FanGraphs Baseball


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  1. Fantastic stuff, thanks!

    Comment by Peter R — December 18, 2012 @ 3:15 pm

  2. Awesome visual. It might be good to add p-values for the differences in size using a ChiSq

    Comment by abreutime — December 18, 2012 @ 3:19 pm

  3. I hate that this is even a thing. I wish there was more pressure on the Umpires to improve their performance instead of cherishing their inconsistency as a charming tradition.

    Comment by David — December 18, 2012 @ 3:21 pm

  4. All the more reason to allow computers, and not umpires, call the strikezone. A strike is a strike is a strike. Pitch framing, poor umps, vengeful umps….. none of it should alter the strikezone, which has a set definition.

    Comment by Doug Gray — December 18, 2012 @ 3:22 pm

  5. This is really fantastic stuff. Any chance you could post a LH-vs.-RH breakdown by count for the 75% thresholds, too?

    I think it’d be fascinating to see a strike zone chart by pitch type, as well (I know, it’s easy to say this when someone else is crunching the numbers). I feel like there are tons and tons of curveballs that drop into the top edge of the strike zone that never get called by umps. But maybe that’s a corollary to the vertical shrinkage of the zone in x-1 and x-2 counts (assuming that my intuition is correct and that curveballs tend to be thrown more with 1 or 2 strikes than with zero strikes on hitters).

    Comment by Xander Bogaerts — December 18, 2012 @ 3:26 pm

  6. Let’s take a step back and recognize that you have highly biased samples. You forget that these pitches only get counted if the batter chooses to not swing. Batters will swing at a lot more pitches on the corners in an 0-2 count than they will in a 3-0 count. The pitches they swing at are more frequently the easy-to-recognize strikes. The tricky pitches will more frequently go by without a swing, and thus make it into your sample. It seems quite likely that this sample bias explains the “changing” strike zone rather than a conscious decision by the umpires. Rather, in 0-2 counts umpires have a group of pitches that are much more challenging to categorize and we should expect a much higher error rate.

    Comment by StatGeek — December 18, 2012 @ 3:37 pm

  7. THIS!!!! When oh WHEN are we going to automate this “feature” of umpiring “ability”.

    Comment by Dave S — December 18, 2012 @ 3:48 pm

  8. “we should expect a much higher error rate.”… YES!

    Which is why we should not be asking human beings to do a job that computers/machines can do much more accurately and much more consistently.

    Comment by Dave S — December 18, 2012 @ 3:52 pm

  9. To me this demonstrates that umpires are affected by their own expectations of pitch location and maybe even by the batter.

    Own expectations: Counts where you would expect the pitcher to throw a strike, the zone grows. Potentially illustrating the umpire look in the zone- expecting the pitch to be there.

    Batter impact: In 0-2 counts, umpires would probably not expect a pitch to be anywhere near the middle of the plate- combine that with the hitter not swinging and the umpire may be less inclined to call boarder line pitches.

    Comment by legendaryan — December 18, 2012 @ 3:52 pm

  10. Those heat maps should be exhibit 1 for ending the misuse of human beings for calling balls and strikes.

    Matthew, I cannot thank you enough for posting them.

    Comment by Dave S — December 18, 2012 @ 3:54 pm

  11. What this clearly and unmistakably demonstrates is that humans are unreliable when it comes to accurately and repeatedly calling balls and strikes.

    Plain and simple.

    Comment by Dave S — December 18, 2012 @ 3:55 pm

  12. Bookmarked.

    Comment by Dave S — December 18, 2012 @ 4:00 pm

  13. I don’t buy it. I think these heat maps demonstrate that for a given location, the same pitch is more likely to be called a strike in a 3-0 count than an 0-2 count. It’s not “tricky” pitches on the corner vs pitches down the middle, it’s corner vs. corner.

