The Z Files: Intriguing 2019 Park Factor Notes

It's time to turn the page on 2019 and begin thinking about 2020. There are already several sets of initial rankings for next season floating around cyberspace. These are all subjective in nature, and there's nothing wrong with that. Personally, I prefer a more objective foundation, involving a statistical projection converted into expected earnings, though both entities are fraught with error. Still, I know this going in and am more comfortable massaging rankings based on my formulaic expectations.

In brief, the manner I generate a player projection is to convert their stats to a neutral environment, apply a weighted average over the last three seasons, regress the appropriate stats to flesh out luck, return the numbers to the player's park context and adjust for playing time.

The first step in the process is determining the 2019 park factors. I use the method described in The Bill James Handbook published by Baseball Info Solutions, with my own twist. A park index of 110 means the venue increases production of that stat by 10 percent. Let's say that's the right-handed home run index for a particular venue. A player projected to hit 20 homers in a neutral environment would be projected for 21 after applying the park factor. The conventional method assumes the away venues average out to neutral, so half the home venue is used to adjust the neutral projection since the player plays half his games at home.

20 x 1.05 = 21

I utilize composite factors. If a team plays