There's been a lot of discussion the last few days on the net and in the mainstream press about the unusually large home field advantage that has shown up this season across the majors. The Mets have been no exception. Going into tonight's game, the Mets have a .607 winning percentage at home and .382 away, which sounds more like a football or basketball differential than a baseball one. The Mets current 2008 differential comes out to a difference of .225 home over away. If extended over a full season, that would be the largest home/away differential in Mets history, topping the previous high of .210 in 1963 (.420 home, .210 away).
Last year the Mets had a home park disadvantage, .580 on the road and only .506 at home.Overall since 1962 the Mets have had an .069 home/road differential. Since 1962, the largest home/road differentials by a single team over one full season have been by the 1996 Rockies and 1987 Twins, who each had win percentages a full .333 greater at home than on the road. This season so far, two teams, Atlanta and Boston, have larger differentials than that. The biggest road advantage by any team since 1962 has been the 1994 Cubs, who were .339 at home and .537 on the road.
Since 1962, on average 15% of teams end up the season with a higher road percentage than home percentage and about 2 to 3% complete a season with identical home and road percentages, while the other 82% or so win more at home than on the road. This season so far (going into tonight's games), only the Giants and Angels among the 30 MLB clubs have a road over home advantage. The Mets, despite having a home over road differential that would be the highest in team history over a full season, have only the seventh highest home/road differential in the majors so far in 2008.