs. :-D
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