Kauffman Park Effects Revisited

Well, after almost half a season I thought it would be good to revisit the park effects at Kauffman stadium I blogged about in January. In that analysis I found that during the period from 1991-1994 when the park was astroturf and the dimensions were as they are now the park factor was 109 (in other words 9% more runs were scored in Kauffman Stadium). During the period from 1995-2003 when grass was installed and the fences moved in the park factor remained 109 although during the period 2001-2003 it was around 127, at or near the top each season.

This offseason the fences were moved back and according to the ESPN calculation the park factor thus far in 2004 is 84, good for 27th in baseball. In addition, the factor for homeruns is 69, 29th out of 30 only leading the new PETCO park in San Diego where it is 64.

So it appears that moving the fences has had an effect although it will probably be several years before we know how big the effect is. The other thing I noticed from my previous analysis is that park factors seem to carry a large standard deviation and so yearly weather patterns and other factors may play almost as big a role as park dimensions (.15 for the Kauffman data) for certain ballparks (I would think more so in the midwest). For example, although I don't have any concrete data, this spring in Kansas City has been wetter and cooler than any I can remember since moving to the area in 1995. This idea was born out to some extent in the analysis done about Coors Field I blogged about earlier this month.