Fun with park factors: A follow-up

Busch Stadium: just one of many unique ballparks that I misrepresented. - Rob Grabowski-USA TODAY Sports

A revised look at park factors, with the an assist from the BtBS community.

A few weeks ago, I published a piece looking at Park Factors, which had the robust Beyond the Box Score and sabermetric community at-large voicing their thoughts and concerns over the methodology used. Now, I'm going to attempt to right the wrongs I've committed.

One of the problems was that I didn't double the numbers; park factors are available on FanGraphs's Guts! page, but they're preceded by a little caveat:

All Park Factors have already been halved for use on full season stats.

I astutely overlooked this key note and proceeded to export the park factors to Excel without doubling them. Mitchel Lichtman — one of the authors of The Book — noticed this, and alerted me of it in the comments. He also brought another fallacy in the piece to my attention: Since the park factors are "running" (multi-year), a year-to-year correlation (which was included in the post) would be useless.

The largest lapse on my part, however, was failing to account for changes in the parks. From moving in the fences to installing different kinds of turf and/or grass to importing a humidor, ballparks aren't static, but my previous post gave the impression that they were. Two other commenters informed me of this; now, I've adjusted accordingly.

Below, you'll find the averages and standard deviations for all of the ballparks. Whereas there were 55 in the original article, there are 88 now, as alterations to the park have been considered. Moreover, these factors are all doubled, and will accurately reflect the stadium's effects.

