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Thursday, May 24, 2018

Key takeaways from MLB study of HR rate

Baseball’s home run surge of recent seasons is attributable not to a bouncier—or “juiced”—baseball, but rather to better carry resulting in longer fly-ball distances, a committee of experts has concluded.

In a report of findings released by Major League Baseball on Thursday and available at MLB.com, the independent committee chaired by Alan Nathan, professor emeritus of physics at the University of Illinois at Urbana-Champaign, concluded its research had achieved “partial success,” in that it had discovered that reduced drag on the baseballs was responsible for the rising home run rate but had not found any changes in properties of the balls that could account for the reduced drag.

MLB’s news release (PDF)

Full report: Report of the Committee Studying Home Run Rates in Major League Baseball (PDF)

Los Angeles El Hombre of Anaheim Posted: May 24, 2018 at 02:16 PM | 23 comment(s) Login to Bookmark
  Tags: chicks dig the long ball

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   1. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 02:38 PM (#5679055)
oncluded its research had achieved “partial success,” in that it had discovered that reduced drag on the baseballs was responsible for the rising home run rate but had not found any changes in properties of the balls that could account for the reduced drag.

Well, keep looking then. I don't think the air has changed.
   2. Barry`s_Lazy_Boy Posted: May 24, 2018 at 02:44 PM (#5679059)

But the report does not rule out the possibility that manufacturing advances have contributed to the reduced drag by creating a more spherically symmetrical ball with a more properly centered pill (which would in theory lead to a lower drag). Nathan said the tools available to the researchers are not precise enough to properly determine one way or another whether that was the case.

   3. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 02:47 PM (#5679062)
But the report does not rule out the possibility that manufacturing advances have contributed to the reduced drag...


It has to be something about the ball. If drag is lower, the ball has changed.
   4. Baldrick Posted: May 24, 2018 at 02:47 PM (#5679063)
Nathan said he understands that there will be people unsatisfied with the committee's incomplete answers.

"As a scientist, it is what it is," he said. "We don't want to claim more than we can legitimately claim. To admit that there are things that we don't know, we don't like to have to admit that. But that's what we have to admit."

I'm glad they did this. And it seems like it was a serious and comprehensive effort. I have to say, though, that I'm a little bit skeptical of their ability to rule out all the things they discussed. Obviously SOMETHING is happening, and I'm not sure I'm persuaded that "it doesn't seem like any of the obvious things" is more persuasive than "something about the way we measured things led us to believe it wasn't X, but we'll eventually realize we made a mistake."

Curious to see what else is done on this front.
   5. Kiko Sakata Posted: May 24, 2018 at 02:49 PM (#5679065)
Baseball’s home run surge of recent seasons is attributable not to a bouncier—or “juiced”—baseball, but rather to better carry resulting in longer fly-ball distances, a committee of experts has concluded.


I'm not an expert in physics, and haven't read the report (because I'm not sure how well I'd understand it) but the above sentence seems to me to misunderstand what I've always understood people to mean when they talk about a "juiced" ball. I've always understood the term to be a colloquialism where "juiced ball" equals "ball with better carry". In other words, the second half of that sentence reads to me like it says that the issue is, indeed, a "juiced" baseball.
   6. PreservedFish Posted: May 24, 2018 at 02:50 PM (#5679066)
Guys, guys, the balls aren't bouncier, they just bounce further and faster than they used to! Huge difference.
   7. Adam Starblind Posted: May 24, 2018 at 02:51 PM (#5679067)
Pitchers have said the ball feels "slicker."
   8. Los Angeles El Hombre of Anaheim Posted: May 24, 2018 at 03:04 PM (#5679077)
That's just responsible manscaping.
   9. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 03:16 PM (#5679094)
Pitchers have said the ball feels "slicker."

Yes. That would make the ball have less drag. It could also hinder the ability to throw breaking pitches.

I wouldn't mind the latter (to cut down on Ks) if they deadened the ball to prevent the HR spike.
   10. Tom Nawrocki Posted: May 24, 2018 at 03:39 PM (#5679109)
Reduced drag would allow pitchers to throw the ball slightly faster as well. It would help to explain the rise in both Ks and HRs.
   11. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 03:50 PM (#5679118)
Reduced drag would allow pitchers to throw the ball slightly faster as well. It would help to explain the rise in both Ks and HRs.

True. It would also encourage the use of "foreign substances" to add spin.
   12. Walt Davis Posted: May 24, 2018 at 05:42 PM (#5679180)
#5: I assume they are distinguishing between the "elasticity" (probably not the proper physics term) of the ball (i.e. its "juiciness") vs. other physical properties. Basically (I think), the ball isn't coming off of the bat faster, it's (for some reason) facing less resistance after it leaves the bat. For a strained analogy, you can make a car go faster by putting in a bigger engine or by making it lighter or by improving its aerodynamics. They're saying it's the aerodynamics, not the weight or the engine that has changed.

But sure, when we say "juiced", we don't really care why it's juiced.

On the "manufacturing advances" issue ... well, maybe. The curious thing about the HR surge has always been that it appeared in mid-2015. HR rate was 2.5% before the break, 2.85% after. That pretty much ruled out changes in batter strategy or league-wide juicing of the other sort. It should be easy enough to know when those balls were produced and whether any manufacturing changes happened at the same time.

