[StyxNCa]

Originally Posted by Garlon

I created all of the historical park factors myself for OOTP9. It was weeks and weeks of work. I used the park data from retrosheet to calcualte the discreet park factors of BA/2B/3B/HR for all parks 1956-present. The park factor each year is actually calculated based on 5 years worth of data with the focus year being half the weight in the analysis. This is how Bill James created his park factors when he created Win Shares. So to see calculate the HR factor for instance you find the HR/AB rate for what a team and their opponent did in the home park and compare it to the HR/AB of what that team and their opponent did on the road.

We don't have 2B and 3B data pre-1956, but we do have Run Scoring data. From the Run Scoring data I had to create a custom formula that involved the Quadratic Formula to create a modifier that could be applied to BA and HR in order to relicate the impact of scoring in each ballpark each season. The variables that go into the Quadratic are different each season for each league.

Ah, ok. Thanks.