Here is how the component park factors I published last night correlate with the overall runs park factor. Bars that exit the shaded area are significant correlations. What I like about this is that it shows what is behind a traditional runs-based park factor. A park's effects on runs per game are determined primarily by: * Home Runs per Ball in Play * Doubles per Ball in Play * Balls in Play per Plate Appearance (or, in mirror image, strikeouts per PA)* All of these trickle down to affect plate appearances per game, which is higher in hitter parks than pitcher parks. Whether the BIP/PA effect is due to the park's specific effects on pitch motion and/or visibility, or players adjusting their approach to the park as Sky suggested, is hard to say.