    Comment by Justin — December 18, 2012 @ 4:06 pm

  14. I wish they would just let Questec call balls and strikes.

    Comment by MikeS — December 18, 2012 @ 4:12 pm

  15. I am curious if the handedness of the pitcher shows any unusual variations.

    Comment by mem — December 18, 2012 @ 4:24 pm

  16. Fantastic research, really enjoyed the article.

    Comment by Jon Roegele — December 18, 2012 @ 4:27 pm

  17. For some research background into this topic, you can start here:

    Comment by studes — December 18, 2012 @ 4:30 pm

  18. Amen, bro’. I can’t think of any other job outside of politics where this much incompetence is tolerated.

    Comment by Baltar — December 18, 2012 @ 4:42 pm

  19. I wonder if there is a bias, on the umpire’s side, to be more likely to call a ball in a 3-1 count for instance as opposed to an 0-2 count?

    What I am trying to say is there a tendency by umpires to call a ball or strike, during any particular selected count, simply because it “is” that count?

    Someone may have already looked at this but it would be interesting to know if a called ball was more likely to happen after an 0-2 count versus a 3-1 count? How much does human emotion and expectation enter into the equation in those situations that might bias the call?

    Interesting work Matt!

    Comment by ettin — December 18, 2012 @ 4:42 pm

  20. Interesting theory, but I don’t buy it either. This data just supports what everyone pretty much knows already from watching the games. Just watching a game, you see pitches all the time at 0-2 that you are sure would have been a strike at 0-0 or 3-0, which are called balls.

    Comment by wahooo — December 18, 2012 @ 4:45 pm

  21. I’m not convinced that umpires can’t be trained (or threatened into) doing a better job. MLB just doesn’t seem to care.

    Comment by Baltar — December 18, 2012 @ 4:47 pm

  22. 3-1 is in the table.

    Comment by Baltar — December 18, 2012 @ 4:49 pm

  23. I think I agree with automating the strike/ball calls, but think how much it would change the game–at least initially. Batters and pitchers are already conditioned to these changing strike zones as well as the LH vs. RH strike zones and changes from where the batter stands…etc. I would predict that some players would benefit much more than others by a true strike zone–and the results of the change would be interesting and unpredictable.

    Comment by wahooo — December 18, 2012 @ 4:49 pm

  24. Sorry SG, but your argument makes no sense at all. It would imply that batters down 0-2 only swing at borderline pitches and always let center zone strikes go by.

    Comment by Pirates Hurdles — December 18, 2012 @ 4:56 pm

  25. What if we let the home plate ump wear some sort of glasses that projected a strike zone box in his field of vision? Seems like it would be a helpful guideline.

    Comment by Steve — December 18, 2012 @ 4:56 pm

  26. But human factors!!!

    Comment by James — December 18, 2012 @ 4:59 pm

  27. Tango once proposed grouping of plate counts as:
    3-0, 3-1, 3-2 // 2-0, 1-0, 0-0 // 2-1, 1-1, 0-1// 2-2, 1-2, 0-2
    (“3-ball counts first, and then you clump by the strike counts”)

    Or alternatively, he suggested grouping by balls minus strikes. I think both of these methods might help the data in your table stand out more.

    Comment by El Vigilante — December 18, 2012 @ 5:02 pm

  28. bookmarked that one too Mr. Studeman, thanks!

    Comment by Dave S — December 18, 2012 @ 5:08 pm

  29. Has anyone done a breakdown like this comparing established pitchers (Rivera, Halladay) to young pitchers?

    Watching a rookie on your favorite team seemingly get squeezed for being a rookie is incredibly frustrating. Then watching the situation worsen if the pitcher reacts, and the umpire perceives it as being ‘shown up’ and makes the strike zone even smaller, forcing the kid to throw meatballs, which causes him to get rocked, which makes oh god I’m getting to angry to talk about this just please automate the strike zone.

    Comment by Eggy Mule — December 18, 2012 @ 5:13 pm

  30. I don’t want to get rid of umpires, or threaten them, or retrain them. I just want technology to do the part that human beings are not well designed to do! Human beings are not good at repetitive accuracy… especially tracking small high speed objects and precisely locating them in a theoretical three dimensional space.

