Wednesday, July 30, 2008

Why is baseball's All-Star Game so non-random?

I've often wondered why the American League seems to win every year, and after this year (when they won again) Columbia's stats blog tallied up the numbers. Since 1965 to the present, the results have been:


With "N" signifying a National league victory, "A" for the American league, and "T" the one year that Bud Selig famously called a tie. As Phil notes,

Predicting next year's winner to be the same as this year's winner would have correctly predicted 80% of the games in [this time period] ... and that's if we pretend the National League won the tie game in 2002. (If we pretend the American League won it, it's 84%).

Especially given how focal these games are, it's very confusing, because saying that one league is better doesn't explain away the trend. How do you explain away the lack of variance?