Theoretically you should not compare different eras in baseball; from Ray Chapman being killed by a pitch he probably did not see in 1920, to integration (why does baseball statistics follow one league and not the Negro leagues ?), the mound being lowered after Bob Gibson's 1.12 ERA in 1968, different parks, weather conditions, strength of schedule, insect attacks, etc.Quoting Wikipedia:QuoteOrganized baseball lends itself to statistics to a greater degree than many other sports. Each play is discrete and has a relatively small number of possible outcomes. (In contrast, sports such as hockey, basketball, soccer, and American football are more fluid and harder to describe as discrete plays.)So the idea that you can compare the players's impact by their numbers is more easily implemented. On a normal game, everyone gets their chance, you don't run plays for this or that player, and it seems possible that you can use statistics to build a better team.Once you considers how many cheaters are in the Hall of Fame, though, you should have Pete Rose, Bonds, McGwire and A-Fraud there too ... they're as much part of the game as players like Ripken, Jeter and others who have a cleaner image.