    I am in no way damning umpires. I think they do as good a job as human beings can do at calling balls and strikes.

    I think they’d be even better if technology took over balls and strikes, and freed the umps to more closely watch other aspects of the game.

    Comment by Dave S — December 18, 2012 @ 5:19 pm

  31. That’s it. You’re tossed.

    Comment by Joe West — December 18, 2012 @ 5:23 pm

  32. How do we use technology to locate a ball in a theoretical three dimensional space?

    Also, baseball is played all over the world and many levels. Instigating technology like this in MLB would alter the game too much from the way it is played everywhere else.

    Baseball works just fine, as long as umpires can remain consistent during the course of a game. Reward umpires that can do that, and get rid of the ones who can not.

    Comment by legendaryan — December 18, 2012 @ 5:24 pm

  33. I seems like the biggest factor in determining size of the strike zone is number of strikes. More balls expand it slightly but more strikes shrink it dramatically.

    Comment by Bip — December 18, 2012 @ 5:28 pm

  34. I think that one day people will look back on this era of baseball as the “fuzzy strike zone” era… the way we look back at the “deadball” era.

    Comment by Dave S — December 18, 2012 @ 5:28 pm

  35. The two things I take from this:

    1. Conventional wisdom dictates that the batter “expand the strike zone” in a 2-strike count to avoid a backwards K. This suggests quite the opposite.

    2. Anecdotally, it seems that LHB post better numbers than RHB. This suggests that some of that may be due to the fact that they have smaller strike zones.

    Comment by Zeezil — December 18, 2012 @ 5:31 pm

  36. They may be in the same location, but in a 3-0 count, those pitches are a lot more likely to be fastballs, and in an 0-2 count more likely to be breaking balls.

    Comment by Bip — December 18, 2012 @ 5:33 pm

  37. legendaryan…

    ask the people that do the systems for professional cricket… or tennis.

    And the “non-major leagues” in those sports (without the technology) continue to get along just fine.

    Not implementing it everywhere is no excuse for not implementing it at the highest level when that capability exists… as it surely does.

    And why weed out those umps that aren’t as good… when you can replace that piece of the task for all umpires with something that is essentially “perfect”… ALL the time, EVERY time ?

    Comment by Dave S — December 18, 2012 @ 5:35 pm

  38. No, it means that if a batter is letting a pitch go by 0-2, it’s more likely to be one that doesn’t look like a strike, which could be a breaking ball on the corner. Some batters take 3-0 almost routinely, and those pitches are often fastballs.

    Comment by Bip — December 18, 2012 @ 5:35 pm

  39. I have a psychological explanation for this, but mine is different than some that others have suggested. I think umpires, in the case of the borderline pitch, rather than make the “expected” call, they are making the “uncontroversial call.”

    If it is 0-2 and a pitch comes in on the border of the strikezone, the ump has two choices. He can make the strong, controversial call of strike or the safe, non-controversial call of ball. If he calls strike, he’s questioning the batter’s judgment of the pitch, he’s ending the at bat, and possibly making an impact of the outcome of the game. He will likely earn some response from the batter and the batter’s manager. Or, he could just call a ball. The pitcher may shake his head, but the outcome of the game will probably be almost the same. The pitcher still has three more chances to get that third strike. In fact, if he hits the same spot, the umpire, still guilty about not giving him that call, ring up the batter on essentially the same pitch. This way, we have the same result as if he had called a strike, but this time he gave the batter a chance, giving him less reason to complain.

    My conclusion: umpires are cowards.

    Comment by Bip — December 18, 2012 @ 5:46 pm

  40. Yep, there is a fundamental bias towards letting the at-bat continue, thereby decreasing the chance the umpire ends the at-bat. I believe this is all the more so when that at-bat matters more (hence why pitchers get routinely rung up on 0-2, and why Drew Storen shouldn’t try to paint the corners when looking for strike 3 in the 9th inning of Game 5).

