An example is a right-handed pitcher will throw his change-up five times as often to a lefty as he will to a righty. I never knew that. I think everybody in baseball knew it except me. I’ve been around baseball for a longtime but I don’t pick that stuff up. I still don’t understand pitching patterns at all, basically
I can't believe Bill James didn't know that. I'll give him another one: That same RHP will throw many more sliders to a RH batter than he does to a LH batter. It has to do with the principle of ball movement. As a pitcher you generally want to throw balls that tail away from a hitter. A lot of pitchers are throwing circle changes these days and that will tend to have a screwball effect; that is it'll dart down and away from a LH hitter given Bill James example.
This gives me the impression that he's spent too much time immersed in numbers and not enough time watching games