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Monday, October 18, 2004

Kauffman Park Effects 2004

Since the season is over for the Royals I thought I'd update the Kauffman Stadium run scoring spreadsheet that I started before the season started and blogged about previously.

My interest in this began when considering how the fences being moved back 10 feet at the K last winter would affect the run scoring at the park. So here are the updated numbers:

	Home				Away			Index		

Games Royals Opp Opp%+ Games Royals Opp Opp%+ Royals Opp Overall
2004 80 338 426 26% 82 382 479 25% -9% -9% -9%
2003 80 433 512 18% 82 403 355 -12% 10% 48% 28%
2002 81 434 505 16% 81 303 386 27% 43% 31% 36%
2001 81 382 485 27% 81 347 373 7% 10% 30% 20%
2000 81 451 488 8% 81 428 442 3% 5% 10% 8%
1999 80 441 449 2% 81 415 472 14% 8% -4% 2%
1998 80 353 492 39% 81 461 407 -12% -22% 22% -1%
1997 80 387 434 12% 81 360 386 7% 9% 14% 11%
1996 80 372 369 -1% 81 374 417 11% 1% -10% -5%
1995 72 285 346 21% 72 344 345 0% -17% 0% -8%
1994 59 325 287 -12% 58 249 245 -2% 28% 15% 22%
1993 81 370 354 -4% 81 305 340 11% 21% 4% 12%
1992 81 314 346 10% 81 296 331 12% 6% 5% 5%
1991 81 344 378 10% 81 383 344 -10% -10% 10% -1%

91-94 302 1353 1365 1% 301 1233 1260 2% 9% 8% 9%
95-03 715 3538 4080 15% 721 3435 3583 4% 4% 15% 9%

As you might have expected the end result is that fewer runs were scored at Kauffman Stadium this season than on the road to the tune of 9% - obviously a big difference from the trend of 2001-2003 when about 26% more runs were scored at the K and the historical trend of +9% since 1991. One shudders to think how many runs Darrell May and Brian Anderson might have given up with the fences at their 2003 distances. As it was they gave up 38 and 33 homeruns respectively, the former setting a Royals record.

However, these quick and dirty numbers don't translate directly into park factors used by sabermetricians to normalize statistics such as OPS and Runs Created. The calculation of BPF (Batter Park Factor) and PPF (Pitcher Park Factor) is rather complicated and a complete explanation can be found on baseball-reference.com using the same basic formula as Total Baseball and originally documented in The Hidden Game of Baseball.

Suffice it to say the BPF and PPF also take into account things like:

1) the innings pitched difference between home and road games (a good team at home will get fewer at bats and thus score fewer runs than on the road)
2) the impact of the team's park on the park factors of other teams
3) the fact that hitters don't get to bat against their own pitchers and vice versa
4) and that a player only plays half his games at his home park.

In addition they are typically calculated using averages over several seasons (I think it might make more sense to use weighted averages since I would assume that weather patterns varied by groups of years as well as single years). This is important since there is a large element of variation in run totals in a park from season to season based on weather, individual players, and simply luck. So I wouldn't be surprised if run scoring increased at the K next year since we had a cooler and wetter summer in KC than in years past.

So the BPF and PPF for these seasons from baseball-reference.com, which uses a 3 year average, actually calculate to:

Year BPF PPF
2004 95 96
2003 113 112
2002 117 115
2001 110 109
2000 104 103
1999 101 101
1998 104 105
1997 102 103
1996 97 98
1995 103 103
1994 104 104
1993 104 105
1992 103 103
1991 100 101

Obviously this tends to even out the fluctuations between 1994-95 and 1997-98. And it would appear that the factors of 95/96 for 2004 may not be the result of a three year average. If they were the BPF would have to have been very low indeed. If not, then this makes sense when configuration changes are made to the park as was the case at the K this season.

1 comment:

Anonymous said...

Are you going to do 2005?