Actually, baseball is a sport where home field advantage makes a noticeable difference in the game, stemming from the home team batting last. In football and basketball it's much more of a minimal difference. So, for situations like the last Astro series, the games could've been played in Wrigley with the Astros batting last, and they'd have more of a home field advantage than the Cubs. Without actually looking at statistics, I think it would be hard to guess which sport (between football, baseball and basketball) as a biggest HFA. Baseball probably has the least variation, but I believe that to be because over the long grind of a baseball season, these things tend to even out at least a tiny bit.