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Tuesday, January 31, 2012
Dissecting a mystery pitch
The always affable, generous, and insightful Alan Nathan follows up.
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Technology
Wednesday, January 25, 2012
Rod Cross: Smooth patch on a baseball, to get a curve
Looks like fascinating stuff. I believe Rod Cross, Emeritus Professor at the University of Sydney, is a partner of Alan Nathan.
You can watch the whole thing, or start at the 2:30 minute mark (which is where I have it set). Then there’s video of a pitch from a game.
Glove-slap: G.M.
Thursday, December 29, 2011
Wanna work for the Astros?
Many of you are familiar with the new GM of the Astros, Jeff Luhnow. A week or so ago, I linked to his recent chat on one of the Astros Fan sites. Jeff is highly intelligent, innovative, and a great all-around guy. I imagine that the Astros are going to be an exciting organization to work for.
If you are interested in a database/IT job with the ‘Stros, here is a link to their job offering:
http://baseballjobs.teamworkonline.com/teamwork/r.cfm?i=41068
I’m guessing that it will be sabermetric oriented, among other things. If you apply, tell them you heard about it from The Book/MGL.
Wednesday, December 21, 2011
Alan Nathan’s site
Alan made some re-organization of his site, to make it cleaner and more user-friendly.
Tuesday, October 25, 2011
Practice swings with same or lighter bat, not heavier bat
http://www.ncbi.nlm.nih.gov/pubmed/19593220
That’s a study from the “Department of Kinesiology, Human Performance Laboratory, California State University”. Their testing says to bat with the same or lighter bat, not a heavier bat.
Saturday, October 22, 2011
Batter-pitcher i[Apple] app
Someone want to check this out?
Tom:
I was wondering if you would be interested in taking a look at an iPhone app that I released earlier this year called Batter vs. Pitcher. Much like the Pennant iPad app, it incorporates the Retrosheet.org professional baseball play-by-play event data, but that is where the similarity ends. My app focuses on batter/pitcher match ups, providing summary stats and at-bat details. These stats can be invaluable to people researching the history of the game or fantasy baseball players looking for information to give them an edge on who to sit and who to start. There is also a game mode in the app that baseball enthusiasts should like.
If you have an iPhone, iPod touch, or iPad, and you would like to try the app out, here is a link to the app in the iTunes App Store:
http://itunes.apple.com/us/app/batter-vs-pitcher/id445287806?mt=8&ls=1
Here is a promotional code so that you can get the BvP app for free:
(removed. email and tell him Tango sent you; I don’t know if he will give it to you, but I sure hope he gives it out to at least 5 of you guys )
Also, there is a free “Lite” version of the app available at this link:
http://itunes.apple.com/us/app/batter-vs.-pitcher-lite/id459881743?ls=1&mt=8
If you don’t have a device that the app is compatible with, please feel free to pass the promotional code along to someone who will use it. And if you do use the code, please let me know if you have any questions or problems, or any comments or ideas you might have about the app. Thanks for your time.
Brian Prescott
Wave 39 LLC
Friday, September 16, 2011
College bat impact
Brian gives us the lowdown as to how much the new bats impacted stats. Alan gets prominent mention as well.
Thursday, September 08, 2011
iTunes baseball app
This fellow wrote to me, and said that if you post in the comments (in my thread) asking for a promo code, he’ll give you one.
I would then like you to post on his site, and review it. Be honest.
Wednesday, September 07, 2011
Physics of baseball in the rain
I saw the Yankee highlights, and all the HR hit in the rain. At first I thought it would be extremely hard to hit HR in the rain. But then I thought it would be hard to pitch in the rain too.
I’d be interested to hear from the physicists and those who have played in the rain on the matter. What happens to a pitched ball, to a hit ball. What happens to the grip, to the plane of the swing.
I’d also be interested to hear how PITCHf/x responds to rain, and how accurate the trajectory estimates are.
Thanks for teaching…
Monday, September 05, 2011
What’s up with the interference call in Florida?
Most of you probably read about or watched the controversial umpire call in the PHI/FLO game yesterday. If not, here is a recap:
Score tied 2-2 in the top of the 6th. No outs and Howard on 1st for the Phillies. Hunter Pence hits a line drive to the wall in RF. The Marlin’s RF’er goes back and leaps for the ball at the top of the wall. Some fans ostensibly reach over the wall at the same time. The ball caroms off the wall and Pence has a double with Ryan on third.
Peterson and some other Marlin players are motioning that the fans interfered with the ball. The Marlin’s manager comes out and argues with crew chief Joe West.
The umpires get together, view the play on video, come out, and declare Pence out for fan interference and send Howard back to first.
Manuel, the Phillies’ manager comes out of the dugout to argue, gets ejected from the game (I guess you can’t argue replay calls), and files a protest.
The Phillies and their fans are basically arguing that the play is not reviewable since only a “HR call” is reviewable. They are also arguing, I guess, that even if the play was reviewed as a “HR call,” they cannot then rule on interference based on the replay.