    Comment by Aaron (UK) — December 18, 2012 @ 6:22 pm

  41. Or just have him wear an earpiece that says ball or strike based on a computer, but he still gets to do his silly routine. Don’t even tell people you’re doing it. Everyone wins.

    Comment by TKDC — December 18, 2012 @ 7:32 pm



    Comment by Above the Rim Soundtrack — December 18, 2012 @ 8:12 pm

  43. NBA official.

    Comment by algionfriddo — December 18, 2012 @ 8:21 pm

  44. Computers please. And for yardage in football.

    Comment by mike wants wins — December 18, 2012 @ 8:28 pm

  45. How does batter height play into this? The stance should vary to some degree by batter and by stance. Not that I’ve noticed batters crouching more in 0-2 counts, but if they did it would change the zone.

    Comment by Crumpled Stiltskin — December 18, 2012 @ 8:34 pm

  46. There’ll be an adjustment period to be sure, but I bet both pitchers and hitters would love having a consistent strike zone.

    Comment by David — December 18, 2012 @ 9:51 pm

  47. @Dave S

    I don’t care about Umpires at all; if they show any resistance to an increased role for technology to assist them in calling the game correctly I would rather they be fired. Officials are ideally invisible; I’m often amazed at how little I see NFL refs during play. Every once in a while I’ll notice that a ref is set up in the middle of the field amongst the players, but I almost never notice them on replays. NFL refs go largely unnoticed until they need to make a call, which is exactly how it should be.

    Comment by David — December 18, 2012 @ 10:08 pm

  48. A computer-called strike zone would be a disaster for the pitchers. An unchanging strike zone with no variance depending on the count would greatly favor hitters as they learn the exact limits of their personal swings. Part of baseball is the uncertainty as a hitter where the exact strike zone is at the plate. It’s not codified in the rules like that but has been played since time immemorial in that manner.

    Comment by Phantom Stranger — December 18, 2012 @ 10:14 pm

  49. Tommy Lasorda: “If you’re going to do that, why don’t we just get robots and let them play the game? If you don’t need umpires out there, and you can put robots out there, then why do we need ballplayers?”

    Comment by Best. Quote. Ever. — December 18, 2012 @ 10:17 pm

  50. FG, hire this robot to write articles, it will save you loads on writers!

    Comment by monkey business — December 18, 2012 @ 11:24 pm

  51. I imagine that it would result is many more walks and strikeouts, particularly as batters adjust, and a aesthetically less pleasing product overall as fewer PAs are decided by balls in play.

    It should have an interesting impact on pitch values, since the de facto strike zone is wider and squatter than the de jure one. I think we’d see the curveball gain effectiveness while the slider lost some, while fastball velocity might gain even more value as it becomes harder to shave the outside of the zone with middling velocity.

    Comment by Bhaakon — December 18, 2012 @ 11:36 pm

  52. I came in here to post that, too late!

    Comment by I Agree Guy — December 18, 2012 @ 11:58 pm

  53. Me either.

    Comment by Gary Bettman — December 19, 2012 @ 12:51 am

  54. I would love to see an automatic strike zone for reasons already listed, but also for two more:
    mlb would have to fess up exactly where the zone ends upstairs, and I want to see how long it takes before mlb starts to change the zone to get more hitting or more pitching.

    Comment by james wilson — December 19, 2012 @ 2:24 am

  55. One thing to be careful of with this is the total number of called pitches in a given count. In an 0-2 count a batter is much more likely to swing at a pitch anywhere close to the strike zone, thus reducing the number of pitches in the zone that the umpire can call a strike. When using the locally weighted regression technique, as you have, this can cause for an over-fitted zone, and an exaggeration of the decrease in strike-zone size. While some of this is definitely due to the umpire, at least some of it is a result of the location of the pitches that they have an opportunity to call.

    Comment by Jackson — December 19, 2012 @ 2:40 am

  56. Um…because the umpires are not playing the game. A great ump is one you don’t even notice. A robot should be very good at this. A ballplayer plays the game. Playing and officiating are completely different things.

