Handed Park Factors: Tacoma

by Matthew on Apr 26, 2010 7:00 AM PDT in Seattle Mariners Stats

About half my excitement over the new park factors by handedness that I discussed previously was that I finally had park factors to look at that separated events by the batter's handedness so that we could finally put numbers on. The other half was that I also had these factors for minor league parks as well, similarly compared aginst their respective league*. I went over Safeco Field's factors already, but I thought I would run down our various minor league affiliates as well.

The American League is a league, Major League Baseball is a level. Tacoma's park factors are compared against the rest of the Pacific Coast League, not the rest of Triple-A. League factors will come at a later date.

Most of these factors will not be surprising, but just as with Safeco, it's good to get a more exact bearing on just how harmful or beneficial these environments are when we peruse through our prospects. What interests me right away is how similar Tacoma's factors are to Seattle's. They're a little more extreme in areas and I'll take that opening to remind you that sample sizes on some of these (e.g. triples) are so small as to make the error margins -- even with three plus years of data -- rather substantial, but overall Tacoma follows the same general flow as Seattle.

Factor	LH	RH
K	107	107
BB	102	109
HBP	90	71
GB	94	92
FB	97	98
LD	103	107
IF	119	110
1B	103	95
2B	84	102
3B	59	45
HR/BIA	85	86
wOBA	94	94

K, BB, HBP, GB, FB, LD and IF are all factored on a per PA basis since they are all discrete possible results of a PA. 1B, 2B and 3B are factored on a per batted ball basis. HR is factored by balls in the air (i.e. non-ground-ball batted balls). wOBA is based on what the league average line would have looked like given the above factors. A rough guide to 95% confidence intervals for these is given here.

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Great stuff

The HR factors will get some attention, and while it looks initially like it’s a much harder park to homer in than Cheney, remember that this is compared to the rest of the PCL. The PCL average is brought up by parks like Salt Lake, Albuquerque, Colorado Springs, etc. I think the spread within leagues is going to be much wider at the minor league levels – the difference between Tacoma/New Orleans and Alb/SLC is much wider than anything you see in MLB, and the spread between High Desert and Inland Empire should be pretty huge as well.

Looking forward to the rest of this, Matthew… very cool.

by marc w on Apr 26, 2010 9:41 AM PDT reply actions

The PCL is really crazy.

It’s got some of the nation’s best pitching parks and some of the nation’s best hitting parks. Feast or famine

by Matthew on Apr 26, 2010 11:30 AM PDT up reply actions

Yup.

I’d guess the NWL might be up there too, at least for certain components. Salem-Keiser v. Tri-Cities for HRs, for example.

by marc w on Apr 26, 2010 1:30 PM PDT up reply actions

Love it

by Jeff Sullivan on Apr 26, 2010 9:55 AM PDT reply actions

Oh, and I'm guessing the spreads for batted ball types could be wider as well

As the Gameday folks in the minors are locals and don’t travel (as far as I know). In MLB, they’ve got workarounds for this, like stringers who use video to classify batted balls, and they’re rotated throughout the league (so one scorer wouldn’t have a big effect on one park/team).

by marc w on Apr 26, 2010 10:02 AM PDT reply actions 1 recs

This is both interesting and informative!

by Dewey N on Apr 26, 2010 10:20 AM PDT reply actions

Cool. This stuff is really useful.

Two small questions.

These park factors are made in a way where if you wanted to adjust a player’s performance to make it park-neutral you would take their home performance and then multiply by these park factors and then add it to their road performance. You wouldn’t just multiply their total line by these numbers.

Also, I was thinking about how you were calculating these park factors and had just a very small question about the process. You want to compare how Cheney for example plays vs the average ballpark. In your average, you exclude Cheney. Its really semantics and I’m not saying you did it right or wrong but do people usually exclude the park from the average when they are making park factors?

by Edgar for Pres on Apr 26, 2010 11:08 AM PDT reply actions

.

These park factors are made in a way where if you wanted to adjust a player’s performance to make it park-neutral you would take their home performance and then multiply by these park factors and then add it to their road performance. You wouldn’t just multiply their total line by these numbers.

This is incorrect. You would take their overall line and multiply by the average park factor they played in. Typically this number can be approximated as (home park+100)/2.

by Graham MacAree on Apr 26, 2010 11:20 AM PDT up reply actions

Ok, thanks.

So one thing to keep in mind with these is if we have a RHB who was at Cheney for a year and had 20 hr we would take 20/0.93 = 21.5 HR. We have seen this for Safeco when you do the numbers too but it always surprises me a little. Even for a park that drastically affects something like HR, a player only has 1/2 his AB at the park so the absolute effect of these park factors is usually smaller than I think it would be.

by Edgar for Pres on Apr 26, 2010 11:42 AM PDT up reply actions