I don’t think there is a clear answer, I don’t know how the protest will play out (protests are rarely upheld), but I have some comments nonetheless:
First of all, I think that the chief umpire, West, lied afterward about several things in order to cover his ass, similar to the way Doug Eddings lied after the “ball hitting the dirt after a K - or not” - episode in the playoffs a few years ago.
For what it is worth, West is generally considered a terrible, arrogant umpire. Eddings is also considered a terrible umpire (along with C.B. Bucknor and Angel Hernandez). From many years of watching baseball, I agree with that consensus (about those 4 umpires).
Here is what West said according to MLB.com and other media websites:
“Because the Phillies wanted me to go look to see if it was a home run, I’ve got to judge whether it went over the fence or not,” West said. “But the plate umpire [Chad Fairchild] already thought it was spectator interference. So now we go look at the replay, we have to take all the evidence we get from the replay. That’s why we came out with, ‘This is the correct ruling.’ ”
He said that the Phillies wanted him to see if it was a HR. Manuel said he did not. If you watch the video, it does not look like Manuel ever came out of the dugout until after the review. So who exactly on the Phillies wanted or asked for a review (to see if it was a HR)? Plus it definitely did not look like a HR so I am not sure why anyone on the Phillies would ask for a review. If anything, they would NOT want a review because of the possibility of fan interference. And who else but Manuel could or would ask for a review? Again, I don’t think he ever came out of the dugout prior to the review.
That being said, according to the rules, no one needs to ASK for a review I don’t think. Here is the rule according to MLB.com:
“Instant replay will apply only to home run calls—whether they are fair or foul, whether they have left the playing field, or whether they have been subject to fan interference. The decision to use instant replay will be made by the umpire crew chief, who also will make the determination as to whether or not a call should be reversed.”
The bolding is mine. Obviously the decision is up to the umpires (the crew chief - West), but the above rule doesn’t say that anyone has to ASK for a review.
That being said, the rule clearly states that replay will only be used for HR calls. So did West decide to review the play to see if it was indeed a HR (absent fan interference or whatever I guess)? I don’t think so. I think he wanted to placate McKeon and the Marlins and see whether there was interference or not. I think that afterward when he realized that he couldn’t do that, he lied about the, “Phillies wanting to review the call to see if it was a HR?”
He didn’t have to use that lie (if indeed it was a lie). He could have simply said that there was some question among the umpires that it might be a HR, so they decided to review it. That would be perfectly legit, as far as I can tell from the above rule.
Now, let’s say that the review was legit. Can they review the play as a “HR call” (obviously when they say “HR call” in the rule, they also mean a “double call” which might have been a HR, IOW a “possible” HR) and then also decide whether it was interference or not? That is the part that is not clear, and I don’t think that there is anything in the rule that suggests they can or they can’t.
In other words, if an umpiring crew properly reviews a “HR call” (fair or foul, over the wall or not, fan interference or not), can they rule on something else that they happen to see (clearly, I assume) in the video? For example, what if they see that the fielder threw his glove at the ball, which is a penalty in and of itself, and they did not see that in live mode?
Now, the replay rule also talks about fan interference. Here is that part again:
“Instant replay will apply only to home run calls—whether they are fair or foul, whether they have left the playing field, or whether they have been subject to fan interference...”
So maybe according to that, they CAN rule on interference. The rule says, “whether they (the batted ball presumably) have been subject to fan interference.”
Obviously this ball WAS subject to fan interference, so it seems that they can rule on it, as long as they were reviewing the play based upon whether it was a HR or not, and not whether there was interference or not.
Back to Country Joe’s statements. Remember he also said this:
But the plate umpire [Chad Fairchild] already thought it was spectator interference. So now we go look at the replay, we have to take all the evidence we get from the replay. ..
I think he is lying about that too! There was no indication that any of the umpires thought it was interference. If they did, they would have called the interference right away, I think. Perhaps, when they got together after McKeon came out to argue, and after the Marlins were complaining about interference, Fairchild said something like, “You know, the fans might have interfered with that ball.” But clearly no one called interfercne right away or at any time for that matter.
Again, even if one of the umpires thought they might have seen interference, or there was some legitimate question as to whether it occurred, they can not, as far as I can tell, look at the replay to clarify that only. That seems to be what they did. I don’t think anyone thought that it might be a HR and I definitely don’t think anyone on the Phillies asked for a HR review.
Now, let’s say that they reviewed the play properly and determined (correctly) that there was fan interference. What is the remedy?
Here is the rule on that:
When there is spectator interference with any thrown or batted ball, the ball shall be dead at the moment of interference and the umpire shall impose such penalties as in his opinion will nullify the act of interference. If spectator interference clearly prevents a fielder from catching a fly ball, the umpire shall declare the batter out.
Again, the bolding is mine. The first part can not always be clear since an umpire can not always know what would have happened if there was no interference. If you watch this video and ask 100 people whether Peterson would have made the catch, I think you are going to get something like a 50/50 response, 70/30 at worst (and I’m not even sure in what direction). But the second part is clearer. The interference must clearly prevent a fielder from catching the ball. Sort of like clear and convincing evidence or some such thing.