    Comment by ZenMadman — December 19, 2012 @ 7:55 am

  57. Because people don’t pay to watch umpires make calls, they play to see players play the game. Umpire mistakes take away from the fairness of the game, player mistakes do not.

    Comment by Kyle Murray — December 19, 2012 @ 7:55 am

  58. I could not disagree with that more completely.

    Computer strike zone would be completely adaptable. I believe there would be some initial issues, until you got the strike zone designed to balance pitchers and batters… but once you locked in the proper size of it, you’re golden. Then every batter would get the same exact strike zone, all day, everyday. And so would the pitchers.

    As a side comment, I also, would like to see the strike zone be exactly the same for all batters, no matter how tall or short they are.

    Tall batters shouldn’t have to cover more strike zone simply because they are tall. Short batters shouldn’t have to cover a smaller zone, simply because they are short. It should be democratic. One guaranteed uniform strike zone for all batters and pitchers.

    But that’s getting well ahead of things…

    Comment by Dave S — December 19, 2012 @ 8:21 am

  59. I think those would both be very good things. And I wouldn’t have a problem with MLB altering the zone to increase offense or defense… as it sees fit. At least it would be known and transparent to everyone. Thats at least fair.

    But again, this is getting ahead of things. Would just be happy with a uniform strike zone for now.

    Comment by Dave S — December 19, 2012 @ 8:24 am

  60. So why has it been that the error has consistently and to an extreme degree always gone in the same direction?? If it is a matter of mere difficulty, we would expect to see an expansion of the zone just as often as we see a diminution, but that is in fact never what we see or have seen.

    Comment by Kris — December 19, 2012 @ 8:40 am

  61. Great work. Any chance you could give us some tips on how to do this sort of analysis ourselves? (most importantly, where and how to download the data)

    Comment by Nick — December 19, 2012 @ 8:48 am

  62. How long before conspiracies popped up that Albert Pujols or Giancarlo Stanton or whoever is the superstar of the day gets a tweaked strike zone because he is a superstar?

    Comment by Kris — December 19, 2012 @ 8:48 am

  63. You can do it yoursel for each umpire:

    Comment by Jeff Zimmerman — December 19, 2012 @ 9:20 am

  64. MANY more walks and strikeouts? I don’t see why that would be the long term outcome; after hitters and pitchers have adjusted it should feel like watching the same game.

    Comment by David — December 19, 2012 @ 9:55 am

  65. I’d be interested to see how this lays out by pitch type, or break. How much of this variation is due to the count and how much by the break of the ball?

    I also wonder where the decide the plane of the strike zone to be. Since the zone actually has a depth, it sort of bothers me to always see it represented as a plane surface. I wonder if umpires change the plane on breaking balls, and maybe we could find a different plane that mirrors the called zone size of fastballs. Ive umpired for years, and this is a great article to me.

    Comment by bobabaloo — December 19, 2012 @ 9:58 am

  66. The batter may still expand the strikezone in that he is more prone to swing at a borderline pitch for fear that it may strike him out if he watches it go by, but umps seem to be giving the batter quite the advantage in an 0-2 count.

    Comment by David — December 19, 2012 @ 10:02 am

  67. Immediately

    Comment by David — December 19, 2012 @ 10:06 am

  68. Well, I suppose that it would depend on your subjective definition of “many,” but yes. It’s not just a matter of batter and pitchers adjusting, it’s a matter of the very obvious evidence above that the umpire fudge the zone quite a bit to extend 3-0/0-2 counts. With that gone, more Ks and BB are inevitable.

    Comment by Bhaakon — December 19, 2012 @ 10:31 am

  69. How would the strike zone be automatically adjusted from batter to batter?

    Comment by ttnorm — December 19, 2012 @ 10:57 am

  70. I think this data suggests that a consistent strike zone would force pitchers to throw more hittable pitches in 3-0 counts, which would limit walks. They would also be able to throw less hittable pitches in 0-2 counts, so I agree that that should lead to more strikeouts.

