OOTP Developments Forums - View Single Post

Garlon · 03-31-2019, 09:54 AM

The park factors were calculated from retrosheet data for every park every season from 1871 to present. I created the original file and the calculator to generate the factors. This was a very big project. Pstrickert has been using the calculator to update the file these past few seasons (thank you Pstrickert). The factors are based on 3 seasons of data. If a park generated say 14% more offense than the other parks in the league, then using the quadratic formula we are able to find a value for both BA and HR that generates that result, and this depends on how teams were scoring in a given season based on HR/2B/3B from the league stat totals for every season. The BA factor affects 2B and 3B as well so that's why those stay at 1.000 in the file. Retrosheet does not have the L/R data for ballparks so that's why those are the same for both sets of values.

Keep in mind that what you are arguing probably doesn't affect any individual player's HR totals for Home vs Road by more than 1 or 2 in a season. For example, you mention 12% fewer HR. If your player in question has 40 HRs for the season, and roughly 20 at home, that 12% becomes about 2-3 HR that get redistributed to road vs home. But the file itself is fairly subtle in terms of the factors because if you increase BA/2B/3B/HR by say 5% your scoring will probably increase more than 10%.

I am not understanding what you are saying about the 2018 factors for Fenway Park. Both BA and HR should be 1.03056 according to the file. Over the 2017-2018 seasons there was 5.24% more offense at Fenway than on the road and the 1.03056 factor is designed to recreate that in the game as best as possible.

03-31-2019, 09:54 AM	#7
Garlon Hall Of Famer Join Date: Jun 2004 Posts: 4,258	The park factors were calculated from retrosheet data for every park every season from 1871 to present. I created the original file and the calculator to generate the factors. This was a very big project. Pstrickert has been using the calculator to update the file these past few seasons (thank you Pstrickert). The factors are based on 3 seasons of data. If a park generated say 14% more offense than the other parks in the league, then using the quadratic formula we are able to find a value for both BA and HR that generates that result, and this depends on how teams were scoring in a given season based on HR/2B/3B from the league stat totals for every season. The BA factor affects 2B and 3B as well so that's why those stay at 1.000 in the file. Retrosheet does not have the L/R data for ballparks so that's why those are the same for both sets of values. Keep in mind that what you are arguing probably doesn't affect any individual player's HR totals for Home vs Road by more than 1 or 2 in a season. For example, you mention 12% fewer HR. If your player in question has 40 HRs for the season, and roughly 20 at home, that 12% becomes about 2-3 HR that get redistributed to road vs home. But the file itself is fairly subtle in terms of the factors because if you increase BA/2B/3B/HR by say 5% your scoring will probably increase more than 10%. I am not understanding what you are saying about the 2018 factors for Fenway Park. Both BA and HR should be 1.03056 according to the file. Over the 2017-2018 seasons there was 5.24% more offense at Fenway than on the road and the 1.03056 factor is designed to recreate that in the game as best as possible.