I've seen documentaries about pitching, especially going back into the old days where people state that left handed pitchers have an advantage on batters. These reasons span from batter position, unique lefty throwing techniques and even the physiology of a human's left hand vs. their right.
Can someone provide detailed evidence whether this is actually true or false?
First of all 10% of the population are left-handed, but amazingly 25% of baseball players are left-handed.
This 2.5 times than average isn't randomly, This fact helps proving that left-handed baseball players has an advantage in baseball.
We need to distinguish between 2 claims:
First one is that Left-handed pitchers have an advantage in baseball.
Washington University aerospace engineer David Peters has done research on this issue and his main conclusions were:
The biggest advantage has to do with the angle of the ball. Three quarters of pitchers are right-handed. A right-handed batter has to look over his left shoulder and the ball is coming at quite an angle. The offset of your eyes gives you depth perception. So when you're looking over your shoulder, you have lost the distance between your two eyes quite a bit, so you have lost that 10th of a second to see the ball. That's why batters switch hit.
Twenty-five percent of players are left-handed, where in real life only 10 percent [of people] are left-handed, so that's proof that they are two-and-a-half-times better.
left-handed batter is closer to first base, so he's got a couple steps advantage trying to beat out a grounder.
Batters mostly have learned from right-handed pitchers.
Second one is that Left-handed pitchers have an advantage over left handed batters
This isn't related to Left-handed but referring to the fact that pitcher has an advantage over batter who bat with the same hand, The claim is that:
This is because a right-handed pitcher's curveball breaks to the left, from his own point of view, which causes it to cross the plate with its lateral movement away from a right-handed batter but towards a left-handed batter (and vice-versa for a left-handed pitcher), and because batters generally find it easier to hit a ball that is over the plate.
So according to the above the answer is Yes.