    Comment by David — December 19, 2012 @ 12:51 pm

  71. Those 3-0 fastballs should be easy to call, which doesn’t explain why the zone is so large.

    Comment by David — December 19, 2012 @ 1:06 pm

  72. Is there anyone who actually thinks that isn’t already happening?

    Comment by Synovia — December 19, 2012 @ 1:43 pm

  73. Can’t wait for the day that there’s an automated strike zone so that it becomes a new opportunity for cheating. Old cheating: vaseline on the baseball. New cheating: hack the automated strike zone to be “off” by a fraction of an inch.

    Also can’t wait for a day that a game is called on account of computer crash.

    That said, this is legitimately groundbreaking research here, and some fascinating insights into how much the limits, bias or competence of the umpires may skew some results.

    At some point I imagine we can get to some overlays of what the strike zone is by count, what a pitcher throws, what the hitter swings at, what the ump called and what the ‘true’ strike zone is, to get some unmistakeable trend lines in individual games. I.e. we should be able to use this game to look at individual at-bats and determine which ones were so far ‘off’ that it eventually radically altered the rest of the game. We could invalidate individual at-bats, perhaps throw out entire games or series, based on having some hard data that the umpiring was game-changingly terrible.

    Comment by Joe — December 19, 2012 @ 4:10 pm

  74. Robo. Ump. Now!

    Comment by zenbitz — December 19, 2012 @ 4:12 pm

  75. I suspect this may be a factor as well, but no idea as to the magnitude.
    Actually, doesn’t pitch f/x track location swing or no swing?

    Comment by zenbitz — December 19, 2012 @ 4:16 pm

  76. Couldn’t this be (partially) explained by pitch type?

    Maybe umpires have a smaller strike zone for off-speed pitches (more likely to be thrown in 0-2 counts) than for fastballs (more likely to be thrown in 3-0 counts, and probably 0-0 counts as well).

    Comment by cyberwulf — December 19, 2012 @ 4:20 pm

  77. how bout breaking them down by league…id love to see statistical analysis either proving or disproving the theory of the national league’s larger strike zone.

    Comment by Ty — December 19, 2012 @ 10:34 pm

  78. Exactly correct. Sample selection bias all the way.

    Comment by David — December 20, 2012 @ 7:57 am

  79. You cannot be so naive as to think that star players already don’t get preferential treatment in every sport.

    Comment by a — December 20, 2012 @ 8:34 am

  80. Thats a pretty trivial problem.

    If the cameras can pick up a the rotation, speed, and position of an object in 3D space, do you really think they can’t pick up a guys knees?

    Comment by Synovia — December 20, 2012 @ 10:20 am

  81. “Also can’t wait for a day that a game is called on account of computer crash.”

    We have imbedded computer systems running pretty much every critical piece of equipment in the world. Its trivial at this point to design simple systems like this and have them run reliably.

    You ever see a fetal heart rate monitor crash? I haven’t either.

    Comment by Synovia — December 20, 2012 @ 10:23 am

  82. Matthew,

    1. You should really be using an interaction of the horizontal and vertical locations in a single smooth. The strike zone is not symmetric as it is shown here. I ran into problems before when I initially proposed GAM instead of loess a while back:

    2. Which visualization package are you using in R to make the heat maps? It looks like “image”, but I find “filled.contour” to be prettier (Dave Allen and others have used this in the past).

    3. In one of your older posts at Lookout Landing, it looks like you were having the same problem I had: But here it looks like you fixed it (using mgcv now, I assume?).

    4. Why not refer people back to previous work by Walsh (THT), Dave Allen (BA), J-Doug (BtB), Weinstock (THT), Mills (PoS), Scorecasting on this? How is this piece adding to that?

    I think this is all very nice and great for another audience. But give credit where credit is due?

    Comment by Millsy — December 20, 2012 @ 1:08 pm

  83. 1. I’ll look at that. Thanks.

    2. I don’t like filled.contour because I find the attached key to be distracting, unneeded and takes space away from the main graph.