Stadium Years Changes Overall Average 1B Average 2B Average 3B Average HR Average
Coors Field 1995-2001 145.1 123.1 120.6 153.1 151.7
Mile High Stadium 1993-1994 128.0 112.0 108.0 226.0 112.0
Coors Field 2002- Humidor installed 124.7 113.3 116.0 147.2 124.0
Atlanta-Fulton County Stadium 1974-1996 110.8 105.7 101.2 79.0 128.9
Globe Life Park 1994- 109.3 103.9 104.4 133.4 110.4
Chase Field 1998- 108.8 101.8 110.9 151.4 157.8
Metrodome 1982-1986 108.4 101.6 120.8 137.6 105.2
Wrigley Field 1974- 108.4 103.1 101.6 97.2 119.4
Fenway Park 1974- 108.2 103.7 124.6 102.0 98.6
Jarry Park Stadium 1974-1976 108.0 108.0 98.0 116.0 106.0
U.S. Cellular Field 2001- Fences moved in 106.5 97.5 95.8 76.8 124.5
Exhibition Stadium 1977-1989 106.3 96.9 115.7 135.8 106.3
Yankee Stadium (II) 2009- 106.0 100.0 94.0 69.6 120.0
Kauffman Stadium 1995- AstroTurf uninstalled 105.8 106.1 106.2 128.7 95.4
Comiskey Park 1974-1975 105.0 104.0 100.0 122.0 86.0
Metropolitan Stadium 1974-1981 104.8 102.8 95.0 122.3 105.3
Citizens Bank Park 2004-2005 104.0 100.0 98.0 94.0 118.0
Riverfront Stadium 2001-2002 Fences moved in, AstroTurf uninstalled 104.0 98.0 110.0 74.0 110.0
Riverfront Stadium 1974-2000 103.6 96.3 110.9 98.1 108.4
Rogers Centre 2010- AstroTurf installed 103.5 94.5 109.0 114.5 112.0
Great American Ball Park 2003- 103.5 97.3 98.5 80.7 120.7
Metrodome 1987-2009 AstroTurf installed 103.0 100.3 108.1 120.4 96.3
Kingdome 1977-1999 102.9 96.1 107.1 89.9 120.2
Veterans Stadium 1974-2000 102.9 96.7 110.0 116.3 103.1
Citizens Bank Park 2006- Fences moved out 102.5 98.5 100.0 87.5 110.8
Rogers Centre 1990-2004 102.4 96.8 109.1 106.5 106.0
Minute Maid Park 2000-2008 102.4 99.8 96.7 123.6 109.6
Comiskey Park 1976-1985 AstroTurf uninstalled 102.2 99.8 97.6 130.2 90.4
Tropicana Field 1998-1999 102.0 100.0 106.0 114.0 102.0
Three Rivers Stadium 1974-1982 102.0 100.2 104.0 104.9 104.0
Marlins Park 2012- 102.0 102.0 102.0 118.0 78.0
Kauffman Stadium 1974-1994 101.8 101.0 116.1 154.9 77.1
Tiger Stadium 1974-1999 101.5 96.0 91.2 99.1 117.2
Cleveland Stadium 1974-1993 101.3 103.9 94.7 83.6 101.2
Comiskey Park 1986-1990 Fences moved in 101.2 101.2 98.8 144.4 83.6
Rogers Centre 2005-2009 FieldTurf installed 101.2 94.4 104.4 128.4 112.5
Miller Park 2009- Bluegrass installed 100.8 96.0 101.2 102.4 115.6
Three Rivers Stadium 1983-2000 AstroTurf installed 100.8 97.2 106.3 105.6 99.3
Comerica Park 2003- Fences moved in 100.7 103.3 94.7 135.1 96.9
Olympic Stadium 1983-2004 Fences moved in 100.6 97.2 109.8 103.3 94.1
Busch Memorial Stadium 1974-1976 100.0 104.0 102.0 122.0 78.0
Olympic Stadium 1981-1982 Fences moved out 100.0 97.0 109.0 103.0 87.0
Nationals Park 2008- 100.0 103.0 102.0 94.0 99.0
Safeco Field 2013- Fences moved in 100.0 100.0 106.0 78.0 94.0
Target Field 2010- 100.0 102.0 102.0 118.0 86.0
Miller Park 2001-2008 99.8 93.3 99.8 98.5 105.6
Busch Memorial Stadium 1977-1995 AstroTurf installed 99.5 99.6 105.9 130.2 84.2
Camden Yards 1992- 99.5 102.3 91.5 75.5 109.7
Arlington Stadium 1974-1993 99.1 102.5 96.4 89.1 97.4
PNC Park 2001-2008 98.8 104.5 108.8 89.8 88.8
Milwaukee County Stadium 1974-2000 98.8 102.0 90.3 98.8 90.3
Progressive Field 1994- 98.3 100.7 102.2 75.7 94.4
Tropicana Field 2000-2006 FieldTurf installed 98.3 99.7 99.4 117.1 96.6
Turner Field 1997- 98.1 100.9 95.8 95.2 95.4
Minute Maid Park 2009- AstroTurf installed 97.6 98.0 98.8 106.0 108.0
Qualcomm Stadium 1982-1995 Fences moved in 97.3 97.0 88.7 94.7 116.3
Olympic Stadium 1977-1980 97.0 96.5 104.5 123.0 82.5
Busch Memorial Stadium 1996-2005 AstroTurf uninstalled 97.0 99.0 99.2 80.8 97.4
Angel Stadium 1998- Fences raised 96.8 101.9 96.8 77.8 95.4
Angel Stadium 1974-1997 96.4 100.3 90.8 68.0 105.4
Yankee Stadium (I) 1976-2008 96.3 99.4 93.2 86.2 100.1
Memorial Stadium 1980-1989 Fences moved in 96.0 97.2 92.4 57.8 103.6
Veterans Stadium 2001-2003 NexTurf installed 96.0 92.0 104.0 106.0 94.0
Memorial Stadium 1990-1991 Fences moved in 96.0 98.0 96.0 62.0 104.0
Shea Stadium (Yankees) 1974-1975 96.0 96.0 102.0 94.0 94.0
Sun Life Stadium 1993-2011 95.9 98.4 95.7 119.3 90.2
U.S. Cellular Field 1991-2000 95.2 99.2 91.6 102.0 95.2
Candlestick Park 1974-1999 94.9 97.3 95.1 89.4 93.5
PNC Park 2009- Bluegrass installed 94.8 101.6 101.2 84.4 82.4
AT&T Park 2000- 94.4 100.7 100.1 123.1 81.4
Shea Stadium (Mets) 1978-2008 Fences moved in 94.1 99.5 93.5 83.3 94.6
Comerica Park 2000-2002 94.0 106.0 90.0 150.0 80.0
Busch Stadium 2006- 94.0 101.0 93.8 85.0 83.8
Citi Field 2009-2011 94.0 98.0 94.0 118.0 86.0
O.co Coliseum 1974- 92.4 97.3 89.0 82.6 91.9
RFK Memorial Stadium 2005-2007 92.0 96.0 96.0 104.0 82.0
Citi Field 2012- Fences moved in 92.0 94.0 88.0 78.0 106.0
Tropicana Field 2007- FieldTurf Duo installed 91.7 96.3 91.4 118.6 93.4
Dodger Stadium 1974- 91.5 101.1 83.9 57.1 96.3
Shea Stadium (Mets) 1974-1977 91.5 96.0 95.5 87.0 93.5
Safeco Field 2000-2012 90.8 96.5 90.8 76.5 90.2
Petco Park 2013- Fences moved in 90.0 96.0 88.0 108.0 96.0
Astrodome 1989-1999 Fences moved in 90.0 96.4 101.6 104.4 77.6
Memorial Stadium 1974-1979 89.0 94.0 95.7 67.0 88.0
Astrodome 1974-1988 88.8 97.7 94.7 115.1 63.6
Qualcomm Stadium 1974-1981 88.8 100.3 92.0 93.8 77.8
Qualcomm Stadium 1996-2003 Scoreboard put up 86.8 97.8 83.5 88.3 91.8
Petco Park 2004-2012 83.6 93.6 82.4 108.9 79.6