Was it clear that Peterson would have caught the ball? I don’t think so, but that is a judgment call.
If MLB decides that the review itself was proper and that the interference call was also proper, I don’t think that they can uphold the protest based on the wording of the interference rule since that is a judgment call. West and co. can simply say, “We thought that the interference clearly prevented the RF’er from catching the ball,” and that would be the end of the story…
Tuesday, August 30, 2011
Physics of tennis courts
I didn’t know that the surface of tennis matches is not covered by its rule book. Fascinating.
But the physics of tennis — those impersonal forces shaping every shot — are not constant. Instead, they largely depend on three separate factors determined by the court surface.
The most important factor is the “coefficient of friction,” a measurement of the abrasive force between the ground and the tennis ball. Courts with high frictional coefficients interfere with the movement of the ball, disrupting its forward momentum. Think of a sluggish clay court. According to experiments performed by the ITF, a shot hit without spin and traveling at 67 mph will lose about 43 percent of its ground speed after contact with the clay surface, slowing down to a leisurely 38 mph. (The reason clay steals momentum is rooted in the friction of all that loose brick, which clumps around the ball. Each clump is like a little speed bump.) As a result, players have a few extra milliseconds to hit a return....
Monday, July 11, 2011
Physics of bats and balls
A nice recap article, with mentions of Alan Nathan.
To test the theory, the authors placed several dozen balls in conditions ranging from 11 percent to 97 percent relative humidity for weeks, and temperatures from the 30s to nearly 100 degrees, then fired them against metal cylinders that approximate bats. Again measuring the coefficient of restitution, they found that the colder and moister a ball was, the less bounce it had. Translation: a ball hit on a hot dry day at an Arizona ballpark will go noticeably farther than the same ball hit on a frigid, foggy day at Boston’s Fenway Park.
As for Denver’s Coors Field, the researchers calculate that a humidity increase from 30 percent to 50 percent would take 14 feet off a 380-foot fly ball—enough to decrease the chances of a home run by 25 percent.
Friday, June 17, 2011
Sportvision Summit
Call for Abstracts
We encourage interested participants and analysts to submit a paper for presentation at the 2011 PITCHfx Summit. Topics relating to PITCHf/x, HITf/x, COMMANDf/x and FIELDf/x are welcome. Previous years included a lively group of speakers that delivered presentation topics including: Pitch Classification, Player Evaluation, Base running, Aerodynamics, and many, many more! Further developments in those areas as well as new topics are encouraged.
Submissions are due: July 11th, 2011
Please submit abstracts and data sample requests to:
Graham Goldbeck
Wednesday, May 25, 2011
Corked bats and humans
I think we talked about this, and we probably linked to Alan’s research. Anyway, here it is again:
http://webusers.npl.illinois.edu/~a-nathan/pob/corked-bat-remarks.pdf
As well as a followup:
http://paws.kettering.edu/~drussell/bats-new/Papers/CheatingPaper.pdf
Bill James noted:
To jump from the conclusion that there’s no trampoline effect to the conclusion that there is no overall effect....I wouldn’t believe it.
Now, what could account for an effect to actually exist, if physics says there shouldn’t be a change? Isn’t it possible that there’s a change in the swing that is too small for us to notice, but has an overall effect? That is, Alan is saying that the speed of swing and weight of bat, and consistency of cork has an overall no effect, all other things equal. But, what if the plane of the swing changes slightly because of the corking? What if accuracy is improved?
Shouldn’t the test therefore be to observe the swings of hitters with and without cork to see if their swing is actually different? What if it’s even a placebo affect that a batter thinks he can wait .01 seconds longer before swinging, and swings harder, while maintaining accuracy?
What if the corking of a bat is simply a change in human response?
***
I’m reminded of the new basketball that was introduced, and immediately panned by the players. The same thing with the new hockey sweaters. Physics can tell us in a controlled environment, all other things equal, what happens. But things change with humans. They sweat, and if the experiment didn’t include a human sweating, then they couldn’t predict the new basketball reaction to sweat. A hockey player will skate in various patterns, and if the players say the sweater is too tight, then that means the experiment didn’t have a good enough human parameter set.
Could this happen with corked bats?
Tuesday, April 19, 2011
College bats
Huge change:
Jeff Sackmann, of CollegeSplits.com, found that college home runs are down by about half from the same point last season. Three percent of batted balls left the park last year, but now the number is 1.7% per batted ball.
...
But there’s a chance the new bat has dampened offense too much. “It’s worse than wood,” one scout said. “Even when [the ball] hits the sweet spot, it doesn’t go anywhere.” It would seem like basic physics. When wood meets ball, the grain in the wood grips the ball and gives it backspin, which leads to loft. Right?Physics professor Alan Nathan is skeptical. As part of the committee that advised the NCAA on the bat change, Nathan initially thought the idea might have had some merit, but then he performed an experiment that showed there was no difference between the spin of a ball off an aluminum bat versus a wood bat. He said the aim of the new bat was to approximate wood with aluminum, not to deaden the bat more than wood.
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