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A second study confirms that home runs are up due to a change in the baseball

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Two weeks ago Ben Lindbergh and Mitchel Lichtman released their study at The Ringer which convincingly argues that changes in the composition and construction of the baseball is responsible for the dramatic spike in home runs we’ve seen since the middle of the 2015 season. Yesterday their work was corroborated.

Rob Arthur of FiveThirtyEight, who had last year conducted a study with Lindbergh which proved inconclusive on the matter, has revisited the baseballs as well. Specifically, he used baseball’s data with respect the speed of the ball when it is released from a pitcher’s hand and when it crosses the plate and, based on the loss in velocity in that short period, calculated the ball’s drag coefficient. From that he could compare the drag on the ball from before mid-2015 and the drag since mid-2015.

His conclusion: there has been a significant decrease in the drag on baseballs over the past two years and that decreased drag can account for about five feet of carry on a given fly ball. That, in turn, would account for a 10-15% spike in home runs on average, and a bigger spike in any given month depending on other factors. Arthur:

It’s highly unlikely that we’d see that kind of difference by chance without a real change to the ball: The monthly variation in estimated drag coefficients in the past five seasons varied from around 0.34 to 0.355, a far wider range than we’d expect from random variance alone. In total, the practical effect of shifting from a high-drag month to a low-drag month could be around a 30 percent difference in home run rates.

Arthur cautions us not to become conspiracy theorists here. The change in the ball need not be nefarious as even small alterations in the manufacturing process could lead to these changes. At the same time, he reminds us, that we should ignore MLB’s statements that the balls still fall under the league’s manufacturing requirements and performance parameters, because those parameters are quite broad and allow for these significant variations in ball flight. Even if no one is intentionally doing this and even if the balls are officially up to snuff, they can nonetheless have changed significantly and are the likely culprit for the dramatic home run spike.

Stepping back from the research, this makes a lot of sense. As we’ve noted in the past, there is a long and rich history of changes — even slight changes — to baseball composition leading to dramatic increases and decreases in offensive levels. The dead ball era ended, in large part, because different wool was used beginning in 1919. The National League changed balls in order to intentionally boost offense in 1930 and it worked almost too well. There was a change of baseball manufacturers in the late 1970s which led to a mini spike. 1987 was the year of the so-called “rabbit ball.” That was never fully explained, but there are strong suspicions that Major League Baseball messed with the ball that year.

Other factors matter — new parks with shorter porches, batters making a point to swing with an uppercut, diluted pitching, PEDs, etc. — but none are as significant as changes to the ball itself and none account for the almost immediate spike in homers in the middle of the 2015 season.

Anyway, enjoy the dingers. They’re here to stay. Or at least until the baseballs change again.

 

Bryce Harper defeats Kyle Schwarber 19-18 to win the 2018 Home Run Derby

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Bryce Harper, who said he was tired after taking his cuts in the first round, certainly appeared gassed in the final round. So, too, did his dad, who was throwing to him. But Harper caught fire, going on a tear and tying Kyle Schwarber with 18 home runs before time expired in the final round of the 2018 Home Run Derby. Harper unlocked 30 seconds of bonus time by hitting two home runs at least 440 feet. With his second swing in bonus time, Harper homered to straightaway center field for No. 19. He tossed his bat in celebration, grabbed his trophy, then gave it to his dad before he was mobbed on the field by his All-Star teammates.

Harper hit 13 home runs in the first round, eliminating Freddie Freeman and advancing to the semifinals. In the semis, Harper topped Max Muncy 13-12 to advance to the finals. On Schwarber’s side of the bracket, he bested Alex Bregman 16-15, then defeated Rhys Hoskins 21-20.

Harper is the first member of the Nationals (or Expos) to win the Home Run Derby. Harper participated in the 2013 Derby but finished in second place behind Yoenis Céspedes. Harper is also the first left-handed hitter to win the Derby since Prince Fielder in 2012. The only players to win the Derby in their home park are Todd Frazier in 2015 and Ryne Sandberg in 1990.

As a spectator, the 2018 Home Run Derby was tons of fun. The four-minute clock adds a lot of tension and intrigue even to the initial rounds. Seeing teammates cheer and get excited for their teammates in the Derby is really fun. Of course, watching dinger after dinger is cool, too. Can’t wait for next year.