Stadium Years Changes Overall SD 1B SD 2B SD 3B SD HR SD
Wrigley Field 1974- 6.48 3.63 5.80 9.79 14.36
Coors Field 2002- Humidor installed 6.34 2.36 2.58 8.06 6.16
Camden Yards 1992- 4.78 2.36 6.32 6.71 6.86
Atlanta-Fulton County Stadium 1974-1996 4.78 2.45 4.56 9.90 19.23
AT&T Park 2000- 4.73 2.22 2.45 14.87 3.96
Candlestick Park 1974-1999 4.68 2.35 4.20 22.57 8.14
Tiger Stadium 1974-1999 4.53 2.35 7.45 12.85 4.65
Three Rivers Stadium 1974-1982 4.52 1.75 0.94 4.82 7.66
Minute Maid Park 2000-2008 4.50 1.47 2.83 12.25 0.83
Milwaukee County Stadium 1974-2000 4.36 3.08 4.41 6.98 3.76
Progressive Field 1994- 4.21 2.55 2.18 11.01 6.47
Metrodome 1987-2009 AstroTurf installed 4.04 1.73 6.66 11.79 5.42
Fenway Park 1974- 4.04 2.51 5.61 7.24 10.67
Comerica Park 2003- Fences moved in 3.93 1.54 5.14 11.39 5.28
Sun Life Stadium 1993-2011 3.92 2.21 5.00 9.36 3.89
Kauffman Stadium 1995- AstroTurf uninstalled 3.89 2.47 5.58 15.23 9.29
Angel Stadium 1974-1997 3.87 2.11 3.64 7.70 10.81
Olympic Stadium 1983-2004 Fences moved in 3.78 1.56 3.56 9.77 7.83
Dodger Stadium 1974- 3.55 4.29 5.84 7.92 8.81
Riverfront Stadium 1974-2000 3.53 3.11 5.00 11.78 8.56
Kingdome 1977-1999 3.48 1.82 6.77 11.06 17.45
Angel Stadium 1998- Fences raised 3.46 1.49 3.99 4.74 6.11
Exhibition Stadium 1977-1989 3.31 2.56 5.25 11.41 4.63
O.co Coliseum 1974- 3.19 1.77 6.29 11.77 5.92
Qualcomm Stadium 1982-1995 Fences moved in 3.17 2.24 1.79 7.03 6.76
Three Rivers Stadium 1983-2000 AstroTurf installed 3.14 2.02 2.52 6.31 5.54
U.S. Cellular Field 1991-2000 3.12 0.98 3.67 6.20 6.94
Astrodome 1974-1988 3.08 3.34 2.02 15.85 6.86
Arlington Stadium 1974-1993 2.93 2.75 2.94 16.06 8.20
Tropicana Field 2007- FieldTurf Duo installed 2.91 0.70 0.90 4.50 2.56
Globe Life Park 1994- 2.78 1.34 2.65 11.24 5.57
Chase Field 1998- 2.63 1.39 2.74 6.99 4.35
Yankee Stadium (I) 1976-2008 2.47 1.65 2.83 17.90 5.72
Rogers Centre 1990-2004 2.44 1.22 3.99 15.13 7.52
Comiskey Park 1976-1985 AstroTurf uninstalled 2.44 1.89 2.65 6.35 5.71
Busch Memorial Stadium 1977-1995 AstroTurf installed 2.41 2.01 2.55 17.28 4.05
Comiskey Park 1986-1990 Fences moved in 2.40 0.98 2.71 3.88 5.43
Coors Field 1995-2001 2.36 2.36 1.76 6.66 2.71
Shea Stadium (Mets) 1978-2008 Fences moved in 2.32 2.26 2.78 11.50 5.23
Veterans Stadium 1974-2000 2.27 1.24 3.31 9.84 5.67
Memorial Stadium 1974-1979 2.24 0.00 1.80 3.79 3.65
U.S. Cellular Field 2001- Fences moved in 2.10 1.39 1.23 7.08 2.73
Astrodome 1989-1999 Fences moved in 2.09 2.53 2.53 9.33 5.24
Safeco Field 2000-2012 2.01 2.10 2.55 3.34 3.80
Olympic Stadium 1981-1982 Fences moved out 2.00 1.00 3.00 5.00 1.00
Tropicana Field 2000-2006 FieldTurf installed 1.98 1.28 5.83 3.18 2.97
Metrodome 1982-1986 1.96 0.80 1.60 2.33 1.60
Great American Ball Park 2003- 1.92 0.96 2.71 17.19 2.45
