From: jjd@TEAK.CRAY.COM (Jeff Drummond)
Newsgroups: rec.sport.baseball
Subject: Re: Home/road differentials (was ARTIFICIAL TURF: EMBARRASSMENT)
Date: 28 Jul 92 17:16:49 GMT



In article <1992Jul27.192402.12683@nntpd.lkg.dec.com> g_waugaman@nac.enet.dec.com (Glenn R. Waugaman) writes:

>Okay, here is the effect that I've been referring to, given by the 
>home/road numbers of each MLB team over the period that the Twins have 
>been in the Metrodome, 1982-1991.  Note that the difference between the
>Twins and the team with the second greatest home/road differential, Kansas
>City, is almost as large as the difference between Kansas City and the MLB
>average.  If you remove the Twins' numbers, the distribution in home/road
>performance is almost perfect (-.11 to +.10); the Twins are off the scale 
>at +.18!  Any theories?
>
>1982-91	HOME	AWAY	RATIO
>
>MLB AVE	.542	.458	1.18
> 1. Min	.557	.410	1.36
> 2. KC		.580	.453	1.28
> 3. Hou	.557	.437	1.28
> 4. Tex	.523	.411	1.27
  [ other teams deleted to save space ]
>23. Atl	.481	.436	1.10
>24. Mon	.528	.484	1.09
>25. Cal	.532	.491	1.08
>26. Cin	.504	.473	1.07

Thanks for posting the numbers, Glenn.  Just a couple of nits to pick.  :-)

First, I don't know if it's legitimate to mix AL and NL teams together
as you've done.  If you used the regular-season data, then all games
were strictly intraleague.  Thus, the home/away differentials for the
two leagues are more-or-less independent variables.  If you look at
your table, you'll notice that 11 of the 14 AL teams are at or above
the MLB average.  If you compare just the AL teams and compute a League
average (should be higher than the overall MLB average, I figure about
1.20 for the AL and about 1.16 for the NL), the Twins' advantage over
their League-mates won't be quite as large.

Second, two AL teams moved to new parks in the 82-91 timeframe (Chicago
and Toronto).  If we just want to focus on ballpark effects, perhaps
they should be excluded; or else just drop off the '91 stats, since I
believe both teams moved in '91.

Third, I think the key comparison is not between Minnesota and the
MLB (or even League) average, but between Minnesota and Kansas City.
After all, KC's home-field advantage seems to be acceptable and draws
no Usenet wrath (to my knowledge).  They also have a rug, which means
the roof becomes a major difference between Royal's Stadium and the
MetroMuffin (Mr. Waugaman said in a previous post that it was mainly
the roof, in his opinion, which accounted for the Twins home-field
advantage).

If we fix Minnesota's away record, then what would their home record
have be in order for them to have the same differential as Kansas
City?  It works out to about a .524 home winning percentage.  The
difference between their .557 home record and a .524 home record is
about 2.5 wins over the course of an 81-home-game season.  Could be
a factor in a close division race, but hardly enough to get Abner
Doubleday to roll over in his grave (maybe twitch a little).

We could argue about whether 2.5 wins/year is significant, either
statistically or otherwise.  We could argue about what could possibly
cause the Twins to win an extra 2.5 home games per year (Home Cooking
or MetroMuffin Voodoo Effect).  But why bother?

Tell you what, MetroMuffin Mashers, I'm feeling generous.  Pick out
any 3 games played in the MetroMuffin this year and you can claim,
without dispute from me, whatever Voodoo Effects you like.  Twins
outfielders wear polarized contact lens to aid tracking of the ball?
OK.  Speaker wires are controlled from Twins bench?  I'll accept that.
Twins bats are harmonically tuned to MetroMuffin resonant frequency?
Sounds credible to me.

But for the other 78 MetroMuffin games:  SHUT UP!                :-)

Mr. Waugaman may have already claimed 2 or 3 games of the allotment
during Boston's last visit.  The rest of you will have to fight it
out amongst yourselves for any remaining game(s).

>---
>Glenn Waugaman
>Digital Equipment Corporation
>Littleton, MA
>g_waugaman@nac.enet.dec.com
>---

-Jeff    jjd@cray.com
--
"They that give up possible outs by intentionally walking batters to
set-up double-plays deserve neither outs nor double-plays." -Benjamin
Franklin in "Poor Richard's Baseball Almanac"
Newsgroups: rec.sport.baseball