Homer Havens?

In a story posted on mlb.com by Jesse Sanchez the top homerun parks in the majors are discussed. While the story was well-written and interesting with its quotes from players as to their favorite parks in which to hit and to hit homeruns, anyone with a sabermetric bent will immediately spot the analytical problem with the article.

The article lists the following as the homer havens.

1. U.S. Cellular Field
2. Citizens Banks
3. Coors Field
4. Wrigely Field
5. Yankee Stadium
6. Great American Ballpark
7. Ameriquest Field
8. Bank One
9. Fenway Park
10. Oakland Coliseum

And the top 5 parks that are not homer havens are:

1. Olympic Stadium
2. PETCO Park
3. Shea Stadium
4. Miller Park
5. PNC Park

Both of these lists were determined by looking at the total number of homeruns hit in the park this season. The context, which is the home team's hitters and pitchers is entirely missing. Could it be that Yankee Stadium makes the top 10 because they have Giambi, Sheffield, ARod and the rest? In order to more accurately see which are the homer havens and which parks suppress homeruns you need to contextualize the stats by looking at the difference in homeruns for home and away games for the team in the park using a formula like the one used on ESPN:

HR PF = (HR in Park/Games in Park)/(HR in Road Games/Road Games)

Doing that you get the following lists:

1. Turner Field
2. Wrigley Field
3. U.S. Cellular Field
4. Coors Field
5. Skydome
6. Citizens Bank
7. Bank One
8. Network Coliseum
9. Fenway Park
10. Ameriquest Field

While eight of the ten parks are the same, Turner Field goes from nowhere to first while Yankee Stadium and the Great American Ballpark drops out with Skydome entering the list. This is the case because the Braves don't hit that many homeruns while the Yankees do.

On the other end of the spectrum the bottom five are:

1. PETCO
2. Jacobs Field
3. Shea Stadium
4. Busch Stadium
5. Kauffman Stadium

Only three of the five listed in the Sanchez article actually depress homeruns very much (Olympic Stadium was sixth) and PNC Park actually has a positive HR factor (1.022).