Kauffman Stadium 1974-1994 1.84 1.46 4.16 7.87 3.98
Cleveland Stadium 1974-1993 1.82 2.64 2.85 6.05 8.21
Olympic Stadium 1977-1980 1.73 0.87 0.87 1.73 0.87
Qualcomm Stadium 1974-1981 1.71 0.66 1.41 3.38 4.29
Citizens Bank Park 2006- Fences moved out 1.66 2.18 1.73 3.43 3.86
Busch Memorial Stadium 1974-1976 1.63 0.00 0.00 0.00 0.00
Rogers Centre 2005-2009 FieldTurf installed 1.60 1.50 2.65 7.31 2.19
Miller Park 2009- Bluegrass installed 1.60 0.00 0.98 5.43 5.71
PNC Park 2009- Bluegrass installed 1.60 0.80 1.60 0.80 3.20
Metropolitan Stadium 1974-1981 1.39 0.97 1.00 11.38 3.31
PNC Park 2001-2008 1.39 0.87 0.97 2.11 1.39
Miller Park 2001-2008 1.20 0.97 1.20 4.21 2.54
Turner Field 1997- 1.08 1.00 2.16 3.70 1.50
Comiskey Park 1974-1975 1.00 0.00 0.00 0.00 0.00
Busch Memorial Stadium 1996-2005 AstroTurf uninstalled 1.00 1.00 2.99 3.49 5.06
Qualcomm Stadium 1996-2003 Scoreboard put up 0.97 2.33 1.66 9.61 6.51
Memorial Stadium 1980-1989 Fences moved in 0.89 1.60 2.80 5.17 3.56
Shea Stadium (Mets) 1974-1977 0.87 0.00 0.87 1.73 0.87
Rogers Centre 2010- AstroTurf installed 0.87 0.87 1.73 11.26 2.60
Petco Park 2004-2012 0.83 0.83 2.79 4.91 1.26
Minute Maid Park 2009- AstroTurf installed 0.80 0.00 0.98 3.10 0.00
Busch Stadium 2006- 0.00 1.00 0.66 4.36 0.66
Safeco Field 2013- Fences moved in 0.00 0.00 0.00 0.00 0.00
Marlins Park 2012- 0.00 0.00 0.00 0.00 0.00
Citi Field 2009-2011 0.00 0.00 0.00 0.00 0.00
Citi Field 2012- Fences moved in 0.00 0.00 0.00 0.00 0.00
Jarry Park Stadium 1974-1976 0.00 0.00 0.00 0.00 0.00
RFK Memorial Stadium 2005-2007 0.00 0.00 0.00 0.00 0.00
Nationals Park 2008- 0.00 1.00 0.00 4.00 1.00
Petco Park 2013- Fences moved in 0.00 0.00 0.00 0.00 0.00
Veterans Stadium 2001-2003 NexTurf installed 0.00 0.00 0.00 0.00 0.00
Citizens Bank Park 2004-2005 0.00 0.00 0.00 0.00 0.00
Tropicana Field 1998-1999 0.00 0.00 0.00 0.00 0.00
Riverfront Stadium 2001-2002 Fences moved in, AstroTurf uninstalled 0.00 0.00 0.00 0.00 0.00
Mile High Stadium 1993-1994 0.00 0.00 0.00 0.00 0.00
Comerica Park 2000-2002 0.00 0.00 0.00 0.00 0.00
Target Field 2010- 0.00 0.00 0.00 0.00 0.00
Shea Stadium (Yankees) 1974-1975 0.00 0.00 0.00 0.00 0.00
Yankee Stadium (II) 2009- 0.00 0.00 0.00 0.80 0.00
Memorial Stadium 1990-1991 Fences moved in 0.00 0.00 0.00 0.00 0.00

If you know of any ballpark modifications that I've left out, feel free to notify me in the comments or on Twitter.

. . .

All statistics courtesy of FanGraphs.

Ryan Romano writes for Beyond the Box Score, the FanGraphs Community blog, and Camden Chat that one time. Follow him on Twitter at @triple_r_ if you enjoy angry tweets about Maryland sports and live tweeting about Community, Thursdays at 8/7c on NBC. Cool. Coolcoolcool.

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