Park Factors

Baseball Info Solutions has published (PDF) their park factors for 2006 and for the 2004-2006 seasons combined (which are more reliable). Some highlights:

• Over the past three years, Fenway's effect on right-handed hitters has been minimal - no effect on batting averages, and only a 6% reduction for home runs. For lefties, it has increased batting averages by 7%, but cut home runs by 23% (no shock there). Fenway is by far the best park for hitting doubles, increasing them by 34%.
• Yankee Stadium has not been a problem for right-handed hitters recently - it has increased batting average by 2% and home runs by 5%. Lefties see their batting averages cut by 3%, but there home runs increased by 10%. Despite all this, Yankee Stadium remains a pitcher's park mainly because of its effect on reducing doubles and triples.
• Comiskey is the best home run park in the AL for both lefties and righties.