2011 Park Factors
Posted by John Autin on July 15, 2011
With the caveat that a 50-game sample is not really enough to form sound conclusions, let's take a look some park factor trends this year:
-- ESPN's park factors* for the first half of 2011:
- Runs: Coors Field 1.47, Rangers Ballpark 1.44, ..., Tropicana Field (TBR) 0.76, AT&T Park (SFG) 0.74
(B-R one-year park factors: Coors Field 124, Rangers Ballpark 116, ..., Tropicana Field 90, AT&T Park 89.) - Hits: Coors Field 1.24, Fenway 1.22, ..., Dodger Stadium 0.85, Busch Stadium 0.84
- HRs: Rangers Ballpark 1.64, Progressive Field (CLE) 1.63, ..., PNC Park (PIT) 0.58, AT&T Park (SFG) 0.56
- Doubles: Fenway 1.36, Rangers Ballpark 1.28, ..., Safeco Field (SEA) 0.82, Busch Stadium (STL) 0.69
* ESPN's Park Factor for a team's park is the ratio of the avg./G in that team's home games to the avg./G in that team's road games; averages are based on combined totals for both teams in each game.
Let's put those ratios into actual numbers of events ... First, the most run-friendly parks so far:
Coors Field
-- Avg. per game in Rockies' home / road games (both teams combined):
- Runs -- 10.6 / 7.2
- Hits -- 19.1 / 15.4
- Batting Average -- .277 / .233
-- The highest one-year park factor in Rockies history is 129 (2000, 1996); it's 124 so far this year, continuing the upward trend of the past two years. The one-year Coors Field park factors since 2005: 110, 107, 109, 105, 113, 118 (2010), 125 (2011 1st half).
Rangers Ballpark
-- Avg. per game in Rangers' home / road games (both teams combined):
- Runs -- 10.9 / 7.6
- Hits -- 19.1 / 16.6
- HRs -- 2.9 / 1.8
- Doubles -- 3.9 / 3.0
- Triples -- 0.4 / 0.1
-- Since Rangers Ballpark at Arlington opened in 1994, the highest one-year batting park factor (B-R method) was 112 in 2004. It's 116 so far this year.
And now, the most run-inhibiting parks thus far, Tropicana Field and AT&T Park:
-- Avg. total runs per game in these teams' home / road games:
- Rays -- 6.9 / 9.1
- Giants -- 6.0 / 8.1
There were 4 runs or less in 16 of SF's 44 home games; the Giants are 12-4 in those games.
-- Seattle's Safeco Field is hard on hitters, but their .224 team batting average is no mere park effect. They're hitting .220 at home, .228 away, with a little more power at home; they have a MLB-low 23 HRs in 43 road games. Last year, the Mariners batted .235 at home, .236 away.
Returning to the caveat ... Keep in mind that these are small samples, and B-R's multi-year park factors are likely better predictors of 2nd-half park trends than are the 1st-half trends. Here are the 2010 multi-year park factors for the parks listed above, and some other notables:
- Coors Field (COL), 117
- Rangers Ballpark, 107
- Fenway Park, 106
- Yankee Stadium, 105
- Citizens Bank Park (PHI), 102
- AT&T Park (SF), 99
- "New Shea" (NYM), 98
- Tropicana Field (TBR), 95
- Safeco Field (SEA), 95
- Petco Park (SD), 91
Finally, here's the weirdest team split I've seen so far this year: Washington pitchers have walked 78% more batters in road games than in home games. They've averaged 2.17 BB/9 at home, 3.85 BB/9 away. Their hitters have no such difference.
July 15th, 2011 at 9:29 am
I'm frankly surprised that Citi Field isn't mentioned as a low HR park, but then again the Mets aren't offensive juggernauts on the road, either.
July 15th, 2011 at 9:41 am
[...] 2011 Park Factor Notes: B-R’s John Autin takes a look at park factor trends from the 1st half of the 2011 season. [...]
July 15th, 2011 at 9:47 am
The difference between the ESPN and B-R run factors is because B-R adjusts them for the fact half the games occur on the road. (~47% more runs have been scored in Rockies home games, but their stats are only inflated ~24% because half the games were on the road.)
Also, B-R makes tweaks based on extra inning games and stuff which I'm not sure ESPN does.
***
Citi Field has been quite a bad HR park the past two seasons. There have just been a few parks even worse.
July 15th, 2011 at 10:05 am
@3
Exactly. bb-ref park factors are for setting the run context so they account for only half of their games being played at home. There's also a second order correction because a team doesn't play any road games in their home park. The BPF and PPF actually look at the strength of the teams pitchers/batters because their own batters/pitchers never face those.
July 15th, 2011 at 10:39 am
[...] View article: 2011 Park Factors » Baseball-Reference Blog » Blog Archive [...]
July 15th, 2011 at 10:45 am
@3, M.R. notes that: "Citi Field has been quite a bad HR park the past two seasons."
-- True, but as I've mentioned many times, you can't tell it from the Mets hitters, who have the exact same 1.92 HR% (as a % of PAs) at home and away over 2010-11, and a fractionally higher HR rate as a % of ABs or of hits.
The park's HR factor is being driven entirely by Mets pitchers vs. visiting hitters, who've allowed a HR% that's 77% higher on the road (2.93%) than at home (1.66%) for 2010-11 when measured against PAs, and 58% higher when measured against hits.
