Park Effects

[RobC]

Is there any data to explain the three year park tendencies?
Some seem obvious e.g. short right field in Yankee Stadium and thin air in Colorado.
Why the increase in RHB HR in Yankee Stadium? Wind currents?

[ToddZola]

Each venue is different. I'm not saying for sure this is the reason for a high RHB HR index at Yankee Stadium, but it's plausible. The calculation is designed to flesh out team bias, but there are instances it falls short. If the Yankees have righty swingers adept at going the other way, they also benefit from the short porch in right. This is possible to look up...be right back.

[ToddZola]

OK, I'm back.

It's not just Yankee hitters, it's visitors too. The short porch greatly increases oppo HR for RHB. The league average for oppo RHB HR is 13 percent. At Yankee Stadium, it's 27 percent. This is from 2016-2017.

[RobC]

Thanks Todd.
I would be interesting to have more data on the causes of park effects.
Are BB and K effects more a reflection on the home team pitchers and hitters than the physical park itself?

US Cellular Field effects seem odd in that LHB HR +22%, RHB HR +10% while LHB BA -10% and Runs -5%
Any ideas? Thick grass creating more ground outs and double plays? More foul territory?
Three true outcome players?

Why does Tropicana suppression R, LHB BA, RHB BA, RHB HR and increase K?

I remember hitters had credited the black back drop behind center field at Veteran's Stadium helping them hit better.
There was one year Philadelphia put a white silhouette of the city sky line there but removed it after hitters complained.

[ToddZola]

Thanks Todd.
I would be interesting to have more data on the causes of park effects.
Are BB and K effects more a reflection on the home team pitchers and hitters than the physical park itself?

Quality of home team bats and arms aren't supposed to matter. Sometimes all the bias can't be fleshed out, but in general, park factors are designed to be independent of home team quality. BB and K factors are normally things like foul territory, batter's eye and sometimes atmospheric conditions.

US Cellular Field effects seem odd in that LHB HR +22%, RHB HR +10% while LHB BA -10% and Runs -5%
Any ideas? Thick grass creating more ground outs and double plays? More foul territory?
Three true outcome players?

One of the biggest mistakes made is homers equate to runs in terms of factor -- they don't always correlate. In smaller parks, more non-HR fly balls are caught, lowering the runs factor. This could be the case with Guaranteed Rate Park. It's the case with Yankee Stadium.

Why does Tropicana suppression R, LHB BA, RHB BA, RHB HR and increase K?

Addressed earlier- Don't know exactly why. Could be several reasons. Maybe there's a depth perception thing with the dome.

I remember hitters had credited the black back drop behind center field at Veteran's Stadium helping them hit better.
There was one year Philadelphia put a white silhouette of the city sky line there but removed it after hitters complained.

Fenway Park doesn't sell seats in the triangle to provide a better hitter's eye.

[Astros34]

Addressed earlier- Don't know exactly why. Could be several reasons. Maybe there's a depth perception thing with the dome.

I think the case with the Trop is similar to the old Astrodome: terrible visibility. That was what made the 'Dome one of the most draconian pitchers' parks ever. It had deep fences but even when they were pulled in during the 90s it was STILL a pitchers' park par excellence.