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This single paragraph is all the specifications for a legal ball in baseball[0]: > 3.01 (1.09) The Ball > The ball shall be a sphere formed by yarn wound arou

This single paragraph is all the specifications for a legal ball in baseball[0]: > 3.01 (1.09) The Ball > The ball shall be a sphere formed by yarn wound around a small core of cork, rubber or similar material, covered with two strips of white horsehide or cowhide, tightly stitched together. It shall weigh not less than five nor more than 5 ¼ ounces avoirdupois and measure not less than nine nor more than 9 ¼ inches in circumference. So it leaves a lot of wiggle room, intentional or not, for modifying the baseball to produce different results. As the article points out, 2014 was a great year for pitchers with the fewest home runs since 1995. And that year, 1995, is significant as that was the year of the strike shortened season. I'm still on the fence as to whether this is a good or bad thing (juiced balls) as in the 20s there were rule changes regarding how balls were treated that led to the live ball era[1] and the greatest baseball legend, Babe Ruth. Baseball has a way of balancing out over time, so we may see a wild homerun heyday before getting a period of pitching dominance. Both super fun to watch. 0: http://mlb.mlb.com/mlb/official_info/official_rules/official_rules.jsp http://mlb.mlb.com/mlb/official_info/official_rules/official... 1: https://en.wikipedia.org/wiki/Live-ball_era https://en.wikipedia.org/wiki/Live-ball_era

SpikeDad 9y ago
Naturally since MLB baseballs are basically hand-made. I've seen any number of segments showing how they're manufactured. Very low tech - winding by machine but the covers are sewed on by hand. Statistics are always a two-edged sword. Using home run statistics to "prove" a ball had changed is folly unless you have the data on balls over many years including the variance which as you pointed out can be significant.
tialaramex 9y ago
The article says the newer balls differed in mass by 0.5 grams and that this difference was statistically significant For reference the "not less than five nor more than 5 ¼ ounces avoirdupois" in that rule means 141.747615625 to 148.83499640625 grams. (Yes exactly, the "pound avoirdupois" no longer has any definition except that it's so-and-so many SI kilograms). So 0.5 grams is a pretty big change, but it's way inside the variation allowed. Given the change in composition it seems to me that such a change is to be expected and actually suggests the ball makers did NOT go out of their way to hide what's happened here.

SpikeDad 9y ago

Naturally since MLB baseballs are basically hand-made. I've seen any number of segments showing how they're manufactured. Very low tech - winding by machine but the covers are sewed on by hand. Statistics are always a two-edged sword. Using home run statistics to "prove" a ball had changed is folly unless you have the data on balls over many years including the variance which as you pointed out can be significant.

tialaramex 9y ago

The article says the newer balls differed in mass by 0.5 grams and that this difference was statistically significant For reference the "not less than five nor more than 5 ¼ ounces avoirdupois" in that rule means 141.747615625 to 148.83499640625 grams. (Yes exactly, the "pound avoirdupois" no longer has any definition except that it's so-and-so many SI kilograms). So 0.5 grams is a pretty big change, but it's way inside the variation allowed. Given the change in composition it seems to me that such a change is to be expected and actually suggests the ball makers did NOT go out of their way to hide what's happened here.