July 15th, 2011 at 11:02 am
[BTW, I had an erroneous version of comment #6 posted for a minute; refresh your screen to see the corrected numbers.]
Followup to #6 --
Off the top of my head, it seems logical that when a park has some extreme characteristics that create an edge for either hitters or pitchers, the home group should have the largest advantage, due to the individuals' familiarity with the park and the management's opportunity to select players who can take advantage of the park.
To use an example of a park that had extreme characteristics in both directions ... In the original Yankee Stadium, with its very short RF line and cavernous left-center alley, you might expect both the Yankee hitters and pitchers, as a group, to have better numbers at home, on the grounds that (a) they would have had more practice at tailoring their efforts towards the park's dimensions and (b) the personnel would have been selected, to a certain extent, for their ability to do what the park favors.
At the risk of asking a question whose answer might be self-evident ... Does anyone know if this theory generally holds up in practice?
July 15th, 2011 at 12:50 pm
JA, Many Yankee RHB were clearly hurt by the home park, Joe DiMaggio being a famous example. Fenway is bad for LH power, but some can go the other way well enough to hit a lot of doubles off the Monster. I'll note that triples have a much higher home field advantage than any other event, but most of that is on the defensive side, knowing better how to play odd bounces is a big advantage to the home side.
i would expect that both LHP and LHB would be favored in old Yankee Stadium. And let's not forget that the difficulties of RHB (the majority), made it overall a pitcher's ball park, with park factors under 100.
From about 1945 to 1952, a period during which they were in the pennant race almost every year, the Red Sox had an enormous HFA, so they were able to take advantage of the unique factors of the park in an effective manner in those years.
I think the Dodgers have to an extant picked their personnel to fit their park, with more emphasis on pitching a d defense, and less on HR power.
July 15th, 2011 at 1:00 pm
@8, Kds -- Indeed, Joe D and many other RHBs were hurt by the Yankee dimensions. But some RHBs, such as Hank Bauer(?), learned to delay their swing and drive the ball down the opposite line.
Similarly, Yankee RHPs might have been hurt by the park, unless they learned to consistently pitch outside to lefty hitters.
In general, though, more Yankee stars were left-handed than right-handed, because management tended to select players who fit the park. And that's why I spoke of Yankee pitchers or hitters as a group, rather than individually.
July 15th, 2011 at 1:11 pm
@/ John A. - There has also been the theory proposed that while Rockies hitters gain an advantage from Coors, that advantage is pretty much negated when they go on the road. Whatever the Rockies batters do to adapt to Coors Field does not work on the road. Anyone else familar with this?
July 15th, 2011 at 1:46 pm
Lawrence, I have indeed observed that, anecdotally, in several players who had extended stints both with Colorado and with other teams. But I haven't studied it systematically.
July 15th, 2011 at 2:55 pm
One more reason why Barry Bonds was such an amazing hitter. He did all that damage in Candlestick and AT&T Parks...notorious pitcher parks. Unlike Arod and Griffey who both played in the Kingdome and Ballpark at Arlington/Yankee Stadium(Arod) and Great American Ballpark for Jr.
July 15th, 2011 at 3:34 pm
Baseball Prospectus (I think) studied the Rockies systematically several years ago. They definitely found evidence of a Coors hangover effect. I don't remember (and haven't noticed) a particular advantage COL had at home, but they definitely played worse than they "should" when on the road. I don't know if the humidor has mitigated that. This could be due to the altitude effects on the body, as well as the ball.
***
Barry Bonds was such an amazing hitter. He did all that damage in Candlestick and AT&T Parks...notorious pitcher parks.
True...AT&T/PacBell/whatever is especially tough for lefty power. I think in some of those seasons, a ridiculous percentage of all HR hit out in right field were hit by Bonds alone.
But Yankee Stadium, while it's not what it was 40 years ago, is not kind to righties. I don't think A-Rod has gotten any advantage there.
July 15th, 2011 at 3:41 pm
@12, Jeff -- You appear to think that the Kingdome was a good hitter's park. Not so during A-Rod's time there. Here are the one-year batting park factors:
1996 -- 97
1997 -- 100
1998 -- 98
1999 -- 102
Then take a look (link below) at A-Rod's home/road splits in 2000, his only year with Safeco as his home park; it may have something to do with his leaving. (OK, no, it was all about the money.)
http://www.baseball-reference.com/players/split.cgi?id=rodrial01&year=2000&t=b
July 15th, 2011 at 3:48 pm
@13, M.R. -- Naturally, I had to verify any claim in support of both A-Rod and the new Yankee Stadium, but you seem to be right as usual:
-- A-Rod in old Yankee Stadium: .310 BA, .597 SLG, HRs in 7.7% of ABs.
-- A-Rod in new Yankee Stadium: .278 BA, .536 SLG, HRs in 6.6% of ABs.
July 15th, 2011 at 5:18 pm
JA, actually I wasn't referring to a difference between the Stadium of now and of 2008, as I think the left field dimensions are pretty much the same. If A-Rod has played worse in Stadium III, it's probably because of an overall deterioration in his game due to age and injuries. I was thinking of the difference between Stadiums II and III as compared to Stadium I (pre-1974), with the Death Valley in left-center. The parks A-Rod has played in haven't been as tough as that, but I believe they are still relatively tough for RHB.
July 16th, 2011 at 12:40 am
@13,15,16
how much though of that is better attributed to time spent in injured seasons and simply growing old?