    3. I’m not recalling what you’re referring to exactly.

    4. Because I didn’t/haven’t read those.

    Comment by Matthew Carruth — December 20, 2012 @ 1:26 pm

  84. Sorry, the problem in #3 is the vertical stretching of the oval shape. This is not present here.

    Comment by Millsy — December 20, 2012 @ 1:38 pm

  85. Regarding 1) I don’t see where you correct it in the link you provide? I see you raised the concern, but there’s no discussion of an outcome from that concern.

    Comment by Matthew Carruth — December 20, 2012 @ 1:40 pm

  86. Addendum to 4)

    I did find some of the basic R code from a post of yours at some point and clearly the look of the images are similar to yours since out of all the R-based heat maps I’ve seen, I liked your visual presentation best. I should have mentioned that, my apologies.

    Comment by Matthew Carruth — December 20, 2012 @ 1:46 pm

  87. With 1), do you mean the vertical stretching or the interaction? The vertical stretching was a glitch between a new version of R and the “gam” package, which was fixed by using the “mgcv” package (which works better anyway and cross-validates your smoothing parameter). If you mean the interaction term, I have no gone over this at all on my website, but find that it is more representative of what is going on in the zone (though I don’t know that it would have significant effects on the size of the zone).

    Much of my code comes from Dave Allen, but I was mostly talking about the specific problem and methodology. Code is code and that is called open source for a reason. I think everyone (including this) has had additional things to say that are interesting. Just always like to see everything come together and build on the last.

    Comment by Millsy — December 20, 2012 @ 1:58 pm

  88. I meant the interaction, as in what exactly you changed in the code to use that instead.

    However, I’ve actually not been using the mgcv package, wasn’t aware of it. I’m going to test that out now and see how it looks.

    Comment by Matthew Carruth — December 20, 2012 @ 2:38 pm

  89. The interaction would simply use:

    fit1 <- mgcv(strike_call ~ s(px, py, k=50), data=…)

    It gets a bit more into the nitty gritty of the strike calls from what I've seen (evaluates up-and-out, up-and-in, etc.).

    It won't change the relative impacts across counts much, nor will it impact the size of the zone much (well, actually the cross-validated smoothing parameter does). However, it might be more accurate from an R^2 point of view, as well as a "correct call" POV for each umpire.

    Comment by Millsy — December 20, 2012 @ 3:13 pm

  90. cyberwulf,

    Some of the effect does seem to come from pitch type (I have not broken it down visually though). We tend to see fastballs called strikes much more often than other pitches in the same area and in the same given count. This variance is sucked up into the across-count changes. While this won’t change the actual result (strike zone size across count), it could bring into question the causal effect of count on umpire decisions.

    From what I have found, it is a combination of the count, pitch type, and a number of other things.

    Comment by Millsy — December 20, 2012 @ 3:15 pm

  91. PS-I would like for Matt to do the visual breakdown for sure!

    Comment by Millsy — December 20, 2012 @ 3:16 pm

  92. Wow. This is a great idea. I’ll admit that I enjoy the aesthetic of an umpire calling a batter on a strike out, and I think we can all admit those tense moments in big games would be a little less tense with those umpires behind the plate. This idea is a win-win.

    Comment by Ozzie — December 24, 2012 @ 9:14 am

  93. Argh. Without* those umpires behind the plate.

    Comment by Ozzie — December 24, 2012 @ 9:15 am

  94. 1)This could be the result of the league desiring hitters to put the ball in play, so the umpires are instructed accordingly.
    2)Most umpires are right handed and see the left pitches better.
    3)These numbers could also be skewed a bit because good pitchers have more control than bad pitchers. Good pitchers are more likely to get the benefit of the doubt and are less likely to see 3-1 counts.
    4)Also bad catchers at pitch framing are skewing the results as well because the top Aces of baseball rarely pitch to bad pitch framers (look it up yourself). Accordingly, bad pitchers get most of the bad calls from bad pitch framing.

    Comment by kiss my GO NATS — October 26, 2013 @ 2:51 am

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