Anyway, if I get the excerpt right, they're saying "it's got better aerodynamics but we don't know why" ... which given they're physicists is not impressing me very much. Still, glad to see baseball take this seriously enough to appoint a blue ribbon committee. :-)
   13. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 06:03 PM (#5679191)
Anyway, if I get the excerpt right, they're saying "it's got better aerodynamics but we don't know why" ... which given they're physicists is not impressing me very much.

Yeah. Don't they have wind-tunnels and crap to test this sort of thing?
   14. the Hugh Jorgan returns Posted: May 24, 2018 at 06:45 PM (#5679206)
"it's got better aerodynamics but we don't know why"


manufacturing advances have contributed to the reduced drag by creating a more spherically symmetrical ball with a more properly centered pill (which would in theory lead to a lower drag).


Am I missing something? My understanding of physics is about as comprehensive as Cole Calhoun's understanding of hitting right now, but I would think with advances in precise manufacturing producing a ball that is close to a perfect sphere with perfect balance would have less drag. Or am I talking out my arse as usual?
   15. snapper (history's 42nd greatest monster) Posted: May 24, 2018 at 07:00 PM (#5679211)
Am I missing something? My understanding of physics is about as comprehensive as Cole Calhoun's understanding of hitting right now, but I would think with advances in precise manufacturing producing a ball that is close to a perfect sphere with perfect balance would have less drag. Or am I talking out my arse as usual?

I'm not sure. The dimples on a golf ball reduce drag, so I'm not sure a perfect sphere is optimal.

The balance point I agree with. A wobbly ball never carries far.
   16. the Hugh Jorgan returns Posted: May 24, 2018 at 07:43 PM (#5679227)
I'm not sure. The dimples on a golf ball reduce drag, so I'm not sure a perfect sphere is optimal.

The balance point I agree with. A wobbly ball never carries far.


OK, fair enough on both points.

As Walt points out, you would think physicists would kind of know this stuff off the top of their head?
   17. Sunday silence Posted: May 24, 2018 at 07:57 PM (#5679232)
they did a study like this last year (not MLB sponsored) using balls made before and after the surge, not sure if it was before or after the 2015 ASB or between 2015/2016 in any event they found the balls to be bouncier. I sent the article to Jim, but it never showed up and I've given up on submitting articles since the process does not seem to be transparent.

If the balls were more symmetrical or had less wobble, you would think they would be able to compare balls made before and after surge. Was there any mention of this in the article?
   18. Rennie's Tenet Posted: May 24, 2018 at 08:24 PM (#5679245)
Doesn't this support what Canseco said?
   19. Benji Gil Gamesh VII - The Opt-Out Awakens Posted: May 24, 2018 at 10:12 PM (#5679326)
@17, here's the finding that related specifically to pre- and post-ASB 2015:

6. The increase in home runs between pre-ASG 2015 (2015a) and post-ASG
2015 (2015b) do not follow the pattern of subsequent increases.
StatCast data show that the 2015a-2015b increase is primarily due to
increased exit velocity rather than reduced drag. Nevertheless, the
detailed dependence of exit velocity on launch angle is inconsistent
with the pattern that would be expected if the increase were due to
an elevated coefficient of restitution (COR) of the ball. Moreover, an
increased exit velocity between 2015a and 2015b is not confirmed by
HITf/x data, which instead support the conclusion that changes in the
home run rate since 2015 are primarily the result of reduced drag rather
than higher exit velocity. It appears that the 2015a StatCast data are
anomalous. Perhaps that it not surprising, given that 2015 was the
first season for StatCast and contained a number of adjustments and
recalibrations.

   20. Benji Gil Gamesh VII - The Opt-Out Awakens Posted: May 24, 2018 at 10:20 PM (#5679333)
"One of the things we asked Rawlings is to tell us every single change you made to the manufacturing process since 2014," Nathan said. "One of the changes was to the mold they use to manufacture the pill [in May 2015], because the old mold had worn out. We thought long and hard about this and concluded it had no effect whatsoever on any of the parameters we can measure."
Hmmm...mold changes in May 2015. At what point were baseballs delivered to MLB suddenly mostly/entirely produced with that new mold?

That seems to warrant more scrutiny, given the sudden 2015 mid-year surge. More than just "thinking long and hard."
   21. Ray (CTL) Posted: May 24, 2018 at 10:39 PM (#5679340)
There were 412 more home runs hit last year than in the year 2000.

There were 10,237 more drug tests last year than in the year 2000.

And now we have the above study. We had other studies too, back in the day, that didn't support the steroids narrative.

Some folks should revisit their core assumptions. An entire generation of great players were slandered and smeared and told their performances weren't earned or real.
   22. Ray (CTL) Posted: May 24, 2018 at 11:29 PM (#5679387)
<wrong thread>
   23. Jose is an Absurd Force of Nature Posted: May 25, 2018 at 08:43 AM (#5679438)
Sudden league wide changes being attributed to the baseballs seems a hell of a lot more feasible than "suddenly everyone has changed their swing" or "suddenly everyone is taking steroids."

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