texasdave
10-02-2007, 08:23 PM
This is a brief, informal look at home runs and park factors. It is evident that it is easier to home runs in some ballparks than it is in others. I was just curious as to how much difference it would make. I took the 2007 NL park factors for each stadium from ESPN.
(I would have used 3-year park factors, but I couldn't find them so I settled for 1-year park factors.) These park factors where then used to adjust the home runs that each club hit in 2007. The way this was done is that if the park factor for a specific stadium was 1.1 and a team hit 10 home runs there, then 10 was divided by 1.1 to get 9.09. That is the number a that would have been hit had the park factor been 1.0 (or neutral). Of course this isn't the perfect way to make adjustments. But I am not that math-savvy and this probably adjusts it close enough to give a basic understanding of how park factors would affect a team's total home runs. Anyway here is how it played out:
TEAM ACT-HR PFN-HR DIFF %DIFF
MIL 231 221 10 4.5%
PHI 213 188 25 13.3%
CIN 204 180 24 13.3%
FLA 201 203 -2 -1.0%
NYM 177 185 -8 -4.3%
ATL 176 181 -5 -2.8%
ARI 171 166 5 3.0%
SDP 169 199 -30 -15.1%
COL 169 151 18 11.9%
HOU 167 161 6 3.7%
CHC 151 140 11 7.9%
PIT 148 167 -19 -11.4%
STL 141 162 -21 -13.0%
SFG 131 140 -9 -6.4%
LAD 129 128 1 0.8%
WSN 123 145 -22 -15.2%
Adjusting for Park Factor probably gives us a truer picture of a team's power. Philadelphia and Cincinnati had the easiest stadiums to hit homers, according to the ESPN Park Factors, and they both hit around 25 home runs more than they would expect to hit in a Park Factor Neutral stadium. This worked out to about 13% more homers. On the flip side San Diego and Washington were penalized most by their stadiums. They each would have hit about 15% more in a PFN stadium. That adds up to roughly a 30% difference between the easiest and hardest stadiums in which to go yard. Which is quite a difference, IMO.
I then took a look at all NL players who hit more than 20 home runs in 2007 (and any Red who hit more than 15). This is not a knock or evaluation of any player.
PLAYER ACT-HR PFN-HR DIFF %DIFF
FIELDER 50 48 2 4.2%
HOWARD 47 43 4 9.3%
DUNN 40 36 4 11.1%
HOLIDAY 36 31 5 16.1%
CABRERA 34 35 -1 -2.9%
BRAUN 34 34 0 0.0%
BERKMAN 34 33 1 3.0%
SORIANO 33 31 2 6.5%
BELTRAN 33 36 -3 -8.3%
PUJOLS 32 35 -3 -8.6%
C.YOUNG 32 32 0 0.0%
C. LEE 32 31 1 3.2%
UGGLA 31 30 1 3.3%
ROLLINS 30 26 4 15.4%
PHILIPS 30 26 4 15.4%
GRIFFEY 30 27 3 11.1%
AD.GONZ 30 33 -3 -9.1%
BURRELL 30 26 4 15.4%
HAWPE 29 27 2 7.4%
H.RAMRZ 29 29 0 0.0%
C.JONES 29 31 -2 -6.5%
BONDS 28 32 -4 -12.5%
ROWAND 27 23 4 17.4%
GREENE 27 33 -6 -18.2%
HARDY 26 24 2 8.3%
A.RAMRZ 26 24 2 8.3%
A.JONES 26 26 0 0.0%
ATKINS 25 24 1 4.2%
ZIMERMN 24 28 -4 -14.3%
TLWTSKI 24 21 3 14.3%
HART 24 24 0 0.0%
DELGADO 24 24 0 0.0%
UTLEY 22 19 3 15.8%
D. LEE 22 19 3 15.8%
WILNGHM 21 21 0 0.0%
LAROCHE 21 25 -4 -16.0%
JENKINS 21 21 0 0.0%
DUNCAN 21 24 -3 -12.5%
CAMERN 21 26 -5 -19.2%
BYRNES 21 19 2 10.5%
BAY 21 23 -2 -8.7%
NADY 20 21 -1 -4.8%
KENT 20 21 -1 -4.8%
FELIZ 20 21 -1 -4.8%
HAMLTN 19 17 2 11.8%
ROSS 17 14 3 21.4%
EDE 16 14 2 14.3%
AL.GONZ 16 15 1 6.7%
It appears that the upper and lower limits of how much a stadium helps or hurts any particular player in going deep is approximately five.
