Pirate Batters Like Home Cooking

It was pointed out at brewerfan.net that the Pittsburgh offense has done much better at home than on the road this year. Let's compare park adjusted runs/game for all MLB teams so far in 2006:

TEAM      Adj HM R/G   AW R/G   DIFF
Arizona         5.93     4.56    30%
Atlanta         4.80     5.59   -14%
Baltimore       6.15     4.04    52%
Boston          5.39     5.54    -3%
Chicago Cub     4.08     3.77     8%
Chicago Sox     5.73     5.35     7%
Cincinnati      5.32     4.73    13%
Cleveland       5.59     5.81    -4%
Colorado        3.82     4.10    -7%
Detroit         4.62     5.56   -17%
Florida         4.71     4.80    -2%
Houston         4.54     4.62    -2%
Kansas City     4.79     3.41    41%
LA Angels       4.37     4.59    -5%
LA Dodgers      6.10     5.35    14%
Milwaukee       4.85     5.08    -5%
Minnesota       5.27     4.08    29%
NY Mets         4.92     5.28    -7%
NY Yankees      6.26     5.84     7%
Oakland         4.40     4.63    -5%
Philadelphi     4.95     4.95     0%
Pittsburgh      5.88     3.54    66%
San Diego       3.72     6.09   -39%
San Francis     5.27     4.56    16%
Seattle         4.61     4.44     4%
St. Louis       5.14     5.08     1%
Tampa Bay       4.66     3.76    24%
Texas           4.56     5.50   -17%
Toronto         5.86     5.09    15%
Washington      4.39     4.50    -2%
------------------------------------
                                  7%

Wow. While the league average home advantage currently sits at 7%, Pittsburgh batters have pounded out 66% more runs at home than on the road. The next closest team is the Royals, at 41%.

There are a lot of things wrong with these numbers of course. For one, I only accounted for park factors in home games and assumed the road games averaged out. I really should have found a weighted average park factor for each team's away runs/game. Second, I didn't account for the strength of the pitching home or away. There could be significant differences in the level of pitching Pirate batters have had to face at home and on the road.

I think the largest culprit is just dumb luck, however. I bet you'll see these numbers be a lot closer to league average by the end of the year.