Thursday, September 30, 2004

Park Factors and Homefield Advantage

Aaron Gleeman has an article about park factors up at the Hardball Times. In it, he mentions the phenomenon of SBC Park going from a heavy pitcher's park in recent years to a good hitter's park this year. I think there's actually a fairly simple explanation for some of this.

The Giants have an overwhelming home field advantage due to their quirky ballpark, or at least announcers constantly refer to this as if it were true. There's wind, funky angles, all that jazz. I'm betting it's largely true. This means that the Giants are more likely to get outs at home and their opponents are more likely to screw up defensively at SBC. In the past few years, the Giants have had good offenses but better pitching and excellent defense. They had a .751 defensive efficiency ration in 2002 and a .755 DER in 2003; this year they've got a .693 DER. Moreover, the Giants have pretty terrible pitching this year but have had excellent bullpens in each of their previous Pac Bell years and typically very good rotations (especially in 2002 when Rueter had some deity's assistance in compiling a 3.23 ERA). I don't have any significant evidence to support this claim, but I think there's some logic to the argument that the Giants' poor defense and pitching has eliminated much of their home-field advantage in preventing runs. Moreover, the Giants are a better offensive team this year than in years past and perhaps are actually playing to the park's nuances better. The Giants have 168 doubles and 27 triples in 82 games at SBC and 137 2B and 6 3B in 75 games on the road. Their opponents line is 163/25 at SBC, 139/21 away from it. Maybe the Giants' coaching staff figured out that, you know, it might just be a good idea to hit a lot of long fly balls because crazy stuff's going to happen out there. SBC still plays as a pitcher's park for home runs, so there's certainly some strength behind this argument. I think that overall the park factor is likely to fluctuate based on the Giants' particular strengths (as well as the coaching staff's ability to take advantage of the park), in addition, of course, to yearly fluctuation/sample size issues.

Any lessons to be learned from this? Probably not, but I wonder if maybe visiting teams should try out some of this hit it high and far business until the Giants can put out some decent outfielders. This is pretty much anecdotal evidence, but in their ten games at SBC this year, the Dodgers had 12 doubles and one triple while the Giants had 24 doubles and two triples. The pitching and talent levels might not be so much the issue here, as the Dodgers took five of those games (although they were outscored in the process). As Rich Lederer reminded us by channeling Bill James brilliantly once again, homefield advantage can be huge; even more huge might be the ability of some teams to get a thorough understanding of the effects of their opponents' parks and adjust their player's play and personnel decisions accordingly. Which segues right back into...

...my weeklong obsession with the Bobby Cox era. Since 1991, the Braves home winning percentage is .628 and their road winning percentage is .590. Seems pretty fair for a team with their talent. But consider that the this year (sorry, I need to sleep so I can't compile the data for the whole 1991-2004 period) home teams have a .540 win percentage. If that distribution for team won-loss records was uniform, you could find a team's expected road WPCT by multiplying .460 by (home WPCT/.540). That gives the Braves an expected road WPCT of .535 from 1991-2004 and .515 in 2004. Their actual road WPCT has been .590 for that whole period and .577 in 2004. Now, the Braves haven't had as extreme of a park factor all that time as some other teams in the league so perhaps their home/road split shouldn't be expected to be quite so large, and it can be argued that they squandered some potential home-field advantage by building around pitching while they played in slug-heavy Fulton County Stadium. But I have an inkling that part of what Bobby Cox' squad does so well is advanced scouting and quality coaching that reduce their opponents' home-field advantage.

Song of the Day: "I Might Be Wrong," Radiohead

Comments:
hey tom, i've been reading your blog off and on for the past few weeks, and i just wanted to drop a note and say that i enjoy your work a lot, and thank you for taking the time to produce it. i too am a dodgers and A's fan (i picked you up from dodger thoughts) and i graduated from ucb last year, so i sort of feel like you're representing for me :) thanks.

-vishal
 
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