This would indicate that a player who hit 30 home runs in a Park Factor Neutral stadium would hit roughly 35 in the easiest of stadiums in which to hit home runs, and 25 in the most difficult of stadiums in which to hit home runs.
(I would have used 3-year park factors, but I couldn't find them so I settled for 1-year park factors.) These park factors where then used to adjust the home runs that each club hit in 2007. The way this was done is that if the park factor for a specific stadium was 1.1 and a team hit 10 home runs there, then 10 was divided by 1.1 to get 9.09. That is the number a that would have been hit had the park factor been 1.0 (or neutral). Of course this isn't the perfect way to make adjustments. But I am not that math-savvy and this probably adjusts it close enough to give a basic understanding of how park factors would affect a team's total home runs. Anyway here is how it played out:
TEAM ACT-HR PFN-HR DIFF %DIFF
MIL 231 221 10 4.5%
PHI 213 188 25 13.3%
CIN 204 180 24 13.3%
FLA 201 203 -2 -1.0%
NYM 177 185 -8 -4.3%
ATL 176 181 -5 -2.8%
ARI 171 166 5 3.0%
SDP 169 199 -30 -15.1%
COL 169 151 18 11.9%
HOU 167 161 6 3.7%
CHC 151 140 11 7.9%
PIT 148 167 -19 -11.4%
STL 141 162 -21 -13.0%
SFG 131 140 -9 -6.4%
LAD 129 128 1 0.8%
WSN 123 145 -22 -15.2%
Adjusting for Park Factor probably gives us a truer picture of a team's power. Philadelphia and Cincinnati had the easiest stadiums to hit homers, according to the ESPN Park Factors, and they both hit around 25 home runs more than they would expect to hit in a Park Factor Neutral stadium. This worked out to about 13% more homers. On the flip side San Diego and Washington were penalized most by their stadiums. They each would have hit about 15% more in a PFN stadium. That adds up to roughly a 30% difference between the easiest and hardest stadiums in which to go yard. Which is quite a difference, IMO.
I then took a look at all NL players who hit more than 20 home runs in 2007 (and any Red who hit more than 15). This is not a knock or evaluation of any player.
PLAYER ACT-HR PFN-HR DIFF %DIFF
FIELDER 50 48 2 4.2%
HOWARD 47 43 4 9.3%
DUNN 40 36 4 11.1%
HOLIDAY 36 31 5 16.1%
CABRERA 34 35 -1 -2.9%
BRAUN 34 34 0 0.0%
BERKMAN 34 33 1 3.0%
SORIANO 33 31 2 6.5%
BELTRAN 33 36 -3 -8.3%
PUJOLS 32 35 -3 -8.6%
C.YOUNG 32 32 0 0.0%
C. LEE 32 31 1 3.2%
UGGLA 31 30 1 3.3%
ROLLINS 30 26 4 15.4%
PHILIPS 30 26 4 15.4%
GRIFFEY 30 27 3 11.1%
AD.GONZ 30 33 -3 -9.1%
BURRELL 30 26 4 15.4%
HAWPE 29 27 2 7.4%
H.RAMRZ 29 29 0 0.0%
C.JONES 29 31 -2 -6.5%
BONDS 28 32 -4 -12.5%
ROWAND 27 23 4 17.4%
GREENE 27 33 -6 -18.2%
HARDY 26 24 2 8.3%
A.RAMRZ 26 24 2 8.3%
A.JONES 26 26 0 0.0%
ATKINS 25 24 1 4.2%
ZIMERMN 24 28 -4 -14.3%
TLWTSKI 24 21 3 14.3%
HART 24 24 0 0.0%
DELGADO 24 24 0 0.0%
UTLEY 22 19 3 15.8%
D. LEE 22 19 3 15.8%
WILNGHM 21 21 0 0.0%
LAROCHE 21 25 -4 -16.0%
JENKINS 21 21 0 0.0%
DUNCAN 21 24 -3 -12.5%
CAMERN 21 26 -5 -19.2%
BYRNES 21 19 2 10.5%
BAY 21 23 -2 -8.7%
NADY 20 21 -1 -4.8%
KENT 20 21 -1 -4.8%
FELIZ 20 21 -1 -4.8%
HAMLTN 19 17 2 11.8%
ROSS 17 14 3 21.4%
EDE 16 14 2 14.3%
AL.GONZ 16 15 1 6.7%
It appears that the upper and lower limits of how much a stadium helps or hurts any particular player in going deep is approximately five.
This would indicate that a player who hit 30 home runs in a Park Factor Neutral stadium would hit roughly 35 in the easiest of stadiums in which to hit home runs, and 25 in the most difficult of stadiums in which to hit home runs.